gram rainbow t r o u t w e r e continued long enough f o r t h e i r t o x i c i t y c u r v e s t o l e v e l o f f , and asymptotic LC50 concentrations of 0.14 and 0.15 mg/ L were reached i n 8 days; on day 1 9 , a d d i t i o n a l m o r t a l i t i e s occurred. For 2 gram rainbow t r o u t , t h e minimum tested l e v e l of n i t r i t e n i t r o g e n a t which no m o r t a l i t i e s w e r e observed after 10 days was 0.14 mg/ L; f o r the 235 gram t r o u t , t h e minimum l e v e l w i t h no mortality a f t e r 1 0 days w a s 0.06 mg/ L.

It is concluded t h a t ( 1) l e v e l s of n i t r a t e nitrogen a t o r below 90 mg/ L would have no adverse effects on warmwater f i s h ( Knepp and A r k i n , 1 9 7 3 ) ; ( 2 ) n i t r i t e n i t r o g e n a t o r below 5 mg/ L should be p r o t e c t i v e of most warmwater f i s h ( McCoy, 1 9 7 2 ) ; and ( 3) n i t r i t e nitrogen a t o r below 0.06 mg/ L should be protective of salmonid f i s h e s ( Russo e t a l . 1 9 7 4 ; Russo and Thurston,

1975). These l e v e l s e i t h e r are n o t known t o occur o r would be unlikely t o occur i n natural surface waters. I Recognizing t h a t c o n c e n t r a t i o n s of n i t r a t e o r n i t r i t e t h a t would e x h i b i t t o x i c effects on warm o r coldwater f i s h could r a r e l y occur i n nature, r e s t r i c t i v e c r i t e r i a are not recommended.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY NITROBENZENE CRITERIA: Aquatic Life The available data for nitrobenzene indicate that acute toxicity to freshwater aquatic life occurs at concentrations as low as 27,000 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No definitive data are available concerning the chronic toxicity of nitrobenzene to sensitive freshwater aquatic life.

The available data for nitrobenzene indicate that acute toxicity to saltwater aquatic life occurs at concentrations as low as 6,680 ug/ L and would occur at lower concentrations among species thaf; are more sensitive than those tested. No definitive data are available concerning the chronic toxicity of nitrobenzene to sensitive saltwater aquatic life.

Human Health For comparison purposes, two approaches were used to derive criterion levels for nitrobenzene. Based on available toxicity data, to protect public health the derived level is 19.8 mg/ L.

using available organoleptic data, to control undesirable taste and odor qualities of ambient water the estimated level is 30 ug/ L. It should be recognized that organoleptic data have limitations as a basis for establishing a water quality criterion, and have no demonstrated relationship to potential adverse human health effects.

( 4 5 F. R. 79318, November 2 8 , 1980)

NOTE: The U. S. EPA is currently developing Acceptable Daily Intake ( ADI) or Verified Reference Dose ( RID) values for Agency wide use for this chemical. The new value should SEE APPENDIX B FOR METHODOLOGY be substituted when it becomes available. The January, 1986, draft Verified Reference Dose document cites an RfD of .0005 mg/ kg/ day for nitrobenzene. NITROPHENOLS CRITERIA:

Aquatic Life The available data for nitrophenols indicate that acute toxicity to freshwater aquatic life occurs at concentrations as low as 230 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of nitrophenols to sensitive freshwater aquatic life but toxicity to one species of algae occurs at concentrations as low as 150 ug/ L.

The available data for nitrophenols indicate that acute toxicity to saltwater aquatic life occurs at concentrations as low as 4,850 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of nitrophenols to sensitive saltwater aquatic life. 1 Human Health Because of insufficient available data for mono and trinitrophenols, satisfactory criteria cannot be derived at this time, using the present guidelines.

For the protection of human health from the toxic properties of dinitrophenols and 2,4 dinitro o cresol ingested through water and contaminated aquatic organisms, the ambient water criteria are determined to be 70 ug/ L and 13.4 ug/ L, respectively.

For the protection of human health from the toxic properties of dinitrophenols and 2,4 dinitro o cresol ingested through contaminated aquatic organisms alone, the ambient water criteria  are determined t o be 14.3 mg/ L and 765 ug/ L, r e s p e c t i v e l y .

( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY NITROSAMINES Aquatic Life The available data for nitrosamines indicate that acute toxicity to freshwater aquatic life occurs at concentrations as low as 5,850 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of nitrosamines to sensitive freshwater aquatic life.

The available data for nitrosamines indicate that acute toxicity to saltwater aquatic life occurs at concentrations as low as 3,300,000 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of nitrosamines to sensitive saltwater aquatic life.

Human Health For the maximum protection of human health from the potential carcinogenic effects of exposure to N nitrosodiethylamine and all other nitrosamines except those listed below, through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentrations should be zero, based on the non threshold assumption for this chemical. However, zero level may not be attainable at the present time. Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at lo"*, and 1OpcPs The corresponding recommended criteria are 8.0 ng/ L, 0.8 ng/ L, and 0 . 0 8 ng/ L, respectively. If these estimates are made for L 0 consumption of aquatic organisms only, excluding consumption of water, the levels are 12,400 ng/ L, 1,240 ng/ L, and 124 ng/ L,

respectively.

For the maximum protection of human health from the potential carcinoqenic effects of exposure to N nitrosodimethylamine through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentrations should be zero, based on the nonthreshold assumption for this chemical.

However, zero level may not be attainable at the present time.

Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at 10

6, and The corresponding recommended criteria are 14 ng/ L, 1.4 ng/ L, and 0.14 ng/ L, respectively. If these estimates are made for consumption of aquatic organisms only, excluding consumption of water, the levels are 160,000 ng/ L, 16,000 ng/ L,

and 1,600 ng/ L, respectively.

For the maximum protection of human health from the potential carcinogenic effects of exposure to N nitrosodibutylamine through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentrations should be zero,

based on the non threshold assumption for this chemical.

However, zero level may not be attainable at the present time.

Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at 10

6, and The corresponding recommended criteria are 64 ng/ L, 6.4 ng/ L, and 0.64 ng/ L, respectively. If these estimates are made for consumption of aquatic organisms only,

excluding consumption of water, the levels are 5,868 ng/ L, 587 ng/ L, and 58.7 ng/ L, respectively.

0 For the maximum protection o'f human health from the potential carcinogenic effects of exposure to N nitrosopyrrolidine through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentrations should be zero based on the nonthreshold assumption for this chemical. However, zero level may not be attainable at the present time. Therefore, the levels which may result in incremental increase of cancer risk . over the lifetime are estimated at and The corresponding recommended criteria are 160 ng/ L, 16 ng/ L, and 1.6 ng/ L, respectively. If these estimates are made for consumption of aquatic organisms only, excluding consumption of water, the levels are 919,000 ng/ L, 91,900 ng/ L, and 9,190 ng/ L,

respectively.

For the maximum protection of human health from the potential carcinogenic effects of exposure to N nitrosodiphenylamine through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentrations should be zero,

based on the non threshold assumption f o r this chemical.

However, zero level may not be attainable at the present time.

Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at 10 5,

The corresponding recommended criteria are 49,000 ng/ L, 4,900 ng/ L, and 490 ngfL, respectively. If these estimates are made for consumption of aquatic organisms only,

excluding consumption of water, the levels are 161,000 ng/ L, 16,100 ng/ L, and 1,610 ng/ L, respectively. and L, ( 4 5 F. R. 79318, November 2 8 , 1980) SEE APPENDIX B FOR METHODOLOGY OIL AND GREASE

For domestic water supply: Virtually free from oil and grease, particularly from the tastes and odors that emanate from petroleum products.

For aquatic life:

( 1) 0.01 of the lowest continuous flow 96 hour LC50 to several important freshwater and marine species, each having a demonstrated high susceptibility to oils and petrochemicals.

( 2) Levels of oils or petrochemicals in the sediment which cause deleterious effects to the biota should not be allowed.

( 3 ) Surface waters shall be virtually free from floating nonpetroleum oils of vegetable or animal origin, as well as petroleum derived oils. 1 INTRODUCTION:

It has been estimated that between 5 and 10 million metric tons of oil enter the marine environment annually ( Blumer, 1970).

A major difficulty encountered in the setting of criteria for oil and grease is that these are not definitive chemical categories, but include thousands of organic compounds with varying physical, chemical, and toxicological properties. They may be volatile or nonvolatile, soluble or insoluble, persistent or easily degraded.

RATIONALE :

Field and laboratory evidence have demonstrated both acute lethal toxicity and long term sublethal toxicity of o i l s to aquatic organisms. Events such as the Tampico Maru wreck of 1957 in Baja, California, ( Diaz Piferrer, 1962), and the No. 2 fuel oil spill in West Falmouth, Massachusetts, in 1969 .. I ( Hampson and Sanders, 1 9 6 9 ) , both of which caused immediate death t o a wide v a r i e t y o f organisms, a r e i l l u s t r a t i v e o f t h e l e t h a l t o x i c i t y t h a t may be a t t r i b u t e d t o o i l p o l l u t i o n . S i m i l a r l y , a g a s o l i n e s p i l l i n South Dakota i n November 1969 ( Bugbee and Walter, 1973) was reported t o have caused immediate death t o t h e majority of freshwater i n v e r t e b r a t e s and 2,500 f i s h , 30 percent of which were n a t i v e s p e c i e s of t r o u t . Because o f t h e wide range o f compounds i n c l u d e d i n t h e c a t e g o r y of o i l , it is impossible t o establish meaningful 96 hour LC50 v a l u e s f o r o i l and g r e a s e w i t h o u t s p e c i f y i n g t h e p r o d u c t i n v o l v e d .

However, a s t h e d a t a i n T a b l e 6 show, t h e most s u s c e p t i b l e category of organisms, t h e marine l a r v a e , appear t o be i n t o l e r a n t o f p e t r o l e u m p o l l u t a n t s , p a r t i c u l a r l y t h e w a t e r s o l u b l e compounds, a t concentrations as low as 0.1 mg/ L.

T h e long term s u b l e t h a l e f f e c t s of o i l p o l l u t i o n refer t o i n t e r f e r e n c e s with c e l l u l a r and physiological processes such as f e e d i n g and r e p r o d u c t i o n and do n o t lead t o i m m e d i a t e death of t h e organism. Disruption of such behavior apparently can r e s u l t from petroleum p r o d u c t c o n c e n t r a t i o n s a s low a s 1 0 t o 100 ug/ L ( see T a b l e 7).

T a b l e 7 summarizes some of t h e s u b l e t h a l t o x i c i t i e s f o r various petroleum p o l l u t a n t s and aquatic species. I n a d d i t i o n t o s u b l e t h a l effects reported a t t h e 10 t o 100 ug/ L l e v e l , it has been shown t h a t petroleum p r o d u c t s can harm a q u a t i c l i f e a t concentrations as low a s 1 ug/ L ( Jacobson and Boylan, 1973).

Bioaccumulation of petroleum products presents two e s p e c i a l l y important p u b l i c h e a l t h problems: ( 1) t h e t a i n t i n g o f edible, aquatic species, and ( 2 ) the possibility of edible marine organisms incorporating the high boiling, carcinogenic polycyclic aromatics in their tissues. Nelson Smith ( 1971) reported that 0.01 mg/ L of crude oil caused tainting in oysters. Moore et al.

( 1973) reported that concentrations as low as 1 to 10 ug/ L could lead to tainting within very short periods of time. It has been shown that chemicals responsible for cancer in animals and man ( such as 3,4 benzopyrene) occur in crude oil ( Blumer, 1970). It also has been shown that marine organisms are capable of incorporating potentially carcinogenic compounds into their body fat where the compounds remain unchanged ( Blumer, 1970).

Oil pollutants may also be incorporated into sediments.

There is evidence that once this occurs in the sediments below the aerobic surface layer, petroleum oil can remain unchanged and toxic for long periods, since its rate of bacterial degradation is slow. For example, Blumer ( 1970) reported that No. 2 fuel oil incorporated into the sediments after the West Falmouth spill persisted for over a year, and even began spreading in the form of oil laden sediments to more distant areas that had remained unpolluted immediately after the spill. The persistence of unweathered oil within the sediment could have a long term effect on the structure of the benthic community or cause the demise of specific sensitive important species. Moore et al. ( 1973)

reported concentrations of 5 mg/ L for the carcinogen 3, 4

benzopyrene in marine sediments.

Mironov ( 1967) reported that 0 01 mg/ L oil produced deformed and inactive flatfish larvae. Mironov ( 1970) also reported inhibition or delay of cellular division in algae by oil , concentrations of to 10 1 mg/ L. Jacobson and Boylan ( 1973)

reported a reduction in the chemotactic perception of food by the snail, Nassarius  obsoletus at kerosene concentrations of 0.001 to 0.004 mg/ L. Bellen et al. ( 1972) reported decreased survival and fecundity in worms at concentrations of 0.01 to 10 mg/ L of detergent.

Because of the great variability in the toxic properties of oil, it is difficult to establish a numerical criterion which would be applicable to all t jpes of oil. Thus, an application factor of 0.01 of the 96 hour LC50 as determined by using continuous flow with a sensitive resident species should be employed for individual petrochemical components.

There is a paucity of toxicological data on the ingestion of the components of refinery wastewaters by humans or by test animals. It is apparent that any tolerable health concentrations for petroleum derived substances far exceed the limits of taste and odor. Since petroleum derivatives become organoleptically objectionable at concentrations far below the human chronic toxicity, it appears that hazards to humans will not arise from drinking oil polluted waters ( Johns Hopkins Univ., 1956; Mckee and Wolf, 1963). Oils of animal or vegetable origin generally are nontoxic to humans and aquatic life.

In view of the problem of petroleum oil incorporation in sediments, its persistence and chronic toxic potential, and the present lack of sufficient toxicity data to support specific criteria, concentrations of oils in sediments should not approach levels that cause deleterious effects to important species or the bottom community as a whole.

Petroleum and nonpetroleum o i l s share some similar physical and chemical p r o p e r t i e s . Because they share common p r o p e r t i e s ,

t h e y may c a u s e s i m i l a r h a r m f u l e f f e c t s i n t h e a q u a t i c environment by forming a sheen, f i l m , o r d i s c o l o r a t i o n on t h e s u r f a c e of t h e water. L i k e petroleum o i l s , nonpetroleum o i l s may occur a t four levels of t h e aquatic environment: ( a) f l o a t i n g on t h e s u r f a c e , ( b) e m u l s i f i e d i n t h e water column, ( c)

s o l u b i l i z e d , and ( d) s e t t l e d on t h e bottom a s a sludge. Analogous t o t h e g r e a s e b a l l s from v e g e t a b l e o i l and animal f a t s are t h e t a r b a l l s of petroleum o r i g i n which have been found i n the marine environment o r washed ashore on beaches.

O i l s of any kind can cause ( a) drowning of waterfowl because of loss of buoyancy, exposure because of loss of i n s u l a t i n g c a p a c i t y of f e a t h e r s , and s t a r v a t i o n and v u l n e r a b i l i t y t o 0 predators because of lack of mobility; ( b) l e t h a l effects on f i s h by c o a t i n g e p i t h e l i a l s u r f a c e s of g i l l s , t h u s p r e v e n t i n g r e s p i r a t i o n ; ( c) p o t e n t i a l f i s h k i l l s r e s u l t i n g from biochemical oxygen demand: ( d) a s p h y x i a t i o n of b e n t h i c l i f e forms when f l o a t i n g masses become engaged w i t h surface debris and s e t t l e on t h e bottom: a n d ( e ) a d v e r s e a e s t h e t i c e f f e c t s of f o u l e d s h o r e l i n e s and beaches. These and o t h e r e f f e c t s have been documented i n t h e U. S. Department of H e a l t h , Education and Welfare r e p o r t on Oil S p i l l s A f f e c t i n g t h e Minnesota and M i s s i s s i p p i R i v e r s and t h e 1975 P r o c e e d i n g s o f t h e J o i n t Conference on Prevention and Control of Oil S p i l l s .

e O i l s of animal o r vegetable o r i g i n g e n e r a l l y are chemically _ ,

nontoxic t o humans o r aquatic l i f e ; however, f l o a t i n g sheens of such oils result in deleterious environmental effects described in this criterion. Thus, it is recommended that surface waters shall be virtually free from floating nonpetroleum oils of vegetable or animal origin. This same recommendation applies to floating oils of petroleum origin since they too may produce similar effects.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY DISSOLVED OXYGEN 0 NATIONAL CRITERIA:

The national criteria for ambient dissolved oxygen concentra

tions for the protection of freshwater aquatic life are presented in Table 1. The criteria are derived from the production impair

ment estimates which are based primarily upon growth data and information on temperature, disease, and pollutant stresses. The average dissolved oxygen concentrations selected are values 0.5 mg/ L above the slight production impairment values and repre

sent values between no production impairment and slight production impairment. Each criterion may thus be viewed as an estimate of the threshold concentration below which detrimental effects are expected.

Criteria for coldwater fish are intended to apply to waters containing a population of one or more species in the family Salmonidae { Bailey et al., 1970) or to waters containing other coldwater or coolwater fish deemed by the user to be closer to salmonids in sensitivity than to most warmwater species.

Although the acute lethal limit  or salmonids is at or below 3 mg/ L, the coldwater minimum has been established at 4 mg/ L because a significant proportion of the insect species common to salmonid habitats are less tolerant of acute exposures to low dissolved oxygen than are salmonids. Some coolwater species may require more protection than that afforded by the other life stage criteria for warmwater fish and it may be desirable to protect sensitive coolwater species with the coldwater criteria. Many states have more stringent dissolved oxygen standards for cooler waters, waters that contain either ._ a salmonids, nonsalmonid coolwater fish, or the sensitive centra

chid, the smallmouth bas5 The warmwater criteria are necessary to protect early life stages of warmwater fish as sensitive as as channel catfish and to protect other life stages of fish as sensitive as largemouth bass. Criteria for early life stages are intended to apply only where and when these stages occur. These criteria represent dissolved oxygen concentrations which EPA believes provide a reasonable and adequate degree of protection for freshwater aquatic life.

The criteria do not represent assured no effect levels.

However, because the criteria represent worst case conditions ( i. e. for wasteload allocation and waste treatment plant design) ~

conditions will be better than the criteria nearly all of the time at most sites. In situations where criteria conditions are just maintained for considerable periods the proposed criteria represent some risk of production impairment. This impairment would depend on innumerable other factors. If slight production impairment or a small but undefinable risk of moderate impairment is unacceptable, than one should use the " no production impair

ment" values given in the document as means and the " slight production impairment') values as minima. The table which pre

sents these concentrations is reproduced here as table 2 .

The criteria do represent dissolved oxygen concentrations believed to protect the more sensitive populations of organisms against potentially damaging production impairment. The dissolved oxygen concentrations in the criteria are intended to be protective at typically high seasonal environmental tempera

tures for the appropriate taxonomic and life stage classi Table 1. Water quality criteria for ambient dissolved oxygen 0 concentration.

Coldwater Criteria Warmwater Criteria Stages Ue Stages Stages Stages Other Life Early kife Other Life 30 Day Mean NA3 6.5 NA 5.5 7 Day Mean 9.5 ( 6.5) NA 6.0 NA 7 Day Mean NA Minimum 5.0 NA 4.0 1 Day 8.0 ( 5.0) 4.0 5.0 3.0 Minimum 415 These are water column concentrations recommended to achieve the required intergravel dissolved oxygen concentrations shown in parentheses. The 3 mg/ L differential is discussed in the criteria document. For species that have early life stages exposed directly to the water column, the figures in parentheses apply.

Includes all embryonic and larval stages and all juvenile forms to 30 days following hatching. 0 3 NA ( not applicable).

For highly manipulatable discharges, further restrictions apply ( see page 37)

A l l minima should be considered as instantaneous concentrations to be achieved at all times.

fications, temperatures which are often higher than those used in the research from which the criteria were generated, especially for other than early life stages.

Where natural conditions a l o n e c r e a t e d i s s o l v e d oxygen concentrations less than 110 percent of the applicable criteria means or minima or both, the minimum acceptable concentration is 90 percent of the natural concentration. These values are similar to those presented graphically by Doudoroff and Shumway ( 1970) and those calculated from Water Quality Criteria 1972 ( NAS/ NAE, 1973). Absolutely no anthropogenic dissolved oxygen depression in the potentially lethal area below the 1 day minima should be allowed unless special care is taken to ascertain the tolerance of resident species to low dissolved oxygen.

. If daily cycles of dissolved oxygen are essentially sinusoidal, a reasonable daily average is calculated from the day's high and low dissolved oxygen values. A time weighted average may be required if the dissolved oxygen cycles are decidedly non sinusoidal. Determining the magnitude of daily dissolved oxygen cycles requires at least two appropriate

ly timed measurements daily, and characterizing the shape of the cycle requires several more appropriately spaced measurements.

Once a series of daily mean dissolved oxygen concentrations are calculated, an average of these daily means can be calcu

lated ( Table 3). For embryonic, larval, and early life stages,

the averaging period should not exceed 7 days. This short time is needed to adequately protect these often short duration, most sensitive life stages. Other life stages can probably be adequately protected by 30 day averages. Regardless of the averaging period, the average should be considered a moving average rather than a calendar week or calendar month average. Table 2. Dissolved Oxygen Concentrations ( mg/ L) Versus 0 Quantitative Level of Effect.

1. Salmonid Waters a. Embryo and Larval Stages No Production Impairment = 11* ( 8 ) Slight Production Impairment = 9* ( 6) Moderate Production Impairment = 8* ( 5) Severe Production Impairment = 7* ( 4 ) Limit to Avoid Acute Mortality = 6* ( 3)

(* Note: These are water column concentrations recommended to achieve the required intergravel dissolved oxygen concentrations shown in parentheses. The 3 mg/ L difference is discussed in the criteria document.)

b. Other Life Stages No Production Impairment = 8 light Production Impairment = 6 Moderate Production Impairment = 5 Severe Production Impairment = 4 Limit to Avoid Acute Mortality = 3 2. Nonsalmonid Waters a. Early Life Stages No Production Impairment = 6 . 5 Slight Production Impairment = 5.5 Moderate Production Impairment = 5 Severe Production Impairment = 4 , 5 Limit to Avoid Acute Mortality = 4 b. Other Life Stages No Production Impairment = 6 Slight Production Impairment = 5 Moderate Production Impairment = 4 Severe Production Impairment = 3.5 Limit to Avoid Acute Mortality = 3 3 . Invertebrates No Production Impairment = 8 Some Production Impairment = 5 Acute Mortality Limit = 4 Table 3 . Sample calculations for determining daily means and 7 day mean dissolved oxygen concentrations ( 30 day averages are calculated in a similar fashion using 30 days data). Dissolved Oxygen ( mg/ L)

Day Daily Max. Daily Min. Daily Mean 9.0 7.0 10.0 7.0 11.0 8.0 12. oa 8.0 10.0 8.0 11.0 9 0 12.03 10.0 8.0 8.5 9.5 9.0 10.0 1Q. 5c 9.5b 57.0 65.0 1 day Minimum 7.0 ? day Mean Minimum 8.1 ? day Mean 9.3 a Above air saturation concentration ( assumed to be 11.0 mg/ L for this example).

b ( 11.0  b 8.0) 2.

c ( 11 0 + 10.0) 2.

The criteria have been established on the basis that the maximum dissolved oxygen value actually used in calculating any daily mean should not exceed the air saturation value. This consideration is based primarily on analysis of studies of c y c l i n g d i s s o l v e d oxygen and the growth of largemouth bass ( Stewart et al., 1967), which indicated that high dissolved oxygen levels (> 6 mg/ L) had no beneficial effect on growth.

During periodic cycles of dissolved oxygen concentrations,

minima lower than acceptable constant exposure levels are toler

able so long as: 1. the average concentration attained meets or exceeds the 2 . the average dissolved oxygen concentration is calculated as 3 . criterion;

recommended in Table 3 ; and the minima are not unduly stressful and clearly are not lethal.

A daily minimum has been included to make certain that no acute mortality of sensitive species occurs as a result of lack of oxygen. Because repeated exposure to dissolved oxygen concentrations at or near the acute lethal threshold will be stressful and because stress can indirectly produce mortality or other adverse effects ( e g., through disease), the criteria are designed to prevent significant episodes of continuous or regularly recurring exposures to dissolved oxygen concentrations at or near the lethal threshold. This protection has been achieved by setting the daily minimum for early life stages at the subacute lethality threshold, by the use of a 7 day averaging period for early life stages, by stipulating a 7 day mean minimum value for other life stages, and by recommending additional limits for manipulatable discharges.

The previous EPA criterion for dissolved oxygen published in Quality Criteria for Water ( USEPA, 1976) was a minimum of 5 mg/ L ( usually applied as a 7410) which is similar to the current criterion minimum except for other life stages of warmwater fish which now allows a criteria are similar of the Federal Water 7 day mean minimum of 4 mg/ L. The new to those contained in the 1968 " Green Book"

Pollution Control Federation ( FWPCA, 1968). A. The Criteria and Monitoring and Design Conditions The acceptable mean concentrations should be attained most of the time, but some deviation below these values would probably not cause significant harm. Deviations below the mean will probably be serially correlated and hence apt to occur on consecutive days. The significance of deviations below the mean will depend on whether they occur continuously or in daily cycles, the former being more adverse than the latter. Current knowledge regarding such deviations is limited primarily to labo

ratory growth experiments and by extrapolation to other activity

related phenomena.

Under conditions where large daily cycles of dissolved oxygen occur, it is possible to meet the criteria mean values and consistently violate the mean minimum criteria. Under these conditions the mean minimum criteria will clearly be the limiting regulation unless alternatives such as nutrient control can dampen the daily cycles.

The significance of conditions which fail to meet the recommended dissolved oxygen criteria depend largely upon five factors: ( 1) the duration of the event; ( 2) the magnitude of the dissolved oxygen depression; ( 3 ) the frequency of recurrence; ( 4 )

the proportional area of the site failing to meet the criteria,

and ( 5) the biological significance of the site where the event occurs. Evaluation of an event's significance must be largely case and site specific. Common sense would dictate that the magnitude of the depression would be the single most important factor in general, especially if the acute value is violated. A logical extension of these considerations is that the event must be considered in the context of the level of resolution of the monitoring or modeling effort. Evaluating the extent, duration,

and magnitude of an event must be a function of the spatial and temporal frequency of the data. Thus, a single deviation below the criterion takes on considerably less significance where continuous monitoring occurs than where sampling is com

prised of once a week grab samples. This is so because based on continuous monitoring the event is provably small, but with the much less frequent sampling the event is not provably small and can be considerably worse than indicated by the sample. The frequency of recurrence is of considerable interest to those modeling dissolved oxygen concentrations because the return period, or period between recurrences, is a primary modeling consideration contingent upon probabilities of receiving water volumes, waste loads, temperatures, etc. It should be apparent that return period cannot be isolated from the other four factors discussed above. Ultimately, the question of return period may be decided on a site specific basis taking into account the other factors ( duration, magnitude, areal extent, and biologi

cal significance) mentioned above. Future studies of temporal patterns of dissolved oxygen concentrations, both within and between years, must be conducted to provide a better basis for selection of the appropriate return period.

In conducting wasteload a1 location and treatment plant design computations, the choice of temperature in the models will be important. Probably the best option would be to use temperatures consistent with those expected in the receiving water over the critical dissolved oxygen period for t h e biota.

B. The C r i t e r i a and Manipulatable Discharges If d a i l y minimum D O s are p e r f e c t l y s e r i a l l y c o r r e l a t e d ,

i. e, i f t h e annual lowest d a i l y minimum dissolved oxygen concen

t r a t i o n is a d j a c e n t i n t i m e t o t h e n e x t lower d a i l y minimum d i s s o l v e d oxygen c o n c e n t r a t i o n and one of these two minima is a d j a c e n t t o t h e t h i r d l o w e s t d a i l y minimum d i s s o l v e d oxygen c o n c e n t r a t i o n , etc., t h e n i n o r d e r t o meet t h e 7 day mean minimum c r i t e r i o n it is u n l i k e l y t h a t t h e r e w i l l be more t h a n three o r four consecutive d a i l y minimum v a l u e s below t h e accept

able 7 day mean minimum. Unless t h e d i s s o l v e d oxygen p a t t e r n is e x t r e m e l y e r r a t i c , it i s a l s o u n l i k e l y t h a t t h e l o w e s t d i s s o l v e d oxygen concentration w i l l be appreciably below t h e a c c e p t a b l e 7 day mean minimum o r t h a t d a i l y minimum v a l u e s below t h e 7 day mean minimum w i l l occur i n more t h a n one o r two weeks each y e a r . For some d i s c h a r g e s , t h e d i s t r i b u t i o n of d i s s o l v e d oxygen concentrations can be manipulated t o varying degrees. Applying t h e d a i l y minimum t o manipulatable discharges would a l l o w repeated weekly c y c l e s of minimum a c u t e l y acceptable d i s s o l v e d oxygen v a l u e s , a condition of unacceptable stress and p o s s i b l e adverse b i o l o g i c a l effect. For t h i s r e a s o n , t h e a p p l i c a t i o n of t h e one day minimum c r i t e r i o n t o m a n i p u l a t a b l e d i s c h a r g e s must l i m i t e i t h e r t h e frequency of o c c u r r e n c e o f v a l u e s below t h e a c c e p t a b l e 7 day mean minimum o r must impose f u r t h e r l i m i t s on t h e e x t e n t of excursions below t h e 7 day mean minimum. For such c o n t r o l l e d discharges, it is recommended t h a t t h e o c c u r r e n c e of d a i l y minima below t h e a c c e p t a b l e 7 day mean I minimum b e l i m i t e d t o 3 weeks per year or t h a t t h e acceptable one day minimum be increased t o 4 . 5 mg/ L f o r coldwater f i s h and 3 . 5 mg/ L f o r warmwater f i s h , Such d e c i s i o n s c o u l d be s i t e

s p e c i f i c based upon the extent of control and s e r i a l correlation. e PARATHION CRITERION:

0.04 ug/ L f o r freshwater and marine a q u a t i c l i f e .

RATIONALE:

Acute s t a t i c LC50 v a l u e s of t h e organophosphorus p e s t i c i d e ,

parathion, f o r freshwater f i s h have ranged g e n e r a l l y from about 50 ug/ L f o r more s e n s i i t i v e s p e c i e s such a s b l u e g i l l s , Lepomis macrochi=, t o about 2.5 mg/ L f o r t h e more r e s i s t a n t s p e c i e s s u c h as minnows ( U. S. Environ. P r o t . Agency, 1975). I n f l o w i n g w a t e r e x p o s u r e s , S p a c i e ( 1975) o b t a i n e d 96 hour LC50 v a l u e s o f 0.5 mg/ L, 1 . 6 mg/ L, and 1 . 7 6 mg/ L f o r b l u e g i l l s , _ Lepomis ____

macrochirus, f a t h e a d minnows,  Pimep& ales p r o m e l a s , and brook t r o u t , S a l v e l i n u s _ _ _ _ _ _ _ I f o n t i n a l i s r e s p e c t i v e l y . Korn and E a r n e s t ( 1974) found a 96 hOUr LC50 o f 18 ug/ L f o r j u v e n i l e f r e s h w a t e r and e s t u a r i n e s t r i p e d bass, Morone s a x a t i l i s , i n a flowing water system, I Few c h r o n i c e x p o s u r e d a t a a r e a v a i l a b l e f o r a q u a t i c organisms. Brown bullheads, f c t a l u r u s nebulosus, exposed t o 30 ug/ L p a r a t h i o n f o r 30 days e x h i b i t e d t r e m o r s ; a t 6 0 ug/ L t h e y convulsed and were found to have developed a deformed vertebral column ( Mount and Boyle, 1 9 6 9 ) . I n a 23 mOnth exposure o f b l u e g i l l s , S p a c i e ( 1975) o b s e r v e d d e f o r m i t i e s ( s c o l i o s i s and a characteristic protrusion i n t h e t h r o a t region) a t 0.34 ug/ L, b u t n o t a t 0.16 ug/ L. Tremors, c o n v u l s i o n s , h y p e r s e n s i t i v i t y , and hemorrhages also were evident at higher concentrations.

Reproductive impairment and d e f o r m i t i e s were observed i n f a t h e a d minnows e x p o s e d t o 4 . 0 ug/ L f o r 8 1 / 2 months. Development of brook trout, S, fontinalis  embryos exposed to 32 ug/ L was abnormal and mortalities associated with premature hatching were observed. Embryos at 10 ug/ L appeared normal. No adverse effects on juveniles and adults was evident during 9 months' exposure to 7 ug/ L.

Inhibition of cholinesterase enzymes is the well established mode of physiological action of parathion and other organic phosphorus pesticides ( Weiss, 1958). The degree of inhibition of brain acetylcholinesterase ( AChE) activity has been the most frequently used measure of effect of these pesticides. Various studies ( Weiss, 1958, 1959, 1961; Murphy et al., 1968; Gibson et al. 1969) have shown the degree of inhibition to be dependent upon toxicant concentration, length of exposure, and species sensitivity. The results of these studies have also indicated AChE inhibition ranging from 25 to 90 ( 1959) also showed that susceptibility of recovery of AChE activity following that death results from percent of normal. Weiss depended upon the extent prior exposure and that the recovery period for fish exposed to parathion was relatively long. In bluegills, AChE activity was only 50 percent recovered 30 days after exposure to 1 mg/ L for 6 to 7 hours ( Weiss, 1961).

Some of the other physiological effects observed to result from exposure of fish to parathion have been inhibition of spermatogenesis in guppies, _______ Poecilia reticulata at 10 ug/ L ( Billard and deKinkelin, 1970), alternation of oxygen consumption rate in bluegills, Lepomis macrochirus, at 100 ug/ L ( Dowden, 1966), and liver enlargement associated with increased pesticide hydrolizing capability in mosquitof ish, Gambusia affinis ( Ludke, 1970). 0 Parathion has been found acutely toxic to aquatic invertebrates at under 1 ug/ L e. g., a 50 hour LC50 of 0.8 ug/ L for  Daphnia maqgg; 48 hour LC50 of 0.6 ug/ L for  Daphnia  pulex;

48 hour LC50 of 0.37 for Simocephalus _ ______ serrulatus ( a daphnid)

( Sanders and Cope, 1966); a 5 day LC50 of 0.93 ug/ L for the larval stonefly, Acroneuria pacifica ( Jensen and Gaufin, 1964);

and a 96 hour LC50 of 0.43 ug/ L for the larval caddisfly  HydroEsychc    californica   ( Gaufin et al. 1965). Mulla and Khasawinah ( 1969) obtained a 24 hour LC50 of 0.5 ug/ L for 4th instar larvae of the midge  Tanypus  qrodhausi. Spacie ( 1975)

obtained 96 hour LC5O's in flow through bioassays of 0.62 ug/ L for Daphnia magna, 0.40 ug/ L for the scud, Gammarus fasciatus and 31.0 ug/ L for 4th instar of Chironomous tentans, a midge.

Other invertebrates have been found acutely sensitive to parathion in concentrations of from 1 to 30 ug/ L in water ( U. S.

Environ. Prot. Agency, 1975).

Few longer exposures have been conducted. Jensen and Gaufin ( 1964) obtained 30 day LC50' s for Pteronarcys   I californica and Acroneuria _ pacifica  of 2.2 and 0.44 ug/ L, respectively. Spacie ( 1975) found the 3 week LC50 for Daphnia mxna  to be 0.14 ug/ L.

Statistically significant reproductive impairment occurred at concentrations above 0.08 ug/ L. A 43 day LC50 of 0.07 ug/ L was reported for Gammarus fasciatus and a concentration of 0.04 ug/ L produced significantly greater mortality than among controls.

Limited information is available on persistence of parathion ~

in water. Eichelberger and Lichtenberg ( 1971) determined the half life in river water ( pH 7.3  8.0) to be 1 week. Using AChE inhibitory capacity as the indicator, Weiss and Gakstatter ( 1964) found the half life of parathion or its active breakdown products to be 40, 35, and 2 0 days in ` lnaturalll waters having a pH of 5.1. 7.0, and 8.4, respectively. The possibility of breakdown resulting in compounds more toxic than parathion was suggested by Burke and Ferguson ( 1969) who determined that the toxicity of this pesticide to mosquitofish 1 Gambusia _ I affinis was greater in static than in flowing water test systems.

Sanders ( 1972), in 96 hour bioassays with the scud, Gammarus _

 I fasciatus and glass shrimp, Palaemonetes _ I_ kadiakensis I also observed greater toxicity under static than in flow through conditions.

a Tissue accumulations of parathion by exposed aquatic organisms are not great and do not appear to be very persistent.

Mount and Boyle ( 1969) observed concentrations in the blood of bullhead,  Ictalurus melas      I up to about 50 times water concentrations. Spacie ( 1975) found muscle concentrations in chronically exposed brook trout,  S . ____ I fontinalis to be several hundred times water concentrations; bluegills,  Lepomis

macrochirus, had about 25 times water concentrations in their bodies. Leland ( 1968) demonstrated a biological half life of parathion in rainbow trout, Salmo Eirdneri 1 exposed and then placed in fresh water to be only 30 to 4 0 hours. It is not expected that parathion residues in aquatic organisms exposed to the recommended criterion concentrations will be a hazard to consumer organisms. a Weiss and Gakstatter ( 1964) have shown that 15 day continuous exposure to parathion ( 1.0 ug/ L) can produce progressively greater ( i. e, cumulative) brain AChE inhibition in a fish species. After substantial inhibition by parathion exposure, it takes several weeks for brain AChE of exposed fishes to return to normal even though exposure is discontinued ( Weiss, 1959,

1961). fishes by 46 percent or more has been associated with harmful effects in exposures to organophosphate pesticides for one life cycle ( Eaton, 1970) and for short periods ( Carter, 1971; Coppage and Duke, 1971; Coppage,

1972; Coppage and Matthews, 1974; Post and Leasure, 1974; Coppage et al. 1975). It has been shown that a concentration of 10 ug Inhibition of brain AChE of parathion/ L of flowing seawater kills 40 to 60 percent of the marine fishes & agodon   rhomboides ( pinfish) and Leostomus

xanthurus __ ( spot) in 24 hours and causes about 87 to 92 percent brain AChE inhibition ( Coppage and Matthews, 1974.) Similar inhibition of AChE and mortality were caused in sheepshead minnows, Cyprinodon variegatus, in 2, 24, 48, and 72 hours at concentrations of 5,000, 2,000, 100, and 10 ug/ L, respectively in static tests ( Coppage, 1972). These data indicate that reductions of brain AChE activity of marine fishes by 70 to 80 percent or more in short term exposures to parathion may be associated with some deaths. 0 Other estimates of parathion toxicity to marine organisms follow. The 48 hour EC50 for parathion to Penaeus duorarum was found to be 0.2 ug/ L ( Lowe et al. 1970). Lahav and Sarig ( 1969)

reported the 96 hour LC50 for mullet, Mugil cephalus to be 125 ug/ L. The shell growth of the oyster, Crassostrea virginica, was found by Lowe et al. ( 1970) to be decreased by 22 percent after 96 hours in 1.0 mg/ L.

An application factor of 0.1 is applied to the 96 hour LC50 data for invertebrates which range upward from 0.4 ug/ L. A criteria of 0.04 ug/ L is recommended for marine and freshwater aquatic life.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY CRITERIA: 0 PENTACHLOROPHENOL Aquatic Life The available data for pentachlorophenol indicate that acute and chronic toxicity to freshwater aquatic life occurs at concentrations as low as 55 and 3.2 ug/ L, respectively, and would occur at lower concentrations among species that are more sensitive than those tested.

The available data for pentachlorophenol indicate that acute and chronic toxicity to saltwater aquatic life occur at concentrations as l o w as 53 and 34 ug/ L, respectively, and would occur at lower concentrations among species that are more sensitive than those tested.

Human Health For comparison purposes, two approaches were used to derive criterion levels for pentachlorophenol. Based on available toxicity data, to protect public health the derived level is 1.01 W/ L. Using available organoleptic data, to control undesirable taste and odor qualities of ambient water the estimated level is 30 ug/ L. It should be recognized that organoleptic data have limitations as a basis for establishing a water quality criterion, and have no demonstrated relationship to potential adverse human health effects.

( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY CRITERIA:

Range 5  9 Domestic water supplies ( welfare)

6.5  9.0 Freshwater aquatic l i f e 6.5  8.5 Marine aquatic l i f e ( but not more than 0.2 u n i t s o u t s i d e of normal lyoccurring range. )

INTRODUCTION :

I8pH" is a measure of t h e hydrogen i o n a c t i v i t y i n a water sample. It i s mathematically r e l a t e d t o hydrogen i o n a c t i v i t y according t o t h e expression: pH =  log 10 ( H'), where ( H') is t h e hydrogen ion a c t i v i t y .

The pH o f n a t u r a l waters is a measure of acid base equilibrium achieved by t h e various dissolved compounds, s a l t s ,

and gases. The p r i n c i p a l system r e g u l a t i n g p H i n n a t u r a l waters is t h e c a r b o n a t e system which i s composed of carbon d i o x i d e ( C02), c a r b o n i c a c i d , ( H z C 0 3 ) , b i c a r b o n a t e i o n ( H C 0 3 ) and c a r b o n a t e i o n s ( C o g ) . The i n t e r a c t i o n s and k i n e t i c s of t h i s system have been described by Stumm and Morgan ( 1970).

pH is an important f a c t o r i n t h e chemical and b i o l o g i c a l systems of n a t u r a l waters. The d e g r e e o f d i s s o c i a t i o n of weak a c i d s o r bases i s affected by changes i n pH. T h i s effect is important because t h e t o x i c i t y of many compounds is affected by t h e degree of dissociation. One such example is hydrogen cyanide ( HCN). Cyanide t o x i c i t y t o f i s h i n c r e a s e s a s t h e p H i s lowered

because t h e chemical e q u l i b r i u m is s h i f t e d toward a n i n c r e a s e d c o n c e n t r a t i o n o f HCN. S i m i l a r r e s u l t s h a v e been shown f o r hydrogen s u l f i d e ( Has) ( Jones, 1 9 6 4 ) . The solubility of metal compounds contained in bottom sediments or as suspended material, also is affected by pH. For example, laboratory equilibrium studies under anaerobic conditions indicated that pH was an important parameter involved in releasing manganese from bottom sediments ( Delfino and Lee,

1971).

The pH of a water does not indicate ability to neutralize additions of acids or bases without appreciable change. This characteristic, termed " buffering capacity," is control led by the amounts of alkalinity and acidity present.

RATIONALE:

Knowledge of pH in the raw water used  or public water supplies is important because without adjustment to a suitable level, such waters may be corrosive and adversely affect treatment processes including coagulation and chlorination.

Coagulation for removal of colloidal color by use of aluminum o r iron salts generally has an optimum pH range of 5.0 to 6  5 ( Sawyer, 1960). Such optima are predicated upon the availability of sufficient alkalinity to complete the chemical reactions.

The effect of pH on chlorine in water principally is on the equilibrium between hypochlorous acid ( HOC1) and the hypochlorite ion ( OC1) according to the reaction:

HOCl = H+ + OC1

Butterfield ( 1984) has shown that chlorine disinfection is more effective at values less than pH 7. Another study ( Reid and Carlson, 1974) has indicated, however, that in natural waters no significant difference in the kill rate for Escherichia  coli was c observed between pH 6 and pH 8.

corrosion of plant equipment and piping in the distribution system can lead to expensive replacement as well as the introduction of metal ions such as copper, lead, zinc, and cadmium. Langelier ( 1936) developed a method to calculate and control water corrosive activity that employs calcium carbonate saturation theory and predicts whether the water would tend to dissolve or deposit calcium carbonate. By maintaining the pH at the proper level, the distribution system can be provided with a protective calcium carbonate lining which prevents metal pipe corrosion. Generally, this level is above pH 7 and frequently approaches pH 8.3, the point of maximum bicarbonate/ carbonate buffering.

Since pH is relatively easily adjusted prior to and during water treatment, a rather wide range is acceptable for waters serving as a source of public water supply. A range of p~ from 5.0 to 9.0 would provide a water treatable by typical ( coagulation, sedimentation, filtration, and chlorination)

treatment plant processes. As the range is extended, the cost of neutralizing chemicals increases.

A review of the effects of pH on fresh water fish has been published by the European Inland Fisheries Advisory Commission ( 1969). The commission concluded:

There is no definite pH range within which a fishery is unharmed and outside which it is damaged, but rather, there is a gradual deterioration as the pH values are further removed from the normal range. The pH range which is not directly lethal to fish is 5  9; however, the toxicity of several common pollutants is markedly affected by pH changes within this range, and increasing acidity or alkalinity may make these poisons more toxic. A l s o , an acid discharge may liberate sufficient C02 from bicarbonate in the water either to be directly toxic, or to cause the pH range 5  6 to become lethal.

Mount ( 1973) performed bioassays on the fathead minnow,

Pimephal promelas, for a 13 mQnth, one generation time period to determine chronic pH effects. Tests were run at pH levels of 4.5, 5.2.

PH Range Effect on Fish*

5.0  6.0 Unlikely to be harmful to any species unless either the concentration of free C02 is greater than 20 ppm, or the water contains iron salts which are precipitated as ferric hydroxide, the toxicity of which is not known.

is present in excess of 100 ppm. 6.0  6.5 Unlikely to be harmful to fish unless free carbon dioxide 6.5  9.0 Harmless to fish, although the toxicity of other poisons may be affected by changes within this range.

EIFAC, 1969 5.9, 6.6, and a c o n t r o l o f 7.5. A t t h e two l o w e s t pH v a l u e s ( 4.5 and 5.2) behavior was abnormal and t h e f i s h were deformed. A t pH v a l u e s less t h a n 6.6, egg p r o d u c t i o n and h a t c h a b i l i t y w e r e reduced when compared w i t h t h e c o n t r o l . It w a s concluded t h a t a pH of 6.6 w a s marginal f o r v i t a l l i f e functions.

B e l l ( 1971) performed b i o a s s a y s w i t h nymphs of c a d d i s f l i e s ( t w o s p e c i e s ) s t o n e f l i e s ( f o u r s p e c i e s ) , d r a g o n f l i e s ( two s p e c i e s ) , and m a y f l i e s ( one s p e c i e s ) . A l l a r e i m p o r t a n t f i s h food organisms. The 30 day TL50 v a l u e s ranged from 2.45 t o 5.38 w i t h t h e c a d d i s f l i e s being t h e most t o l e r a n t and t h e m a y f l i e s being t h e l e a s t t o l e r a n t . The pH v a l u e s a t which 50 percent of t h e organisms emerged ranged from 4.0 t o 6.6 w i t h i n c r e a s i n g p e r c e n t a g e emergence o c c u r r i n g w i t h t h e i n c r e a s i n g pH v a l u e s .

Based on p r e s e n t e v i d e n c e , a pH r a n g e of 6.5 t o 9.0 a p p e a r s t o provide adequate p r o t e c t i o n f o r t h e l i f e of freshwater f i s h and bottom dwelling i n v e r t e b r a t e s f i s h food organisms. Outside of t h i s range, f i s h s u f f e r adverse p h y s i o l o g i c a l effects increasing i n s e v e r i t y a s t h e d e g r e e of d e v i a t i o n i n c r e a s e s u n t i l l e t h a l l e v e l s are reached.

Conversely, r a p i d i n c r e a s e s i n pH c a n c a u s e i n c r e a s e d NH3 concentrations t h a t a r e a l s o t o x i c . Ammonia has been shown t o be 1 0 t i m e s as t o x i c a t pH 8.0 as a t pH 7.0 ( EIFAC, 1969).

T h e c h e m i s t r y of marine w a t e r s d i f f e r s f r o m that of fresh water because of t h e l a r g e c o n c e n t r a t i o n of s a l t s p r e s e n t . I n a d d i t i o n t o a l k a l i n i t y based on t h e c a r b o n a t e system, there i s a l s o a l k a l i n i t y from o t h e r weak a c i d s a l t s such a s b o r a t e .

Because of t h e b u f f e r i n g system p r e s e n t i n seawater, t h e n a t u r a l l y o c c u r r i n g v a r i a b i l i t y o f pH is less t h a n i n f r e s h water. Some marine communities are more s e n s i t i v e t o pH change than others ( NAS, 1974). Normal pH v a l u e s i n seawater are 8.0 t o 8.2 a t t h e s u r f a c e , d e c r e a s i n g t o 7.7 t o 7.8 w i t h i n c r e a s i n g d e p t h ( Capurro, 1970). The NAS Committee's review ( NAS, 1974)

indicated t h a t plankton and benthic i n v e r t e b r a t e s are probably more s e n s i t i v e t h a n f i s h t o changes i n pH and t h a t mature forms and larvae of o y s t e r s are adversely affected a t t h e extremes of t h e pH r a n g e o f 6.5 t o 9.0. However, i n t h e s h a l l o w ,

b i o l o g i c a l l y a c t i v e w a t e r s i n t r o p i c a l o r s u b t r o p i c a l areas,

l a r g e d i u r n a l pH c h a n g e s o c c u r n a t u r a l l y b e c a u s e o f p h o t o s y n t h e s i s . pH v a l u e s may r a n g e from 9.5 i n t h e daytime t o 7.3 i n t h e e a r l y morning b e f o r e dawn. A p p a r e n t l y , t h e s e communities are adapted t o such v a r i a t i o n s or i n t o l e r a n t s p e c i e s are a b l e t o a v o i d extremes bymoving o u t o f t h e a r e a .

For open ocean waters where t h e d e p t h i s s u b s t a n t i a l l y g r e a t e r than t h e euphotic zone, t h e pH should not be changed more than 0.2 u n i t s o u t s i d e of t h e n a t u r a l l y occurring v a r i a t i o n o r i n any c a s e o u t s i d e t h e range of 6.5 t o 8.5. For s h a l l o w , h i g h l y productive c o a s t a l and e s t u a r i n e a r e a s where n a t u r a l l y occurring v a r i a t i o n s approach t h e l e t h a l l i m i t s f o r some species, changes i n pH s h o u l d be avoided, b u t i n any case n o t exceed t h e l i m i t s e s t a b l i s h e d f o r fresh water, i. e., pH of 6.5 t o 9.0. A s w i t h f r e s h w a t e r c r i t e r i a , r a p i d pH f l u c t u a t i o n s t h a t are caused by waste discharges should be avoided. Additional support f o r these l i m i t s i s p r o v i d e d by Z i r i n o a n d Yamamoto ( 1 9 7 2 ) . These i n v e s t i g a t o r s developed a model which i l l u s t r a t e s t h e effects of 0 %.

variable pH on copper, zinc, cadmium, and lead; small changes i n p~ cause large shifts in these metallic complexes. Such changes may affect toxicity of these metals.

For the industrial classifications considered, the NAS report ( NAs, 1974) tabulated the range of pH values used by industry for various process and cooling purposes. In general, process waters used varied from pH 3.0 to 11.7, while cooling waters used varied from 5.0 to 8.9. Desirable pH values are undoubtedly closer to neutral to avoid corrosion and other deleterious chemical reactions. Waters with pH values outside these ranges are considered unusable for industrial purposes.

The pH of water applied for irrigation purposes is not normally a critical parameter. Compared with the large buffering capacity of the soil matrix, the pH of applied water is rapidly changed to approximately that of the soil. The greatest danger in acid soils is that metallic ions such as iron, manganese, or aluminum may be dissolved in concentrations which are subsequently directly toxic to plants. Under alkaline conditions,

the danger to plants is the toxicity of sodium carbonates and bicarbonates either directly or indirectly ( NAS, 1974).

To avoid undesirable effects in irrigation waters, the pH should not exceed a range of 4.5 to 9.0.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY CRITERIA: 0 PHENOL Aquatic Life The available data for phenol indicate that acute and chronic toxicity to freshwater aquatic life occurs at concentrations as l o w as 10,200 and 2,560 ug/ L, respectively, and would occur at lower concentrations among species that are more sensitive than those tested.

The available data for phenol indicate that toxicity to saltwater aquatic life occurs at concentrations as low as 5,800 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. NO data are available concerning the chronic toxicity of phenol to sensitive saltwater aquatic life.

0 Human Health For comparison purposes, two approaches were used to derive criterion levels for phenol. Based on available toxicity data,

to protect public health the derived level is 3.5 mg/ L.

Using available organoleptic data, to control undesirable taste and odor qualities of ambient water the estimated level is 0.3 mg/ L. It should be recognized that organoleptic data have limitations as a basis for establishing a water quality criterion, and have no demonstrated relationship to potential adverse human health effects.

NOTE: The U. S. EPA is currently developing Acceptable Daily Intake ( ADI) or Verified Reference Dose ( RfD) values for Agency wide use for this chemical. The new value should be s u b s t i t u t e d when it becomes available. The January, 1986, draft Verified Reference Dose document cites an RfD of 0.1 mg/ kg/ day for phenol. .'/ ( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY 0 PHOSPHORUS CRITERION::

0.10 ug/ L yellow ( elemental) phosphorus f o r marine o r e s t u a r i n e water.

INTRODUCTION:

Phosphorus i n t h e elemental form is p a r t i c u l a r l y t o x i c and is s u b j e c t t o bioaccumulation i n much t h e same way a s mercury.

Phosphorus a s phosphate i s one bf t h e major n u t r i e n t s r e q u i r e d f o r p l a n t n u t r i t i o n and is e s s e n t i a l f o r l i f e . I n excess of a cr it ica 1 concent r a t i o n , phosphates stirnu l a t e p 1 a n t growths.

During t h e p a s t 30 years, a formidable case has developed f o r t h e b e l i e f t h a t i n c r e a s i n g s t a n d i n g c r o p s of a q u a t i c p l a n t s , which o f t e n i n t e r f e r e w i t h water u s e s and are n u i s a n c e s t o man,

frequently are caused by increasing s u p p l i e s of phosphorus. Such phenomena a r e a s s o c i a t e d w i t h a c o n d i t i o n o f accelerated eutrophication o r aging of waters. Generally, it is recognized t h a t phosphorus is not t h e s o l e cause of eutrophication but there is s u b s t a n t i a t i n g evidence t h a t frequently it is t h e key element of a l l of t h e e l e m e n t s r e q u i r e d by f r e s h w a t e r p l a n t s , and g e n e r a l l y , it is p r e s e n t i n t h e l e a s t amount r e l a t i v e t o need.

Therefore, an increase i n phosphorus allows use of other already p r e s e n t n u t r i e n t s for p l a n t growth. F u r t h e r , of a l l of t h e elements r e q u i r e d f o r p l a n t growth i n t h e water environment,

phosphorus is t h e most e a s i l y c o n t r o l l e d by man.

Large d e p o s i t s of phosphate rock are found n e a r t h e western shore of C e n t r a l F l o r i d a , a s w e l l a s i n a number of o t h e r States.

Deposits i n F l o r i d a are found i n t h e form of p e b b l e s which v a r y 0 . ., in size from fine sand to about the size of a human foot. These pebbles are embedded in a matrix of clay and sand. The phosphate rock beds lie within a few feet of the surface and mining is accomplished by using hydraulic water jets and a washing operation that separates the phosphates from waste materials. The process is similar to that of strip mining.

Florida, Idaho, Montana, North Carolina, South Carolina,

Tennessee, Utah, Virginia, and Wyoming share phosphate mining activities.

Phosphates enter waterways from several different sources.

The human body excretes about one pound per year of phosphorus expressed as I1Pt1. The use of phosphate detergents and other domestic phosphates increases the per capita contribution to about 3 . 5 pounds per year of phosphorus as P. Some industries,

such as potato processing, have wastewaters high in phosphates.

Crop, forest, idle, and urban land contribute varying amounts of phosphorus diffused sources in drainage to watercourses. This drainage may be surface runoff of rainfall, effluent from tile lines, or return flow from irrigation. Cattle feedlots,

concentrations of domestic duck or wild duck populations, tree leaves, and fallout from the atmosphere all are contributing sources.

Evidence indicates that: ( 1) high phosphorus concentrations are associated with accelerated eutrophication of waters, when other growth promoting factors are present: ( 2) aquatic plant problems develop in reservoirs and other standing waters at phosphorus values lower than those critical in flowing streams:

( 3 ) reservoirs and lakes collect phosphates from influent streams and s t o r e a portion of them within consolidated sediments, thus s e r v i n g a s a phosphate s i n k ; and ( 4 ) phosphorus c o n c e n t r a t i o n s c r i t i c a l t o noxious p l a n t growth v a r y and n u i s a n c e growths may r e s u l t from a p a r t i c u l a r c o n c e n t r a t i o n of phosphate i n one g e o g r a p h i c a l a r e a b u t n o t i n a n o t h e r . The amount o r p e r c e n t a g e of i n f l o w i n g n u t r i e n t s t h a t may be r e t a i n e d by a l a k e o r reservoir is v a r i a b l e and w i l l depend upon: ( 1) t h e n u t r i e n t loading t o t h e l a k e o r r e s e v o i r ; ( 2 ) t h e volume of t h e euphotic zone; ( 3 ) t h e extent of b i o l o g i c a l activities; ( 4 ) t h e detention time w i t h i n a l a k e b a s i n o r t h e t i m e a v a i l a b l e f o r b i o l o g i c a l a c t i v i t i e s ;

t h e penstock from t h e r e s e r v o i r . and ( 5 ) t h e l e v e l of d i s c h a r g e from t h e l a k e o r of Once n u t r i e n t s are combined w i t h i n t h e a q u a t i c ecosystem,

t h e i r removal is tedious and expensive. Phosphates a r e used by a l g a e and h i g h e r a q u a t i c p l a n t s and may b e s t o r e d i n excess of use within t h e p l a n t c e l l . With decomposition of t h e p l a n t c e l l ,

some phosphorus may be released immediately through b a c t e r i a l a c t i o n   o r r e c y c l i n g w i t h i n t h e b i o t i c community, w h i l e t h e remainder may be deposited with sediments. Much of t h e material t h a t combines with t h e c o n s o l i d a t e d sediments w i t h i n t h e l a k e bottom is bound permanently and w i l l n o t be r e c y c l e d i n t o t h e s y s tern. 0 RATIONAm :

Elemental Phosphorus I s o m ( 1960) reported an LC50 of 0.105 mg/ L a t 4 8 h o u r s and 0.025 mg/ L a t 1 6 0 h o u r s f o r b l u e g i l l s u n f i s h , __ Lepomis _

y. ~

macrochirus, exposed t o ye1 low phosphorus i n d i s t i l l e d water a t ~ ~

 ~~

__

26 OC and pH 7. The 125 and 195 hour LC50' s of yellow phosphorus to Atlantic cod, Gadus morhua, and Atlantic salmon, Salmo salar,

smolts in continuous exposure experiments were 1.89 and 0.79 ug/ L, respectively ( Fletcher and Hoyle, 1972). No evidence of an incipient lethal level was observed since the lowest concentration of p4 tested was 0.79 ug/ L. Salmon that were exposed to elemental phosphorus concentrations of 40 ug/ L or less developed a distinct external red color and showed signs of extensive hemolysis. The predominant features of p4 poisoning in salmon were external redness, hemolysis, and reduced hematocrits.

Following the opening of an elemental phosphorus production plant in Long Harbour, Placentia Bay, Newfoundland, divers observed dead fish upon the bottom throughout the Harbour ( Peer,

1972). Mortalities were confined to a water depth of less than 18 meters. There was visual evidence of selective mortality among benthos. Live mussels were found within 300 meters of the effluent pipe, while all scallops within this area were dead.

Fish will concentrate elemental phosphorus from water containing as little as 1 ug/ L ( Idler, 1969). In one set of experiments, a cod swimming in water containing 1 ug/ L elemental phosphorus for 18 hours concentrated phosphorus to 5 0 ug/ kg in muscle, 150 ug/ kg in fatty tissue, and 25,000 ug/ kg in the liver ( Idler, 1969; Jangaard, 1970). The experimental findings showed that phosphorus is quite stable in the fish tissues. The criterion of 0.10 ug/ L elemental phosphorus for marine or estuarine waters is .1 of demonstrated lethal levels to important marine organisms and of levels that have been found to result in significant bioaccumulation. 0 Phosphate Phosphorus Although a t o t a l phosphorus c r i t e r i o n t o c o n t r o l nuisance a q u a t i c growths i s n o t p r e s e n t e d , it is b e l i e v e d t h a t t h e following r a t i o n a l e t o support such a c r i t e r i o n , which c u r r e n t l y is evolving, should be considered.

T o t a l phosphate phosphorus c o n c e n t r a t i o n s i n excess of 1 0 0 ug/ L P may interfere with coagulation i n water treatment plants.

When such concentrations exceed 25 ug/ L a t the t i m e of the spring turnover on a volume weighted b a s i s i n l a k e s o r r e s e r v o i r s , they may occasionally s t i m u l a t e excessive o r nuisance growths of algae and o t h e r a q u a t i c p l a n t s . A l g a l growths i n p a r t ' u n d e s i r a b l e tastes and odors t o water, i n t e r f e r e with water treatment, become a e s t h e t i c a l l y u n p l e a s a n t , and a l t e r t h e chemistry of t h e water s u p p l y . They c o n t r i b u t e t o t h e phenomenon o f c u l t u r a l 0 eutrophication.

To p r e v e n t t h e development o f b i o l o g i c a l n u i s a n c e s and t o c o n t r o l accelerated o r c u l t u r a l eutrophication, t o t a l phosphates as phosphorus ( P) should not exceed 50 ug/ L i n any stream a t t h e p o i n t where it e n t e r s any l a k e o r r e s e r v o i r , n o r 2 5 ug/ L w i t h i n t h e l a k e o r r e s e r v o i r . A desired g o a l f o r t h e p r e v e n t i o n of p l a n t n u i s a n c e s i n streams o r o t h e r f l o w i n g w a t e r s n o t discharging d i r e c t l y t o l a k e s o r impoundments is 100 ug/ L t o t a l P ( Mackenthun, 1973) Most r e l a t i v e l y uncontaminated l a k e d i s t r i c t s axe known t o have s u r f a c e w a t e r s t h a t c o n t a i n from 10 t o 30 ug/ L t o t a l phosphorus as P ( Hutchinson, 1957).

T h e m a j o r i t y of t h e N a t i o n ' s e u t r o p h i c a t i o n problems a r e associated with l a k e s o r r e s e r v o i r s and c u r r e n t l y there are more 0 , .. .. data t o support t h e establishment of a l i m i t i n g phosphorus l e v e l i n t h o s e waters t h a n i n streams o r r i v e r s t h a t do n o t d i r e c t l y impact such water. There a r e n a t u r a l c o n d i t i o n s , a l s o , t h a t would d i c t a t e t h e c o n s i d e r a t i o n of e i t h e r a more o r l e s s s t r i n g e n t phosphorus l e v e l . Eutrophication problems may occur i n waters where t h e phosphorus c o n c e n t r a t i o n is less than t h a t i n d i c a t e d above and, o b v i o u s l y , such waters would need more s t r i n g e n t n u t r i e n t l i m i t s . L i k e w i s e , there a r e t h o s e waters w i t h i n the Nation where phosphorus is not now a l i m i t i n g n u t r i e n t and where t h e need f o r phosphorus l i m i t s i s s u b s t a n t i a l l y diminished. Such conditions are described i n the l a s t paragraph of t h i s r a t i o n a l e .

There a r e two basic needs i n e s t a b l i s h i n g a phosphorus c r i t e r i o n f o r flowing waters: ode is t o c o n t r o l the development of p l a n t n u i s a n c e s w i t h i n t h e f l o w i n g water and, i n t u r n , t o c o n t r o l and prevent animal p e s t s t h a t may become associated w i t h such p l a n t s ; t h e o t h e r is t o p r o t e c t t h e downstream r e c e i v i n g waterway, r e g a r d l e s s o f its proximity i n l i n e a r distance. It is e v i d e n t t h a t a p o r t i o n o f t h a t phosphorus t h a t e n t e r s a s t r e a m o r other flowing waterway e v e n t u a l l y w i l l reach a r e c e i v i n g lake o r e s t u a r y e i t h e r a s a component of t h e f l u i d m a s s , as bed l o a d sediments t h a t are carried downstream, o r a s f l o a t i n g o r g a n i c materials t h a t may d r i f t j u s t above the stream's bed o r f l o a t on its water's s u r f a c e . Superimposed on t h e l o a d i n g from t h e i n f l o w i n g waterway, a l a k e o r e s t u a r y may r e c e i v e a d d i t i o n a l p h o s p h o r u s a s f a l l o u t from t h e a i r s h e d o r a s a d i r e c t introduction from s h o r e l i n e areas. A n o t h e r method t o c o n t r o l t h e i n f l o w o f n u t r i e n t s ,

p a r t i c u l a r l y phosphates, i n t o a l a k e is t h a t of p r e s c r i b i n g a n annual l o a d i n g t o t h e r e c e i v i n g water. Vollenweider ( 1973)

suggests t o t a l phosphorus ( P) loadings i n grams per square meter of s u r f a c e a r e a p e r y e a r t h a t w i l l be a c r i t i c a l l e v e l f o r e u t r o p h i c c o n d i t i o n s w i t h i n t h e r e c e i v i n g waterway f o r a p a r t i c u l a r water volume where t h e mean d e p t h of t h e l a k e i n meters is d i v i d e d by t h e h y d r a u l i c d e t e n t i o n t i m e i n y e a r s .

Vollenweider's data suggest a range of loading v a l u e s t h a t should r e s u l t i n o l i g o t r o p h i c l a k e water q u a l i t y . 0 Eutrophic or C r i t i c a l Oligotrophic o r Mean Depth/ Hydraulic Permissible Detention Time Loading Loading ( meters/ year) ( grams/ meter2/ year) ( grams/ meter2/ year)

0.5 1.0 2.5 5.0 7.5 10.0 25.0 50.0 75.0 100.0 0.07 0.10 0.16 0.22 0.27 0.32 0.50 0.71 0.87 1 00 0 14 0.20 0.32 0.45 0.55 0.63 1.00 1.41 1.73 2.00 There may be waterways wherein higher concentrations o r loadings of t o t a l phosphorus do not produce eutrophy, as w e l l a s those waterways wherein lower concentrations o r loadings of t o t a l 0 L 7 phosphorus may be associated with populations of nuisance organisms. Waters now containing less than the specified amounts of phosphorus should not be degraded by the introduction of additional phosphates.

It should be recognized that a number of specific exceptions can occur to reduce the threat of phosphorus as a contributor to lake eutrophy: 1. Naturally occurring phenomena may limit the development of plant nuisances. 2 . Technological or cost

effective limitations may help control introduced pollutants. 3.

Waters may be highly laden with natural silts or colors which reduce the penetration of sunlight needed  or plant photosynthesis. 4. Some waters morphometric features of steep banks, great depth, and substantial flows contribute to a history of no plant problems. Wateks may be managed primarily for waterfowl or other wildlife. 7 . In some waters nutrient other than phosphorus is limiting to plant growth: the level and nature of such limiting nutrient would. not be expected to increase to an extent that would influence eutrophication. 6. In some waters phosphorus control cannot be sufficiently effective under present technology to make phosphorus the limiting nutrient. 5.

No national criterion is presented for phosphate phosphorus for the control of eutrophication.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY PHTHALATE ESTERS CRITERIA:

Aquatic Life The available data for phthalate esters indicate that acute and chronic toxicity to freshwater aquatic life occurs at concentrations as low as 940 and 3 ug/ L, respectively, and would occur at lower concentrations among species that are more sensitive than those tested.

The available data for phthalate esters indicate that acute toxicity to saltwater aquatic life occurs at concentrations as low as 2,944 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of phthalate esters to sensitive saltwater aquatic life but toxicity to one species of algae occurs at concentrations as low as 3.4 ug/ L. ,

0 Human Health For the protection of human health from the toxic properties of dimethyl phthalate ingested through water and contaminated aquatic organisms, the ambient water criterion is determined to be 313 mg/ L.

For the protection of human health from the toxic properties of dimethyl phthalate ingested through contaminated aquatic organisms alone, the ambient water criterion is determined to be 2.9 g / l . For the protection of human health from the toxic properties of diethyl phthalate ingested through water and contaminated aquatic organisms, the ambient water criterion is determined to be 350 mg/ L.

For the protection of human health from the toxic properties of diethyl phthalate ingested through contaminated aquatic organisms alone, the ambient water criterion is determined to be 1.8 g / l .

For the protection of human health from the toxic properties of dibutyl phthalate ingested through water and contaminated aquatic organisms, the ambient water criterion is determined to be 34 mg/ L.

For the protection of human health from the toxic properties of dibutyl phthalate ingested through contaminated aquatic organisms alone, the ambient water criterion is determined to be 154 mg/ L.

For the protection of human health from the toxic properties of di 2 ethylhexyl phthalate ingested through water and contaminated aquatic organisms, the ambient water criterion is determined to be 15 mg/ L.

For the protection of human health from the toxic properties of di 2 ethylhexyl phthalate ingested through contaminated aquatic organisms alone, the ambient water criterion is determined to be 50 mg/ L.

( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY POLYCHLORINATED BIPHENYLS Aquatic Life For polychlorinated biphenyls the criterion to protect freshwater aquatic life as derived using the Guidelines is 0.014 ug/ L as a 24 hour average. The concentration of 0.014 ug/ L is probably too high because it is based on bioconcentration factors measured in laboratory studies, but field studies apparently produce factors at least 10 times higher for fishes. The available data indicate that acute toxicity to freshwater aquatic life probably will occur only at concentrations above 2.0 ug/ L and that the 24 hour average should provide adequate protection against acute toxicity.

For polychlorinated biphenyls the criterion to protect 0 saltwater aquatic life as derived using the Guidelines is 0.030 ug/ L as a 24 hour average. The concentration of 0.030 ug/ L is probably too high because it is based on bioconcentration factors measured in laboratory studies, but field studies apparently produce factors at least 10 times higher for fishes. The available data indicate that acute toxicity to saltwater aquatic life probably will only occur at concentrations above 10 ug/ L and that the 24 hour average criterion should provide adequate protection against acute toxicity.

Human Health For the maximum protection of human health from the potential carcinogenic effects of exposure to polychlorinated biphenyls through ingestion of contaminated water and contaminated aquatic 0 . i" i organisms, the ambient water concentration should be zero, based on the nonthreshold assumption for this chemical. However,

zero level may not be attainable at the present time. Therefore,

the levels which may result in incremental increase of cancer risk over the lifetime are estimated at and The corresponding recommended criteria are 0.79 ng/ L, 0.079 ng/ L,

and 0.0079 ng/ L, respectively. If these estimates are made for consumption of aquatic organisms only, excluding consumption of water, the levels are 0.79 ng/ L, 0.079 ng/ L, and 0.0079 ng/ L,

respectively.

( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY POLYNUCLEAR AROMATIC HYDROCARBONS CRITERIA :

Aquatic Life The limited freshwater data base available for polynuclear aromatic hydrocarbons, mostly from short term bioconcentration studies with two compounds, does not permit a statement concerning acute or chronic toxicity.

The available data for polynuclear aromatic hydrocarbons indicate that acute toxicity to saltwater aquatic life occurs at concentrations as low as 300 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of polynuclear aromatic hydrocarbons to sensitive saltwater aquatic life.

Human Health For the maximum protection of human health from the potential carcinogenic effects of exposure to polynuclear aromatic hydrocarbons through ingestion of contaminated water and contaminated aquatic organisms, the ambient water concentration should be zero, based on the nonthreshold assumption for this chemical. However, zero level may not be attainable at the present time. Therefore, the levels which may result in incremental increase of cancer risk over the lifetime are estimated at lom6, and The corresponding recommended criteria are 28.0 ng/ L, 2.8 ng/ L, and 0 . 2 8 ng/ L, respectively.

If these estimates are made for consumption of aquatic organisms only, excludinq consumption of water, the levels are 311.0 nq/ L. 31.1 ng/ L, and 3.11 ng/ L, r e s p e c t i v e l y .

( 45 F. R. 79318, November 28, 1980) SEE APPENDIX B FOR METHODOLOGY SELENIUM CRITERIA:

Aquatic Life For total recoverable inorganic selenite the criterion to protect freshwater aquatic life as derived using the Guidelines is 35 ug/ L as a 24 hour average, and the concentration should not exceed 260 ug/ L at any time.

For total recoverable inorganic selenite the criterion to protect saltwater aquatic life as derived using the Guidelines is 54 ug/ L as a 24 hour average, and the concentration should not exceed 410 ug/ L at any time.

The available data for inorganic selenate indicate that acute toxicity to freshwater aquatic life occurs at concentrations as low as 760 ug/ L and would occur at lower concentrations among species that are more sensitive than those tested. No data are available concerning the chronic toxicity of inorganic selenate to sensitive freshwater aquatic life.

No data are available concerning the toxicity of inorganic selenate to saltwater aquatic life.

Human Health The ambient water quality criterion for selenium is recommended to be identical to the existing water standard which is 10 ug/ L. Analysis of the toxic effects data resulted in a calculated level which is protective of human health against the ingestion of contaminated water and contaminated aquatic ( organisms. The calculated value is comparable to the present 0 standard. For t h i s reason a s e l e c t i v e c r i t e r i o n based on exposure solely from consumption o f 6.5 grams of a q u a t i c organisms was not derived.

( 45 F. R. 79318, November 2 8 , 1980) SEE APPENDIX B FOR METHODOLOGY SILVER A q u a t i c  L i f e For f r e s h w a t e r a q u a t i c l i f e t h e c o n c e n t r a t i o n ( i n ug/ L) of t o t a l recoverable s i l v e r should not exceed t h e numerical v a l u e g i v e n by e ( l . 7 2 [ l n ( h a r d n e s s ) 3  6.52) a t any t i m e . For example, a t h a r d n e s s e s of 5 0 , 1 0 0 , and 2 0 0 mg/ L as CaC03, t h e concentration of t o t a l recoverable s i l v e r should not exceed 1 . 2 , 4.1, and 13 ug/ L, r e s p e c t i v e l y , a t any t i m e . The a v a i l a b l e d a t a i n d i c a t e t h a t c h r o n i c t o x i c i t y t o freshwater a q u a t i c l i f e may occur a t concentrations as low as 0.12 ug/ L.

For saltwater a q u a t i c l i f e t h e c o n c e n t r a t i o n of t o t a l recoverable s i l v e r s h o u l d n o t exceed 2.3 ug/ L a t any t i m e . N o data are a v a i l a b l e concerning the chronic t o x i c i t y of s i l v e r t o s e n s i t i v e saltwater aquatic l i f e .

Human Health The a m b i e n t w a t e r q u a l i t y c r i t e r i o n f o r s i l v e r i s recommended t o be i d e n t i c a l t o t h e e x i s t i n g water s t a n d a r d ,

which is 50 ug/ L. Analysis of t h e t o x i c e f f e c t s d a t a r e s u l t e d i n a c a l c u l a t e d l e v e l which is p r o t e c t i v e of human h e a l t h a g a i n s t t h e i n g e s t i o n of contaminated w a t e r and contaminated a q u a t i c organisms. T h e c a l c u l a t e d v a l u e i s comparable t o t h e p r e s e n t s t a n d a r d . For t h i s reason a s e l e c t i v e c r i t e r i o n based on e x p o s u r e s o l e l y from c o n s u m p t i o n o f 6 . 5 grams o f a q u a t i c organisms w a s not derived.

a  '. ' ( 45 F. R. 79318, November 2 8 , 1980) SEE APPENDIX B FOR METHODOLOGY SOLIDS ( DISSOLVED) AND  SALINlTY CRITERION:

250 mg/ L f o r chlorides and s u l f a t e s i n domestic water s u p p l i e s ( welfare).

INTRODUCTION:

D i s s o l v e d s o l i d s and t o t a l d i s s o l v e d s o l i d s a r e terms g e n e r a l l y a s s o c i a t e d w i t h f r e s h w a t e r systems and c o n s i s t of inorganic s a l t s , small amounts of organic matter, and dissolved materials ( Sawyer, 1960). The e q u i v a l e n t terminology i n Standard Methods is f i l t r a b l e residue ( Standard Methods, 1971). S a l i n i t y is an oceanographic term, and although n o t p r e c i s e l y e q u i v a l e n t t o t h e t o t a l dissolved s a l t content it is related t o it ( Capurro,

1970). For most purposes, t h e terms t o t a l dissolved s a l t content and s a l i n i t y a r e e q u i v a l e n t . T h e p r i n c i p a l i n o r g a n i c a n i o n s dissolved i n water include t h e carbonates, c h l o r i d e s , s u l f a t e s ,

and n i t r a t e s ( p r i n c i p a l l y i n ground waters) ; t h e p r i n c i p a l cations a r e sodium, potassium, calcium, and magnesium.

RATIONALE :

Excess dissolved s o l i d s are objectionable i n drinking water because of p o s s i b l e physiological e f f e c t s , unpalatable mineral t a s t e s , and h i g h e r c o s t s because of c o r r o s i o n o r t h e n e c e s s i t y f o r a d d i t i o n a l treatment.

The p h y s i o l o g i c a l effects d i r e c t l y r e l a t e d t o d i s s o l v e d s o l i d s include l a x a t i v e e f f e c t s p r i n c i p a l l y from sodium s u l f a t e and magnesium s u l f a t e and t h e adverse effect of sodium on c e r t a i n p a t i e n t s a f f l i c t e d w i t h cardiac disease and women w i t h toxemia a s s o c i a t e d w i t h pregnancy. One s t u d y w a s made u s i n g d a t a ,. ~

e collected from wells in North Dakota. Results from a questionnaire showed that with wells in which sulfates ranged from 1,000 to 1,500 mg/ L, 62 percent of the respondents indicated laxative effects associated with consumption of the water.

However, nearly one quarter of the respondents to the questionnaire reported difficulties when concentrations ranged from 200 to 500 mg/ L ( Moore, 1952). To protect transients to an area, a sulfate level of 250 mg/ L should afford reasonable protection from laxative effects.

As indicated, sodium frequently is the principal component of dissolved solids. Persons on restricted sodium diets may have an intake restricted from 500 to 1,000 mg/ day ( Nat. Res. Coun.,

1954). That portion ingested in water must be compensated by reduced levels in food ingested so that the total does not exceed the allowable intake. Using certain assumptions of water intake ( e. g., 2 liters of water consumed per day) and sodium content of food, it has been calculated that for very restricted sodium diets, 20 mg/ L in water would be the maximum, while for moderately restricted diets, 270 mg/ L would be maximum. Specific sodium levels for entire water supplies have not been recommended but various restricted sodium intakes are recommended because:

( 1) the general population is not adversely affected by sodium,

but various restricted sodium intakes are recommended by physicians for a significant portion of the population, and ( 2)

270 mg/ L of sodium is representative of mineralized waters that may be aesthetically unacceptable, but many domestic water supplies exceed this level. Treatment for removal bf sodium in water supplies is costly ( NAS, 1974).

A study based on consumer surveys in 29 California water systems was made to measure the taste threshold of dissolved salts in water ( Bruvold et al., 1969). Systems were selected to eliminate possible interferences from other taste causing substances than dissolved salts. The study revealed that consumers rated waters with 319 to 397 mg/ L dissolved solids as llexcellentlt while those with 1,283 to 1,333 mg/ L dissolved solids were " unacceptable" depending on the rating system used. A * lgoodll rating was registered for dissolved solids less than 658 to 755 mg/ L. The 1962 PHS Drinking Water Standards recommended a maximum dissolved solids concentration of 500 mg/ L unless more suitable supplies were unavailable.

Specific constituents included in the dissolved solids in water may cause mineral tastes at lower concentrations than other constituents. Chloride ions have frequently been cited as having a low taste threshold in water. Data from Ricter and MacLean ( 1939) on a taste panel of 53 adults indicated that 61 mg/ L NaCl was the median level for detecting a difference from distilled water. At a median concentration of 395 mg/ L chloride a salty taste was distinguishable, although the range was from 120 to 1,215 mg/ L. Lockhart, @ t al. 1955) evaluated the effect of chlorides on water used for brewing coffee indicated threshold concentrations for chloride ranging from 210 mg/ L to 310 mg/ L depending on the associated cation. These data indicate that a level of 250 mg/ L chlorides is a reasonable maximum level to 0 \. p protect consumers of drinking water. The causation of corrosion and encrustation of metallic surfaces by water containing dissolved solids is well known. In water distribution systems corrosion is controlled by insulating dissimilar metal connections by nonmetallic materials, using pH control and corrosion inhibitors, or some form of galvanic or impressed electrical current systems ( Lehmann, 1964). In household systems water piping, wastewater piping, water heaters,

faucets, toilet flushing mechanisms, garbage grinders and both clothes and dishwashing machines incure damage.

By using water with 1,150 mg/ L dissolved solids as compared with 250 mg/ L, service life was reduced from 70 percent for toilet flushing mechanisms to 30 percent for washing equipment.

Such increased corrosion was calculated in 1968 to cost the consumer an additional $ 0.50 per 1,000 gallons used.

All species of fish and other aquatic life must tolerate a range of dissolved solids concentrations in order to survive under natural conditions. Based on studies in Saskatchewan it has been indicated that several common freshwater species survived 10,000 mg/ L dissolved solids, that whitefish and pike

perch survived 15,000 mg/ L, but only the stickleback survived 20,000 mg/ L dissolved solids. It was concluded that lakes with dissolved solids in excess of 15,000 mg/ L were unsuitable for most freshwater fishes ( Rawson and Moore, 1944). The 1968 NTAC Report also recommended less than that caused chloride. maintaining osmotic pressure levels of by a 15,000 mg/ L solution of sodium Marine f i s h e s a l s o e x h i b i t v a r i a n c e i n a b i l i t y t o t o l e r a t e s a l i n i t y changes. However, f i s h k i l l s i n Laguna Madre o f f t h e Texas coast h a v e o c c u r r e d w i t h s a l i n i t i e s i n t h e range o f 75 t o 1 0 0 o/ oo. Such c o n c e n t r a t e d seawater is caused by e v a p o r a t i o n and l a c k of exchange w i t h t h e Gulf of Mexico ( R o u n s a f e l l and Everhart, 1953).

E s t u a r i n e s p e c i e s of f i s h a r e t o l e r a n t of s a l i n i t y changes ranging from f r e s h t o brackish t o seawater. Anadromous s p e c i e s likewise are t o l e r a n t although evidence i n d i c a t e s t h a t t h e young cannot t o l e r a t e t h e change u n t i l t h e normal t i m e o f m i g r a t i o n ( Rounsefell and Everhart, 1953). Other a q u a t i c s p e c i e s are more dependent on s a l i n i t y f o r p r o t e c t i o n from p r e d a t o r s o r r e q u i r e c e r t a i n minimal s a l i n i t i e s f o r successful hatching of eggs. The o y s t e r d r i l l c a n n o t t o l e r a t e s a l i n i t i e s less t h a n 12.5 o/ oo,

Therefore, e s t u a r i n e segments containing s a l i n i t i e s below about 1 2 . 5 o/ oo p r o d u c e most of t h e seed o y s t e r s f o r p l a n t i n g ( Rounsefell and Everhart, 1953). Based on similar examples, the 1968 NTAC Report recommended t h a t t o p r o t e c t f i s h and o t h e r marine animals no changes i n hydrography o r stream flow should be allowed t h a t permanently change i s o h a l i n e p a t t e r n s i n t h e estuary by more than 10 percent from n a t u r a l v a r i a t i o n .

Many of t h e recommended game b i r d l e v e l s f o r d i s s o l v e d s o l i d s concentrations i n drinking water have been e x t r a p o l a t e d from d a t a c o l l e c t e d on domestic species such a s chickens. However, young d u c k l i n g s were r e p o r t e d poisoned i n S u i s a n Marsh by s a l t when maximum summer s a l i n i t i e s v a r i e d from 0.55 t o 1 . 7 4 o/ oo w i t h ~

means a s high a s 1.26 o/ oo ( G r i f f i t h , 1963). I n d i r e c t e f f e c t s of excess dissolved s o l i d s are primarily the elimination of desirable food p l a n t s and other habitat forming p l a n t s . Rapid s a l i n i t y changes cause plasmolysis of t e n d e r l e a v e s and stems because of changes i n osmotic p r e s s u r e . The 1968 NTAC Report recommended t h e following l i m i t s i n s a l i n i t y v a r i a t i o n from natural t o protect w i l d l i f e habitats:

Natural S a l i n i t y Variation Permitted ( O / O O ) ( o/ oo)

0 t o 3.5 1 3.5 t o 13.5 2 13.5 t o 35 4 A g r i c u l t u r a l uses of water a r e a l s o l i m i t e d by e x c e s s i v e d i s s o l v e d s o l i d s concentrations. S t u d i e s have i n d i c a t e d t h a t chickens, swine, c a t t l e , and sheep can survive on s a l i n e waters up t o 1 5 , 0 0 0 mg/ L of s a l t s of sodium and calcium combined with b i c a r b o n a t e s , c h l o r i d e s , and s u l f a t e s b u t o n l y 1 0 , 0 0 0 mg/ L of corresponding s a l t s of potassium and magnesium. The approximate l i m i t f o r highly a l k a l i n e waters containing sodium and calcium carbonates is 5,000 mg/ L ( NTAC, 1968).

I r r i g a t i o n use of water depends n o t o n l y upon t h e osmotic effect of dissolved s o l i d s , but a l s o on t h e r a t i o of t h e various c a t i o n s p r e s e n t . I n a r i d and s e m i a r i d a r e a s g e n e r a l c l a s s i f i c a t i o n of s a l i n i t y hazards has been prepared ( NTAC, 1968)

( see Table 9 ) .

Table 9. Dissolved Solids Hazard f o r I r r i g a t i o n Water ( mg/ L).

water from which no detri mental effects w i l l usually be noticed 500  . . .. ,, water which can have detri mental e f f e c t s on s e n s i  500 1,000 t i v e crops

water t h a t may have adverse effects on many c r o p s and r e q u i r e s c a r e f u l manage merit practices 1,000 2,000 water t h a t can be used f o r t o l e r a n t p l a n t s on perme a b l e s o i l s w i t h c a r e f u l management practices 2,000 5,000 The amount of sodium and t h e percentage of sodium i n r e l a t i o n t o o t h e r c a t i o n s a r e o f t e n i m p o r t a n t . I n a d d i t i o n t o c o n t r i b u t i n g t o osmotic p r e s s u r e , sodium is t o x i c t o c e r t a i n p l a n t s , e s p e c i a l l y f r u i t s , and f r e q u e n t l y causes problems i n s o i l s t r u c t u r e , i n f i l t r a t i o n , and p e r m e a b i l i t y rates ( A g r i c u l t u r e Handbook # 60, 1954). A high percentage of exchangeable sodium i n s o i l s c o n t a i n i n g c l a y s t h a t s w e l l when w e t c a n c a u s e a s o i l c o n d i t i o n adverse t o water movement and p l a n t growth. T h e exchangeable sodium percentage ( ESP) * is an index of t h e sodium s t a t u s o f s o i l s . An ESP o f 1 0 t o 15 p e r c e n t is c o n s i d e r e d excessive i f a h i g h p e r c e n t a g e o f s w e l l i n g c l a y m i n e r a l s is p r e s e n t ( A g r i c u l t u r a l Handbook # 60, 1954). 0 For s e n s i t i v e f r u i t s , t h e t o l e r a n c e f o r sodium f o r i r r i g a t i o n water is f o r a sodium a d s o r p t i o n r a t i o ( SAR)** o f a b o u t 4 ,

whereas for g e n e r a l c r o p s and forages a r a n g e of 8 t o 1 8 is g e n e r a l l y considered u s a b l e ( NTAC, 1968). It is emphasized t h a t a p p l i c a t i o n of these f a c t o r s must be i n t e r p r e t e d i n r e l a t i o n t o s p e c i f i c s o i l c o n d i t i o n s e x i s t i n g i n a g i v e n l o c a l e and t h e r e f o r e f r e q u e n t l y r e q u i r e s f i e l d i n v e s t i g a t i o n .

I n d u s t r i a l r e q u i r e m e n t s r e g a r d i n g t h e d i s s o l v e d s o l i d s . ,

c o n t e n t o f raw waters is q u i t e v a r i a b l e . T a b l e 10 i n d i c a t e s Table 10. Total Dissolved Solids Concentrations of Surface Waters That Have Been Used as Sources for Industrial Water Supplies Industry/ Use Maximum Concentration ( m g m Textile 150 Pulp and Paper 1,080 Chemical 2,500 Petroleum 3,500 Primary Metals . 1,500 Boiler Make up 35,000 maximum values accepted by various industries for process requirements ( NAS, 1974). Since water of almost any dissolved 0 solids concentration can be de ionized to meet the most stringent requirements, the economics of such treatment are the 1 imiting factor for industry.

* ESP = 100 [ a + b( SAR)] 1 [ a + b( SAR)]

where: a = intercept respresenting experimental error ( ranges from  0.06 to 0.01)

from 0.014 to 0.016) b = slope of regression line ( ranges ** SAR = sodium adsorption ratio = Na  [ 0.5( Ca + Mg)]""

SAR is expressed as milliequivalents ( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY 0 SOLIDS ( SUSPENDED, SETTLEABLE)  AND TURBIDITY CRITERIA Freshwater f i s h and o t h e r a q u a t i c l i f e :

S e t t l e a b l e and suspended s o l i d s should n o t reduce the depth of t h e compensation p o i n t f o r photosynthetic a c t i v i t y by more t h a n 1 0 p e r c e n t from t h e s e a s o n a l l y e s t a b l i s h e d norm f o r aquatic l i f e .

INTRODUCTION:

The term lkuspended and s e t t l e a b l e s o l i d s t 1 is d e s c r i p t i v e of t h e o r g a n i c and i n o r g a n i c p a r t i c u l a t e matter i n water. The e q u i v a l e n t terminology used f o r s o l i d s i n Standard Methods ( APHA,

1971) is t o t a l suspended m a t t e r f o r suspended s o l i d s , settleable matter f o r s e t t l e a b l e s o l i d s , v o l a t i l e suspended matter f o r v o l a t i l e s o l i d s and fixed suspended matter f o r fixed suspended s o l i d s . The term l t s o l i d s t l i s used i n t h i s d i s c u s s i o n because of its more common u s e i n t h e water p o l l u t i o n c o n t r o l l i t e r a t u r e . 0 RAT1 ONALE :

Suspended s o l i d s and t u r b i d i t y a r e i m p o r t a n t parameters i n b o t h m u n i c i p a l and i n d u s t r i a l w a t e r s u p p l y practices. F i n i s h e d d r i n k i n g waters h a v e a maximum l i m i t o f 1 t u r b i d i t y u n i t where t h e water e n t e r s t h e d i s t r i b u t i o n system. T h i s l i m i t is based on h e a l t h c o n s i d e r a t i o n s a s it r e l a t e s t o e f f e c t i v e c h l o r i n e d i s i n f e c t i o n . S u s p e n d e d m a t t e r p r o v i d e s a r e a s where microorganisms d o n o t come i n t o c o n t a c t w i t h t h e c h l o r i n e d i s i n f e c t a n t ( NAS, 1 9 7 4 ) . The a b i l i t y o f common water t r e a t m e n t p r o c e s s e s ( i. e., c o a g u l a t i o n , s e d i m e n t a t i o n , f i l t r a t i o n , and c h l o r i n a t i o n ) t o remove suspended matter t o a c h i e v e acceptable f i n a l t u r b i d i t i e s is a f u n c t i o n o f t h e c o m p o s i t i o n of t h e m a t e r i a l a s w e l l as its concentration. Because o f t h e v a r i a b i l i t y 0 of such removal efficiency, it is not possible to delineate a general raw water criterion for these uses.

Turbid water interferes with recreational use and aesthetic enjoyment of water. Turbid waters can be dangerous for swimming,

especially if diving facilities are provided, because ofthe possibility of unseen submerged hazards and the difficulty in locating swimmers in danger of drowning ( NAS, 1974). The less turbid the water the more desirable it becomes for swimming and other water contact sports. Other recreational pursuits such as boating and fishing will be adequately protected by suspended solids criteria developed for protection of fish and other aquatic life.

Fish and other aquatic life requirements concerning suspended solids can be divided into those whose effect occurs in the water column and those whose effect occurs following sedimentation to the bottom of the water body. Noted effects are similar for both fresh and marine waters.

The effects of suspended solids on fish have been reviewed by the European Inland Fisheries Advisory Commission ( EIFAC, 1965).

This review in 1965 identified four effects on the fish and fish food populations, namely:

( 1) by acting directly on the fish swimming in water in which solids are suspended, and either killing them or reducing their growth rate, resistance to disease, etc.;

( 2) by preventing the successful development of fish eggs and larvae;

( 3 ) by modifying natural movements and migrations o f fish; ( 4 ) by reducing t h e abundance o f food a v a i l a b l e to t h e f i s h ; . . .

S e t t l e a b l e materials which blanket t h e bottom of water bodies damage t h e invertebrate populations, block g r a v e l spawning beds,

and i f o r g a n i c , remove d i s s o l v e d oxygen from o v e r l y i n g waters ( E l F A C , 1965; Edberg and Hofsten, 1973). I n a s t u d y downstream from the discharge of a rock quarry where i n e r t suspended s o l i d s were i n c r e a s e d t o 80 mg/ L, t h e d e n s i t y of m a c r o i n v e r t e b r a t e s decreased by 60 percent while i n a r e a s of sediment accumulation b e n t h i c i n v e r t e b r a t e p o p u l a t i o n s a l s o decreased by 60 p e r c e n t regardless of t h e suspended sol i d concantrations ( Gammon, 1970).

similar e f f e c t s have been reported downstream from an area which was i n t e n s i v e l y logged. Major i n c r e a s e s i n stream suspended s o l i d s ( 25 ppm t u r b i d i t y upstream v e r s u s 390 ppm downstream)

caused smothering of bottom i n v e r t e b r a t e s , reducing organism d e n s i t y t o o n l y 7.3 p e r s q u a r e f o o t v e r s u s 25.5 p e r s q u a r e f o o t upstraam ( Tebo, 1955).

When s e t t l e a b l e s o l i d s b l o c k g r a v e l spawning beds which contain eggs, high m o r t a l i t i e s r e s u l t although there is evidence t h a t some s p e c i e s of salmonids w i l l n o t spawn i n such areas ( EIFAC, 1965).

I t has been p o s t u l a t e d t h a t silt attached t o t h e eggs prevents s u f f i c i e n t exchange of oxygen and carbon dioxide between t h e egg and t h e o v e r l y i n g water. The important v a r i a b l e s are p a r t i c l e s i z e , stream v e l o c i t y , and degree of turbulence ( EIFAC,

1965). Deposition of organic materials to the bottom sediments can cause imbalances in stream biota by increasing bottom animal density principally worm populations, and diversity is reduced as pol lution sensitive forms disappear ( Mackenthun, 1973). Algae 1 ikewise flourish in such nutrient rich areas although forms may become less desirable ( Tarzwell and Gaufin, 1953).

Plankton and inorganic suspended materials reduce light penetration into the water body, reducing the depth of thephotic zone. This reduces primary production and decreases fish food.

The NAS commitee in 1974 recommended that the depth of light penetration not be reduced by more than 10 percent ( NAS, 1974).

Additionally, the near surface waters are heated because of the greater heat absorbency of the particulate material which tends to stabilize the water column and prevents vertical mixing ( NAS,

1974). Such mixing reductions decrease the dispersion of dissolved oxygen and nutrients to lower portions of the water body.

One partially offsetting benefit of suspended inorganic material in water is the sorption of organic materials such as pesticides. Following this sorption process subsequent sedimentation may remove these materials from the water column into the sediments ( NAS, 1974).

Identifiable effects of suspended solids on irrigation use of water include the formation of crusts on top of the soil which inhibits water infiltration and plant emergence, and impedes soil aeration; the formation of films on plant leaves which blocks sunlight and impedes photosynthesis and which may reduce the marketability of some leafy crops like lettuce, and finally the adverse effect on irrigation reservoir capacity, delivery canals,

and other distribution equipment ( NAS, 1974). 0 The criterion for freshwater fish and other aquatic lifeare essentially that proposed by the National Academy of Sciences and the Great Lakes Water Quality Board.

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY CRITERION: SULFIDE = HYDROGEN SULFIDE 2 ug/ L'undissociated HZS f o r f i s h and other aquatic l i f e , fresh and marine water.

INTRODUCTION:

Hydrogen s u l f i d e is a s o l u b l e , h i g h l y poisonous, gaseous compound h a v i n q t h e c h a r a c t e r i s t i c odor o f r o t t e n eggs. It is detectable i n a i r by humans a t a d i l u t i o n of 0.002 ppm. It w i l l d i s s o l v e i n w a t e r a t 4 , 0 0 0 mg/ L a t 20' C and one atmosphere of pressure. Hydrogen s u l f i d e b i o l o g i c a l l y is an active compound t h a t is found primarily as an anaerobic degradation product of both organic s u l f u r compounds and inorganic s u l f a t e s . S u l f i d e s a r e c o n s t i t u e n t s of many i n d u s t r i a l wastes s u c h a s t h o s e from t a n n e r i e s , paper m i l l s , chemical p l a n t s , and g a s works. T h e anaerobic decomposition of sewage, sludge beds, algae, and other n a t u r a l l y d e p o s i t e d o r g a n i c m a t e r i a l i s a major s o u r c e of hydrogen s u l f i d e . 0 When s o l u b l e s u l f i d e s are added t o water t h e y react w i t h hydrogen ions t o form HS o r HZS, t h e proportion of each depending on t h e pH. The t o x i c i t y of s u l f i d e s derives p r i m a r i l y from H2S r a t h e r t h a n from t h e h y d r o s u l f i d e ( HS) o r s u l f i d e ( S=) ions'

When hydrogen s u l f i d e d i s s o l v e s i n water it dissociates according to t h e reactions:

H2S HS + H+ and HS S= + H+

A t pH 9 about 99 p e r c e n t of t h e s u l f i d e is i n t h e form of HS

, a t pH 7 t h e s u l f i d e is e q u a l l y d i v i d e d between HS and. H2S: and a t pH 5 about 9 9 p e r c e n t of t h e s u l f i d e is p r e s e n t a s H2S ( NAS 0  _

a 1974). The f a c t t h a t H2S is o x i d i z e d i n w e l l a e r a t e d water by n a t u r a l b i o l o g i c a l systems t o s u l f a t e s o r is b i o l o g i c a l l y oxidized t o elemental s u l f u r has caused i n v e s t i g a t o r s t o minimize t h e t o x i c effects of H2S on f i s h and o t h e r a q u a t i c l i f e .

RATIONALE:

The degree of hazard exhibited by s u l f i d e t o a q u a t i c animal l i f e is dependent on t h e t e m p e r a t u r e , pH, and d i s s o l v e d oxygen.

A t l o w e r pH v a l u e s a g r e a t e r p r o p o r t i o n is i n t h e form of t h e t o x i c u n d i s s o c i a t e d H2S. I n w i n t e r when t h e pH is n e u t r a l o r below o r when d i s s o l v e d oxygen l e v e l s are low b u t n o t l e t h a l t o f i s h , t h e hazard from s u l f i d e s i s exacerbated. F i s h e x h i b i t a s t r o n g a v o i d a n c e r e a c t i o n t o s u l f i d e . Based on data from experiments with the s t i c k l e b a c k , Jones ( 1964) hypothesized t h a t i f f i s h e n c o u n t e r a l e t h a l c o n c e n t r a t i o n of s u l f i d e there is a r e a s o n a b l e chance t h e y w i l l be r e p e l l e d by it b e f o r e t h e y are harmed. T h i s , of course, assumes t h a t an escape r o u t e is open.

Many p a s t d a t a on t h e t o x i c i t y of hydrogen s u l f i d e t o f i s h and o t h e r a q u a t i c l i f e h a v e been based on e x t r e m e l y s h o r t exposure periods. Consequently, these e a r l y data have i n d i c a t e d t h a t c o n c e n t r a t i o n s between 0.3 and 0.4 mg/ L p e r m i t f i s h t o s u r v i v e ( Van Horn 1958, Boon and F o l l i s 1967, Theede e t a l . ,

1969). Recent : ong term d a t a , both i n f i e l d s i t u a t i o n s and under c o n t r o l l e d 1 a b o r a t o r . y c o n d i t i o n s , demonstrate hydrogen s u l f i d e t o x i c i t y a t lower concentrations.

Colby and Smiti i ( 1967) found t h a t c o n c e n t r a t i o n s a s high a s 0.7 mg/ L h a v e been found w i t h i n 2 0 mm of t h e bottom o f s l u d g e beds, and t h e l e v e l s o f 0.1 t o 0.02 mg/ L w e r e common w i t h i n t h e first 20 mm o f water above t h i s l a y e r . Walleye ( S t i z o s t e d i o n vitreum) eggs h e l d i n t r a y s i n t h i s zone d i d n o t hatch. Adelman and Smith ( 1970) reported t h a t t h e h a t c h a b i l i t y of northern pike ( Esox l u c i u s ) eggs was s u b s t a n t i a l l y reduced a t 2 5 ug/ L H2S: a t 4 1 ug/ L m o r t a l i t y was almost complete. Northern p i k e f r y had 96

hour LC50 v a l u e s t h a t v a r i e d from 17 t o 32 ug/ L a t normal oxygen l e v e l s o f 6.0 mg/ L. T h e h i g h e s t c o n c e n t r a t i o n of hydrogen s u l f i d e t h a t had no observable effect on eggs and f r y w a s 1 4 and 4 ug/ L, r e s p e c t i v e l y . S m i t h and Oseid ( 1 9 7 2 ) , working on eggs,

fry and j u v e n i l e s o f w a l l e y e s and w h i t e s u c k e r s ( Catostomus commersoni) and Smith ( 1971), Safe l e v e l s i n working on walleyes and fathead minnows, Pimephales promelas, were found t o vary from 2.9 ug/ L t o 1 2 ug/ L w i t h eggs b e i n g t h e l e a s t s e n s i t i v e and j u v e n i l e s being t h e most s e n s i t i v e i n short term tests. I n 96

hour bioassays, fathead minnows and g o l d f i s h , Carassius a u r a t u s ,

varied g r e a t l y i n t o l e r a n c e t o hydrogen s u l f i d e w i t h changes i n t e m p e r a t u r e . They were more t o l e r a n t a t low t e m p e r a t u r e s ( 6 t o 10, C ) . H o l l a n d , e t a l . ( 1960) r e p o r t e d t h a t 1.0 mg/ L s u l f i d e caused 100 percent m o r t a l i t y i n 72 hours with P a c i f i c salmon. 0 On t h e b a s i s of chronic tests e v a l u a t i n g growth and s u r v i v a l ,

t h e s a f e H2S l e v e l f o r b l u e g i l l ( Lepomis macrochirus) j u v e n i l e s and a d u l t s was 2 ug/ L. Egg deposition i n b l u e g i l l s w a s reduced a f t e r 4 6 days i n 1.4 ug/ L H 2 S ( S m i t h and O s e i d , 1 9 7 4 ) . White sucker eggs were hatched a t 15 ug/ L, b u t j u v e n i l e s showed growth r e d u c t i o n s a t 1 ug/ L. Safe l e v e l f o r fathead minnows were between 2 and 3 ug/ L. S t u d i e s showed t h a t s a f e l e v e l s f o r Gammarus Pseudolimnaeus and Hexagenia  limbata were 2 and 15 ug/ L,

r e s p e c t i v e l y ( Oseid and S m i t h , 1974a, 197413). Some s p e c i e s 0 c typical of normally stressed habitats, Asellus spp., were much more resistant ( Oseid and Smith, 1974~).

Sulfide criteria for domestic or livestock use have not been established because the unpleasant odor and taste would preclude such use at hazardous concentrations.

It is recognized that the hazard from hydrogen sulfide to aquatic life is often localized and transient. Available data indicate that water containing concentrations of 2.0 ug/ L undissociated H2S would not be hazardous to most fish and other aquatic wildlife, but concentrations in excess of 2.0 ug/ L would constitute a long term hazard.

I ( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY TAINTING SUBSTANCES Materials should not be present in concentrations that individually or in combination produce undesirable flavors which are detectable by organoleptic tests performed on the edible portions of aquatic organisms.

RATIONALE :

Fish or shellfish with abnormal flavors, colors, tastes or odors are either not marketable or will result in consumer complaints and possible rejection of the food source even though subsequent lots of organisms may be acceptable. Poor product quality can and has seriously affected or eliminated the commercial fishing industry in some areas. Recreational fishing also can be affected adversely by off flavored fish. For the majority of sport fishermen, the consumption of their catch is part of their recreation and off flavored catches can result in diversion of the sportsmen to other water bodies. This can have serious economic impact on the established recreation industries such as tackle and bait sales and boat and cottage rental. 0 Water Quality Criteria, 1972 ( NAS, 1974) lists a number of wastewaters and chemical compounds that have been found to lower the palatability of fish flesh. Implicated wastewaters included those from 2,4 D manufacturing plants, kraft and neutral sulfite pulping processes, municipal wastewater treatment plants, oily wastes, refinery wastes, phenolic wastes, and wastes from slaughterhouses. The 9 ist of imp1 icated chemical compounds is long: it includes cresol and phenol compounds, kerosene,

naphthol, styrene, toluene, and exhaust outboard motor fuel. As little as 0.1 ug/ L o chlorophenol was reported to cause tainting ... a of fish flesh.

Shumway and a Palensky 1973) determined estimated threshold concentrations for 22 organic compounds. The values ranged from 0.4 ug/ L ( 2 , 4 dichl orophenol ) to 9 5,000 ug/ L ( formaldehyde) . An additional 12 compounds were tested, 7 of which were not found to impair flavor at or near lethal levels.

Thomas ( 1973) reviewed the literature review on tainting substances revealed serious problems that have occurred. Detailed studies and methodology used to evaluate the palatability of fishes in the Ohio River as affected by various waste discharges showed that the susceptibility of fishes to the accumulation of tainting substances is variable and dependent upon the species,

length of exposure, and the polJutant. As little as 5 ug/ L of gasoline can impart off flavors to fish ( Boyle, 1967).

( QUALITY CRITERIA FOR WATER, JULY 1976) PB 263943 SEE APPENDIX C FOR METHODOLOGY TEMPERATURE Freshwater Aquatic Life For any time of year, there are two upper limiting temperatures for a location ( based on the important sensitive species found there at that time):

1. One limit consists of a maximum temperature for short exposures that is time dependent and is given by the species

specific equation:

Temperature = ( l/ b) ( log [ time 3  a)  2, C ( C,) 10 ( min)

where: loglo = logarithm to base 10 ( common logarithm)

a = intercept on the " y" or logarithmic axis of the l'ine fitted to experimental data and which is available for some species from Appendix 11 C, National Academy of Sciences 1974 document.

b = slope of the line fitted to experimental data and available for some species from Appendix 11 C, of the National Academy of Sciences document.

and 2. The second value is a limit on the weekly average temperature that:

a. In the cooler months ( mid October to mid April in the north and December to February in the south) will protect against mortality of importr to mid April in the north and December to February in the south) will protect against mortality of important species if the elevated plume temperature is suddenly dropped to the ambient temperature, with the limit being the b. acclimation temperature minus apt0 when the lower lethal threshold temperature equals the ambient water temperature ( in some regions this limitation may also be applicable in summer).

or In the warmer months ( April through October in the north and March through November in the south) is determined by adding to the physiological optimum temperature ( usually for growth) a factor calculated as one third of the difference between the ultimate upper incipient lethal temperature and the optimum temperature  or the most sensitive important species ( and appropriate life state) that normally is found at that location and time.

or c. During reproductive seasons ( generally April through June and September through October in the north and March through May and October through November in the south) the limit is that temperature that meets site

specific requirements for successful migration,

spawning, egg incubation, fry rearing, and other reproductive functions of important species. These local requirements should supersede all other requirements when they are applicable.

or d. There is a site specific limit that is found necessary to preserve normal species diversity or prevent appearance of nuisance organisms. Marine Aquatic  Life In order to assure protection of the characteristic indigenous marine community of a water body segment from adverse thermal effects:

a. the maximum acceptable increase in the weekly average temperature resulting from artificial sources is 1'

C ( 1.8 F) during all seasonsofthe year, providtng the summer maxima are not exceeded;

and b. daily temperature cycles characteristic of the water body segment should not be altered in either amplitude or frequency.

Summer thermal maxima, which define the upper thermal limits for the communities of the discharge area, should be established on a site specific basis. Existing studies suggest the following regional limits: 0 Short term Maximum Maximum True Daily Mean* Sub tropical regions ( south of Cape Canaveral and Tampa Bay, Florida, and Hawaii 32.2' C ( 90 ° F) 29.4O C ( 85' F)

Cape Hatteras, N. C., to Cape Canaveral, Fla.

Long Island ( south shore) 3 0 . 6 O C ( 87O F) 27.8O C ( 82O F) 32.2' C ( 90' F) 29.4O C ( 85O'F)

to Cape Hatteras, N. C.

(* True Daily Mean = average of 24 hourly temperature readings.)

Baseline thermal conditions should be measured at a site where there is no unnatural thermal addition from any source,

which is in reasonable proximity to the thermal discharge ( within 5 miles) and which has similar hydrography to that of . the receiving waters at the discharge.

INTRODUCTION:

The uses of water by man in and out of its natural situs in the environment are affected by its temperature. Offstream domestic uses and instream recreation are both partially temperature dependent. Likewise, the 1 ife associated with the aquatic environment in any location has its species composition and activity regulated by water temperature. Since essentially all of these organisms are so called " cold blooded" or poikilotherms, the temperature of the water regulates their metabolism and ability to survive and reproduce effectively.

Industrial uses for process water and for coolingare likewise regulated by the water's temperature. Temperature, therefore, is an important physical parameter which to some extent regulates many of the beneficial uses of water. The Federal Water Pollution Control Administration in 1967 called temperature a catalyst, a depressant, an activator, a restrictor, a stimulator,

a controller, a killer, one of the most important and most influential water quality characteristics to life in water." 0 RATIONALE :

The suitability of water for total body immersion is greatly affected by temperature. In temperate climates, dangers from exposure to low temperatures is more prevalent than exposure to elevated water temperatures. Depending on the amount of activity by the swimmer, comfortable temperatures range from 20 ° C to 30 ° e. Short durations of lower and higher temperatures can be tolerated by most individuals. For example, for a 30 minute period, temperatures of 10' C or 35O C can be tolerated without harm by most individuals ( NAS, 1974).

Temperature also affects the self purification phenomenon in water bodies and therefore the aesthetic and sanitary qualities that exist. Increased temperatures accelerate the biodegradation of organic material both in the overlying water and in bottom deposits which makes increased demands on the dissolved oxygen resources of a given system. The typical situation is exacerbated by the fact that oxygen becomes less soluble as water temperature increases. Thus, greater demands are exerted on an increasingly scarce resource which may lead to total oxygen depletion and obnoxious septic conditions. These effects have been described by Phelps ( 1944) , Carp ( 1963), and Velz ( 1970).

Indicator enteric bacteria, and presumably enteric pathogens,

are likewise affected by temperature. It has been shown that  both total and fecal coliform bacteria die away more rapidly in the environment with increasing temperatures ( Ballentine and Kittrell, 1968).

Temperature effects have been shown for water treatment processes. Lower temperatures reduce the effectiveness of coagulation with alum and subsequent rapid sand filtration. In one study, difficulty was especially pronounced below 5O C ( Hannah, et al., 1967). Decreased temperature also decreases the effectiveness of chlorination. Based on studies relating chlorine dosage to temperature, and with a 30 minute contact time, dosages required for equivalent disinfective effect increased by as much as a factor of 3 when temperatures were decreased from 2 0 ° C to loo C ( Reid and Carlson, 1974).

Increased temperature may increase the odor of water because of the increased volatility of odor causing compounds ( Bumson,

1938). Odor problems associated with plankton may also be aggravated.

The effects o f temperature on aquatic organisms have been the subject of comprehensive literature reviews ( Brett, 1956; Fry,

1967; FWPCA, 1967; Kine, 1970) and annual literature reviews published by the Water Pollution Control Federaticn ( Coutant,

1968, 1969, 1970, 1971; Coutant and Goodyear, 1972; Coutant and Pfuderer, 1973, 1974). Only highlights from the thermal effects on aquatic life are presented here.

Temperature changes in water bodies can alter the existing aquatic community. The dominance of various phytoplankton groups in specific temperature ranges has been shown. For example, from 20 ° C to 25' C, diatoms predominated; green algae predominated from 30' C: to 35O C and blue greens predominated above 3.5' C a i r n s , 1956). Likewise, changes from a coldwater f i s h e r y t o a warm water f i s h e r y can occur because temperature may be d i r e c t l y l e t h a l t o a d u l t s o r f r y c a u s e a r e d u c t i o n of a c t i v i t y o r l i m i t 0 ( c reproduction ( B r e t t , 1960)

Upper and lower l i m i t s f o r temperature have been established f o r many a q u a t i c organisms. C o n s i d e r a b l y more d a t a e x i s t f o r u p p e r a s opposed t o l o w e r l i m i t s . T a b u l a t i o n s of l e t h a l temperatures f o r f i s h and o t h e r organisms a r e a v a i l a b l e ( Jones,

1 9 6 4 : FWPCA, 1 9 6 7 NAS, 1 9 7 4 ) . F a c t o r s s u c h a s d i e t , a c t i v i t y ,

age, g e n e r a l h e a l t h , osmotic stress, and even weather c o n t r i b u t e t o t h e l e t h a l i t y of t e m p e r a t u r e . The a q u a t i c species, thermal accumulation s t a t e and exposure t i m e a r e considered t h e c r i t i c a l f a c t o r s ( Parker and Xrenkel, 1969).

The e f f e c t s o f s u b l e t h a l t e m p e r a t u r e s o n m e t a b o l i s m ,

r e s p i r a t i o n , behavior, d i s t r i b u t i o n and migration, feeding rate,

growth, and reproduction have been summarized by Be S y l v a ( 1969).

Another s t u d y h a s i l l u s t r a t e d t h a t i n s i d e t h e t o l e r a n c e zone t h e r e is encompassed a more r e s t r i c t i v e t e m p e r a t u r e r a n g e i n which normal a c t i v i t y and growth o c c u r and y e t a n e v e n more r e s t r i c t i v e zone i n s i d e t h a t i n which normal reproduction w i l l occur ( B r e t t , 1960).

D e S y l v a ( 1969) has summarized a v a i l a b l e data on t h e combined effects of i n c r e a s e d t e m p e r a t u r e and t o x i c m a t e r i a l s o n f i s h i n d i c a t e t h a t t o x i c i t y g e n e r a l l y i n c r e a s e s w i t h i n c r e a s e d t e m p e r a t u r e and t h a t o r g a n i s m s s u b j e c t e d t o stress from t o x i c m a t e r i a l s a r e less t o l e r a n t o f temperature extremes.

The t o l e r a n c e o f o r g a n i s m s t o extremes o f t e m p e r a t u r e is a f u n c t i o n o f t h e i r g e n e t i c a b i l i t y t o a d a p t t o t h e r m a l c h a n g e s 0 ~ within their characteristic temperature range, the acclimation temperature prior to exposure, and the time of exposure to the elevated temperature ( Coutant, 1972). The upper incipient lethal temperature or the highest temperature that 50 percent of a sample of organisms can survive is determined on the organism at the highest sustainable acclimation temperature. The lowest temperature that 50 percent of the warm acclimated organisms can survive in is the ultimate lower incipient lethal temperature.

True acclimation to changing temperatures requires several days ( Brett, 1941). The lower end of the temperature accommodation range for aquatic life is 0' C in fresh water and somewhat less for saline waters. However, organisms acclimated to relatively warm water, when subjected to reduced temperatures that under other conditions of acclimation would not be detrimental, may suffer a significant mortality caused by thermal shock ( Coutant,

1972).

Through the natural changes in climatic conditions, the temperatures of water bodies fluctuate daily, as well as seasonally. These changes do not eliminate indigenous aquatic populations, but affect the existing community structure and the geographic distribution of species. Such temperature changes are necessary to induce the reproductive cycles of aquatic organisms and to regulate other life factors ( Mount, 1969).

Artificially induced changes such as the return of cooling water or the release of cool hypolimnetic waters from impoundments may alter indigenous aquatic ecosystems ( Coutant,

1972). Entrained organisms may be damaged by temperature increases across cooling water condensers if the increase is sufficiently great or the exposure period sufficiently long.

Impingement upon condenser screens, chlorination for slime control, or other physical insults damage aquatic life ( Raney,

1969: Patrick, 1969 ( b)). However, Patrick ( 1969( a)) has shown that algae passing through condensers are not injured if the temperature of the outflowing water does not exceed 345O C.

In open waters elevated temperatures nay affect periphyton,

benthic invertebrates, and fish, in addition to causing shifts in algal dominance. Trembley ( 1960) studies of the Delaware River downstream from a power plant concluded that the periphyton population was considerably altered by the discharge.

The number and distribution of bottom organisms decrease as water temperatures increase. The upper tolerance limit for a balanced benthic population structure is approximately 32O C, A 0 large number of these invertebrate species are able to tolerate higher temperatures than those required for reproduction ( FWPCA,

1967).

In order to define criteria for fresh waters, Coutant ( 1972)

cited the following was cited as currently definable requirements:

1. Maximum sustained temperatures that are consistent with maintaining desirable levels of productivity,

2. maximum levels of metabolic acclimation to warm temperatures that will permit return to ambient winter temperatures should artificial sources of heat cease,

3. Time dependent temperature 1 imitations f o r survival of brief exposures to temperature extremes, both upper and lower, 4 . Restricted temperature ranges for various states of reproduction, including ( for fish) gametogenesis, spawning migration, release of gametes, development of the embryo, commencement of independent feeding ( and other activities) by j uv eni 1 es , and temper a tur es re qu ired for met amorphos is, emergence, or other activities of lower forms,

5. Thermal limits for diverse species compositions of aquatic communities, particularly where reduction in diversity creates nuisance growths of certain organisms, or where important food sources ( food chains) are altered,

6. Thermal requirements of downstream aquatic life ( in rivers) where upstream diminution of a coldwater resource will adversely affect downstream temperature requirements.

The major portion of such information that is available,

however, is for freshwater fish species rather than lower forms of marine aquatic life.

The temperature time duration for short term exposures such that 50 percent of a given population will survive an extreme temperature frequently is expressed mathematically by fitting experimental data with a staright line on a semi logarithmic plot with time on the logarithmic scale and temperature on the linear scale ( see fig. 1). In equation form this 50 percent mortality relationship is:

loglo ( time ( minutes)) = a + b ( Temperature ( O C ) )

where: loglo= logarithm to base 10 ( common logarithm)

a = intercept on the " y " or logarithmic axis of the line fitted to experimental data and which is available for some species from Appendix 11 C, of the National Academy of Sciences document.

b = slope of the line fitted to experimental data and which is available for some species from Appendix 11 C, of the National Academy of Sciences document.