Chlorine Dioxide

Environmental Hazard and Risk Assessment

Case 4023

Genevieve Angle

Office of Pesticide Programs

Antimicrobials Division

U.S. Environmental Protection Agency

  SEQ CHAPTER \h \r 1 1200 Pennsylvania Avenue, NW

Washington, DC 20460

July 13, 2006

Chlorine Dioxide and Sodium Chlorite: Environmental Hazard and Risk Assessment

Introduction

The toxicity endpoints (e.g. LC50, NOEC) included in this section are based on the results of sodium chlorite and chlorine dioxide toxicity studies that were submitted to EPA for review. Chlorine dioxide and sodium chlorite are used as antimicrobial pesticides at numerous use sites.  Sodium chlorite is used as a precursor in the generation of chlorine dioxide.  The antimicrobial registered uses of chlorine dioxide/sodium chlorite fall into several major categories including use in the treatment of human drinking water systems; in industrial process and water systems; as a materials preservative; and as a general disinfectant in medical, residential, agricultural, commercial and industrial settings. The once-through cooling tower use of chlorine dioxide/sodium chlorite has been selected for risk assessment because out of all the uses of these chemicals, it is the one expected to have the most potential for environmental exposure.  The environmental risk assessment will be conducted using sodium chlorite endpoints because under environmental conditions, chlorine dioxide converts mostly into chlorite ions.  Currently, a quantitative evaluation of the likelihood of the ecological exposures resulting from the industrial uses of chlorine dioxide and sodium chlorite overlapping spatially and temporally with the exposures resulting from the agricultural uses of chlorine dioxide and sodium chlorite is not possible.  Therefore, the ecological risks are not aggregated in this assessment.

Data Gaps

Several data requirements, necessary to support the once-through cooling tower use of chlorine dioxide/sodium chlorite, are not fulfilled:

72-4/850.1300		Fish early life-stage testing-freshwater			TGAI

72-4b/850.1400	Invertebrate life-cycle testing - freshwater			TGAI

123-1/850.4225	Seedling emergence dose-response in rice			TEP

123-1/850.4250	Vegetative vigor dose-response in rice			TEP

123-2/850.4400	Aquatic vascular plant dose-response toxicity- Lemna sp. TGAI or TEP

123-2/850.5400	Acute algal dose-response toxicity - 4 species		TGAI or TEP

Ecological Hazard Assessment:

I. Toxicity to Terrestrial Animals

A. Birds, Acute and Subacute

An acute oral toxicity study using the technical grade of the active ingredient (TGAI) is required to establish the toxicity of chlorine dioxide/sodium chlorite to birds.  The preferred test species is either mallard duck (a waterfowl) or bobwhite quail (an upland game bird).  The results of several toxicity studies are provided in the following table.

Table 1.  Acute Oral Toxicity of Chlorine Dioxide and Sodium Chlorite to Birds

Substance/%

Active Ingredient

(AI)

Organism

Endpoints/Results

(95% conf. interval)

mg/kg

Reference

Study Classification

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

LD50 = 382 (300-520)

NOAEL = 175

Robaidek, 1985

ACC # 259373

acceptable

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

LD50 = 390 (310-490)

NOAEL = N.R.

Robaidek and Johnson, 1985

ACC # 257341

acceptable

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

LD50 = 395 (272-573)

NOAEL = N.R.

Fletcher, 1984

ACC # 253378

acceptable

Sodium Chlorite/83%

Northern bobwhite

(Colinus virginianus)

LD50 = 660 (540-810)

Fletcher, 1973

MRID # 31610

acceptable

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

LD50 = 467 (372-585)

Beavers, 1984

ACC # 254177

acceptable

Sodium Chlorite/80%

Mallard Duck (Anas platyrhynchos)

LD50 > 31.25

Beavers, 1984

ACC # 254176

supplemental

Sodium Chlorite/25%

Northern bobwhite

(Colinus virginianus)

LD50 = 797(420-2594)

NOAEL= 125

MBA Laboratories, 1984

ACC# 252854

acceptable

Note: LD50=Median Lethal Dose; NOAEL=No Observed Adverse Effect Level; N.R. = Not Reported

These results indicate that chlorine dioxide/sodium chlorite range from slightly to highly toxic to birds on an acute oral basis.  The guideline requirement (71-1/OPPTS 850.2100) is fulfilled.

Two subacute dietary studies using the technical grade of the active ingredient are required to establish the toxicity of a pesticide to birds.  The preferred test species are mallard duck (a waterfowl) and bobwhite quail (an upland gamebird).  Results of avian subacute dietary tests are tabulated below.

Table 2.  Avian Subacute Dietary Toxicity of Chlorine Dioxide and Sodium Chlorite

Substance/% AI

Organism

LC50

(ppm)

(95 % c.i.)

NOAEC

(ppm)

Reference

Study Classification

Sodium Chlorite/80%

Mallard Duck (Anas platyrhynchos)

>5000

5000

Johnson, 1984

MRID # 94068008

acceptable

Sodium Chlorite/80%

Northern bobwhite (Colinus virginianus)

> 5000

N.R.

Fletcher, 1984

ACC # 253378

acceptable

Sodium Chlorite/80%

Mallard Duck (Anas platyrhynchos)

> 5000

N.R.

Fletcher, 1984

ACC # 253378

acceptable

Sodium Chlorite/80%

Northern bobwhite (Colinus virginianus)

> 5000

N.R.

Johnson, 1984

MRID # 94068005

acceptable

Sodium Chlorite/80%

Mallard Duck (Anas platyrhynchos)

> 5620

N.R.

Beavers, 1984

ACC # 254178

acceptable

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

> 5620

N.R.

Beavers, 1984

ACC # 254179

acceptable

Sodium Chlorite/80%

Northern bobwhite

(Colinus virginianus)

>10,000

N.R.

Fink, 1977

MRID # 130649

acceptable

Sodium Chlorite/80%

Mallard Duck (Anas platyrhynchos)

>10,000

N.R.

Fink, 1977

MRID # 130650

acceptable

Sodium Chlorite/25%

Mallard Duck (Anas platyrhynchos)

18686 (8186-109184)

N.R.

MBA Laboratories, 1983

ACC # 252854

acceptable

Sodium Chlorite/25%

Northern bobwhite (Colinus virginianus)

2031(1226-3903)

417

MBA Laboratories, 1984

ACC #252854

acceptable

Note: LC50=Median Lethal Concentration; NOAEC=No Observed Adverse Effect Concentration; N.R. = Not Reported

These results indicate that chlorine dioxide/sodium chlorite range from slightly toxic to practically non-toxic to birds on a subacute dietary basis.  The guideline requirement (71-2/OPPTS 850.2200) is fulfilled.

 		B.  Birds, Chronic

Avian reproduction studies using the technical grade of the active ingredient are required for a pesticide when any of the following conditions are met: (1) birds may be subject to repeated or continuous exposure to the pesticide, especially preceding or during the breeding season, (2) the pesticide is stable in the environment to the extent that potentially toxic amounts may persist in animal feed, (3) the pesticide is stored or accumulated in plant or animal tissues, and/or (4) information derived from mammalian reproduction studies indicates reproduction in terrestrial vertebrates may be adversely affected by the anticipated use of the product.  The currently registered uses of chlorine dioxide/sodium chlorite do not require avian reproduction testing.

II.   Toxicity to Freshwater Aquatic Animals

A.  Freshwater Fish, Acute

Two fish toxicity studies using the TGAI are required to establish the toxicity of a pesticide to freshwater fish.  The preferred test species are rainbow trout (a cold water fish) and bluegill sunfish (a warm water fish).  The results of studies submitted for sodium chlorite are provided in the following table.

Table 3.  Acute Toxicity of Chlorine Dioxide and Sodium Chlorite to Freshwater Fish

Substance/%

Active Ingredient

(AI)

Organism

Endpoints/Results

(ppm)

(95% conf. interval)

Reference

Study Classification

Sodium Chlorite/80%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 360 (216-600)

NOAEC = 216

Barrows, 1984

MRID # 94068007

acceptable

Sodium Chlorite/80%

Bluegill

(Lepomis macrochirus)

LC50 = 244 (196-304)

NOAEC = 108

Larkin, 1984

ACC # 254181

acceptable

Sodium Chlorite/80%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 360 (216-600)

NOAEC = 216

Larkin, 1984

ACC # 254180

acceptable

Sodium Chlorite/80.25%

Bluegill

(Lepomis macrochirus)

LC50 = 265 (231-309)

NOAEC = 130

EG&G Bionomics, 1978

ACC # 69809

supplemental

Sodium Chlorite/79%

Bluegill

(Lepomis macrochirus)

LC50 = 208 (165-262)

NOAEC = N.R.

Sleight III, 1971

MRID # 131351

supplemental

Sodium Chlorite/79%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 50.6 (38.8-65.8)

NOAEC = N.R.

Sleight III, 1971

MRID # 131351

supplemental

Sodium Chlorite/80%

Rainbow trout (Oncorhynchus mykiss)

LC50 >100

NOAEC = N.R.

McMillen, 1985

ACC # 253743

supplemental

Sodium Chlorite/80%

Bluegill (Lepomis macrochirus)

LC50 >100

NOAEC = N.R.

McMillen, 1985

ACC # 253743

supplemental

Sodium Chlorite/25%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 203 (175-236)

NOAEC = 100

MBA Laboratories, 1984

ACC # 252854

acceptable

Sodium Chlorite/25%

Bluegill (Lepomis macrochirus)

LC50 = 222 (207-237)

NOAEC = 186

MBA Laboratories, 1983

ACC # 252854

supplemental

Sodium Chlorite/81.5%

Bluegill (Lepomis macrochirus)

LC50 = 310 (270-350)

NOAEC = 220

Sousa, 1981

ACC # 245697

acceptable

Sodium Chlorite/80.25%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 290 (250-340)

NOAEC = <70

EG&G Bionomics, 1979

ACC # 69810

acceptable

Sodium Chlorite/80%

Rainbow trout (Oncorhynchus mykiss)

LC50 = 340 (220-600)

NOAEC = 130

Sousa and Surprenant, 1984

ACC # 253379

acceptable

Sodium Chlorite/80%

Bluegill (Lepomis macrochirus)

LC50 = 420 (220-600)

NOAEC = 220

Sousa and Surprenant, 1984

MRID # 94068006

acceptable

Note: LC50=Median Lethal Concentration; NOAEC=No Observed Adverse Effect Concentration; N.R. =Not Reported

These results indicate that chlorine dioxide/sodium chlorite range from slightly toxic to practically non-toxic to freshwater fish on an acute basis.  The guideline requirement (72-1/OPPTS 850.1075) is fulfilled.

B.  Freshwater Fish, Chronic

A freshwater fish early life-stage test using the technical grade of the active ingredient is required for a pesticide when it may be applied directly to water or if the end-use product is expected to be transported to water from the intended use site, and any of the following conditions are met: (1) the pesticide is intended for use such that its presence in water is likely to be continuous or recurrent regardless of toxicity, (2) any aquatic acute LC50 or EC50 is less than 1 mg/l, (3) the EEC (estimated environmental concentration) in water is equal to or greater than 0.01 of any acute LC50 or EC50 value, or (4) the actual or estimated environmental concentration in water resulting from use is less than 0.01 of any acute LC50 or EC50 value and any one of the following conditions exist: studies of other organisms indicate the reproductive physiology of fish may be affected, physicochemical properties indicate cumulative effects, or the pesticide is persistent in water (e.g., half-life greater than 4 days).  The preferred test species is rainbow trout, but other species may be used.  Freshwater fish early life-stage testing is required for chlorine dioxide and sodium chlorite in order to support once-through cooling tower uses. No data under this topic have been submitted; therefore Guideline 72-4/OPPTS 850.1300 is not fulfilled.

C.  Freshwater Invertebrates, Acute

A freshwater aquatic invertebrate toxicity test using the TGAI is required to establish the toxicity of chlorine dioxide and sodium chlorite to freshwater aquatic invertebrates.  The preferred test species is Daphnia magna.  Results of this test are tabulated below.

Table 4.  Acute Toxicity of Chlorine Dioxide and Sodium Chlorite to Freshwater Invertebrates

Substance/%

Active Ingredient

(AI)

Organism

Endpoints/Results

(ppm)

(95% conf. interval)

Reference

Study Classification

Sodium Chlorite/80%

Daphnia magna

EC50 = 0.027 (0.021-0.031)

NOAEC = 0.003

Barrows, 1984

MRID # 146162

acceptable

Sodium Chlorite/80%

Daphnia magna

EC50 = 0.39 (0.32-0.54)

NOAEC =N.R.

Hoberg and Surprenant, 1984

MRID # 141149

acceptable

Sodium Chlorite/79%

Daphnia magna

EC50 = 0.29

(0.25-0.33)

NOAEC = 0.10

Vilkas, 1976

MRID # 131350

acceptable

Sodium Chlorite/80%

Daphnia magna

EC50 = 0.08

(0.06-0.10)

NOAEC = 0.06

Larkin, 1984

ACC # 254182

acceptable

Sodium Chlorite/80%

Daphnia magna

EC50 = 0.146

 (0.12 - 0.18)

NOAEC = 0.06

Nackord, 1984

MRID # 94068009

acceptable

Sodium Chlorite/25%

Daphnia magna

EC50 = 1.4 (1.0-1.9 )

NOAEC = 0.4

MBA Laboratories, 1984

ACC # 252854

supplemental

Note: EC50=Median Effective Concentration; NOAEC=No Observed Adverse Effect Concentration; N.R. =Not Reported

These studies indicate that chlorine dioxide and sodium chlorite range from very highly toxic for technical grade sodium chlorite a.i. to moderately toxic for the formulated product to aquatic invertebrates on an acute basis.  The guideline requirement (72-2/OPPTS 850.1010) is fulfilled.

D.  Freshwater Invertebrates, Chronic

A freshwater aquatic invertebrate life-cycle test using the technical grade of the active ingredient is required for a pesticide if the end-use product may be applied directly to water or expected to be transported to water from the intended use site, and any of the following conditions are met: (1) the pesticide is intended for use such that its presence in water is likely to be continuous or recurrent regardless of toxicity, (2) any aquatic acute LC50 or EC50 is less than 1 mg/l, (3) the EEC in water is equal to or greater than 0.01 of any acute EC50 or LC50 value, or (4) the actual or estimated environmental concentration in water resulting from use is less than 0.01 of any aquatic acute EC50 or LC50 value and any of the following conditions exist: studies of other organisms indicate the reproductive physiology of invertebrates may be affected, physicochemical properties indicate cumulative effects, or the pesticide is persistent in water (e.g., half-life greater than 4 days).  The preferred test species is Daphnia magna. Freshwater fish early life-stage testing is required for chlorine dioxide/sodium chlorite in order to support once-through cooling tower uses.  No data under this topic have been submitted; therefore Guideline 72-4b/OPPTS 850.1400 is not fulfilled.

E.  Freshwater Field Studies

Freshwater field testing is required for pesticides in cases where there are risks of concern from labeled use patterns.  This testing was not required for chlorine dioxide and sodium chlorite and is reserved at the present time.

III.   Toxicity to Estuarine and Marine Animals

A.  Estuarine and Marine Fish, Acute

Acute toxicity testing with estuarine/marine fish using the technical grade of the active ingredient is required for a chemical when the end-use product is intended for direct application to the marine/estuarine environment or the active ingredient is expected to reach this environment because of its use in coastal counties.  The preferred test species is sheepshead minnow.  Results of this test are tabulated below.

Table 5.  Acute Toxicity of Chlorine Dioxide/Sodium Chlorite to Estuarine/Marine Fish

Substance/% Active Ingredient (AI)

Organism

96 hr LC50

mg/L (ppm)

(95% conf. interval)

NOAEC mg/L (ppm)

Reference

Study Classification

Sodium Chlorite/79%

Sheepshead minnow

(Cyprinodon variegatus)

75 (62.6-89.8)

13.9

Yurk and Overman, 1994

MRID # 43259401

acceptable

Note: LC50=Median Lethal Concentration; NOAEC=No Observed Adverse Effect Concentration

The results indicate that chlorine dioxide/sodium chlorite are slightly toxic to estuarine/marine fish on an acute basis.  The guideline requirement (72-3a/OPPTS 850.1025) is fulfilled.

B.  Estuarine and Marine Fish, Chronic

Estuarine/marine fish early life-stage testing is not required for the currently registered uses of chlorine dioxide and sodium chlorite.  Since freshwater and estuarine/marine fish are comparably sensitive to sodium chlorite on an acute basis, the freshwater early life-stage endpoints will suffice for assessing risk to estuarine/marine fish species.  However, as noted above, the data requirement for freshwater fish early life-stage testing (72-4a/850.1300) has not been fulfilled.

C.  Estuarine and Marine Invertebrates, Acute

Acute toxicity testing with estuarine/marine invertebrates using the technical grade of the active ingredient is required for a pesticide when the end-use product is intended for direct application to the marine/estuarine environment or the active ingredient is expected to reach this environment because of its use in coastal counties.  The preferred test species are the mysid shrimp and eastern oyster.  Results of these tests are tabulated below.

Table 6:  Acute Toxicity of Chlorine Dioxide and Sodium Chlorite to Estuarine/Marine Invertebrates

Substance/

% Active Ingredient (AI)

Organism

96-hour

EC50 mg/L (ppm)

(95% conf. interval)

Reference

Study Classification

Sodium Chlorite/79%

Eastern oyster

(Crassostrea virginica)

21.4 (14.3-27.1)

NOAEC = 14.3

Yurk and Overman, 1994

MRID # 43259403

acceptable

Sodium Chlorite/79%

Mysid

(Mysidopsis bahia)

0.576 (0.44-0.75)

NOAEC= N.R.

Yurk and Overman, 1994

MRID # 43259402

acceptable

Note: EC50=Median Effective Concentration; NOAEC=No Observed Adverse Effect Concentration

The results indicate that chlorine dioxide/sodium chlorite range from highly toxic to slightly toxic to estuarine/marine invertebrates on an acute basis.  The guideline requirements (72-3b and 72-3c/OPPTS 850.1035 and 850.1045) are fulfilled.

D.  Estuarine and Marine Invertebrate, Chronic

An estuarine/marine invertebrate life-cycle toxicity test is required for a pesticide if the end-use product may be applied directly to estuarine or marine waters, or is expected to be transported to these waters from the intended use site, and any of the following conditions are met: (1) the pesticide is intended for use such that its presence in water is likely to be continuous or recurrent regardless of toxicity, (2) any aquatic acute LC50 or EC50 is less than 1 mg/l, (3) the EEC in water is equal to or greater than 0.01 of any acute EC50 or LC50 value, or (4) the actual or estimated environmental concentration in water resulting from use is less than 0.01 of any aquatic acute EC50 or LC50 value and any of the following conditions exist: studies of other organisms indicate the reproductive physiology of invertebrates may be affected, physicochemical properties indicate cumulative effects, or the pesticide is persistent in water (e.g., half-life greater than 4 days).  Due to the high acute toxicity of sodium chlorite to estuarine/marine invertebrates, life-cycle testing is necessary; however, freshwater invertebrates tend to be more sensitive than estuarine/marine invertebrates to sodium chlorite on an acute basis, and, therefore, freshwater life-cycle endpoints will suffice for assessing risk to estuarine/marine invertebrate species. As noted above, freshwater invertebrate life-cycle testing (72-4b/850.1400) has not been submitted.

E.  Estuarine and Marine Field Studies

No estuarine or marine field study testing is currently required for chlorine dioxide and sodium chlorite.

IV.   Toxicity to Plants

A. Terrestrial/Semi-aquatic

Currently, terrestrial plant testing is not required for pesticides other than herbicides except on a case-by-case basis (e.g., labeling bears phytotoxicity warnings, incidents of plant damage have been reported, or literature indicating phytotoxicity is available). The once-through cooling tower use of chlorine dioxide/sodium chlorite requires such testing, due to the algaecidal nature of the chemical and the likelihood of exposure to semi-aquatic plants along surface waters receiving industrial facility outfall from the cooling system.  Results of these tests are tabulated below.

Table 7.  Toxicity of Chlorine Dioxide/Sodium Chlorite to Terrestrial/Semi-aquatic Plants

Substance/% Active Ingredient (AI)

Organism

EC25

(ppm)

Reference

Study Classification

Sodium Chlorite/80%

Monocots & Dicots (10 Species)

>3.5

Backus et al., 1990

MRID # 41843101

acceptable

Sodium Chlorite/80%

Monocots & Dicots (9 Species)

>3.5

Backus et al., 1990

MRID # 41843102

acceptable

Sodium Chlorite/80%

Buckwheat (Polygonum convolvulus)

<3.5

Backus et al., 1990

MRID # 41843102

acceptable

Note: EC25=Effective Concentration (25th Percentile)

The results indicate that chlorine dioxide/sodium chlorite are moderately toxic to terrestrial plants.  The guideline requirement (122-1/OPPTS 850.4100 and 850.4150) is fulfilled.  However, since the maximum label rate for many of the chlorine dioxide/sodium chlorite once-through cooling labels was not used in these tests, it is necessary to conduct Tier II testing with rice.  Guideline 123-1/OPPTS 850.4225 and 850.4250, Seedling Emergence and Vegetative Vigor testing with Rice (Oryza sativa) is not fulfilled.

B.  Aquatic

The once-through cooling tower use of chlorine dioxide/sodium chlorite requires that 5 aquatic plant tests be conducted due to the algaecidal nature of the chemical and the likelihood of exposure to aquatic plants in surface waters receiving industrial facility outfall from the cooling system.  Guideline 123-2/OPPTS 850.4400 and 850.5400, Vascular Aquatic Plant and Algal dose-response toxicity testing (5 species), is not fulfilled because only one study (1 species) under this topic has been submitted and 5 are required.  The results of this test are tabulated below.  The following aquatic plant studies are still required: blue-green cyanobacteria (Anabaena flos-aquae), freshwater diatom (Navicula pelliculosa), marine diatom (Skeletonema costatum) and floating macrophyte (Lemna gibba).

Table 8.  Toxicity of Chlorine Dioxide/Sodium Chlorite to Aquatic Plants

Substance/% Active Ingredient (AI)

Organism

96 hr EC50 (ppm) (95% conf. interval)

Reference

Study Classification

Sodium Chlorite/80%

Green algae (Selenastrum capricornutum)

1.32 (1.18-1.47)

NOAEC = <0.62

Ward and Boeri, 1991

MRID # 41880403

supplemental

Note: EC50=Median Effective Concentration; NOAEC=No Observed Adverse Effect Concentration

The results indicate that chlorine dioxide/sodium chlorite are moderately toxic to aquatic plants.

Risk Assessment and Characterization:

Risk assessment integrates the results of the exposure and ecotoxicity data to evaluate the likelihood of adverse ecological effects. One method of integrating the results of exposure and ecotoxicity data is called the quotient method.  For this method, risk quotients (RQs) are calculated by dividing exposure estimates by ecotoxicity values, both acute and chronic:

           RQ = EXPOSURE/TOXICITY

RQs are then compared to levels of concern (LOCs).  These LOCs are criteria used by OPP to indicate potential risk to nontarget organisms and the need to consider regulatory action.  The criteria indicate that a pesticide used as directed has the potential to cause adverse effects on nontarget organisms.  LOCs currently address the following risk presumption categories: (1) acute high - the potential for acute risk is high, regulatory action may be warranted in addition to restricted use classification; (2) acute restricted use - the potential for acute risk is high, but this may be mitigated through restricted use classification; (3) acute endangered species - the potential for acute risk to endangered species is high, and regulatory action may be warranted, and (4) chronic risk - the potential for chronic risk is high, and regulatory action may be warranted.   Currently, AD does not perform assessments for chronic risk to plants, acute or chronic risks to nontarget insects, or chronic risk from granular/bait formulations to mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the acute and chronic risk quotients are derived from the results of required studies.  Examples of ecotoxicity values derived from the results of short-term laboratory studies that assess acute effects are: (1) LC50 (fish and birds) (2) LD50 (birds and mammals) (3) EC50 (aquatic plants and aquatic invertebrates) and (4) EC25 (terrestrial plants). The NOAEC value is used as the ecotoxicity test value in assessing chronic effects.

Risk presumptions, along with the corresponding RQs and LOCs are tabulated below.

Risk Presumptions for Terrestrial Animals

Risk Presumption

RQ

LOC

Birds and Wild Mammals

Acute High Risk

EEC1/LC50 or LD50/sqft2 or LD50/day3

0.5

Acute Restricted Use

EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 50 mg/kg)

0.2

Acute Endangered Species

EEC/LC50 or LD50/sqft or LD50/day

0.1

Chronic Risk

EEC/NOEC

1

 1  abbreviation for Estimated Environmental Concentration (ppm) on avian/mammalian food items

 2    mg/ft2             	3  mg of toxicant consumed/day

   LD50 * wt. of bird             	LD50 * wt. of bird

Risk Presumptions for Aquatic Animals

Risk Presumption

RQ

LOC

Acute High Risk

EEC1/LC50 or EC50

0.5

Acute Restricted Use

EEC/LC50 or EC50

0.1

Acute Endangered Species

EEC/LC50 or EC50

0.05

Chronic Risk

EEC/MATC2 or NOEC

1

 1  EEC = (ppm or ppb) in water

 2  MATC = maximum allowable toxicant concentration

Risk Presumptions for Plants

Risk Presumption

RQ

LOC

Terrestrial and Semi-Aquatic Plants

Acute High Risk

EEC/EC25

1

Acute Endangered Species

EEC/EC05 or NOEC

1

Aquatic Plants

Acute High Risk

EEC1/EC50

1

Acute Endangered Species

EEC/EC05 or NOEC

1

 1  EEC = (ppb/ppm) in water

1.  Environmental Fate Assessment Summary

This section is a summary of the Environmental Fate Risk Assessment.

Chlorine dioxide and sodium chlorite are assessed together because chlorine dioxide is produced by a reaction of sodium chlorite (and sometime sodium chlorate) and hypochlorite/acid. In addition, chlorite is a breakdown product of chlorine dioxide.

Chlorine dioxide has a short half life and in the presence of sunlight and will break down into chloride and chlorate ions (between pH 4 and 7).  At pH lower than 4, its breakdown products are chlorite and chlorate. Chlorite is the dominant breakdown product.  Ultimately, oxygen is formed.  Sodium chlorite dissolves in water, breaking down into chloride and chlorate ions under similar conditions as chlorine dioxide. Chemical degradation of sodium chlorite commonly occurs in water as well as in the presence of suspended soil particles containing ions, like Fe(II), Mn(II),  I-, and S-2, through redox reactions. The final breakdown products are chloride and oxygen.  These same end products are obtained when sodium chlorite is heated.

Chlorate and chlorite ions tend to only undergo biodegradation only under anaerobic conditions.  Biodegradation of chlorate and chlorite have been observed in anoxic groundwater, sediments and some soils. The end products are the same as stated above: chloride and oxygen.  No adsorption/desorption constants (Kds) have been measured or reported in published literature for either chlorite or chlorate. These ions are likely to be mobile and may travel from surface to groundwater easily.  The estimated log Kow of chlorine dioxide is -3.22 and for sodium chlorite is -7.17.  It is not expected that either would bioaccumulate in aquatic organisms.

2.  Environmental Exposure Assessment

The Probabilistic Distribution Model version 4 (PDM4) was used to estimate exposure from once-through cooling tower uses.  The details of this model can be found in the   SEQ CHAPTER \h \r 1 Chlorine Dioxide and Sodium Chlorite Environmental Modeling Chapter.  This screening-level model was used to provide the percentage of days per year various concentrations are exceeded for several different flow, application, and dosing scenarios.

Three different flow regimes were considered: high flow [power plants with average stream flow rates of 1000±50 million gallons per day (MGD)]; medium flow (power plants with average stream flow rates of 500±50  MGD); and low flow (power plants with average stream flow rates of 100±10 MGD).  These plants were taken from the NPDES database of plant codes; 12 plants were used in each the low and medium flow category, and 6 plants were used in the high flow category (see Environmental Modeling Chapter, page 5, for a listing of these plants).  The 7Q10 flow rate (a flow rate that a stream is expected to be below for seven consecutive days once every ten years) for each of the selected plants was used to develop a mean 7Q10 flow rate for each category.  This mean 7Q10 flow rate was used as the input parameter for flow in the PDM4 model.

Two pesticide application scenarios, continuous feed and intermittent feed, were used in the modeling, based on label instructions.  For continuous feed use, the label rates ranged from 0.10 ppm to 2.0 ppm chlorine dioxide/sodium chlorite in the water.  For intermittent use, the label rates ranged from 0.10 ppm to 25 ppm chlorine dioxide/sodium chlorite in the water.  A single label contained the rate of 800 ppm chlorine dioxide/sodium chlorite and did not specify whether this was for continuous or intermittent use.  It is believed that the single label with the 800 ppm dose rate will be either cancelled or amended by the registrant to delete this dose. The concentrations (the concentrations of concern, or COC) used in the model were endpoints from aquatic organism toxicity studies with sodium chlorite.

Exceedance values for average and worst-case situations were modeled.  The average values were calculated by averaging all of the values for a given flow category.  The worst-case values were calculated by averaging the highest (peak) values for a given flow category.

Additional details on the PDM4 model and the specific inputs, assumptions, and output can be found in the Environmental Modeling Chapter.

Risk to Aquatic Organisms from Once-Through Cooling Use of Chlorine Dioxide/Sodium Chlorite

Since the modeling for chlorine dioxide/sodium chlorite provides results as percent days per year a particular concentration is exceeded, Risk Quotients were not used in the usual way to provide numeric estimates of risk.  Instead, the endpoints from various toxicity studies were adjusted to determine the numeric Level of Concern (LOC) for each taxa for both acute and chronic effects.  The adjustment factor is the same as the one used with the RQ method, e.g. 0.5 * LC50 or EC50 for acute effects, and 0.05 * LC50 or EC50 for acute endangered species risks.  The chronic LOC needs no adjustment.  The modeling results provided the percentage of days concentrations were exceeded for a range encompassing the numeric LOCs.  When a specific LOC was not listed in the modeling output tables, the percent days exceeded for the LOC was interpolated from the closest numbers above and below the specific LOC.  The percentage of days was then multiplied by 365 to provide the number of days per year the LOC is exceeded.

Values for LOC percent days exceeded were interpolated where necessary, using Tables 5 through 10 and 23 through 28 of the Environmental Modeling Chapter.  If the number of days an LOC is exceeded is greater than the number of days used to determine the endpoint in toxicity testing, risk is assumed.  This assumes that the number of days exceeded are consecutive, a conservative but not impossible assumption.

In the following tables, “risk” indicates that the LOC was exceeded for more than 2 days per year for freshwater invertebrates and for more than 4 days per year for all other organisms.  Where there is risk, the number of days the LOC was exceeded is indicated in bold type.

Tables 9A-L: Number of Days per Year Levels of Concern are Exceeded by the Once-Through Cooling Use of Chlorine Dioxide/Sodium Chlorite

A.  Continuous feed, 800 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[262.44 days]

{363.54 days}

2.53 ppm

[340.74 days]

{365 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[365 days]

{365 days}

0.001 ppm

[365 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[246.74 days]

{359.16 days}

3.75 ppm

[325.86 days]

{365 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[286.45 days]

{365 days}

1.07 ppm

[358.54 days]

{365 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[365 days]

{365 days}

0.029 ppm

[365 days]

{365 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[355.49 days]

{365 days}

0.62 ppm (NOEC)

[363.70 days]

{365 days}

The average scenario of a continuous feed of 800 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of a continuous feed of 800 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

B. Continuous feed, 800 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[170.82 days]

{363.54 days}

2.53 ppm

[296.74 days]

{365 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[365 days]

{365 days}

0.001 ppm

[365 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[147.46 days]

{359.16 days}

3.75 ppm

[273.16 days]

{365 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[216.34 days]

{365 days}

1.07 ppm

[324.96 days]

{365 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[355.88 days]

{365 days}

0.029 ppm

[365 days]

{365 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[320.12 days]

{365 days}

0.62 ppm (NOEC)

[335.35 days]

{365 days}

The average scenario of a continuous feed of 800 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of a continuous feed of 800 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

C. Intermittent feed, 800 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[1.11 days]

{3.46 days}

2.53 ppm

[139.49 days]

{223 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[356.19 days]

{365 days}

0.001 ppm

[365 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[0.35 days]

{1.25 days}

3.75 ppm

[89.53 days]

{147.50 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[9.34 days]

{21.77 days}

1.07 ppm

[199.29 days]

{313.35 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[259.52 days]

{362.81 days}

0.029 ppm

[338.65 days]

{365 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[189.05 days]

{297.88 days}

0.62 ppm (NOEC)

[220.75 days]

{341.31 days}

The average scenario of an intermittent feed of 800 ppm in a high flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of an intermittent feed of 800 ppm in a high flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

D. Intermittent feed, 800 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[1.73 days]

{18.54 days}

2.53 ppm

[73.88 days]

{230.80 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[320.76 days]

{365 days}

0.001 ppm

[364.64 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[0.89 days]

{10.11 days}

3.75 ppm

[47.09 days]

{168.96 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[6.54 days]

{53.54 days}

1.07 ppm

[105.97 days]

{304.80 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[165.71 days]

{359.16 days}

0.029 ppm

[293.61 days]

{365 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[100.48 days]

{292.13 days}

0.62 ppm (NOEC)

[120.43 days]

{329.19 days}

The average scenario of an intermittent feed of 800 ppm in a low flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of an intermittent feed of 800 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

E.  Intermittent feed, 25 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[9.78x10-7 days]

{5.40x10-6 days}

2.53 ppm

[1.03 days]

{3.05 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[249.07 days]

{343.39 days}

0.001 ppm

[329.96 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[1.24x10-7 days]

{7.01x10-7 days}

3.75 ppm

[0.53 days]

{1.58 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[7.49x10-5 days]

{3.88x10-4 days}

1.07 ppm

[1.63 days]

{4.80 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[12.15 days]

{27.23 days}

0.029 ppm

[204.15 days]

{293.61 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[1.52 days]

{4.50 days}

0.62 ppm (NOEC)

[2.91 days]

{7.65 days}

The average scenario of an intermittent feed of 25 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater invertebrates and endangered and non-endangered marine/estuarine invertebrates.  The worst-case scenario of an intermittent feed of 25 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

F. Intermittent feed, 25 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[4.42x10-5 days]

{5.29x10-4 days}

2.53 ppm

[1.34 days]

{13.82 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[163.81 days]

{341.49 days}

0.001 ppm

[267.55 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[5.11x10-6 days]

{6.13x10-5 days}

3.75 ppm

[0.71 days]

{7.33 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[2.55x10-3 days]

{0.03 days}

1.07 ppm

[2.09 days]

{21.58 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[8.03 days]

{61.32 days}

0.029 ppm

[125.34 days]

{292.38 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[1.96 days]

{20.25 days}

0.62 ppm (NOEC)

[2.92 days]

{27.80 days}

The average scenario of an intermittent feed of 25 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater invertebrates and endangered and non-endangered marine/estuarine invertebrates.  The worst-case scenario of an intermittent feed of 25 ppm in a low flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

G. Continuous feed, 2.0 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[9.89x10-3 days]

{0.04 days}

2.53 ppm

[47.99 days]

{77.19 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[324.83 days]

{364.86 days}

0.001 ppm

[364.64 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[2.03x10-3 days]

{9.75x10-3 days}

3.75 ppm

[25.71 days]

{42.54 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[0.23 days]

{0.83 days}

1.07 ppm

[74.64 days]

{118.66 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[165.35 days]

{275.21 days}

0.029 ppm

[303.90 days]

{364.52 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[70.08 days]

{111.56 days}

0.62 ppm (NOEC)

[91.07 days]

{145.89 days}

The average scenario of a continuous feed of 2.0 ppm in a high flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of a continuous feed of 2.0 ppm in a high flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

H. Continuous feed, 2.0 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[0.10 days]

{1.19 days}

2.53 ppm

[22.60 days]

{98.70 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[259.22 days]

{364.57 days}

0.001 ppm

[348.58 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[0.03 days]

{0.41 days}

3.75 ppm

[12.82 days]

{62.60 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[0.68 days]

{7.74 days}

1.07 ppm

[34.31 days]

{141.90 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[78.84 days]

{264.26 days}

0.029 ppm

[229.80 days]

{363.55 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[32.30 days]

{134.50 days}

0.62 ppm (NOEC)

[42.03 days]

{165.88 days}

The average scenario of a continuous feed of 2.0 ppm in a low flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.  The worst-case scenario of a continuous feed of 2.0 ppm in a low flow facility results in acute risk to endangered freshwater fish, endangered and non-endangered freshwater invertebrates, endangered marine/estuarine fish, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

I. Continuous feed, 0.10 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[negligible]

{negligible}

2.53 ppm

[0.06 days]

{0.24 days}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[200.47 days]

{310.07 days}

0.001 ppm

[294.19 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[negligible]

{negligible}

3.75 ppm

[0.03 days]

{0.12 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[6.55x10-7 days]

{3.96x10-6 days}

1.07 ppm

[0.09 days]

{0.37 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[1.28 days]

{3.94 days}

0.029 ppm

[143.21 days]

{225.21 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[0.09 days]

{0.35 days}

0.62 ppm (NOEC)

[0.23 days]

{0.79 days}

The average scenario of a continuous feed of 0.10 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater invertebrates and endangered marine/estuarine invertebrates.  The worst-case scenario of a continuous feed of 0.10 ppm in a high flow facility results in acute risk to endangered and non-endangered freshwater invertebrates and endangered marine/estuarine invertebrates.

J. Continuous feed, 0.10 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[1.53x10-7 days]

{1.84x10-6 days}

2.53 ppm

[0.25 days]

[2.92 days]

FW invert.

48hEC50 = 0.027

0.0135 ppm

[109.28 days]

{304.56 days}

0.001 ppm

[228.86 days]

{365 days}

ME fish

96hLC50 = 75

37.5 ppm

[1.10x10-8 days]

{1.20x10-7 days}

3.75 ppm

[0.13 days]

{1.52 days}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[3.20x10-5 days]

{3.85x10-4 days}

1.07 ppm

[0.39 days]

{4.60 days}

ME invert.

96hLC50 = 0.576

0.288 ppm

[1.88 days]

{19.97 days}

0.029 ppm

[77.42 days]

{234.40 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[0.37 days]

{4.31 days}

0.62 ppm (NOEC)

[0.59 days]

{6.67 days}

The average scenario of a continuous feed of 0.10 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater invertebrates and endangered marine/estuarine invertebrates.  The worst-case scenario of a continuous feed of 0.10 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater invertebrates, endangered and non-endangered marine/estuarine invertebrates and endangered and non-endangered aquatic plants.

K. Intermittent feed, 0.10 ppm, high flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[negligible]

{negligible}

2.53 ppm

[negligible]

{negligible}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[0.09 days]

{0.34 days}

0.001 ppm

[16.06 days]

{34.31 days}

ME fish

96hLC50 = 75

37.5 ppm

[negligible]

{negligible}

3.75 ppm

[negligible]

{negligible}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[negligible]

{negligible}

1.07 ppm

[negligible]

{negligible}

ME invert.

96hLC50 = 0.576

0.288 ppm

[negligible]

{1.83x10-8 days}

0.029 ppm

[0.05 days]

{0.22 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[negligible]

{negligible}

0.62 ppm (NOEC)

[negligible]

{negligible}

The average scenario of an intermittent feed of 0.10 ppm in a high flow facility results in acute risk to endangered freshwater invertebrates.  The worst-case scenario of an intermittent feed of 0.10 ppm in a high flow facility results in acute risk to endangered freshwater invertebrates.

L. Intermittent feed, 0.10 ppm, low flow scenario

Levels of Concern (LOC)

Taxa

Endpoint value from study (ppm)

Acute Nontarget (0.5*LC50) [average # of days exceeded]

{worst case # of days exceeded}

Acute Endangered Species (0.05*LC50) [average # of days exceeded]

{worst case # of days exceeded}

FW fish

96hLC50 = 50.6

25.3 ppm

[0 days]

{0 days}

2.53 ppm

[negligible]

{negligible}

FW invert.

48hEC50 = 0.027

0.0135 ppm

[0.37 days]

{4.26 days}

0.001 ppm

[9.82 days]

{70.08 days}

ME fish

96hLC50 = 75

37.5 ppm

[0 days]

{0 days}

3.75 ppm

[negligible]

{negligible}

ME mollusk

96hEC50 = 21.4

10.7 ppm

[0 days]

{0 days}

1.07 ppm

[negligible]

{negligible}

ME invert.

96hLC50 = 0.576

0.288 ppm

[8.40x10-8 days]

{1.01x10-6 days}

0.029 ppm

[0.24 days]

{2.74 days}

Aquatic plant

96hEC50 = 1.32

1.32 ppm (LC50)

[negligible]

{negligible}

0.62 ppm (NOEC)

[negligible]

{negligible}

The average scenario of an intermittent feed of 0.10 ppm in a low flow facility results in acute risk to endangered freshwater invertebrates.  The worst-case scenario of an intermittent feed of 0.10 ppm in a low flow facility results in acute risk to endangered and non-endangered freshwater invertebrates.

3.  Environmental Risk Assessment

a.  Terrestrial Organisms

No model is available to estimate exposure and risk to birds and mammals from discharge of once-through cooling system effluents into surface waters.  The rapid degradation of the chemicals, coupled with the generally low toxicity of chlorine dioxide and sodium chlorite to birds and mammals, make risk to these organisms unlikely.  The very limited data available to assess the phytotoxicity of chlorine dioxide/sodium chlorite make it difficult to determine the risk to terrestrial/semi-aquatic plants.

b.  Aquatic Organisms

Acute risk to aquatic organisms may occur from the use of chlorine dioxide/sodium chlorite in once-through cooling towers based on the screening level assessment conducted.  At the highest doses, the model shows risk to freshwater and marine/estuarine fish and invertebrates and aquatic plants, and at the lowest doses the model shows risk only to freshwater invertebrates.  See Table 9 A-L for details.

Chronic risk to aquatic organisms cannot be assessed at this time due to the lack of chronic toxicity endpoints for fish and aquatic invertebrates.  When the required aquatic chronic toxicity testing described above is submitted, chronic risk to these organisms will be assessed.

4.  Listed Species

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2), requires all federal agencies to consult with the National Marine Fisheries Service (NMFS) for marine and anadromous listed species, or the United States Fish and Wildlife Services (FWS) for listed wildlife and freshwater organisms, if they are proposing an “action” that may affect listed species or their designated habitat.  Each federal agency is required under the Act to insure that any action they authorize, fund, or carry out is not likely to jeopardize the continued existence of a listed species or result in the destruction or adverse modification of designated critical habitat.  To jeopardize the continued existence of a listed species means “to engage in an action that reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of the species.” 50 C.F.R. § 402.02.

To facilitate compliance with the requirements of the Endangered Species Act subsection (a)(2) the Environmental Protection Agency, Office of Pesticide Programs has established procedures to evaluate whether a proposed registration action may directly or indirectly reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of any listed species (U.S. EPA, 2004).  After the Agency’s screening-level risk assessment is performed, if any of the Agency’s Listed Species LOC Criteria are exceeded for either direct or indirect effects, a determination is made to identify if any listed or candidate species may co-occur in the area of the proposed pesticide use.  If determined that listed or candidate species may be present in the proposed use areas, further biological assessment is undertaken.  The extent to which listed species may be at risk then determines the need for the development of a more comprehensive consultation package as required by the Endangered Species Act.

Acute risks to listed birds and mammals are not anticipated from the use of chlorine dioxide and sodium chlorite products due to low exposure and low toxicity.  The screening level model used in this assessment indicates that there may be acute risks to listed aquatic organisms from the once through cooling tower use of chlorine dioxide/sodium chlorite.  Further, potential indirect effects on any species dependent upon a species that experiences effects from use of chlorine dioxide/sodium chlorite cannot be precluded based on the screening level ecological risk assessment.  These findings are based solely on EPA’s screening level assessment and do not constitute “may effect” findings under the Endangered Species Act.

Chronic risks to listed aquatic organisms cannot be assessed at this time; this risk will be assessed when required chronic toxicity data are submitted to and evaluated by the Agency.

REFERENCES

ACC 245697.  Sousa, J.V.  1981.  Acute Toxicity of Sodium Chlorite to Bluegill (Lepomis macrochirus).  Unpublished Data.  Conducted by EG&G, Bionomics for Olin Chemicals.

ACC 252854.  1984.  96-Hour LC50 in Juvenile Rainbow Trout.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 252854.  1983.  96-Hour LC50 in Bluegill Perch.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 252854.  1984.  48-Hour LC50 in Daphnia magna.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 252854.  1984.  Avian Dietary LC50 in Bob White Quail.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 252854.  1983.  Avian Dietary LC50 in Mallard Ducks.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 252854.  1984.  Avian Single-Dose Oral LD50 in Bobwhite Quail.  Unpublished Data.  Conducted by Microbiological and Biochemical Assay Laboratories for Magna Corporation.

ACC 253378. Fletcher, D.  1984.  8-Day Dietary LC50 Study with Sodium Chlorite in Mallard Ducklings.  Unpublished Data.  Conducted by Bio-Life Associates, Ltd. for Calgon Corporation.

ACC 253378. Fletcher, D.  1984.  8-Day Dietary LC50 Study with Sodium Chlorite in Bobwhite Quail.  Unpublished Data.  Conducted by Bio-Life Associates, Ltd. for Calgon Corporation.

ACC 253378. Fletcher, D.  1984.  Acute Oral Toxicity Study with Sodium Chlorite in Bobwhite Quail.  Unpublished Data.  Conducted by Bio-Life Associates, Ltd. for Calgon Corporation.

ACC 253379.  Sousa, J.V. and D.C. Surprenant.  1984.  Acute Toxicity of AC-66 to Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted by Springborn Bionomics, Inc. for Calgon Corporation.

ACC 253743.  McMillen, C.  1984.  Static Bioassay on Sodium Chlorite to Rainbow Trout and Bluegill Sunfish.  Unpublished Data.  Conducted by Environmental Research Group, Inc. for Rio Linda Chemical Company, Inc.

ACC 254176.  Beavers, 1984.  An Acute Oral Toxicity Study in the Mallard with Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for TR America Chemicals, Inc.

ACC 254177.  Beavers, 1984.  An Acute Oral Toxicity Study in the Bobwhite with Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for TR America Chemicals, Inc.

ACC 254178.  Beavers, 1984.  A Dietary LC50 Study in the Mallard Duck with Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for TR America Chemicals, Inc.

ACC 254179.  Beavers, 1984.  A Dietary LC50 Study in the Bobwhite with Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for TR America Chemicals, Inc.

ACC 254180.  Larkin, J.  1984.  The Acute Toxicity of Sodium Chlorite to Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted by Biospherics Incorporated for TR America Chemicals, Inc.

ACC 254181.  Larkin, J.  1984.  The Acute Toxicity of Sodium Chlorite to Bluegill Sunfish (Lepomis macrochirus).  Unpublished Data.  Conducted by Biospherics Incorporated for TR America Chemicals, Inc.

ACC 254182.  Larkin, J.  1984.  Acute Toxicity of Sodium Chlorite to Daphnia magna Strauss.  Unpublished Data.  Conducted by Biospherics Incorporated for TR America Chemicals, Inc.

ACC 257341. Robaidek and Johnson, 1985. Avian Single-dose Oral LD50: Bob White Quail (Colinus virginianus).  Unpublished Data.   Conducted by Hazleton Laboratories America, Inc. for Rio Linda Chemical Company.

ACC 259373.  Robaidek, E.  1985.  Avian Single-Dose Oral LD50 Bobwhite Quail.  Unpublished Data.  Conducted by Hazleton Laboratories America, Inc. for Degussa Corporation.

ACC 69809.  1978.  Acute Toxicity of Sodium Chlorite to Bluegill (Lepomis macrochirus).  Unpublished Data.  Conducted by EG&G, Bionomics, Aquatic Toxicology Laboratory for Olin Chemicals.

ACC 69810.  1979.  Acute Toxicity of Sodium Chlorite to Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted by EG&G, Bionomics, Aquatic Toxicology Laboratory for Olin Chemicals.

MRID 130649.  Fink, R.  1977.  Eight-day Dietary LC50 - Bobwhite Quail – Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for Olin Corporation.

MRID 130650.  Fink, R.  1977.  Eight-day Dietary LC50 – Mallard Duck – Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd. for Olin Corporation.

MRID 131350.  Vilkas, A.G.  1976.  Acute Toxicity of Textone to the Water Flea Daphnia magna Strauss.  Unpublished Data.  Conducted by Aquatic Environmental Sciences for Olin Corporation.

MRID 131351.  Sleight III, B.H.  1971.  Acute Toxicity of Sodium Chlorite to Bluegill (Lepomis macrochirus) and Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted by Bionomics, Inc.

MRID 141149.  Hoberg, J.R. and D.C. Surprenant.  1984.  Acute Toxicity of AC-66 to Daphnids (Daphnia magna).  Unpublished Data.  Conducted by Springborn Bionomics, Inc. for Calgon Corporation.

MRID 146162.  Barrows, 1984.  The Acute Toxicity of Sodium Chlorite Technical to the Water Flea, Daphnia magna in a Static Test System.  Unpublished Data.  Conducted by Biospherics Incorporated for Degussa Corporation.

MRID 31610.  Fletcher, D. 1973.  Acute Oral Toxicity Study with Sodium Chlorite in Bobwhite Quail.  Unpublished Data.  Conducted by Industrial BIO-TEST Laboratories, Inc. for Olin Corporation.

MRID 41843101.  Backus, P., K.E. Crosby and L.J. Powers.  1990.  Effect of Sodium Chlorite on Vegetative Vigor of Plants (Tier I).  Unpublished Data.  Conducted by Ricerca, Inc. for the Sodium Chlorite Reregistration Task Force.

MRID 41843102.  Backus, P., K.E. Crosby and L.J. Powers.  1990.  Effect of Sodium Chlorite on Seed Germination/Seedling Emergence (Tier I).  Unpublished Data.  Conducted by Ricerca, Inc. for the Sodium Chlorite Reregistration Task Force.

MRID 41880403.  Ward, T.J. and R.L. Boeri.  1991.  Static Acute Toxicity of Sodium Chlorite to the Freshwater Alga, Selenastrum capricornutum.  Unpublished Data.  Conducted by EnviroSystems Division, Resource Analysis, Inc. for the Sodium Chlorite Reregistration Task Force.

MRID 43259401.  Yurk, J.J. and M.A. Overman.  1994.  Acute Toxicity of Sodium Chlorite to the Sheepshead Minnow (Cyprinodon variegatus).  Conducted by Environmental Science & Engineering, Inc. for the Chemical Manufacturers Association.

MRID 43259402.  Yurk, J.J. and M.A. Overman.  1994.  Acute Toxicity of Sodium Chlorite to Mysid Shrimp.  Conducted by Environmental Science & Engineering, Inc. for the Chemical Manufacturers Association.

MRID 43259403.  Yurk, J.J. and M.A. Overman.  1994.  Effect of Sodium Chlorite on New Shell Growth in Eastern Oyster (Crassostrea virginica).  Conducted by Environmental Science & Engineering, Inc. for the Chemical Manufacturers Association.

MRID 94068005.  Johnson, G.  1984.  Avian Dietary LC50 Bobwhite Quail (Colinus virginianus).  Unpublished Data.  Conducted by Hazleton Laboratories America, Inc. for Degussa Corporation.

MRID 94068006.  Sousa and Surprenant, 1984.  Acute Toxicity of A-66 (Technical Sodium Chlorite) to Bluegill (Lepomis macrochirus).  Unpublished Data.  Conducted by Springborn Binomics, Inc for Calgon Corporation.

MRID 94068007.  Barrows, B. 1984.  The Acute Toxicity of Sodium Chlorite Technical to the Rainbow Trout, Salmo gairdneri, in a Static Test System.  Unpublished Data.  Conducted by Biospherics Incorporated for Degussa Corporation.

MRID 94068008.  Johnson, G.  1984.  Avian Dietary LC50 Mallard Duck (Anas platyrhynchos).  Unpublished Data.  Conducted by Hazleton Laboratories America, Inc. for Degussa Corporation.

MRID 94068009.  Nachrord, S.  1984.  Daphnia LC50 Bioassay.  Unpublished Data.  Conducted by Anater Tesconi Circle for Rio Linda Chemical Company, Inc.

USEPA.  2004.  Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs U.S. Environmental Protection Agency - Endangered and Threatened Species Effects Determinations, 1/23/04.

TGAI = technical grade active ingredient

TEP = typical end-use product

 EC50=Median Effective Concentration

Page  PAGE  28  of   NUMPAGES  32


[Federal Register Volume 78, Number 18 (Monday, January 28, 2013)]
[Notices]
[Page 5797]
[FR Doc No: 2013-01612]

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DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Docket No. Rm11-12-000]

Availability of e-Tag Information to Commission Staff; Notice
Specifying webRegistry Code

    In Order No. 771,\1\ the Federal Energy Regulatory Commission
amended its regulations to grant the Commission access, on a non-public
and ongoing basis, to the complete electronic tags (e-Tags) used to
schedule the transmission of electric power interchange transactions in
wholesale markets. Order No. 771 requires e-Tag Authors (through their
Agent Service) and Balancing Authorities (through their Authority
Service), beginning March 15, 2013, to take appropriate steps to ensure
Commission access to the e-Tags covered by this Final Rule by
designating the Commission as an addressee on the e-Tags.
---------------------------------------------------------------------------

    \1\ Availability of E-Tag Information to Commission Staff, 77 FR
76367 (Dec. 28. 2012), 141 FERC ] 61,235 (2012) (FR).
---------------------------------------------------------------------------

    In Order No. 771, the Commission stated that, ``following issuance
of this Final Rule and the Commission's registration in the OATI
webRegistry, the Commission will issue a notice specifying which entity
code should be used to ensure that the Commission is an addressee on
the e-Tag'' (fn. 103). Although the Commission has not completed the
registration process, the Commission intends to facilitate the
continued development of compliance software and processes by issuing
this notice to specify that ``FERC'' will be the likely entity and tag
codes registered in the Purchasing-Seller Entity section of OATI
webRegistry. This code should be used to designate the Commission as an
addressee to comply with 18 CFR 366.2(d) of the Commissions
regulations.
    As stated in footnote 103 of the Final Rule, the Commission will
issue a further notice at the completion of the registration process.

    Dated: January 18, 2013.
Kimberly D. Bose,
Secretary.
[FR Doc. 2013-01612 Filed 1-25-13; 8:45 am]
BILLING CODE 6717-01-P


[Federal Register Volume 87, Number 248 (Wednesday, December 28, 2022)]
[Notices]
[Pages 79932-79935]
[FR Doc No: 2022-28242]

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DEPARTMENT OF TRANSPORTATION

Federal Motor Carrier Safety Administration

[Docket No. FMCSA-2022-0122]

Entry-Level Driver Training: State of Alaska; Application for
Exemption

AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT.

ACTION: Notice of final disposition; grant of application for
exemption.

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SUMMARY: FMCSA announces its decision to grant a two-year exemption to
the State of Alaska from the limitations imposed by the commercial
driver's license (CDL) regulations on the State's ability to issue
restricted CDLs. The exemption allows the State to waive specified
portions of the CDL skills test for drivers in 14 defined geographical
areas that lack infrastructure to allow completion of the full skills
test. Drivers who receive a restricted CDL under the provisions of this
exemption are also

exempt from the Entry-Level Driver Training (ELDT) regulations. FMCSA
concludes that granting the exemption, subject to the terms and
conditions set forth below, is likely to achieve a level of safety
equivalent to or greater than the level of safety that would be
obtained absent the exemption.

DATES: The exemption is effective from December 28, 2022 through
December 30, 2024.

FOR FURTHER INFORMATION CONTACT: Mr. Richard Clemente, FMCSA Driver and
Carrier Operations Division; Office of Carrier, Driver and Vehicle
Safety Standards;<PHONE_NUMBER>; [email protected]. If you have
questions on viewing or submitting material to the docket, contact
Docket Services at<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

I. Public Participation

Viewing Comments and Documents

    To view comments, go to www.regulations.gov, insert the docket
number ``FMCSA-2022-0122'' in the keyword box, and click ``Search.''
Next, sort the results by ``Posted (Newer-Older),'' choose the first
notice listed, and click ``View Related Comments.''
    To view documents mentioned in this notice as being available in
the docket, go to www.regulations.gov, insert the docket number
``FMCSA-2022-0122'' in the keyword box, click ``Search,'' and choose
the document to review.
    If you do not have access to the internet, you may view the docket
by visiting Dockets Operations in Room W12-140 on the ground floor of
the DOT West Building, 1200 New Jersey Avenue SE, Washington, DC 20590,
between 9 a.m. and 5 p.m., ET, Monday through Friday, except Federal
holidays. To be sure someone is there to help you, please call (202)
366-9317 or<PHONE_NUMBER> before visiting Dockets Operations.

II. Legal Basis

    FMCSA has authority under 49 U.S.C. 31136(e) and 31315(b) to grant
exemptions from certain Federal Motor Carrier Safety Regulations
(FMCSRs). FMCSA must publish a notice of each exemption request in the
Federal Register (49 CFR 381.315(a)). The Agency must provide the
public an opportunity to inspect the information relevant to the
application, including any safety analyses that have been conducted.
The Agency must also provide an opportunity for public comment on the
request.
    The Agency reviews safety analyses and public comments submitted,
and determines whether granting the exemption would likely achieve a
level of safety equivalent to, or greater than, the level that would be
achieved by the current regulation (49 CFR 381.305(a)). The decision of
the Agency must be published in the Federal Register (49 CFR
381.315(b)) with the reasons for denying or granting the application
and, if granted, the name of the person or class of persons receiving
the exemption, and the regulatory provision from which the exemption is
granted. The notice must also specify the effective period (up to 5
years) and explain the terms and conditions of the exemption. The
exemption may be renewed (49 CFR 381.300(b)).

III. Background

Current Regulatory Requirements

    Under 49 CFR 383.3(e) the State of Alaska may waive certain
knowledge and skills tests requirements and issue restricted CDLs,
subject to certain conditions. To be eligible for a restricted CDL
under 49 CFR 383.3(e), which is not valid outside Alaska, drivers must
operate exclusively over roads that are not connected to the State
highway system and are not connected to any highway or vehicular way
with an average daily traffic volume greater than 499 (Sec.
383.3(e)(2)). The Federal Highway Administration, FMCSA's predecessor
agency, set the daily traffic volume limit at 499 in 1996 (54 FR
33230).
    The ELDT regulations, implemented on February 7, 2022, and set
forth in 49 CFR 380, subparts F and G, establish minimum training
standards for individuals applying for certain CDLs and defined
curriculum standards for theory and behind-the-wheel (BTW) training.
The ELDT curriculum in 49 CFR part 380, Appendix A, Section A3.1,
requires Class A CDL applicants to demonstrate proficiency in proper
techniques for initiating vehicle movement, executing left and right
turns, changing lanes, navigating curves at speed, entry and exit on
the interstate or controlled access highway, and stopping the vehicle
in a controlled manner. Under 49 CFR 380.603(a)(2), drivers issued a
restricted CDL by the State of Alaska are exempt from the ELDT
requirements.

Applicant's Request

    The State of Alaska (Alaska) requested an exemption from the ELDT
curriculum in 49 CFR part 380, appendix A, section A3.1, which requires
Class A CDL applicants to demonstrate proficiency in proper techniques
for initiating vehicle movement, executing left and right turns,
changing lanes, navigating curves at speed, entry and exit on the
interstate or controlled access highway, and stopping the vehicle in a
controlled manner. Alaska stated that the exemption is necessary
because the current threshold for determining whether a driver is
eligible for a restricted CDL, set forth in 49 CFR 383.3(e), is
outdated and excludes some remote communities that have unpaved, two-
lane roads not connected to the National Highway System. Consequently,
these areas ``do not have the infrastructure or driving scenarios'' to
complete the portions of ELDT that require the driver-trainee to
demonstrate proficiency in vehicle control maneuvers on the interstate
or controlled access highway. Alaska asserts that, because CDL
applicants from these remote communities are not currently eligible to
receive a restricted CDL, and thus be exempt from ELDT, they would be
required to fly into larger cities and incur travel costs and lost
wages to complete the BTW training requirements related to controlled
access highways.
    In its request for exemption, Alaska asserts ``that the new
regulations define off-highway licenses under 49 CFR 383.3(e)(2)(ii) as
average daily traffic count of 499 or less, which excludes many remote
Alaska communities, so their commercial drivers are now subject to the
new ELDT requirements.'' Alaska describes this result as having
``devastating impact on rural Alaska's movement of produce,
prescriptions, people, and other goods.''

IV. Method To Ensure an Equivalent or Greater Level of Safety

    The Agency believes permitting the issuance of restricted CDLs to
drivers operating a commercial motor vehicle (CMV) in 14 geographically
remote communities identified in Section VI of this notice will achieve
a level of safety that is equivalent to, or greater than, the level of
safety achieved without the exemption (49 CFR 381.305(a)).

V. Public Comments

    On July 6, 2022, FMCSA published notice of the State of Alaska
application and requested public comment (87 FR 40334). The Agency
received 30 comments, 24 of which supported the exemption. Those filing
in support included Alaskan driver training schools, Alaskan cities/
boroughs, the Alaska Department of Labor and Workforce Development, the
Alaska Trucking Association, motor carriers, and several individuals.
Five commenters opposed the exemption, including the Owner-Operator
Independent Driver's Association (OOIDA), the AFL-CIO/Transportation

Trades Division (AFL-CIO/TTD) and three other individuals. One
commenter filed neither for nor against the exemption request.
    The Prince of Wales Vocational/Technical School's comments in
support of the exemption included points that were echoed by others,
stating that the ELDT regulations ``inadvertently will have a
devastating effect on most of the State of Alaska by requiring road
testing on roads that simply do not exist in most of the State. The
shortage of and retention of CDL drivers will be negatively affected by
this regulation.''
    The Petersburgh Borough added support for the exemption request in
their filed comments, stating that ``the costs for regulatory compliant
CDL training in combination with the inconvenience of having to spend
extended time in another community to receive the training are
egregious hardships on employers and the employees seeking to better
themselves through attainment of a CDL. By allowing us to continue
local rural training and testing, you would show Alaskans that you
understand and appreciate that Alaska is a unique landscape.'' Another
commenter stated, ``Traveling to a community where training and testing
are available is cost prohibitive as it could cost thousands of
dollars.''
    OOIDA opposed the exemption, citing its participation as an
industry stakeholder on the ELDT Negotiated Rulemaking Committee when
the ``framework'' of the ELDT rule was agreed upon and commented that
these minimum requirements must be strengthened, not waived. The AFL-
CIO/TTD also opposed the exemption, stating that allowing Alaska, or
any locality within the State, to move forward with an exemption from
such basic ELDT requirements would undermine the intent of the ELDT
program to prepare commercial drivers to respond safely in situations
that they will encounter while driving.

VI. FMCSA Safety Analysis and Decision

    FMCSA has evaluated the State of Alaska's application for exemption
and the public comments and based on its analysis, decided to grant an
exemption from 49 CFR 383.3(e)(2) in lieu of granting an exemption from
the ELDT curriculum in 49 CFR part 380, Appendix A, Section A3.1, as
requested by the State. If FMCSA were to grant the relief requested,
the affected drivers would be eligible to obtain an unrestricted CDL
and operate in any location in the U.S., even though they did not
receive the requisite training to safely operate a CMV when entering
and exiting an interstate or controlled access highway designed for
high-speed vehicular traffic, navigating curves at speed, changing
lanes, and stopping the CMV in a controlled manner. FMCSA concludes
that this outcome would not result in a level of safety equivalent to,
or greater than the level achieved without the requested exemption.
    As noted above, Alaska currently has the discretion, under 49 CFR
383.3(e), to waive certain CDL knowledge and skills tests requirements
and issue a restricted CDL, valid only in Alaska. Currently, drivers
who apply for a restricted CDL are exempt from the ELDT regulations,
pursuant to 49 CFR 380.603(a)(2). However, under Sec.  383.3(e)(2), to
be eligible for a restricted CDL issued under Sec.  383.3(e), which is
not valid outside the State, drivers must operate exclusively over
roads that are not connected to the state highway system and are not
connected to any highway or vehicular way with an average daily traffic
volume greater than 499. This standard was adopted in 1989 by the
Federal Highway Administration, FMCSA's predecessor agency. As the
State pointed out in its exemption request, this standard excludes many
remote Alaska communities, requiring CDL applicants in these areas to
comply with FMCSA's ELDT requirements.
    The Agency believes that granting an exemption allowing Alaska to
issue restricted CDLs, subject to the terms and conditions set forth
below, will achieve a level of safety that is equivalent to, or greater
than, the level of safety achieved without the exemption (49 CFR
381.305(a)). The exemption applies only to CDL applicants who reside in
one of the named remote geographical areas identified below and who
operate only within those defined areas. In addition, the State may
waive only specified elements of the skills test affected by the lack
of infrastructure in the identified communities. Individuals applying
for a restricted CDL covered by this exemption are exempt from ELDT in
accordance with 49 CFR 380.603(a)(2).

VII. Exemption Decision

A. Grant of Exemption

    FMCSA grants an exemption from 49 CFR 383.3(e)(2) for a period of
two years subject to the terms and conditions of this decision.

B. Applicability

    The State of Alaska may issue CDLs under this exemption only to
drivers who reside in the following communities or areas: \1\
---------------------------------------------------------------------------

    \1\ The locales were identified by the State of Alaska's
Department of Administration, Division of Motor Vehicles (DMV) and
independently verified by FMCSA as lacking the infrastructure for
CDL applicants to perform the skills required by 49 CFR
383.113(c)(4) and (c)(5). FMCSA notes that the DMV initially
identified 15 affected locales, but FMCSA determined that one of the
15 communities operates on major connected thoroughfares and the
distances involved are not dissimilar to that experienced by many
rural communities in the western United States. The DMV's letter
identifying the affected areas is available in the docket of this
Notice and can be accessed at Regulations.gov.
---------------------------------------------------------------------------

(1) Bethel--within the local Bethel community road network
(2) Prince of Wales Island
(3) Haines--within the Haines community, and along the Haines Highway
corridor, ending at the Canadian Border
(4) Ketchikan--within the Ketchikan community and the airport area on
the neighboring Annette Island
(5) King Salmon--within the local King Salmon community road network
(6) Kodiak Island
(7) Kotzebue--within the local Kotzebue community road network
(8) Nome--within the local Nome community road network
(9) Mitkof Island (Petersburg)
(10) Sitka--within the local Sitka community road network
(11) Skagway--within the Skagway community and along the Klondike
Highway corridor, ending at the Canadian Border
(12) Unalaska Island
(13) Utqiavik--within the Utqiavik community road network
(14) Wrangell Island

C. Terms and Conditions

    The State of Alaska and drivers operating under this exemption are
subject to the following terms and conditions:
    (1) The State of Alaska must comply with 49 CFR 383.133(b) and
383.135(a) of the knowledge tests standards for testing procedures and
methods set forth in 49 CFR part 383, subpart H, and must continue to
administer knowledge tests that fulfill the content requirements of
subpart G.
    (2) The State of Alaska may waive only the following portions of
the CDL skills test, as set forth in 49 CFR 383.113(c), that cannot be
performed due to infrastructure limitations in the identified
communities or areas:
     ability to adjust speed to the configuration and condition
of the roadway, weather and visibility conditions, traffic conditions,
and motor vehicle, cargo, and driver conditions (Sec.  383.113(c)(3));
and

     ability to choose a safe gap for changing lanes, passing
other vehicles, as well as for crossing or entering traffic (Sec.
383.113(c)(4));
    (3) Drivers applying for a CDL to be issued under this exemption
must reside in one of the 14 geographical areas identified in Section
VII. B of this Notice;
    (4) Drivers issued a restricted CDL under this exemption may
operate only within the 14 geographical areas identified in Section
VII. B of this Notice; and
    (5) The drivers must comply with all other applicable Federal Motor
Carrier Safety Regulations (49 CFR part 350-399).
    (6) The State of Alaska must include notice on a restricted CDL
issued pursuant to this exemption of the geographical area(s) in which
the CDL holder may operate a CMV.

D. Preemption

    In accordance with 49 U.S.C. 31315(d), as implemented by 49 CFR
381.60, during the period this exemption is in effect, no State shall
enforce any law or regulation that conflicts with or is inconsistent
with this exemption with respect to a person operating under the
exemption.

E. Notification to FMCSA

    The State of Alaska must provide to FMCSA, upon request, a list of
all drivers issued CDLs under this exemption.

F. Termination

    FMCSA does not believe that drivers covered by this exemption will
experience any deterioration of their safety record.
    The Agency will, however, rescind the exemption if: (1) the State
of Alaska or drivers operating under the exemption fail to comply with
the terms and conditions of the exemption; (2) the exemption results in
a lower level of safety than was maintained before it was granted; or
(3) continuation of the exemption would not be consistent with the
goals and objective of 49 U.S.C. 31136(e) and 31315(b).

Robin Hutcheson,
Administrator.
[FR Doc. 2022-28242 Filed 12-27-22; 8:45 am]
BILLING CODE 4910-EX-P


[Federal Register Volume 76, Number 182 (Tuesday, September 20, 2011)]
[Notices]
[Pages 58288-58289]
[FR Doc No: 2011-24138]

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DEPARTMENT OF HOMELAND SECURITY

Coast Guard

[Docket No. USCG-2011-0882]

International Maritime Organization Guidelines for Exhaust Gas
Cleaning Systems for Marine Engines To Comply with Annex VI to MARPOL
73/78

AGENCY: Coast Guard, DHS.

ACTION: Notice of meeting.

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SUMMARY: The United States Coast Guard, in consultation with the United
States Environmental Protection Agency, will conduct a public meeting
on the International Maritime Organization guidelines for exhaust gas
cleaning systems for marine engines. The purpose of this meeting in
Washington, DC, is to collect information on how to evaluate exhaust
gas cleaning systems to determine under Annex VI regulation 4 of the
International Convention for the Prevention of Pollution by Ships, 1973
as modified by the Protocol of 1978 (MARPOL) if such a system should be
considered an equivalent that would be at least as effective in
reducing sulfur oxide emissions as the requirements of MARPOL Annex VI
regulation 14.

DATES: This public meeting will be held for 2 days beginning at 9 a.m.
Eastern Time, on Wednesday, October 12, 2011, and ending at 3:30 p.m.,
Eastern Time on Thursday, October 13, 2011. The daily meeting schedule
will be from 9 a.m. until 3:30 p.m. This meeting is open to the public.
Comments and related material for our online docket must either be
submitted via http://www.regulations.gov on or before October 27, 2011,
or reach the Docket Management Facility by that date.

ADDRESSES: The public meeting will be held in Room 2501 of the United
States Coast Guard Headquarters Transpoint building in Washington, DC.
The Transpoint building is located at 2100 Second Street, Southwest, in
Washington, DC 20953, approximately 1 mile from the Southwest-SEU Metro
Station.
    You may submit comments identified by docket number USCG-2011-0882
using any one of the following methods:
    (1) Federal eRulemaking Portal: http://www.regulations.gov.
    (2) Fax:<PHONE_NUMBER>.
    (3) Mail: Docket Management Facility (M-30), U.S. Department of
Transportation, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590-0001.
    (4) Hand delivery: Same as mail address above, between 9 a.m. and 5
p.m., Monday through Friday, except Federal holidays. The telephone
number is<PHONE_NUMBER>.
    To avoid duplication, please use only one of these four methods.
See the ``Public Participation and Request for Comments'' portion of
the SUPPLEMENTARY INFORMATION section below for instructions on
submitting comments.

FOR FURTHER INFORMATION CONTACT: For additional information about this
public meeting you may contact Mr. Wayne Lundy by telephone at 202-372-
1379 or by e-mail at<EMAIL_ADDRESS>If you have questions on
viewing or submitting material in the docket, call Renee V. Wright,
Program Manager, Docket Operations, telephone<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION: The purpose of this meeting is to discuss
guidelines and accompanying washwater discharge criteria developed by
the International Maritime Organization (IMO) for exhaust gas cleaning
systems for marine engines to remove sulfur oxide emissions. Annex VI
regulation 4 of the International Convention for the Prevention of
Pollution by Ships, 1973 as modified by the Protocol of 1978 (MARPOL),
permits the use of equivalents that would be at least as effective in
reducing emissions as required by MARPOL Annex VI regulations. MARPOL
Annex VI regulation 14 sets requirements for sulfur oxide emissions. A
copy of IMO Marine Environment Protection Committee Resolution
MEPC.176(58), which contains the text of MARPOL Annex VI including
regulations 4 and 14 is available in the docket for this notice. A copy
of MEPC Resolution MEPC.184(59) which contains the 2009 Guidelines for
Exhaust Gas Cleaning Systems is also available in the docket for this
notice.
    On July 21, 2008, the Maritime Pollution Prevention Act of 2008,
Public Law 110-280, was enacted. This legislation amended the Act to
Prevent Pollution from Ships (APPS), 33 U.S.C. 1901-1915. APPS, which
defines ``MARPOL Protocol'' to include Annex VI, makes it unlawful to
act in violation MARPOL Annex VI. See 33 U.S.C. 1901 and 1907. Working
with other agencies, under 33 U.S.C. 1903, the Coast Guard is charged
with administering and enforcing the MARPOL Protocol. A copy of 33
U.S.C. chapter 33, containing sections 1901-1915, is available in the
docket.

Agenda of Meeting

    The public meeting will cover:
    (1) Potential approval process;
    (2) Development of explicit test procedures;
    (3) Inspection & verification of compliance;
    (4) Consistency of the sludge from washwater;
    (5) Proper disposal of sludge;
    (6) Adequate reception facilities;
    (7) Safety concerns;
    (8) Training needs; and
    (9) Recordkeeping.
    The U.S. Coast Guard is specifically seeking information about
testing procedures, preliminary results, processes for establishing
certified laboratories, and other items relevant to emission standards
regulation 14 and exhaust gas cleaning systems for marine engines.

Procedural

    This meeting is open to the public. Please note that the public
meeting has a limited number of seats and may close early if all
business is finished. There will be audiovisual arrangements available
for those interested in making presentations. Also, teleconferencing

will be available. Those interested in making presentations or
teleconferencing should contact Mr. Wayne Lundy by telephone at 202-
372-1379 or by e-mail at<EMAIL_ADDRESS>    The IMO guidelines are contained in document MEPC.184(59). A copy
of the IMO guidelines is available in the docket. A limited number of
paper copies will be available at this meeting. Summaries of comments
made, materials presented, and lists of attendees will be available on
the docket at the conclusion of the meeting. To view comments and
materials in the docket, go to http://www.regulations.gov, type the
docket number ``USCG-2011-0882'' in the Keyword box, and press Enter.
If you submit a comment, please include the docket number for this
rulemaking (USCG-2011-0882), indicate the specific section of this
document to which each comment applies, and provide a reason for each
suggestion or recommendation.
    You may submit comments and material to our online docket via
http://www.regulations.gov, by fax, mail, or hand delivery, but please
use only one of these means. We recommend that you include your name
and a mailing address, an e-mail address, or a phone number in the body
of your document so that we can contact you if we have questions
regarding your submission.
    To submit your comment online, go to http://www.regulations.gov,
type the docket number ``USCG-2011-0882'' in the Keyword box, press
Enter, go to the row with the notice of the meeting (or another
submission you wish to comment on), and click on the ``Submit a
Comment'' icon in the ``Actions'' column. If you submit your comments
by mail or hand delivery, submit them in an unbound format, no larger
than 8\1/2\; by 11 inches, suitable for copying and electronic filing.
If you submit comments by mail and would like to know that they reached
the Facility, please enclose a stamped, self-addressed postcard or
envelope.
    All comments received will be posted without change to http://www.regulations.gov and will include any personal information you have
provided. Anyone can search the electronic form of comments received
into any of our dockets by the name of the individual submitting the
comment (or signing the comment, if submitted on behalf of an
association, business, labor union, etc.). You may review a Privacy Act
notice regarding our public dockets in the January 17, 2008, issue of
the Federal Register (73 FR 3316).

Information on Services for Individuals with Disabilities

    For information on facilities or services for individuals with
disabilities or to request special assistance at the meeting, contact
Mr. Wayne Lundy at<PHONE_NUMBER> or by e-mail at<EMAIL_ADDRESS>as soon as possible.
    Public Meeting Location and Dates
    As stated in the DATES and ADDRESSES sections, the Coast Guard will
hold a public meeting October 12 and 13, 2011, at: United States Coast
Guard Headquarters, Transpoint Building, Room 2501, 2100 Second Street,
Southwest, Washington, DC 20953. Each meeting will be conducted from 9
a.m. until 3:30 p.m., with a planned lunch break for approximately 45
minutes at a convenient point each day. The meeting may close early if
all business is finished.
    Attendees will be required to provide a government-issued photo
identification (for example, a driver's license) in order to gain
admittance to the Coast Guard Headquarters building. The building is
located approximately 1 mile from the Southwest-SEU Metro Station.

    Dated: September 14, 2011.
J.G. Lantz,
U.S. Coast Guard, Director of Commercial Regulations and Standards.
[FR Doc. 2011-24138 Filed 9-19-11; 8:45 am]
BILLING CODE 9110-04-P


[Federal Register Volume 83, Number 174 (Friday, September 7, 2018)]
[Notices]
[Page 45438]
[FR Doc No: 2018-19401]

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DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Docket No. CP17-178-000]

Notice of Revised Schedule for Environmental Review of the Alaska
Gasline Development Corporation Alaska LNG Project

    This notice identifies the Federal Energy Regulatory Commission
(FERC) staff's revised schedule for the completion of the environmental
impact statement (EIS) for the Alaska LNG Project (Project). The first
notice of schedule, issued on March 12, 2018, identified December 9,
2019 as the final EIS issuance date. Staff has revised the schedule for
issuance of the final EIS, based on an issuance of the draft EIS in
February 2019. The forecasted schedule for both the draft and final EIS
is based upon the Alaska Gasline Development Corporation providing
complete and timely responses to any future data requests. In addition,
the schedule assumes that the cooperating agencies will provide input
on their areas of responsibility on a timely basis.

Schedule for Environmental Review

Issuance of Notice of Availability of the final EIS--November 8, 2019
90-Day Federal Authorization Decision Deadline--February 6, 2020

    If a schedule change becomes necessary for the final EIS, an
additional notice will be provided so that the relevant agencies are
kept informed of the Project's progress.

Additional Information

    In order to receive notification of the issuance of the EIS and to
keep track of all formal issuances and submittals in specific dockets,
the Commission offers a free service called eSubscription. This can
reduce the amount of time you spend researching proceedings by
automatically providing you with notification of these filings,
document summaries, and direct links to the documents. Go to
www.ferc.gov/docs-filing/esubscription.asp.
    Additional information about the Project is available from the
Commission's Office of External Affairs at (866) 208-FERC or on the
FERC website (www.ferc.gov). Using the eLibrary link, select General
Search from the eLibrary menu, enter the selected date range and Docket
Number excluding the last three digits (i.e., CP17-178), and follow the
instructions. For assistance with access to eLibrary, the helpline can
be reached at<PHONE_NUMBER>, TTY<PHONE_NUMBER>, or at
[email protected]. The eLibrary link on the FERC website also
provides access to the texts of formal documents issued by the
Commission, such as orders, notices, and rule makings.

    Dated: August 31, 2018.
Nathaniel J. Davis, Sr.,
Deputy Secretary.
[FR Doc. 2018-19401 Filed 9-6-18; 8:45 am]
 BILLING CODE 6717-01-P