Pesticide compounds that bind readily to particulate and organic carbon in the water column can eventually settle onto the benthos. This increase in particulate bound pesticides can result in an accumulation of compounds in or on the sediment that may have the potential for toxic impact to benthic and epibenthic aquatic organisms ( e. g., early life stage of many invertebrates and fish, as well as crabs and shrimp). However, evaluating the risk to aquatic life from this exposure becomes problematic especially if there is a lack of adequate sediment toxicity and exposure data. Therefore, in order to assess this potential for pesticide risk to aquatic benthic systems, the Environmental Fate and Effects Division ( EFED) of the Office of Pesticides Program ( OPP) has adopted the method used by the Office of Water that relies on equilibrium partitioning ( EqP) of chemicals. Th EqP theory is based on the hydrophobicity and concentrations of the chemical normalized to organic carbon ( OC) in sediment ( De Toro et al. 1991) and holds that a nonionic chemical in sediment partitions between sediment organic carbon, interstitial ( pore) water and benthic organisms. At  43 equilibrium, if the concentration in any phase is known, then the concentration in the other phases can be predicted. A key component to this theory is the chemicals organic carbon coefficient ( Koc), which is constant for every chemical and represents the ratio of the chemical concentration in water to the concentration in organic carbon. The document, " Technical Basis for the Derivation of Equilibrium Partitioning Sediment Guidelines ( ESGs) for the Protection of Benthic Organisms: Nonionic Organics" ( USEPA, 2000a), demonstrates that biological responses of benthic organisms to nonionic organic chemicals in sediments are different when the sediment concentrations are expressed on a dry weight basis, but similar when expressed on a ug chemical/ g organic carbon basis ( ug/ goc). Similar responses were also observed across sediments when interstitial water concentrations were used to normalize biological availability. The Technical Basis Document further demonstrates that if the toxic effect concentration in water is known ( e. g., LC50), the effect concentration in sediment on a ug/ goc basis can be predicted by multiplying the effect concentration in water by the chemical Koc..

( LC50 ug/ L x Koc L/ kgoc x 1 kgoc/ 1000goc = LC50 ug/ goc)

Since, EFED uses a deterministic method for its screening level risk assessment, the calculation of risk quotient values ( RQ) is important for assessing possible risk. The RQ values are calculated by taking the ratio of the estimated exposure concentrations ( EEC) to the toxicity effect value ( e. g., LC50, NOAEC). The EEC values are model generated ( e. g., PRZM/ EXAMS) and reflect peer evaluated and approved scenarios for assessing pesticide exposure to an aquatic environment. However, the PRZM/ EXAMS output produces water column EEC values, as well as sediment and pore water EEC values. Therefore, in order to assess possible toxic pesticide exposure to aquatic organisms from sediments, EFED is using the PRZM/ EXAMS model which incorporates the principles of the equilibrium partitioning theory, in order to generate EECs from sediment and pore water. By relying on sediment and/ or pore water output values, EFED has two ways for calculating RQ values for sediments by using pore water exposure values and bulk sediment values.

The calculations that rely on pore water can be calculated by dividing the PRZM/ EXAMS output value for pore water concentrations by the dissolved concentrations in the water column that caused toxicity in bioassays ( e. g., LC50).

EEC pore water ug/ L / LC50 ugL If sediment effects data are available ( LC50 ug/ kgoc), RQ can be produced by using the PRZM/ EXAMS sediment output value for sediment.

EEC sediment ug/ ugoc / LC50 ug/ kgoc Assumptions of the equilibrium partitioning model: Three principle observations that underlie the equilibrium partitioning ( EqP) approach:

C The concentrations of nonionic organic chemicals in sediments ( expressed on an organic carbon basis) and in interstitial waters correlate with observed biological effects on sediment dwelling organisms across a range of sediments.

C Partitioning models can relate sediment concentrations for nonionic organic chemicals on an organic carbon basis to freely dissolved concentrations in interstitial water.

C The distribution of sensitivities of benthic organisms is similar to that of water column species.

The EqP approach assumes that the partitioning of a chemical between sediment organic carbon and interstitial  44 water is at or near equilibrium. Another assumption is that the concentration in either phase can be predictive using appropriate partition coefficient and the measured concentration in the other phase. Furthermore, it is assumed that organisms receive equivalent exposure from water only exposures or from any equilibrated phase ( interstitial water via respiration; from sediment via ingestion or other sediment integument exchange). The final assumption is that for nonionic compounds, effect concentrations in sediments on an organic carbon basis can be predicted using the organic carbon partition coefficient ( KOC) and effects concentrations in the water.

The Agency evaluated maximum and typical application of pyrethin relative to expected sediment residues ( Table 10). Maximum application rate produced EEC estimates for benthic pore water ( PRZM/ EXAMS) that range from 0.029  0.209 : g/ L, while the typical application rate resulted in lower EEC values of 0.002  0.010 ug/ L ( peak daily concentrations). The range of EECs follows the pattern exhibited by the surface water EECs with the highest EECs estimated for the IL Corn standard scenario and the lowest EECs for the CA Grape standard scenario. One of the key parameters in the PRZM/ EXAMS model is weather, especially the rainfall pattern. The amount and frequency of rain for scenarios representing MN potato, IL corn, and PN tomato uses created conditions for greater runoff of pyrethrins from the field and into the adjacent pond compared to the warmer, drier climates of the CA grape, FL citrus, and GA peaches standard scenarios.

Table 10. PRZM/ EXAMS output for benthic pore water EECs ( ug/ L) based on pyrethrins use on several crops.

Crop App. rate ( kg/ ha) No. of app./ interval ( days) Peak 96 Hour 21 Day 60 Day 90 Day Annual IL corn 0.056 10/ 1 0.209 0.208 0.204 0.182 0.169 0.103 ME potato 0.056 10/ 1 0.159 0.158 0.154 0.145 0.138 0.098 MS cotton 0.056 10/ 1 0.137 0.137 0.132 0.125 0.115 0.051 PA tomato 0.056 10/ 1 0.117 0.116 0.111 0.098 0.092 0.055 ND wheat 0.056 10/ 1 0.068 0.068 0.065 0.058 0.054 0.037 CA onion 0.056 10/ 1 0.060 0.059 0.065 0.047 0.042 0.021 NC apple 0.056 10/ 1 0.060 0.060 0.058 0.054 0.052 0.035 OR snapbeans 0.056 10/ 1 0.047 0.047 0.046 0.042 0.040 0.026 ID potato 0.056 10/ 1 0.038 0.038 0.037 0.033 0.030 0.020 Table 10. PRZM/ EXAMS output for benthic pore water EECs ( ug/ L) based on pyrethrins use on several crops.

Crop App. rate ( kg/ ha) No. of app./ interval ( days) Peak 96 Hour 21 Day 60 Day 90 Day Annual  45 MN alfalfa 0.056 10/ 1 0.036 0.036 0.035 0.032 0.030 0.019 FL citrus 0.056 10/ 1 0.036 0.036 0.035 0.032 0.029 0.015 GA peaches 0.056 10v 0.039 0.039 0.038 0.033 0.030 0.019 CA grapes 0.056 10/ 1 0.029 0.029 0.028 0.024 0.021 0.011 SPECIAL RUNS WITH TYPICAL INTERVAL BETWEEN APPLICATIONS ( 3 days, normal pest pressure)

IL corn 0.056 10/ 3 0.193 0.192 0.187 0.167 0.155 0.100 ID potato 0.056 10/ 3 0.036 0.036 0.034 0.031 0.029 0.020 CA grapes 0.056 10/ 3 0.040 0.039 0.037 0.032 0.029 0.015 TYPICAL APPLICATION RATE, NUMBER OF APPLICATIONS, AND INTERVAL BETWEEN APPLICATIONS Crop App. Rate ( Kg a. i./ ha) No of app./ interval between app. Peak 96 Hour 21 Day 60 Day 90 Day Annual ID potato 0.0224 1/( N/ A) 0.002 0.002 0.001 0.001 0.001 0.001 PA tomato 0.0067 2/ 3 0.003 0.003 0.002 0.002 0.002 0.001 CA onion 0.0146 2/ 3 0.002 0.002 0.001 0.001 0.001 0.001 OR snap beans 0.0235 5/ 3 0.010 0.010 0.009 0.009 0.008 0.006 b. Aquatic Exposure Modeling for Mosquito Abatement In 2000, more than 200,000 lb of pyrethrin were sold, of which around 6% were used for terrestrial non food uses, and around 1% was used for outdoor recreation ( including mosquito abatement). Pyrethrin can be used in such places like residential, industrial, recreational, and agricultural areas as well as swamps, marshes,  46 overgrown waste areas, roadsides and pastures where adult mosquitoes occur. Some of these places could involve direct or indirect exposure to aquatic environments.

Mosquito adulticides are more efficacious if they come into contact with insects in flight. For that reason, mosquito abatement using pyrethrin ( as well as other mosquito adulticides) is typically applied via aerial spray methods with very fine droplets or mists, to prevent immediate deposition of the pesticide.

The modeling approach for this type of use included calculations of spray drift using the AGricultural DISPersal model ( AGDISP v. 8.08). This model/ computer program estimates the deposition of the pesticide to the treated area, and, by means of its toolbox " deposition assessment," to the adjacent bodies of water ( i. e. the standard pond). In other words, AGDISP estimates the application efficiency and downwind deposition or spray block deposition ( to the water body, equivalent to the level of spray drift). AGDISP provides a better prediction of spray drift under the circumstances where a mosquito adulticide is used.

The ten labels for pyrethrins have few specifications about application methods. For example, the intervals between applications are not specified, the maximum number of applications allowed per time period are not specified, and the boom ( or application release) height is not specified ( except for one label). Labeling statements dealing with the spray droplet size range, wind speed, and time of day to apply pyrethrin are provided as recommendations but are not provided as requirements.

The output data from AGDISP files and PRZM/ EXAMS are provided in Appendix L. Various of the labels for pyrethrin recommended an optimum droplet size of Dv0.5= 30 : m ( half of the volume is contained in droplets less than 30 : m and half of the volume is contained in droplets more than 30 : m; however, the product used as an example to model pyrethrins in AGDISP, Pyrenone ® 25 5 Public Health Insecticide, did not have specifications for aerial applications. Therefore, the user defined droplet was Dv0.5~ 50 : m. The wind speed in some of the labels was recommended as < 5 mph in some labels and < 10 mph in others; the one used in modeling was the one in the label for Pyrenone ® 25 5 Public Health Insecticide, that is, 10 mph. The master label indicated that the wind speed would be < 10 mph. The spray volume selected was 0.1 gal/ A for the maximum application rate. It was assumed that the product was diluted in an oil with specific gravity of 0.8. The boom height was varied according to the table below, since the labels have no specifications. The maximum application rate indicated in the Master Label is lower than that for agricultural settings: 0.008 lb a. i./ A It appears that a typical application rate is 0.0025 lb a. i./ A. EFED selected a temperature and relative humidity of 85 ° F and 90%, respectively, to simulate conditions where mosquitoes grow. For the most part, the conditions selected were the default values in AGDISP.

Since the original pyrethrins assessment was issued, more refinements have been achieved in the way the EFED conducts its adulticide assessment. In order to obtain the level of drift the EFED uses the toolbox " Deposition Assessment." This toolbox of the AGDISP model, can be utilized to obtain the levels of spray drift with buffer zones ( even though it does not apply to this chemical). The dimensions of the standard pond are entered in the toolbox, and the return is the " effective" application rate on the standard pond. By dividing the output of the toolbox by the application rate, the fraction of drift is obtained. This is the input value that should be used in PRZM/ EXAMS. The results obtained are summarized in the following table ( compare to the default values of 95% application efficiency and 5% spray drift, for agricultural applications). Note that variables such as the boom height and the application rate will have an effect on the results obtained. The higher the boom height, the lower the level of deposition and the application efficiency. A low application rate is expected to result in lower EECs, despite the fact that the levels of deposition are similar. In addition, the droplet size is an important factor that determines the level of deposition. Large droplets cause more deposition; they cannot  47 stay in the air as long as small droplets. It was observed that a buffer zone did not have a major effect on the level of deposition, when the boom height is 75 ft. With a buffer zone of 0, 100 and 200 ft, the level of deposition is around 21 ± 1%. Therefore, only the 75 ft boom height with different buffer zones were modeled for illustration; however, only the no buffer zone was calculated or modeled in PRZM/ EXAMS.  48

Table 11. Results from AGDISP for Pyrethrins Parameter Value Droplet Size (: m) 50 50 50 50 40 40 50 50 50 50 Boom height ( ft) 25 75 75 75 75 150 100 150 75 150 Application Rate ( lb a. i./ A) 0.0081 0.008 0.008 0.008 0.008 0.008 0.008 0.008 0.00252 0.0025 Application Rate ( Kg a. i./ ha) 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.009 0.0028 0.0028 Buffer zone ( ft) 0 0 100 200 0 0 0 0 0 0 Application efficiency ( fraction) 0.393 0.015 0.015 0.015 0 0 0 0 0.015 0 Downwind deposition or Spray Drift ( fraction) 0.563 0.200 0.213 0.225 0.125 0.005 0.088 0.013 0.200 0.016 10.008 lb a. i./ A is the maximum application rate supported by the registrant, according to the Master Label. 20.0025 lb a. i./ A appears to be the typical maximum application rate in most labels of the pyrethrins. Furthermore, comments from the Districts and other interested parties indicated that they use the product at an application rate of 0.0020 to 0.0025 lb a. i./ A.

The highlighted columns were modeled in PRZM/ EXAMS.  49 Using the results from AGDISP, the tier 2 aquatic model PRZM/ EXAMS ( using the graphical user interface pe4v01. pl) was used to model surface water EECs using the FL turf site scenario. This scenario appears to be suitable to represent sites such as parks, golf courses, etc. Ponds of various depths ( EXAMS standard ecological Mississippi pond) were simulated. PRZM/ EXAMS runoff component was modified according to the results of AGDISP ( with an application efficiency according to the table above). Furthermore, selected input parameters were modified to capture the depth of the pond ( e. g. CHARL = characteristic length = this is a measure of the depth of the pond). Pond depths were varied to examine the concentration of pyrethrin in shallow ( i. e., marshes) to deep water bodies ( i. e., pond). PRZM/ EXAMS was implemented individually for pond depths of 6 inches, 1 foot, 1 meter ( 3.3 feet), and 2 meters ( 6.6 feet). It should also be clarified that EXAMS uniformly distributes pyrethrins in the water while in real life situations, pyrethrins could be present in higher concentrations in the proximity of the treated site. This makes this analysis less conservative because aquatic animals in the proximity to the field are at greatest risk than farther away.

AGDISP input parameters were those typical for a mosquito adulticide and that were in agreement with the product labels. They are listed in the Table 12. Input parameters for the PRZM/ EXAMS pe4 modeling are listed in Table 13. AGDISP model file is provided in Appendix L. Detailed PRZM/ EXAMS output file, for each pond depth, is also provided in Appendix L. The summary of the PRZM/ EXAMS results appear in Tables 14 to 19. The pore water concentrations were provided in Tables 20 to 25.

Various trends were noted. Modeled EECs increased with increasing pond depth. The trend of increasing EECs with increasing pond depth is noticeable because the EEC's follow the opposite pattern expected by dilution only. The results of these runs indicated that dilution effects are not as influential as other factors when modeling pyrethrins. Other factors, such as sediment adsorption of the chemical appear to be also important with a chemical like this, with a very high KOC.

The lower concentrations in shallow water bodies compared to deep water bodies in this simulation, may be partially explained by three depth dependent variables in the EXAMS model: Henry's Law constant, KOC, and aqueous photolysis half life. The Henry's Law constant suggests a potential for loss of pesticide from the pond via volatilization. Second, with a very high KOC, the pyrethrin tends to partition towards the sediment. This equilibrium will occur more rapidly in shallow waters than in deeper bodies of water. Finally, a third possible explanation is the short aqueous photolysis half life ( 0.5 days) for pyrethrin. According to the Beer Lambert law, light intensity decreases exponentially with increasing water depth ( light is not expected to penetrate into depths longer than about 1 ft.). When a chemical has a short half life ( as in this scenario) and it is concentrated in shallow waters ( i. e., six inches), it can be expected to photodegrade more readily than when it is spread throughout a deeper water column.

Given other same conditions, a larger droplet size caused an increase in the exposure. The peak EECs observed for the runs performed with the maximum application rate ( 0.008 lb a. i./ A), a boom height of 75 ft, and a droplet size of Dv0.5 ~ 40 : m were 0.51 0.59 ppb; with a droplet size of around 50 : m, the peak EECs were 0.81 0.95 ppb.

The boom height has an extraordinary effect on the level of exposure observed in the pond. With the same application rate of 0.008 lb a. i./ A, and droplet size of 50 : m, two boom height were explored: 75 and 150 ft. The respective peak EECs were 0.81 0.95 ppb and 0.05 0.06 ppb. A higher boom height causes more dispersion of the ULV aerosol, and a smaller amount of it reaches the soil and the water.  50 The last variable that was changed and studied was the application rate. In this case, the boom height was 75 ft, the droplet size was 50 : m and the application rates were the maximum: 0.008 lb a. i./ A, and what appears to be a typical application rate from comments obtained in the Phase 5 Comment Period.: 0.0025 lb a. i./ A. The peak EECs' were respectively 0.114 0.133 ppb and 0.036 0.041 ppb.

Table 12. Input parameters for AGDISP for Pyrethrin.

Parameter Value Aircraft type Air Tractor AT 401; fixed wing Swath Width 60 ft Wing semispan 24.5 ft.

Swath Displacement 0 ft.

propeller rpm 2000; propeller rad. 4.5 ft.; 1 engine Fixed wing 1 engine Flight lines 20 Flight speed 120 mph Boom height Refer to Supplementary Table( 1)

Number of nozzles 42 Vortex decay rate 1.25 mph Aircraft drag coefficient 0.1 Propeller efficiency 0.8 Ambient pressure 29.91 in Hg Planform area 294 ft2 Semispan 24.5 ft.

Nozzle spacing ( even) 0.78 ft = 9.36 in.

Wind speed 10 mph Wind direction  90 ° , Perpendicular to flight path Surface roughness 0.0075 Stability Daylight ( solar insolation) Overcast Relative humidity 90% Table 12. Input parameters for AGDISP for Pyrethrin.

Parameter Value  51 Temperature 85 ° F Droplet type User defined Dv0.1 13.7 : m 11.26 : m Dv0.5 51.03 : m 41.17 : m Dv0.9 117.41 : m 94.88 : m Relative span 2.03 : m 2.03 < 141 : 94.9% 97.22%

Spray material Oil Specific gravity, carrier 0.8( 2)

Specific gravity, nonvolatile 0.8 Active rate 0.008 lb a. i./ A = 0.009 Kg a. i./ ha Fraction = 0.012 0.0025 lb a. i./ A = 0.0028 Kg a. i./ ha Fraction = 0.012 Nonvolatile rate Fraction = 1 Spray volume rate 0.1 gal/ A 0.0312 gal/ A Evaporation rate 0 : m2/ ° C/ sec Downwind water body width 208.7 ft Ave. depth 0.5 ft = 6 in; 1 ft.; 3.3 ft ~ 1 m; 6.6 ft. ~ 2 m( 3)

( 1). Release height is not specified on product labels. ( 2). Value selected from recommendations in the label. ( 3). 2 m or standard pond scenario ( 208.7 ft. wide, 6.6 ft. deep, static water body receiving runoff from 10 hectares).

Table 13. Input parameters for PRZM/ EXAMS.

Parameter Value & Units Source Molecular Weight Pyrethrin 1: 328.4 g/ mol Table 13. Input parameters for PRZM/ EXAMS.

Parameter Value & Units Source  52 Water Solubility ( 20oC) 2.0 ppm Max. Solubility, Tomlin, C. D. S., Pesticide manual ( TOXNET) 10x available value ( 0.2 ppm) as per EFED Model Input Guidance ( 2002)

Vapor pressure Pyrethrin 1: 2.03 x 10 5 mm Hg Tomlin, C. D. S., Pesticide manual ( TOXNET)

Henry's Law Constant Pyrethrin 1: 7.7 x 10 7 atm m3/ mol Estimated value from EPISUITE Hydrolysis t ½ , pH 7 ( 25oC) pH 5: stable pH 7: stable pH 9: 17 days MRID 43567502 Spray Drift Fraction 0.076 Modeled with AGDISP v8.07 Application Efficiency 0.300 Modeled with AGDISP v8.07 Aerobic Soil Metabolism t ½ ( 3X available value of 9.5) 28.5 days MRID 43499803 Aerobic Aquatic Metabolism t ½ ( 3X available value of 10.5) 31.5 days MRID 43499802 Anaerobic Aquatic Metabolism t ½ 86 days MRID 43499801 Direct Aqueous Photolysis t ½ 0.5 day MRID 43567601 Soil Water Partition Coefficient ( Kd) N/ A

KOC 35,170 MRID 43096603; Average value, EFED Model Input Guidance, Version II ( 2002)

PLDKRT ( foliage pesticide halflife 0 days EFED Model Input Guidance, Version II ( 2002)

FEXTRC ( foliar extraction) 0.5 EFED Model Input Guidance, Version II ( 2002)

FILTRA ( filtration parameter; required if CAM set to 3) NA  Table 13. Input parameters for PRZM/ EXAMS.

Parameter Value & Units Source  53 PLVKRT ( pesticide decay rate on plant foliage) 0/ day EFED Model Input Guidance, Version II ( 2002)

IPSCND( condition for disposition of foliar pesticide after harvest) 3 PRZM Version 3.0 User's Manual ( Carsel 1998)

CAM ( chemical application method) 2 PRZM Version 3.0 User's Manual ( Carsel 1998)

UPTKF ( plant uptake factor) 0 EFED Model Input Guidance, Version II ( 2002)

DAIR ( diffusion coefficient for pesticide in the air) 0.0 PRZM Version 3.0 User's Manual ( Carsel 1998)

ENPY( enthalpy of vaporization of pesticide) ( Not reported)

Benthic Layer 5 cm EXAMS Default CROP MANAGEMENT Application Rate Florida Turf: 0.008 lb a. i./ A/ application = 0.009 kg a. i./ ha/ application or 0.0025 lb a. i./ A = 0.0028 Kg a. i./ ha for Typical Application Rate Master Label and Product Label for Pyronyl Mosquito Use Number of Applications Florida Turf: 26 Product Label Interval Between Applications ( days) Florida Turf: 4 Product Label Date of First Application Florida Turf: 1 Jun Product Label and EFED PRZM Crop Scenarios ( US EPA)

Application Type and Depth of Incorporation ( cm) Aerial Product Label POND DEPTH SCENARIOSa Scenario Pond Depth ( m) CHARLb ( m)

A 0.1524 ( 6") 0.101 B 0.3048 ( 12") 0.177  54 C 1 0.525 D 2 1.025 a Edit Exams Commands: set charl( 1) to " x"; set dep( 1) to " x"; rec env 4, where x is the corresponding value listed in the pond depth scenarios table. b Characteristic Length = 0.5 ( Pond Layer) + 0.5 ( Benthic Layer) = A measure of pond depth.

Table 14. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 75 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.133 0.078 0.074 0.069 1 m 0.122 0.059 0.054 0.050 1 ft 0.117 0.046 0.041 0.038 6 in 0.114 0.042 0.038 0.035 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 15. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 40 : m; Boom height 75 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.083 0.049 0.046 0.043 1 m 0.076 0.037 0.034 0.031 1 ft 0.073 0.029 0.026 0.024 6 in 0.071 0.027 0.024 0.022 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.  55 Table 16. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 150 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.009 0.005 0.005 0.005 1 m 0.008 0.004 0.004 0.003 1 ft 0.008 0.003 0.003 0.002 6 in 0.007 0.003 0.002 0.002 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 17. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 75 ft; Application rate 0.0025 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.041 0.025 0.023 0.022 1 m 0.038 0.018 0.017 0.016 1 ft 0.036 0.014 0.013 0.012 6 in 0.036 0.013 0.012 0.011 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 18. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 40 : m; Boom height 150 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.003 0.002 0.002 0.002 1 m 0.003 0.001 0.001 0.001 1 ft 0.003 0.001 0.001 0.001 6 in 0.003 0.001 0.001 0.001 Table 18. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 40 : m; Boom height 150 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day  56 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 19. Surface water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 150 ft; Application rate 0.0025 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.003 0.002 0.002 0.002 1 m 0.003 0.001 0.001 0.001 1 ft 0.003 0.001 0.001 0.001 6 in 0.003 0.001 0.001 0.001 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 20. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 75 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.031 0.030 0.028 0.027 1 m 0.030 0.029 0.027 0.026 1 ft 0.028 0.027 0.025 0.024 6 in 0.026 0.025 0.023 0.021 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.  57 Table 21. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 40 : m; Boom height 75 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.020 0.019 0.018 0.017 1 m 0.019 0.018 0.017 0.016 1 ft 0.018 0.017 0.016 0.015 6 in 0.016 0.015 0.014 0.013 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 22. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 150 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.002 0.002 0.002 0.002 1 m 0.002 0.002 0.002 0.002 1 ft 0.002 0.002 0.002 0.002 6 in 0.002 0.002 0.001 0.001 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 23. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 75 ft; Application rate 0.0025 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.010 0.010 0.009 0.009 1 m 0.009 0.009 0.008 0.008 1 ft 0.009 0.008 0.008 0.007 6 in 0.008 0.008 0.007 0.007 Table 23. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 75 ft; Application rate 0.0025 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day  58 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 24. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 40 : m; Boom height 150 ft; Application rate 0.008 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.001 0.001 0.001 0.001 1 m 0.001 0.001 0.001 0.001 1 ft 0.001 0.001 0.001 0.001 6 in 0.001 0.001 0.001 0.001 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

Table 25. Pore water EECs ( ppb or : g/ L) for ecological risk assessment based on pyrethrins mosquito abatement applications calculated using PRZM/ EXAMS for various pond depths. a Conditions as follows: Droplet size 50 : m; Boom height 150 ft; Application rate 0.0025 lb a. i./ A FL Turf Scenario Instantaneous Peak ( 0 day) 21 day 60 day 90 day 2 m 0.001 0.001 0.001 0.001 1 m 0.001 0.001 0.001 0.001 1 ft 0.001 0.001 0.001 0.001 6 in 0.001 0.001 0.001 0.001 a Surface water EECs are referred to as water segment concentrations in the PRZM/ EXAMS output. b Three decimal places are provided to compare ranges in PRZM/ EXAMS output.

c. Aquatic Exposure, " Down the Drain" Assessment The USEPA has received various comments from interested parties during the 60 day comment period, requesting tto address the fact that the pyrethrins are likely to drain and reach water treatment plants. They specifically had  59 mentioned the approach utilized by the Agency for pyrethrin with E FAST ( see below). The USEPA intends hereby to address the issue.

In order to address this issue of pyrethrin release to domestic wastewater treatment, the Agency relied on the Office of Pollution Prevention and Toxics ( OPPT) consumer exposure model, Exposure and Fate Assessment Screening Tool ( E FAST) ( USEPA, 1999). This Down the Drain module of E FAST is specifically designed to address all sources of pyrethrins that could potentially be disposed to domestic wastewater from a " down the drain" application. This model provides screening level estimate of chemical residues in surface water that may result from household uses and the disposal of these consumer products into wastewater. The model uses input parameters that include annual production volume of the pesticide and takes into account the fraction of the chemical removed during wastewater treatment. The assumptions of the model state that in a given year, the entire production volume of the chemical in question is parceled out on a daily per capita basis to the U. S. population and converted to a mass release per capita ( e. g., gm/ person/ day). This mass is diluted into the average daily volume of wastewater released per person per day to arrive at an estimated concentration of target chemical in wastewater prior to entering a treatment facility. The target chemical ( pyrethrins) concentration in untreated wastewater is then reduced by the fraction removed during wastewater treatment process before release into a river or stream. The remaining chemical is discharged into surface water, where it is assumed that it is instantaneously diluted, with no further removal. A Stream Dilution Factor is the volume of the receiving stream flow divided by the volume of the wastewater released from the Publicly Owned Treatment Works ( POTW). The resulting values are used for ecological effects: estimated environmental concentrations ( EECs)

The equations used are as follows:

Daily per capita release of a chemical in household wastewater HR = ProdVol x 1000g/ Kg x 1 year/ 365 days Pop HR Daily per capita release of the chemical to a wastewater treatment facility ( grams/ person/ day) ProdVol Production volume ( Kg/ year) [ use information will be provided by SRRD] Pop US population ( persons) = 2.727x108 persons ( US Bureau of the Census, 1999)

Surface Water Concentrations HR x 1 x ( 1  WWT) x CF1 CSM = _______ QH___________________ SDFM HR x 1 x ( 1  WWT) x CF1 CSH = _______ QH___________________ SDFL CSM Median time averaged surface water concentration (: g/ L) CSH High end time averaged surface water concentration (: g/ L) HR Daily per capita release of chemical ( i. e. pre treatment release, g/ person/ day) QH Daily per capita wastewater volume released ( 364 L/ person/ day, USEPA, 1990; Versar, 1992) WWT Fraction of chemical removed during wastewater treatment [ see alternative values below] SDFM 50th percentile stream dilution factor for stream to which wastewater treatment facilities discharge ( 980.69, Versar, 1992)  60 SDFL 10th percentile stream dilution factor for stream to which wastewater treatment facilities discharge ( 75.44, Versar, 1992) CF1 Conversion factor ( 1x106 : g/ g)

Removal of Pyrethrins ( WWT) Information on the degree of removal of pyrethrins from wastewater at POTWs is unavailable. Therefore, the EPA relied in modeling to obtain this value. The EPIWIN program was utilized. Two levels of removal are obtained from EPIWIN, the most conservative ( the lowest) was utilized in E FAST modeling. WWT value = 92.7%

Production Volume The production volume of pyrethrins was chosen to be very conservative. The total volume of pyrethrins produced for all uses in the United States was reported by BEAD to be approximately 200,000 lb a. i./ A ( Biological and Economic Analysis Division, BEAD).

Substituting the previous values, the following is obtained: HR = 0.000911 g/ person/ day Surface Water Concentrations Surface water concentrations were modeled using computer program E FAST, and the results were as indicated in the following Table ( please, refer to Appendix Q for output files from EPIWIN and E FAST).

Surface Water Concentrations Modeled By E FAST WWT\ Concentration Acute/ ppb Chronic/ ppb 92.7% 0.00242 0.000186 d. Aquatic Exposure Monitoring ( Field Data)

No data were identified to provide information on aquatic exposure monitoring. In addition, at this time, there are limited surface water or groundwater monitoring data available for pyrethrins. The U. S. Geological Survey's National Water Quality Assessment program ( NAWQA) did not have any data regarding the detection of pyrethrins in streams or groundwater.

3. Measures of Terrestrial Exposure A primary concern with pyrethrins is that birds and mammals may be exposed shortly after application through oral or dietary exposure to vegetative plant material or insects when foraging in the treated fields for nesting material or food. The EFED terrestrial exposure model, T REX ( T REX, Version 1.2.3, dated August 8, 2005), is used to estimate exposures and risks to avian and mammalian species. Input values on avian and mammalian toxicity as well as chemical application and foliar halflife data are required to run the model. The model provides estimates of both exposure concentrations and risk quotients ( RQs). Specifically, the model provides estimates of concentrations ( maximum and average) of chemical residues in different types of foliage that may be sources of dietary exposure to avian, mammalian, reptilian, or terrestrial phase amphibian receptors. The exposure concentration ( ppm) is estimated by multiplying the application rate ( pounds active  61 ingredient per acre) by a value specific to each food item. These values ( termed the Hoerger Kenaga estimates) along with a more detailed discussion of the methodology implemented by T REX, are presented in Appendix C ( T REX Model and Results). By comparing these estimated concentrations to acute and chronic toxicity reference values, acute and chronic RQs are calculated.

For this assessment, T REX was run for a single crop use scenario that is considered generally representative of the maximum uses of pyrethrins ( see Table 26). The foliar half life of 1 14 days found for phenothrin and pyrethrin were used in the absence of foliar dissipation studies on pyrethrins. To explore the importance of the foliar half life assumption, multiple calculations were performed and a plot is provided illustrating the relationship between foliar half life and the most sensitive scenario  acute RQs for the small mammal foraging on short grass. The EEC is determined for multiple application scenarios ( 10 applications for pyrethrins) by adding the mass on the surface immediately following the application to the mass of the chemical still present on the surfaces on the day of application ( determined based on first order kinetics using the foliar half life as the rate constant).

Table 26. Input parameters for T REX.

Parameter Value Comment Application rate ( lbs a. i./ A) 0.05 product label Foliar half life ( days) 1  14 Total and dislodgeable residues for phenothrin and pyrethrin, respectively. Willis, G and L. McDowell. 1987. Pesticide Persistance and Foliage. Review of Environmental Contamination and Toxicology. Vol. 100. Springer Verlag, new York, pp 24 73.

Frequency of application ( days) 1 interpreted as the minimum interval between applications; product label ( high pest pressure)

Frequency of applications ( days) 3 Typical application interval ( low pest pressure)

Maximum applications per year 10 product label 4. Non Target Plant Exposure No data were submitted to evaluate the effects of pyrethrin exposure to plants. However the Agency does not consider pyrethrin or the other pyrethroids as being phytotoxic for the following reasons: 1) the compound is used as a spray on agricultural crops with no direct phytotoxic effects; 2) the neural toxic mode of action precludes phtotoxic concerns; 3) the Agency is not aware of any incidents involving aquatic or terrestrial plants and pyrethrin alone. Therefore, EECs were not determined.

C. Ecological Effects Characterization 1. Aquatic Effects a. Aquatic Animals  62 The complete range of toxicity reference values available for aquatic organisms exposed to pyrethrins is given in Appendix E. The most toxic of these reference values are summarized in Table 27a. Toxicity testing was conducted with both pyrethrin extracts or technical grade active ingredient ( TGAI), FEK 99 ( 57.5% a. i.), as well as with a formulated end use product, typically a Pyreonone crop spray ( 6.02% a. i.). The results of the toxicity testing suggests that pyrethrins are very highly toxic to freshwater fish ( LC 50 = 3.2  10 : g/ L) and to invertebrates ( EC 50 = 6.7  11.6 : g/ L), as well as to estuarine/ marine fish ( LC 50 = 3.8  16.0 : g/ L) and to invertebrates ( LC 50 / EC 50 = 0.14  1.4 : g/ L) on an acute basis. Toxicity tests on the formulated product ( 60.25% piperonyl butoxide PBO, and 6.02% pyrethrin) show a relative increase in toxicity when compared to tests on pyrethrin alone. Table 27b gives some indication as to the synergistic effects of PBO that help to increase the effectiveness of the active ingredient. The synergist activity can be seen when data on the formulation is compared to data on the TGAI. As shown in Table 27b, when animals are exposed to the formulation, there is a major difference in acute toxicity that occurs. Across all aquatic species tested, the formulation is more toxic to fish and invertebrates on an acute basis than the TGAI. The greatest difference in toxicity is seen with the estuarine/ marine invertebrates ( e. g., shrimp). There is a 90% difference between LC 50s , when comparing the TGAI to the formulation.

Chronic toxicity studies were conducted with the TGAI only. Studies show that pyrethrins impair growth ( length and weight) of freshwater fish ( LOAEC of 3.0 : g/ L and reproduction of freshwater invertebrates ( LOAEC of 2.0 : g/ L. The chronic NOAECs for freshwater fish and invertebrates were reported as 1.9 and 0.86 : g/ L, respectively. No data were submitted to evaluate the chronic risk to estuarine/ marine fish or invertebrates. However, as shown in Table 27c, based on the acute to chronic ratio method, NOAECs were estimated for the sheepshead minnow and mysid shrimp. The Agency calculated RQ values for agricultural uses by looking at maximum and typical application rates ( TGAI and formulation). For maximum application there are differences in risk quotients calculated for fish and invertebrates when exposure to the active ingredient alone is considered versus the formulation. Shown in Tables 27d through 27g, exposure to the formulated product increases the risk quotients, primarily because of the higher toxicity to fish and invertebrates. In this assessment, the estuarine/ marine invertebrates are most sensitive and have the highest risk estimates. In general, the model shows that maximum application rate can result in acute risk to freshwater invertebrates from exposure to the formulation was equal to or 2X greater than comparable acute risk for freshwater fish. Typical application rate appeared to reduce residue exposure to an aquatic area by about 40% resulting in no acute risk to fish and freshwater invertebrates. However, this same scenario shows that typical use ( formulation) still has the potential for acute risk to estuarine/ marine invertebrates. Four crop scenarios were also chosen to show the influence of drift to possible risk to aquatic areas. The Agency modeled these scenarios by setting the drift component to zero from the normal 5% drift default value. As shown in table 27h, when drift is set to zero, there is a reduction in EECs from 45  89% depending upon the crop scenatio, suggesting that drift is a major contributor to water concentrations for the GA peaches, ID potato, FL citrus, and CA grape crop scenarios.

Since pyrethrins tend to partition to the sediment compartment, data regarding the toxicity of pyrethrins to sediment dwelling organisms are needed. For this risk assessment, the sediment toxicity  63 was estimated based on the aquatic toxicity to aquatic invertebrates multiplied by the Koc value for pyrethrins.

Table 27a. Toxicity reference values for aquatic organisms exposed to the pyrethrin formulation and to the pyrethrin technical grade active ingredient ( TGAI).

Exposure scenario Species Exposure duration Toxicity reference value Referencea Freshwater Fish Acute Rainbow trout ( Oncorhynchus mykiss) 96 hours LC50 = 3.2 : g/ L MRID 43082304 Core, 6.02% a. i.

Acute Rainbow trout ( Oncorhynchus mykiss) 96 hours LC50 = 5.1 : g/ L MRID 43082303 Core, 57.5% a. i.

Chronic Fathead minnow ( Pimephales promelas) early life stage NOAEC = 1.9 : g/ L MRID 43252701, Core, 57.5% a. i.

Freshwater Invertebrates Acute Waterflea ( Daphnia magna) 48 hours EC50 = 6.7 : g/ L MRID 43082306, Core, 6.02% a. i.

Acute Waterflea ( Daphnia magna) 48 hours EC50 = 11.6 : g/ L MRID 43082305, Core, 57.5% a. i.

Chronic Waterflea ( Daphnia magna) reproduction NOAEC = 0.86 : g/ L MRID 43252702, Core, 57.5% a. i.

Esutarine/ Marine Fish Acute Sheepshead minnow ( Cyprinodon variegatus) 96 hours LC50 = 3.8 : g/ L MRID 43082308, Core, 6.02% a. i.

Acute Sheepshead minnow ( Cyprinodon variegatus) 96 hours LC50 = 16.0 : g/ L MRID 43082307, Core, 57.5% a. i.

Chronic: No data submitted; the acute to chronic ration method was used to estimate a NOAEC of 5.9 : g/ L for Sheepshead minnow Estuarine/ Marine Invertebrates Acute Mysid shrimp ( Mysidopsis bahia) 96 hours LC50 = 0.14 : g/ L MRID 43082312, Core, 6.02% a. i.

Acute Mysid shrimp ( Mysidopsis bahia) 96 hours LC50 = 1.4 : g/ L MRID 43082311, Core, 57.5% a. i.

Chronic: No data was submitted, however the acute to chronic ratio method was used to estimate a NOAEC of 0.10 : g/ L for Mysid shrimp Aquatic Plants Table 27a. Toxicity reference values for aquatic organisms exposed to the pyrethrin formulation and to the pyrethrin technical grade active ingredient ( TGAI).

Exposure scenario Species Exposure duration Toxicity reference value Referencea  64 Acute: No data aThe technical grade active ingredient ( TGAI) is 57.5% a. i, using a test substance called FEK 99. The formulation is 6.02% a. i., using a product called PYRENONE ® Crop Spray ( EPA Reg. No. 432 1033) .

Table 27b. Comparison of acute toxicity of pyrethrin extract/ technical grade active ingredient ( FEK 99) to the formulated product ( Pyrenone crop spray).

Test Species Exposure duration LC50 (: g/ L)

Percent Difference in Toxicity TGAI Formulation Freshwater Fish Acute Rainbow trout ( Oncorhynch us mykiss) 96 hours 5.1 3.2 37%

Freshwater Invertebrates Acute Waterflea ( Daphnia magna) 48 hours 11.6 6.7 42%

Esutarine/ Marine Fish Acute Sheepshead minnow ( Cyprinodon variegatus) 96 hours 16.0 3.8 76%

Estuarine/ Marine Invertebrates Acute Mysid shrimp ( Mysidopsis bahia) 96 hours 1.4 0.14 90%  65 Table 27c Acute to chronic ratio method calculations Species Acute LC50 (: g/ L) Chronic NOAEC (: g/ L)

Rainbow Trout 5.1 No data Fathead minnow No data 1.9 Sheepshead minnow 16.0 5.9 ( estimated) a Daphnia magna 11.6 0.86 Mysid shrimp 1.4 0.10 ( estimated) b aThe NOAEC estimated for the sheepshead minnow is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 5.1) / Freshwater NOAEC ( 1.9) = Estuarine/ marine LC50 ( 16.0 ppb)/ X ( estimated value for estuarine/ marine NOAEC). bThe NOAEC estimated for the Mysid shrimp is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 11.6 ppb)/ Freshwater NOAEC ( 0.86 ppb) = Estuarine/ marine LC50 ( 1.4 ppb)/ X ( estimated value for estuarine/ marine NOAEC).  66 Table 27d. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine fish associated with agricultural uses of pyrethrins. Toxicity values are based on studies with rainbow trout ( Oncorhynchus mykiss) ( LC50 = 3.2 : g/ L for PBO formulated product; 5.1 : g/ L for TGAI), and sheepshead minnow ( Cyprinodon variegatus) ( LC50 = 3.8 : g/ L for formulated product; 16 : g/ L for TGAI). EEC values are generated from PRZM/ EXAMS using maximum and typical rates.

EECs (: g/ L ) Freshwater fish Estuarine/ marine fish Scenario ( state/ crop) peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI IL corn 2.77 0.87a, b, c 0.54a, b, c 0.73a, b, c 0.17a, b MS cotton 1.91 0.60a, b, c 0.37a, b 0.50a, b, c 0.12a, b PA tomato 1.51 0.47a, b 0.29a, b 0.40abc 0.10a, b ME potato 1.35 0.42a, b 0.26a, b 0.36a, b 0.08a CA onion 0.78 0.24a, b 0.15a, b 0.21a, b 0.05a ND wheat 0.68 0.21a, b 0.13a, b 0.18a, b 0.04 NC apple 0.61 0.19a, b 0.12a, b 0.16a, b 0.04 FL citrus 0.40 0.13a, b 0.08 0.11a, b 0.03 OR snapbeans 0.45 0.14a, b 0.09 0.12a, b 0.03 GA peaches 0.66 0.21a, b 0.13a, b 0.17a, b 0.04 ID potato 0.37 0.12a, b 0.07 0.10a, b 0.02 MN alfalfa 0.36 0.11a, b 0.07 0.10a, b 0.02 CA grapes 0.35 0.11a, b 0.07 0.10a, b 0.02 SPECIAL RUNS USING 3 DAY INTERVAL BETWEEN APPLICATIONS, NORMAL PEST PRESSURE IL corn 2.40 0.75a, b, c 0.47a, b 0.63a, b, c 0.15a, b ID potato 0.21 0.07a 0.04 0.06a 0.01 CA onion 0.39 0.12a, b 0.08a 0.10a, b 0.02 TYPICAL APPLICATION RATE AND NUMBER OF APPLICATIONS ID potato 0.05 0.02 0.01 < 0.00 0.01 PA tomato 0.03 0.01 0.01 < 0.00 0.01 CA onion 0.04 0.01 0.01 < 0.00 0.01 OR snap beans 0.09 0.03 0.02 0.01 0.02 Table 27d. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine fish associated with agricultural uses of pyrethrins. Toxicity values are based on studies with rainbow trout ( Oncorhynchus mykiss) ( LC50 = 3.2 : g/ L for PBO formulated product; 5.1 : g/ L for TGAI), and sheepshead minnow ( Cyprinodon variegatus) ( LC50 = 3.8 : g/ L for formulated product; 16 : g/ L for TGAI). EEC values are generated from PRZM/ EXAMS using maximum and typical rates.

EECs (: g/ L ) Freshwater fish Estuarine/ marine fish Scenario ( state/ crop) peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI  67 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). cRQ exceeds LOC for acute high risk ($ 0.5).

Table 27e. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine invertebrates associated with agricultural uses of pyrethrins. Toxicity values are based on studies with waterflea ( Daphnia magna) ( EC50 = 6.7 : g/ L for PBO formulated product; EC50 = 11.6 : g/ L for TGAI) and mysid shrimp ( Mysidopsis bahia) ( LC50 = 0.14 : g/ L for formulated product; LC50 = 1.4 : g/ L for TGAI). EEC values are generated from PRZM/ EXAMS using maximum and typical rates.

EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Scenario ( state/ crop) peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI IL corn 2.77 0.41a, b 0.23a, b 19.79a, b, c 1.98a, b, c MS cotton 1.91 0.29a, b 0.16a, b 13.6a, b, c 1.36a, b, c PA tomato 1.51 0.23v 0.13a, b 10.79a, b, c 1.08a, b, c ME potato 1.35 0.20a, b 0.12a, b 9.64a, b, c 0.96a, b, c CA onion 0.78 0.12a, b 0.07a 5.67a, b, c 0.56a, b, c ND wheat 0.68 0.10a, b 0.06a 4.86a, b, c 0.49a, b NC apple 0.61 0.10a, b 0.05a 4.36a, b, c 0.44a, b FL citrus 0.40 0.10a, b 0.03 2.86a, b, c 0.29a, b OR snapbeans 0.45 0.10a, b 0.04 3.21a, b, c 0.32a, b GA peaches 0.66 0.10a, b 0.06a 4.71a, b, c 0.47a, b ID potato 0.37 0.10a, b 0.03 2.64a, b, c 0.26a, b Table 27e. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine invertebrates associated with agricultural uses of pyrethrins. Toxicity values are based on studies with waterflea ( Daphnia magna) ( EC50 = 6.7 : g/ L for PBO formulated product; EC50 = 11.6 : g/ L for TGAI) and mysid shrimp ( Mysidopsis bahia) ( LC50 = 0.14 : g/ L for formulated product; LC50 = 1.4 : g/ L for TGAI). EEC values are generated from PRZM/ EXAMS using maximum and typical rates.

EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Scenario ( state/ crop) peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI  68 MN alfalfa 0.36 0.10a, b 0.03 2.57a, b, c 0.26a, b CA grapes 0.35 0.10a, b 0.03 2.50a, b, c 0.25a, b SPECIAL RUNS USING 3 DAY INTERVAL BETWEEN APPLICATIONS, NORMAL PEST PRESSURE IL corn 2.40 0.36a, b 0.20a, b 17.14a, b, c 1.71a, b, c ID potato 0.21 0.03 0.02 1.50a, b, c 0.15a, b CA onion 0.39 0.10a, b 0.03 2.79a, b, c 0.28a, b TYPICAL APPLICATION RATE AND NUMBER OF APPLICATIONS ID potato 0.05 0.01 < 0.00 0.36a, b 0.04 PA tomato 0.03 < 0.00 < 0.00 0.21a, b 0.02 CA onion 0.04 0.01 < 0.00 0.29a, b 0.03 OR snap beans 0.09 0.01 0.01 0.64a, b, c 0.06a aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). cRQ exceeds LOC for acute high risk ($ 0.5).  69 Table 27f. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. Toxicity values are based on studies with rainbow trout ( Oncorhynchus mykiss) ( LC50 = 3.2 : g/ L for formulated product; 5.1 : g/ L for TGAI), and sheepshead minnow ( Cyprinodon variegatus) ( LC50 = 3.8 : g/ L for PBO formulated product; 16 : g/ L for TGAI). EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario.

EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI 6.0 inches 0.047 0.01 0.01 0.01 < 0.01 12.0 inches 0.049 0.02 0.01 0.01 < 0.01 3.3 feet ( 1 meter) 0.056 0.02 0.02 0.01 < 0.01 6.6 feet ( 2 meters) 0.066 0.02 0.02 0.02 < 0.01 Table 27g. Comparison of the Acute RQs calculated for the TGAI and PBO Formulation for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. Toxicity values are based on studies with waterflea ( Daphnia magna) ( EC50 = 6.7 : g/ L for formulated product; EC50 = 11.6 : g/ L for TGAI) and mysid shrimp ( Mysidopsis bahia) ( LC50 = 0.14 : g/ L for PBO formulated product; LC50 = 1.4 : g/ L for TGAI). EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario.

EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body Peak Acute RQ Formulation Acute RQ TGAI Acute RQ Formulation Acute RQ TGAI Surface Water 6 inches 0.047 < 0.01 < 0.01 0.33a 0.03 12 inches 0.048 0.01 < 0.01 0.34a 0.03 3.3 feet ( 1 meter) 0.050 0.01 < 0.01 0.36a 0.04 6.6 feet ( 2 meters) 0.055 0.01 < 0.01 0.39a 0.04 aRQ exceeds LOC for acute restricted ($ 0.1) and acute endangered species ($ 0.05).  70 Table 27h. Evaluation of acute exposure ( peak EECs) to fish and invertebrates for 4 selected crop scenarios ( GA peaches, ID potatoes, FL citrus, and CA grapes), when spray drift is set to 5% versus when spray drift is set to zero.

EECs (: g/ L )

Crop Scenario Peak EEC Drift set to 5% Peak EEC Drift set to zero Percent reduction in exposure to fish and invertebrates when spray drift component is eliminated GA peaches 0.66 0.344 48%

ID potato 0.37 0.042 89%

FL citrus 0.401 0.221 45%

CA grapes 0.348 0.021 94%

b. Aquatic Plants No data were submitted to evaluate the effects of pyrethrin exposure to non target plants.

2. Terrestrial Effects a. Terrestrial Animals Toxicity reference values for terrestrial organisms exposed to pyrethrins are summarized in Table 28. Pyrethrins appear to be practically non toxic to avian species on a acute oral and dietary basis ( oral LD50 > 2,000 mg/ kg bw; dietary LC50 > 5,620 mg/ kg diet). Reproductive toxicity data were not submitted, so chronic avian risk could not be evaluated. The available toxicity data are listed in Appendix E.

The technical grade active ingredient was used as the test substance in the acute and reproductive mammalian toxicity data. Synergists, such as piperonyl butoxide, work as competitive alternative substrate that bind cytochrome P 450 mixed function oxidase system ( MFO) enzymes, thus delaying the breakdown of toxins like the pyrethrins in both insects and mammals. Since the mammalian MFO system is more active than that of insects, pyrethrins are metabolized more efficiently in these organisms. Studies have suggested that piperonyl butoxide may enhance the production of MFO enzymes in mammals.

Mammalian toxicity data suggest that pyrethrins are slightly toxic to small mammals on an acute oral basis ( LD50 = 700 mg/ kg body weight). In the 2nd generation rat reproduction study, parental male systemic and reproductive toxicity were detected at 1000 ppm ( 65 mg/ kg body weight per day) and parental female systemic toxicity was detected at 3000 ppm ( 196 mg/ kg body weight per day). The NOAEL for parental systemic ( male) and reproductive toxicity was 100 ppm ( 6.4 mg/ kg body weight day).

Acute toxicity studies with honey bees show that pyrethrins are highly toxic on both a contact and an oral basis ( contact LC50 = 0.022 : g a. i./ bee and oral LD50 = 0.15 : g a. i./ bee).  71 Table 28. Toxicity reference values for mammals and birds exposed to pyrethrins.

Exposure Scenario Species Exposure Duration Toxicity Reference Value Referencea Mammals Acute Rat ( Rattus norvegicus) Single dose LD50 = 700 mg/ kg bwb MRID 42008101, 57.467 % a. i.

Chronic Rat ( Rattus norvegicus) 2 generation reproduction NOAEL = 6.4 mg/ kgday MRID 41327501, 57.6% a. i.

Birds Acute Bobwhite quail ( Colinus virginianus) 5 daysc LC50 > 5,620 mg/ kg diet MRID 41968801, Core, 57.6% a. i.

Acute Mallard duck ( Anas platyrhynchos) 5 daysc LC50 > 5,620 mg/ kg diet MRID 41968802, Core, 57.6% a. i.

Chronic: No data However, chronic data from permethrin are used as surrogate information because of similar mode of action NOAEC = 500 ppm.

aTest material reported as FEK 99, 57.467% to 57.6% a. i. pyrethrins, is considered to be representative of technical grade active ingredient ( TGAI). bFemale rats only; LD50 for males in the same study was 2,140 mg/ kg bw. cReferred to as a " subacute study"; 5 day dietary exposure followed by additional 3 day observation period.

b. Terrestrial Plants No data were submitted to evaluate the effects of cypyrethrin exposure to terrestrial plants. However the Agency does not consider pyrethrin or the other pyrethroids as being phytotoxic for the following reasons: 1) the compound is used as a spray on agricultural crops with no phytotoxic effects; 2) the neural toxic mode of action precludes phtotoxic concerns; 3) the Agency is not aware of any incidents involving plants and pyrethrin alone ( e. g., incident reports regarding terrestrial plant impact are inconclusive with regard to direct effect from pyrethrin).

IV. Risk Characterization A. Risk Estimation  Integration of Exposure and Effects Data 1. Non target Aquatic Animals and Plants Details regarding RQs and exceedances of levels of concern ( LOCs) for each scenario are provided below.  72 a. Fish and Aquatic Invertebrates: Agricultural Uses Table 29 shows that acute LOCs are exceeded for fish ( endangered species, restricted uses, and acute high risk) that may be exposed to pyrethrin residues that are associated with agricultural uses and maximum application rate. The risk categories and RQ ranges associated with the agricultural crop scenarios for freshwater fish are: Acute high risk ( RQ = 0.54 for IL corn); acute restricted use ( RQ range = 0.13 to 0.54 for GA peaches, OR snapbeans, FL citrus, NC apple, ND wheat, CA onions, ME potato, PA tomato, MS cotton, and IL corn); and endangered species risk ( RQ range = 0.07 to 0.54 for all crop scenarios CA grapes, MN alfalfa, ID potato, GA peaches, OR snapbeans, FL citrus, NC apple, ND wheat, CA onions, ME potato, PA tomato, MS cotton, and IL corn). The risk categories and RQ ranges associated with the agricultural crop scenarios for estuarine/ marine fish are: Acute restricted use ( RQ range = 0.12 to 0.17 for MS cotton and IL corn); and endangered species risk ( RQ range = 0.05 to 0.17 for CA onions, ME potato, PA tomato, MS cotton, and IL corn). Typical application rates showed no acute or chronic risk ( RQ < 0.0) to fish ( estuarine/ marine or freshwater).

Table 30 shows that acute LOCs for aquatic invertebrates ( endangered species, restricted uses, and acute high risk) were exceeded when the potential for acute exposure was calculated relative to several agricultural uses of pyrethrins and maximum application use. The risk categories and RQ ranges associated with the agricultural crop scenarios for freshwater invertebrates are: Acute restricted use risk ( RQ range = 0.12 to 0.24; crops IL corn, MS cotton, PA tomato, and ME potato); and acute endangered species risk ( RQ range = 0.05 to 0.07 for NC apple, ND wheat, GA peaches and CA onion). The risk categories and RQ ranges associated with the agricultural crop scenarios for estuarine/ marine invertebrates are: Acute high risk ( RQ range = 0.56 to 1.98 for CA onion, ME potato, PA tomato, MS cotton, and IL corn); acute restricted use ( RQ range 0.25 to 1.98 for all crop scenarios CA grapes, MN alfalfa, ID potato, GA peaches, OR snapbeans, FL citrus, NC apple, ND wheat, CA onion, MD potato, PA tomato, MS cotton, and IL corn); and acute endangered species risk ( RQ range = 0.25 to 1.98 for all crop scenarios CA grapes, MN alfalfa, ID potato, GA peaches, OR snapbeans, FL citrus, NC apple, ND wheat, CA onion, MD potato, PA tomato, MS cotton, and IL corn). Typical application rates in general showed no acute or chronic risk ( RQ < 0.0) to aquatic invertebrates ( estuarine/ marine or freshwater),( the OR snap beans scenario produced an endangered species RQ exceedance for estuarine/ marine invertebrates. However, at this time there are no endangered estuarine/ marine invertebrates).

As shown in Tables 29 and 30 there were no chronic risks found for freshwater fish or invertebrates associated with the agricultural uses relative to maximum and typical application rates.. However, there are risk concerns for estuarine/ marine invertebrates that are associated with the agricultural uses. In the absence of chronic data for Mysid shrimp, the NOAEC of 0.10 ppb was estimated and used in the risk assessment. When the 21 day EECs were compared to this estimated NOAEC, chronic LOCs were exceeded for all crops ( CA onion, ID potato, IL corn, CA grapes, MN alfalfa, GA peaches, OR snapbeans, FL citrus, NC apple, ND wheat, MS cotton, and PA tomato; RQ range = 1.5 to 6). A acute to chronic ratio NOAEC estimate of 5.9 ppb was also calculated for the estuarine/ marine fish ( sheepshead minnow). All RQs for chronic risk of pyrethrins to estuarine/ marine fish are below the LOC..  73 Table 43 shows the peak EECs and the RQs for two selected crop scenarios that were run for aerial and ground applications. The scenarios also included three buffer zones and two levels of spray drift ( high end and low end drift scenarios). Even though all the RQs are above the LOC, it is noted that the ground application and the low end drift scenario, with the large buffer zone yield the lower EECs and the lower RQs. The GA peach crop scenario had higher RQs, compared to the ID potato crop scenario. When the run with the drift set to 0% was compared to the standard run with drift set to 5%, it was found that drift was an important component of the peak EECs for both scenarios. It is also noted that even a small buffer zone of 50 ft reduces the RQs by more than 20%, compared to the same conditions with no buffer zone ( for both the high end and low end drift scenarios).

° The acute endangered species LOC and chronic LOC were slightly exceeded for small mammals ( RQ = 0.15 for endangered species and RQ = 1.10 for chronic). Chronic risk to birds could not be evaluated because no bird reproduction data were submitted.

° Although toxicity studies on the degradates were not provided, an evaluation of the structures indicate that they are the result of the rupture of the ester bridge of the parent, resulting in a carboxylic acid ( chrysanthemic acid), and an alcohol ( that subsequently be degraded to an acid as well). The resulting molecules have lost their pyrethroid toxicological activity, therefore, in this assessment, they were not considered of concern. Furthermore, the available data indicated that chrysanthemic acid was formed in small amounts except under hydrolytic conditions at pH 9.

The Master Label provided by the registrant, indicates that 1 day is used when pest pressure is high, but the normal interval between applications is 3 days. Three crop scenarios were selected and run with PRZM/ EXAMS with the same original input parameters, except that the interval between applications was set at 3 days instead of 1 day. The EEC's obtained are summarized in Table 7, and the RQs appear in Tables 12 and 13. It was noted a reduction in the RQs approximately proportional to the EECs, which ranged from around 12 15% for IL corn, to about 45% for ID potato, to about a half for CA onion. The RQs for some of the crop scenarios ( i. e. alfalfa) may not be necessarily the most conservative because certain crops are grown more often than once per year. This assessment assumed a single season per year.  74 Table 29. Acute and chronic RQs for freshwater and estuarine/ marine fish associated with agricultural uses of pyrethrins based on rainbow trout LC50 = 5.1 ug/ L, fathead minnow NOAEC = 1.9 ug/ L, sheepshead minnow LC50 = 16.0 ug/ L, and extraoplated NOAEC sheepshead minnow 5.9 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) Peak 60 day average Freshwater Fish ( Rainbow Trout) Acute RQ TGAI Freshwater Fish ( Fathead Minnow) Chronic RQ TGAI Estuarine/ marine Fish ( Sheepshea d Minnow) Acute RQ TGAI Estuarine/ marine Fish ( Sheepshead Minnow) Chronic RQ TGAI RUNS PERFORMED WITH MINIMUM INTERVAL BETWEEN APPLICATIONS, 1 DAY, HIGH PEST PRESSURE IL corna 2.77 0.37 0.54ab 0.19 0.17ab 0.06 MS cottona 1.91 0.28 0.37ab 0.15 0.12ab 0.05 PA tomatoa 1.51 0.20 0.30ab 0.11 0.09a 0.03 ME potatoa 1.35 0.28 0.26ab 0.15 0.08a 0.05 CA oniona 0.78 0.13 0.15ab 0.07 0.05a 0.02 ND wheata 0.68 0.13 0.13ab 0.07 0.04 0.02 NC applea 0.61 0.13 0.12ab 0.07 0.04 0.02 FL citrus 0.40 0.09 0.08ab 0.05 0.03 0.02 OR snapbeans a 0.45 0.10 0.09ab 0.05 0.03 0.02 GA peaches 0.66 0.10 0.13ab 0.05 0.04 0.02 ID potatoa 0.37 0.09 0.07a 0.05 0.02 0.02 MN alfalfaa 0.36 0.08 0.07a 0.04 0.02 0.01 CA grapes 0.35 0.07 0.07a 0.04 0.02 0.01 SPECIAL RUNS USING A 3 DAY INTERVAL BETWEEN APPLICATIONS, NORMAL PEST PRESSURE IL corn 2.40 0.33 0.47ab 0.17 0.15ab 0.06 Table 29. Acute and chronic RQs for freshwater and estuarine/ marine fish associated with agricultural uses of pyrethrins based on rainbow trout LC50 = 5.1 ug/ L, fathead minnow NOAEC = 1.9 ug/ L, sheepshead minnow LC50 = 16.0 ug/ L, and extraoplated NOAEC sheepshead minnow 5.9 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) Peak 60 day average Freshwater Fish ( Rainbow Trout) Acute RQ TGAI Freshwater Fish ( Fathead Minnow) Chronic RQ TGAI Estuarine/ marine Fish ( Sheepshea d Minnow) Acute RQ TGAI Estuarine/ marine Fish ( Sheepshead Minnow) Chronic RQ TGAI  75 ID potato 0.21 0.08 0.04 0.04 0.01 0.01 CA onion 0.39 0.09 0.08a 0.05 0.02 0.02 TYPICAL APPLICATION RATE AND NUMBER OF APPLICATIONSd ID potatoes 0.05 0.003 0.01 < 0.00 < 0.00 < 0.00 PA tomatoes 0.03 0.005 0.01 < 0.00 < 0.00 < 0.00 CA onions 0.04 0.004 0.01 < 0.00 < 0.00 < 0.00 OR snap beans 0.09 0.021 0.02 0.01 0.01 < 0.00 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). C The NOAEC estimated for the sheepshead minnow is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 5.1) / Freshwater NOAEC ( 1.9) = Estuarine/ marine LC50 ( 16.0 ppb)/ X ( estimated value for estuarine/ marine NOAEC). d For the 60 day values, three significant figures were shown.  76 Table 30. Acute and chronic RQs for freshwater and estuarine/ marine invertebrates associated with agricultural uses of pyrethrins based on Daphnia magna EC50 = 11.6 ug/ L, Daphnia magna NOAEC = 0.86 ug/ L, mysid shrimp EC50 = 1.4 ug/ L, and extraoplated NOAEC mysid shrimp 0.10 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) peak 21 day average Freshwater Invertebrate ( Daphnia magna) Acute RQ TGAI Freshwater Invertebrate ( Daphnia magna) Chronic RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Acute RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Chronic RQ TGAI RUNS PERFORMED WITH MINIMUM INTERVAL BETWEEN APPLICATIONS, 1 DAY, HIGH PEST PRESSURE IL corna 2.77 0.60 0.24ab 0.70 1.98abc 6.0 MS cottona 1.91 0.41 0.16ab 0.48 1.36abc 4.1 PA tomatoa 1.51 0.34 0.13ab 0.40 1.08abc 3.4 ME potatoa 1.35 0.39 0.12ab 0.45 0.96abc 3.9 CA oniona 0.78 0.25 0.07a 0.29 0.56abc 2.5 ND wheata 0.68 0.23 0.06a 0.27 0.49ab 2.3 NC applea 0.61 0.23 0.05a 0.27 0.44ab 2.3 FL citrus 0.40 0.18 0.03 0.21 0.29ab 1.8 OR snapbeansa 0.45 0.19 0.04 0.22 0.32ab 1.9 GA peaches 0.66 0.19 0.06a 0.22 0.47ab 1.9 ID potatoa 0.37 0.17 0.03 0.20 0.26ab 1.7 Table 30. Acute and chronic RQs for freshwater and estuarine/ marine invertebrates associated with agricultural uses of pyrethrins based on Daphnia magna EC50 = 11.6 ug/ L, Daphnia magna NOAEC = 0.86 ug/ L, mysid shrimp EC50 = 1.4 ug/ L, and extraoplated NOAEC mysid shrimp 0.10 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) peak 21 day average Freshwater Invertebrate ( Daphnia magna) Acute RQ TGAI Freshwater Invertebrate ( Daphnia magna) Chronic RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Acute RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Chronic RQ TGAI  77 MN alfalfaa 0.36 0.16 0.03 0.19 0.26ab 1.6 CA grapes 0.35 0.15 0.03 0.17 0.25ab 1.5 SPECIAL RUNS USING A 3 DAY INTERVAL BETWEEN APPLICATIONS, NORMAL PEST PRESSURE IL corn 2.40 0.50 0.21ab 0.58 1.71abc 5 ID potato 0.21 0.12 0.02 0.14 0.15ab 1.2 CA onion 0.39 0.16 0.03 0.19 0.28ab 1.6 TYPICAL APPLICATION RATE AND NUMBER OF APPLICATIONSe ID potatoes 0.05 0.007 < 0.00 0.01 0.04 0.07 PA tomatoes 0.03 0.008 < 0.00 0.01 0.02 0.08 CA onion 0.04 0.008 < 0.00 0.01 0.03 0.08 OR snap beans 0.09 0.038 0.01 0.04 0.06a 0.38 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). cRQ exceeds LOC for acute high risk ($ 0.5). d The NOAEC estimated for the Mysid shrimp is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 11.6 ppb)/ Freshwater NOAEC ( 0.86 ppb) = Estuarine/ marine LC50 ( 1.4 ppb)/ X ( estimated value for estuarine/ marine NOAEC). e For the 21 day values, three significant figures were shown, because the values were small in magnitude.  78 Mosquito Abatement For mosquito control, application directions in the label are insufficient to accurately estimate aquatic exposures that result from application of pyrethrin for controlling mosquitoes. Limitations ( as opposed to recommendations) on product labels for key parameters such as droplet size, wind speed, release height, application interval, and number of applications allowed per year are not specified. The exposure assessment conducted here represents the water concentrations expected from a typical, low level aerial application. Concentrations resulting from actual application of pyrethrin for mosquito control could be significantly higher than modeled concentrations if applicators used different application parameters.

In order to evaluate mosquito abatement with various parameters ( droplet size, boom height, maximum, and typical rates), a different modeling approach was used as compared to agricultural uses. The mosquito adulticides are applied as mists ( very small droplet sizes) that do not deposit rapidly but are expected to drift. Acute risk ( RQs), relative to the level of this drift, were calculated for various water depths. Typically, the FL turf scenario is used in PRZM/ EXAMS ( or decoupled EXAMS) to calculate the EEC's. The toxicity data endpoints used for the mosquito abatement assessment were based on the formulated product ( pyrenone crop spray) and maximum and typical rates. Tables 31 and 32 show that the maximum mosquito rate can result in residues that exceed the acute restricted use and endangered species triggers for estuarine/ marine invertebrates ( RQ range = 0.81 to 0.95) while the acute risk concerns for freshwater invertebrates or fish appears to be low. Using the maximum rate and decreasing the droplet size from 50 um to 40 um resulted in about a 37% reduction in residues but acute risk still exceeded the LOCs for these esturine/ marine organisms ( Tables 32 and 34). Raising the boom height to 150 ft. also reduced the potential acute risk to estuarine/ marine invertebrates by about 90% ( although the endangered species trigger was exceeded this scenario appears to present the lowest risk since there are no endangered estuarine/ marine invertebrates listed at this time). Table 40 shows that maintaining droplet size at 40 um, boom height 150 ft, maximum application rate appears to eliminate the potential for acute risk to estuarine/ marine invertebrates. Table 38 shows that by using the typical application rate ( 0.0025lbs ai/ A) and keeping boom height at 75 ft and droplet size at 50 um, acute risk to estuarine/ marine invertebrates can also be decreased significantly. Since there was no chronic data on the formulated product, chronic risk could not be estimated for the mosquito abatement uses. Although residues may increase with depth, presumably because photodegradation is impeded in deeper water bodies, and the level of adsorption of the chemical by the sediments is decreased as the depth of the water bodies increase, the expected residue levels appear to be below the LOCs for freshwater organisms and estuarine/ marine fish.  79 Table 31. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 50 : m, Boom height 75 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.114 0.03 0.03 12.0 inches 0.117 0.04 0.03 3.3 feet ( 1 meter) 0.122 0.04 0.03 6.6 feet ( 2 meters) 0.133 0.04 0.04 Table 32. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 50 : m, Boom height 75 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.114 0.02 0.81a 12 inches 0.117 0.02 0.84a 3.3 feet ( 1 meter) 0.122 0.02 0.87a 6.6 feet ( 2 meters) 0.133 0.02 0.95a aRQ exceeds LOC for acute ($ 0.5), acute restricted ($ 0.1) and acute endangered species ($ 0.05).  80 Table 33. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 40 : m, Boom height 75 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.071 0.02 0.02 12.0 inches 0.073 0.02 0.02 3.3 feet ( 1 meter) 0.076 0.02 0.02 6.6 feet ( 2 meters) 0.083 0.03 0.02 Table 34. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 40 : m, Boom height 75 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.071 0.01 0.51a 12 inches 0.073 0.01 0.52a 3.3 feet ( 1 meter) 0.076 0.01 0.54a 6.6 feet ( 2 meters) 0.083 0.01 0.59a aRQ exceeds LOC for acute ($ 0.5), acute restricted ($ 0.1) and acute endangered species ($ 0.05).  81 Table 35. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 50 : m, Boom height 150 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.007 < 0.00 < 0.00 12.0 inches 0.008 < 0.00 < 0.00 3.3 feet ( 1 meter) 0.008 < 0.00 < 0.00 6.6 feet ( 2 meters) 0.009 < 0.00 < 0.00 Table 36. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 50 : m, Boom height 150 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.007 < 0.00 0.05a 12 inches 0.008 < 0.00 0.06a 3.3 feet ( 1 meter) 0.008 < 0.00 0.06a 6.6 feet ( 2 meters) 0.009 < 0.00 0.06a aRQ exceeds LOC for acute endangered species ($ 0.05).  82 Table 37. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 50 : m, Boom height 75 ft, Application Rate 0.0025 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.036 0.01 0.01 12.0 inches 0.036 0.01 0.01 3.3 feet ( 1 meter) 0.038 0.01 0.01 6.6 feet ( 2 meters) 0.041 0.01 0.01 Table 38. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 50 : m, Boom height 75 ft, Application Rate 0.0025 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.036 0.01 0.25a 12 inches 0.036 0.01 0.25a 3.3 feet ( 1 meter) 0.038 0.01 0.27a 6.6 feet ( 2 meters) 0.041 0.01 0.29a aRQ exceeds LOC for acute restricted ($ 0.1) and acute endangered species ($ 0.05).  83 Table 39. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 40 : m, Boom height 150 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.003 < 0.00 < 0.00 12.0 inches 0.003 < 0.00 < 0.00 3.3 feet ( 1 meter) 0.003 < 0.00 < 0.00 6.6 feet ( 2 meters) 0.003 < 0.00 < 0.00 Table 40. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 40 : m, Boom height 150 ft, Application Rate 0.008 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.003 < 0.00 0.02 12 inches 0.003 < 0.00 0.02 3.3 feet ( 1 meter) 0.003 < 0.00 0.02 6.6 feet ( 2 meters) 0.003 < 0.00 0.02  84 Table 41. Acute RQs for freshwater and estuarine/ marine fish associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were rainbow trout LC50 = 3.2 ug/ L and sheepshead minnow LC50 = 3.8 ug/ L. Droplet size 50 : m, Boom height 150 ft, Application Rate 0.0025 lb a. i./ A EECs (: g/ L) Freshwater fish Estuarine/ marine fish Depth of water body peak Rainbow Trout Acute RQ Formulation Sheepshead Minnow Acute RQ Formulation Surface Water 6.0 inches 0.003 < 0.00 0.02 12.0 inches 0.003 < 0.00 0.02 3.3 feet ( 1 meter) 0.003 < 0.00 0.02 6.6 feet ( 2 meters) 0.003 < 0.00 0.02 Table 42. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 50 : m, Boom height 150 ft, Application Rate 0.0025 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water 6 inches 0.003 < 0.00 0.02 12 inches 0.003 < 0.00 0.02 3.3 feet ( 1 meter) 0.003 < 0.00 0.02 Table 42. Acute RQs for freshwater and estuarine/ marine invertebrates associated with mosquito abatement uses of pyrethrins. EEC values are generated from AGDISP and PRZM/ EXAMS for pyrethrins applied in a Florida Turf scenario. Effects values on the PBO formulation were Daphnia magnia EC50 = 6.7 ug/ L and mysid shrimp LC50 = 0.14 ug/ L. Droplet size 50 : m, Boom height 150 ft, Application Rate 0.0025 lb a. i./ A EECs (: g/ L ) Freshwater invertebrates Estuarine/ marine invertebrates Depth of water body peak Daphnia magna Acute RQ Formulation Mysid Shrimp Acute RQ Formulation Surface Water  85 6.6 feet ( 2 meters) 0.003 < 0.00 0.02 Table 43. Surface water EECs ( ppb) and RQs for ecological risk assessment based on pyrethrin use on Georgia peaches and California grapes, and buffer zones of 50, 100, and 150 ft. Results using average KOC = 35,170 Crop Peak EEC ( ug/ L) Acute RQ for estuarine/ marine invertebrates exposed to pyrethrin, based on an LC50 of 0.14 : g/ L for mysid shrimp*

Standard Aerial Run, With Spray Drift Set To 5%

Georgia Peaches 0.656 4.69a, b, c Idaho Potatoes 0.366 2.61a, b, c Special Run, With Spray Drift Set To 1%, Ground Application Georgia Peaches 0.421 3.01a, b, c Idaho Potatoes 0.082 0.58a, b, c Special Run, With Spray Drift Set To 0%

Georgia Peaches 0.344 N/ A Idaho Potatoes 0.042 N/ A High end, release height 15 ft, wind speed 15 mph, very fine droplets Buffer Zone 0 ft, 24.0% spray drift for GA peaches/ 31.2% spray drift for ID potatoes Georgia peaches 1.681 12.01a, b, c Table 43. Surface water EECs ( ppb) and RQs for ecological risk assessment based on pyrethrin use on Georgia peaches and California grapes, and buffer zones of 50, 100, and 150 ft. Results using average KOC = 35,170 Crop Peak EEC ( ug/ L) Acute RQ for estuarine/ marine invertebrates exposed to pyrethrin, based on an LC50 of 0.14 : g/ L for mysid shrimp*

 86 Idaho Potatoes 2.259 16.14a, b, c Buffer Zone 50 ft/ 16.8% spray drift for GA peaches/ 23.1% spray drift for ID potatoes Georgia peaches 1.436 10.26a, b, c Idaho Potatoes 1.673 11.95a, b, c Buffer Zone 100 ft, 12.7% spray drift for GA peaches/ 18.4% spray drift for ID potatoes Georgia Peaches 1.164 8.31a, b, c Idaho Potatoes 1.333 9.52a, b, c Buffer Zone 150 ft, 10.2% spray drift for GA peaches/ 15.4% spray drift for ID potatoes Georgia Peaches 0.998 7.13a, b, c Idaho Potatoes 1.116 7.97a, b, c Low end, release heigh 8 ft, wind speed 3 mph, medium to coarse droplets Buffer Zone 0 ft, 2.8% spray drift for GA peaches/ 3.0% spray drift for ID potatoes Georgia Peaches 0.519 3.71a, b, c Idaho Potatoes 0.223 1.59a, b, c Buffer Zone 50 ft, 1.4% spray drift for GA peaches/ 1.5% spray drift for ID potatoes Georgia Peaches 0.431 3.08a, b, c Idaho Potatoes 0.115 0.82a, b, c Buffer Zone 100 ft, 1.1% spray drift for GA peaches/ 1.1% spray drift for ID potatoes Georgia Peaches 0.413 2.95a, b, c Idaho Potatoes 0.087 0.62a, b, c Buffer Zone 150 ft, 0.9% spray drift for GA peaches/ 0.8% spray drift for ID potatoes Georgia Peaches 0.400 2.86a, b, c Idaho Potatoes 0.067 0.48 b, c Table 43. Surface water EECs ( ppb) and RQs for ecological risk assessment based on pyrethrin use on Georgia peaches and California grapes, and buffer zones of 50, 100, and 150 ft. Results using average KOC = 35,170 Crop Peak EEC ( ug/ L) Acute RQ for estuarine/ marine invertebrates exposed to pyrethrin, based on an LC50 of 0.14 : g/ L for mysid shrimp*

 87 Based on 1 in 10 year exceedance probability ( 0.10). Peak EEC's provided with three decimal points for information only. * Mysid shrimp was the most sensitive aquatic species. aRQ meets or exceeds LOC for acute high risk ( LOC = 0.5) bRQ meets or exceeds LOC for acute restricted risk ( LOC = 0.1) cRQ meets or exceeds LOC for acute endangered species risk ( LOC = 0.05).

" Down the Drain" Exposure: Acute and Chronic Risk The Agency has assumed that many of the indoor uses of pyrethrin should not impact ecological systems because of their reduction in exposure potential. Pyrethrin is used in various household products, such as pyrethrin containing prescription drugs, over the counter drugs, and pet products ( like shampoo), available to the US consumers. Potential release of pyrethrin in the domestic wastewater ( referred to as " down the drain" release) may occur from using these household products. The information on the amount of pyrethrin utilized on each of these uses is considered Confidential Business Information and cannot be provided in this report, but it is stressed that these uses are of concern and included in The Agency's assessment. The risk to aquatic systems from products that pass through wastewater treatment plants and the eventual potential exposure to aquatic organisms was assessed. This assessment suggests that pyrethrin residues released to aquatic areas from this process should not cause acute or chronic risk to freshwater or estuarine/ marine fish and invertebrates ( Tables 44 and 45).  88 Table 44. Acute and chronic RQs for freshwater and estuarine/ marine fish associated with " downthe drain" uses of pyrethrins based on rainbow trout LC50 = 5.1 ug/ L, fathead minnow NOAEC = 1.9 ug/ L, sheepshead minnow LC50 = 16.0 ug/ L, and extraoplated NOAEC sheepshead minnow 5.9 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) Peak Chronic Freshwater Fish ( Rainbow Trout) Acute RQ TGAI Freshwater Fish ( Fathead Minnow) Chronic RQ TGAI Estuarine/ marine Fish ( Sheepshea d Minnow) Acute RQ TGAI Estuarine/ marine Fish ( Sheepshead Minnow) Chronic RQ TGAI "

downthe drain" 0.00242 0.000186 < 0.00 < 0.00 < 0.00 < 0.00 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). C The NOAEC estimated for the sheepshead minnow is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 5.1) / Freshwater NOAEC ( 1.9) = Estuarine/ marine LC50 ( 16.0 ppb)/ X ( estimated value for estuarine/ marine NOAEC).

Table 45. Acute and chronic RQs for freshwater and estuarine/ marine invertebrates associated with ` down the drain" uses of pyrethrins based on Daphnia magna EC50 = 11.6 ug/ L, Daphnia magna NOAEC = 0.86 ug/ L, mysid shrimp EC50 = 1.4 ug/ L, and extraoplated NOAEC mysid shrimp 0.10 ug/ L. EEC values are generated from PRZM/ EXAMS.

EECs (: g/ L )

Scenario ( state/ crop) peak chronic Freshwater Invertebrate ( Daphnia magna) Acute RQ TGAI Freshwater Invertebrate ( Daphnia magna) Chronic RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Acute RQ TGAI Estuarine/ marine Invertebrate ( Mysid Shrimp) Chronic RQ TGAI " down thedrain 0.00242 0.000186 < 0.00 < 0.00 < 0.00 < 0.00 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted use ($ 0.1). cRQ exceeds LOC for acute high risk ($ 0.5). d The NOAEC estimated for the Mysid shrimp is based on the acute to chronic ratio method, determined by the following mathematical relationship: Freshwater LC50 ( 11.6 ppb)/ Freshwater NOAEC ( 0.86 ppb) = Estuarine/ marine LC50 ( 1.4 ppb)/ X ( estimated value for estuarine/ marine NOAEC).  89 b. Sediment Organisms The pyrethrins are lipophilic compounds that can adsorb readily to particulate and sediment, thus possibly limiting its exposure to aquatic life in the water column but increasing toxic exposure in the benthos. Sediment can act as a reservoir for lipophilic persistent compounds. Exposure to this sediment can result in a direct impact to aquatic life through respiration, ingestion, dermal contact, as well as indirect impact through alterations of the food chain. In order to evaluate this possible concern the USEPA Office of Water ( OW) has developed the Equilibrium Partitioning Sediment Guidelines ( ESG). The EFED used the Equilibrium Partitioning Guidelines, which are based on the hydrophobicity and concentrations of the chemical normalized to organic carbon ( OC) in sediment ( De Toro et al. 1991), to estimate sediment concentrations and sediment dwellers toxicity.

Since, EFED uses a deterministic method for its screening level risk assessment, the calculation of risk quotient values ( RQ) is important for assessing possible risk. The RQ values are calculated by taking the ratio of the estimated exposure concentrations ( EEC) to the toxicity effect value ( e. g., LC50, NOAEC). The EEC values are model generated ( e. g. by PRZM/ EXAMS). However, the PRZM/ EXAMS output produces water column EEC values, as well as sediment and pore water EEC values. Therefore, in order to assess possible toxic pesticide exposure to aquatic organisms from sediments, EFED used the PRZM/ EXAMS model which incorporates the principles of the equilibrium partitioning theory, in order to generate EECs from sediment and pore water. By relying on sediment and/ or pore water output values.

The calculations that rely on pore water were calculated by dividing the PRZM/ EXAMS output value for pore water concentrations by the dissolved concentrations in the water column that caused toxicity in bioassays ( e. g., LC50).

EEC pore water ug/ L / LC50 ugL For the scenarios modeled in this assessment on pyrethrins, the benthic pore water concentrations ( EECpore) are, on average, estimated to be approximately 60% lower than the surface water concentrations using PRZM/ EXAMS. Therefore, the RQsed value is generally 60% lower than the RQaq value for the same scenario and effects endpoint.

The Agency evaluated the potential for acute and chronic risk from sediments that could act as a repository for pyrethrin residues. Table 46 shows that there are estimated acute risk concerns to estuarine/ marine invertebrates ( restricted use, RQ range 0.10 to 0.15) as noted in the scenarios that represent MS cotton, ME potato, and IL corn ( endangered species risk concerns ( RQ range 0.05 to 0.15 for ND wheat, PA tomato, MS cotton, ME potato, and IL corn were calculated but the Agency acknowledges that currently there are no endangered estuarine/ marine invertebrates listed). Table 47 shows the potential for chronic risks to estuarine/ marine sediment dwelling invertebrates. In the absence of chronic data for estuarine/ marine invertebrates, the NOAEC estimated for estuarine/ marine invertebrates that was used to estimate risk to invertebrates in the water column was also used for sediment. The chronic LOCs were exceeded for estuarine/ marine organisms associated with the agricultural uses ( RQ range = 1.1 to 2, Crops: PA tomato, MS cotton, ME potato, and IL corn). There are no chronic risks to freshwater sediment dwelling invertebrates associated with the agricultural uses.  90 Table 46. Acute Risk Estimation to freshwater and estuarine/ marine sediment dwelling organisms based on data from the surrogate species, Daphnia magna ( EC50 = 11.6 : g/ L ) and Mysid Shrimp ( LC50 = 1.4 : g/ L). EEC values reflect pore water estimates that are in equilibrium with sediment concentrations ( KOC of 35,170 L/ kg) as generated from PRZM/ EXAMS for the agricultural crop uses.

Scenario EEC Acute RQ Pore water peak (: g/ L) Sediment (: g/ kgoc) Freshwater TGAI Estuarine/ marine TGAI IL corn 0.21 7350 0.02 0.15ab ME potato 0.16 5590 0.01 0.11ab MS cotton 0.14 4820 0.01 0.10ab PA tomato 0.12 4110 0.01 0.09a ND wheat 0.07 2390 0.01 0.05a CA onion 0.06 2110 0.01 0.04 NC apple 0.06 2110 0.01 0.04 OR snapbeans 0.05 1650 < 0.01 0.04 ID potato 0.04 1350 < 0.01 0.03 MN alfalfa 0.04 1270 < 0.01 0.03 FL citrus 0.04 1270 < 0.01 0.03 GA peaches 0.04 1370 < 0.01 0.03 CA grapes 0.03 1020 < 0.01 0.02 aRQ exceeds LOC for acute endangered species ($ 0.05). bRQ exceeds LOC for acute restricted ($ 0.1)  91 Table 47. Chronic Risk Estimation to freshwater and estuarine/ marine sediment dwelling organisms based on data from the surrogate species, Daphnia magna ( NOAEC = 0.86 : g/ L ) and Mysid Shrimp ( NOAEC = 0.10 : g/ L ). EEC values reflect pore water estimates that are in equilibrium with sediment concentrations ( KOC of 35,170 L/ kg) as generated from PRZM/ EXAMS for the agricultural crop uses.

Scenarios EECs Chronic RQ Pore water 21 day (: g/ L) Sediment (: g/ kg) Freshwater Estuarine/ marine IL corn 0.20 7170 0.23 2 ME potato 0.15 5420 0.17 1.5 MS cotton 0.13 4640 0.15 1.3 PA tomato 0.11 3900 0.13 1.1 ND wheat 0.07 2290 0.08 0.7 CA onion 0.07 2290 0.08 0.7 NC apple 0.06 2040 0.07 0.6 OR snapbeans 0.05 1620 0.06 0.5 ID potato 0.04 1300 0.05 0.4 MN alfalfa 0.04 1230 0.05 0.4 FL citrus 0.04 1230 0.05 0.4 GA peaches 0.04 1340 0.05 0.4 CA grapes 0.03 985 0.03 0.3 2. Non target Terrestrial Animals a. Mammals Table 19 provides acute and chronic risk quotient ( RQ) values for mammals of different body weight size classes exposed to different forage items. Using the foliar half life of 1 and 14 days, the acute RQs are all mammals ( listed and non listed) are less than the LOC of 0.1. All chronic RQs for listed and nonlisted mammals exposed to pyrethrins in all dietary scenarios are below the LOCs. Both scenarios ( 1  3 day interval) using the typical application rate are depicted in Table 19.  92 Table 48. Acute and chronic RQ calculations for mammalian consumption of plant and insect forage material. The RQs are based on acute LD50 of 700 mg/ kg body weighta and an NOAEC of 100 ppm diet in rats ( Rattus norvegicus). RQ values were calculated for two foliar dissipation residue half lives as found in Willis and McDowell, ( 1987) for surrogate pyrethroids, phenothrin and pyrethrin.

Crop application rate ( lbs ai/ A; no. app.) Forage item Maximum EEC ( ppm) Acute RQsb Chronic RQsb 15 g 35 g 1000 g Various crops 0.050 ( 10), interval between applications 1 day Short grass 23.98  97.01 0.06 0.05 0.03 0.97 Tall grass 10.99  44.46 0.03 0.02 0.01 0.44 Broadleaf/ forage plants and small insects 13.49  55.57 0.03 0.03 0.02 0.55 Fruits/ pods/ seeds/ large insects 1.50  6.06 0.0 0.0 0.0 0.06 Various crops 0.050 ( 10), typical interval between applications 3 day Short grass 13.71  67.25 0.01  0.04 0.1  0.04 0.0  0.02 0.67 Tall grass 6.29  30.82 0.0  0.02 0.0  0.02 0.0  0.01 0.31 Broadleaf/ forage plants and small insects 7.71  37.83 0.0  0.02 0.0  0.02 0.0  0.01 0.38 Fruits/ pods/ seeds/ large insects 0.86  4.20 0.0 0.0 0.0 0.04 aThe acute mammalian LD50 is based on female mortality of rats exposed to FEK 999; the LD50 for male rats in the same study was reported as 2,140 mg/ kg body weight, suggesting a gender specific difference for acute effects ( mortality) of a factor of 3. b RQ calculated for foliar dissipation residue half lives of 1 and 14 days. respectively b. Birds Table 20 provides acute and chronic risk quotient ( RQ) values for avian food items following application of pyrethrins under a maximum use pattern for various crop species. An analysis of the results indicates that avian acute, restricted use, chronic and endangered species LOCs are not exceeded at registered maximum application rates for pyrethrins. Chronic risk to avian species was estimated by using pyrethrin avian NOAEC for Bobwhite quail.( NOAEC = 125 mg/ kg/ diet)..  93 Table 49. Acute RQ calculations for bird consumption of plant and insect forage material. The RQs are based on a dietary LC50 of 5,620 mg/ kg diet with the bobwhite quail ( Colinus virginianus) and mallard duck ( Anas platyrhynchos) a. RQ values were calculated for two foliar dissipation residue half lives as found in Willis and McDowell, ( 1987) for surrogate pyrethroids, phenothrin and pyrethrin.

Crop application rate ( lbs ai/ A; no. appl.) Forage item Maximum EEC ( ppm) Acute RQb Chronic RQbc Various crops 0.050 ( 10), interval between applications 1 day Short grass 23.98  97.01 0.0 0.02 0.02  0.78 Tall grass 10.99  44.46 0.0  0.01 0.09  0.36 Broadleaf/ forage plants and small insects 13.49  55.57 0.0  0.01 0.11 0.44 Fruits/ pods/ seeds/ large insects 1.50  6.06 0.0 0.01 0.05 Various crops 0.050 ( 10), typical interval between applications 3 days Short grass 13.71  67.25 0.0  0.01 0.11  0.54 Tall grass 6.29  30.82 0.0  0.01 0.05  0.25 Broadleaf/ forage plants and small insects 7.71  37.83 0.0  0.01 0.06  0.30 Fruits/ pods/ seeds/ large insects 0.86  4.20 0.0 0.01  0.03 aThe acute toxicity is reported as LC50 > 5,620 mg/ kg diet, suggesting that the actual LC50 was not determined by the dosing regimen. Use of this toxicity value will likely overestimate acute risks. b RQ calculated for foliar dissipation residue half lives of 1 and 14 days. respectively c Avian chronic toxicity was substituted with a NOAEC from pyrethrin c. Insects Currently, EFED does not assess risk to non target insects. Results of acceptable studies are used for recommending appropriate label precautions. Pyrethrins are very toxic to honeybees. Therefore, honeybees and other beneficial insects are expected to be at risk based on aerial applications that may cause wind dispersal of pyrethrins to areas where these insects may pollinate and/ or feed.

3. Non target Terrestrial and Semi aquatic Plants Since toxicity data were unavailable for non target plants, risks were not calculated.

B. Risk Description  Interpretation of Effects Pyrethrins are the active insecticidal components of certain species of chrysanthemum plants that have been used as insecticides for at least two centuries. These compound are moderately persistent, bind to soils ( Koc = 35,170) in the environment but are unstable to sunlight. The degradation products of  94 pyrethrin occur as a result of ester bond breakage resulting in carboxylic acid and an alcohol. Data on the toxicity of the degradates were not available for this review, but because of the disruption of the parent backbone structure during break down, EFED assumes a decrease in effective toxicity. One of the major insecticidal advantages of pyrethrin is their " knockdown" action that induces paralysis in target organisms which is in contrast to their relatively lower killing potential ( parent can be metabolized). However, in order to delay this metabolic action ( help inhibit microsomal enzyme breakdown) and enhance lethality, pyrethrins are often used in combination with other pesticides and synergists ( such as piperonyl butoxide). However, for the purposes of this review only risk to the parent compound will be assessed ( exception is the evaluation for mosquito abatement where a formulation is used).

1. Estimating Risk to Aquatic Systems EFED risk assessment of pyrethrin shows that a major risk of the chemical exposure in the environment can be focused on aquatic systems. The evaluation of this risk to aquatic organisms was approached by dividing aquatic systems into two very general parts or media; water column and the benthos. The first portion is the water column, which is defined as the aquatic area between surface and benthos ( 6" above the bottom). Organisms living in this area are free swimming and can feed and breed at the surface, mid water and/ or on the benthos. Direct pesticidal contact ( e. g., gill lamella, ingestion, and integument) to these organisms is assumed to be from the water column and toxicity assessment points are the acute LC50 and chronic NOAEC that are generated through standard water column toxicity tests. The second aquatic compartment is the benthos which is composed of sediments and the area six inches above the sediment ( epibenthos). The benthos is composed of a diversity of aquatic invertebrates ( e, g,, insect larvae, crustaceans, mollusks), species of fish ( e. g., catfish, loach), as well as certain critical life stages of organisms that reside in the water column; the benthos is also the initial nursery area for several species of fish especially commercial species such as salmonids. The benthos can also be a source of food items for several species of fish ( i. e., water column) actively feeding on the organisms in the sediment and/ or capturing organisms that are emerging from this area.

In order to evaluate the potential for toxic risk from pyrethrin exposure in the water column, EFED used the standard model generated EEC ratio to a most sensitive endpoint as defined from LC50, EC50, or NOAEC. The evaluation of toxic risk to the benthos compartment was approached by assuming equilibrium partitioning of high Koc compounds between the sediment and the interstitial water ( i. e., this is the pore water, the water found between particulate in the sediment). The EEC for pore water were model generated ( PRZM/ EXAMS) and used to calculate RQ values. Since, sediment toxicity data was not available for this report, EFED relied on the most sensitive water column values. The RQ for assessing potential risk to sediment reflects pore water EEC values/ most sensitive water column toxicity value. EFED assumes that there is no difference in sensitivity between water column organisms and comparable benthic organisms regarding toxicity to pyrethrin. These assumptions are supported by the EPA Office of Water which uses a similar approach and assumption in developing sediment guidelines ( ESG) for the protection of benthic organisms ( The ESG Technical Document, USEPA, 2000a).

a. Estimating Risk to Aquatic Systems ( Water Column Exposure)

In evaluating possible pyrethrin risk to aquatic systems from use on agricultural crops, the Agency chose to evaluate maximum and typical application rates. Model generated exposure values suggests that maximum rates can result in acute risk to fish and aquatic invertebrates ( freshwater and estuarine/ marine) with triggers that included restrictive use and endangered species concern ( although  95 estuarine/ marine endangered invertebrate was triggered, EFED realizes that at this time there are no listed species under this category). Evaluating chronic risk from this exposure scenario showed that LOC triggers were exceeded for estuarine/ marine invertebrates, while fish ( freshwater and estuarine/ marine) and freshwater invertebrates may not be at chronic risk from pyrethrin exposure in the water column. This potential for acute and chronic risk reflects exposure from large acreage crops such as corn, cotton, wheat and orchards ( e. g., pome fruit and stone fruits). Concern from citrus use appears to be reflected in possible acute risk to estuarine/ marine fish and invertebrates, as well as chronic risk to estuarine/ marine invertebrates. The risk quotients for some of the crop scenarios may not necessarily be the most conservative because certain crop scenarios ( i. e. alfalfa) are grown more than once per year. This assessment assumed a single season per year.

The second scenario that depicts typical application rate appears to have the potential to reduce risk to aquatic systems. Evaluation of four crop scenarios using the TGAI ( ID potatoes, PA tomatoes, CA onions, OR snap beans) suggests that LOCs for freshwater and estuarine/ marine fish and invertebrates should not be exceeded if typical application rate is used. The Agency also assessed the maximum and typical rates for a pyrethrin formulation with PBO but only evaluated acute exposure to aquatic organisms. The calculated EECs show that acute risk from the maximum formulation rate appeared to be higher than risk calculated only from the TGAI. This evaluation showed that acute risk from the formulation was about 2 7X greater for freshwater and estuarine/ marine fish and about 10X greater for estuarine/ marine invertebrates. However, the typical formulation rate appears to reduce the risk ( freshwater and estuarine/ marine fish and freshwater invertebrates), but this reduction in exposure still presents the potential for acute high, acute restrictive, and chronic risk to estuarine/ marine invertebrates species.

b. Estimating Risk to Aquatic Systems ( Sediment Exposure)

The sediment scenario ( high pest pressure application intervals, 1 day) modeled in this assessment showed that the benthic pore water concentrations ( EECpore) are about 60% lower than the water column levels using the PRZM/ EXAMS model. This decrease in concentration levels suggests lower risk potential. Acute risk to freshwater sediment dwelling invertebrates appears to be below our LOC for all crop scenarios, while RQ values calculated for some crops ( e. g., corn, potatoes, cotton, tomatoes, and wheat) suggest acute risk to estuarine/ marine benthic invertebrates. However, realistically the extent of this acute risk depends on the proximity of these crops to estuatrine/ marine environments; wheat acreage is not usually found in coastal areas, while tomatoes, cotton, potatoes and corn acreage may overlap this area of concern in costal states. Although acute risk may appear to be low for freshwater and estuarine/ marine invertebrates, calculated chronic RQs for estuarine/ marine sediments show LOC exceedances for these crops ( corn, potatoes, cotton, tomatoes) and suggest that there could be the potential for chronic risk to estuarine/ marine invertebrates that may be directly associated with these sediments.

c. Estimating Risk to Aquatic Systems Through Mosquito Abatement EFED used a different modeling approach to evaluate mosquito abatement ( description of modeling scenario in Section III. B. 1. b). Mosquito adulticides are applied as mists ( very small droplet sizes) with the intent that the pesticide will linger in the air as a fog and that the eventual deposition onto the surface will be relatively slow. Therefore, the level of drift can be substantial and has the potential for eventual contact with adjacent bodies of water. Therefore, in order to estimate risk to aquatic systems, EFED  96 calculated the level of drift for such special circumstances ( AGDISP), and the EEC values for bodies of water of various depths using the FL turf scenario ( PRZM/ EXAMS). The toxicity data end points used for this scenario were based on the formulated product ( Pyrenone Crop spray). Calculated RQ values for surface water EECs ranged in depth from ½ to 6.6 feet and suggest that this use pattern should not cause acute risk to fish ( freshwater and estuarine/ marine) or invertebrates ( freshwater). However, there is the potential for acute risk to estuarine/ marine invertebrates like shrimp ( restrictive use category).

The results of this assessment found lower concentrations in shallow water bodies compared to deep water bodies. This may be partially explained by three reasons: The Henry's Law constant suggests a potential for loss of pesticide from the pond via volatilization. Second, with a very high KOC, the pyrethrin tends to partition towards the sediment. This equilibrium will occur more rapidly in shallow waters than in deeper bodies of water. Finally, a third possible explanation is the short aqueous photolysis half life ( 0.5 days) for pyrethrin. When a chemical has a short half life ( as in this scenario) and it is concentrated in shallow waters ( i. e., six inches), it can be expected to photodegrade more readily than when it is spread throughout a deeper water column. Light is not expected to penetrate into depths deeper than about 1 ft.

It was found that for mosquito control, application directions in the label are insufficient to accurately estimate aquatic exposures that result from application of pyrethrin for controlling mosquitoes. Limitations ( as opposed to recommendations) on product labels for key parameters such as droplet size, wind speed, release height, application interval, and number of applications allowed per year are not specified. The exposure assessment conducted here represents the water concentrations expected from a typical, low level aerial application. Concentrations resulting from actual application of pyrethrin for mosquito control could be significantly higher than modeled concentrations if applicators used different application parameters.

It was also found that the shallow pond shows the lower concentration, possibly due to partitioning of the chemical with particulate and the sediment. Variables that have a high impact on the aquatic EECs are the boom height ( higher boom height, the lower the level of deposition), the droplet size ( the smaller droplets, the lower the levels of deposition), the wind speed ( too low wind speeds favor higher deposition), and obviously the application rate ( it appears that for many of the products the maximum application rate is lower than the maximum application rate stated in the Master Label [ 0.0025 lb a. i./ A vs 0.008 lb a. i./ A]). The interval between applications and the number of applications are expected to also have an effect on the EECs ( similar to an agricultural application). In general the Agency evaluation of the adulticide scenario using maximum and typical application rates. The maximum rate showed that there did not appear to be the potential for acute risk to freshwater fish and invertebrates or esrtuarine/ marine fish. However, the LOCs for estuarine/ marine invertebrates were exceeded. This risk to estuarine/ marine invertebrates appeared to be eliminated if the boom height was set at 150 ft and the droplet size was at 40 um. The Agency also evaluated the typical rate and found that potential acute risk to estuarine/ marine invertebrates could be eliminated with a boom height of 75ft and a 50 um droplet size.

d. Estimating Risk to Aquatic Systems Through " Down the Drain" Consideration of Exposure from Pyrethrin Pharmacolsoticals.  97 Pyrethrin is used in various household products, such as pyrethrin containing prescription drugs, over the counter drugs, and pet products ( like shampoo), available to the US consumers. Potential release of pyrethrin in the domestic wastewater system ( referred to as " down the drain" release) may occur from using these household products. The information on the amount of pyrethrin utilized on each of these uses is considered Confidential Business Information and cannot be provided in this report, but it is stressed that these uses are of concern and included in The Agency's assessment. The risk to aquatic systems from products that pass through wastewater treatment plants and the eventual potential exposure to aquatic organisms was assessed. This assessment suggests that pyrethrin residues released to aquatic areas from this process should not cause acute or chronic risk to freshwater or estuarine/ marine fish and invertebrates.

e. Other Special Considerations for Evaluating Aquatic Risk ( Buffer Zones)

The extent to which spray drift may be an important component of the concentrations of pyrethrins reaching bodies of water adjacent to treated areas after their application, was investigated. EFED ran four crop scenarios with spray drift set to 0% and compared the results to the corresponding runs with spray drift set to 5%. The runs with drift set to 0% resulted in EECs lower than the standard runs. When the results of the standard run ( 5% drift) with the special run ( 0% drift), it was found that the level of the peak EEC attributable to spray drift for GA peach and for FL citrus was near 46%, while for ID potato and CA grapes it was > 88%. The selection of crop scenarios was then narrowed down to two. These scenarios were run with standard input for ground applications and with various buffer zones. This was done to see the possible affects of buffer zones in reducing risk from pyrethrin exposure to aquatic systems. The level of spray drift simulated both a high end drift scenario ( high boom, high wind speed, small droplet size), and a low end drift scenario ( low boom height, low wind speed, large droplet size), to bracket the spectrum of possibilities. Calculated RQ values for buffer zones set at 0, 50, 100, and 150 feet and spray drift set at 0,1 and 5% showed acute risk to estuarine/ marine invertebrates. However, as expected, the low end drift scenario yielded lower levels of drift and consequently lower EECs and RQs. Combined with large buffer zones ( 150 ft), the RQs were of similar order of magnitude than those yielded by ground applications. It is also noted that even a small buffer zone of 50 ft reduces the RQs by more than 20%, compared to the same conditions with no buffer zone ( for both the high end and low end drift scenarios).

2. Estimating Risk to Terrestrial Organisms ( Mammals and Birds)

An evaluation of possible risk to terrestrial organisms was conducted using the T REX model that provides estimates of concentrations of chemical residues on different types of food items that may be sources of dietary exposure to avian, mammalian, reptilian, or terrestrial phase amphibian receptors. Acute and chronic RQ values for pyrethrin exposure from various food items to mammals of different weight classes were calculated using foliar dissipation values ( 1  14 days) found in Willis and McDowell, ( 1987) for pyrethroids that have similar chemistry and mode of action as pyrethrin ( pyrethrin and phenothrin). The use of maximum and typical application rate produced acute and chronic RQ values that were less than the Agency's LOC for risks to non listed and listed species mammalian species for all scenarios.

Acute risk quotient ( RQ) values for avian food items following application of pyrethrins under a maximum use pattern for various crop species and foliar dissipation half life of 1  14 days were also  98 calculated. An analysis of these results show that avian acute, restricted use and listed species LOCs are not exceeded at registered maximum application rates for pyrethrins. Chronic risk to avian species was estimated by using pyrethrin NOAEC = 500 mg/ kg/ diet for Bobwhite quail. Calculated RQ values suggest no chronic risk to listed or non listed birds or mammals.

3. Review of Incident Data Incident reports submitted to EPA since approximately 1994 have been tracked by assignment of incident numbers in an Incident Data System ( IDS), microfiched, and then entered to a second database, the Ecological Incident Information System ( EIIS). This second database has some 85 fields for potential data entry. An effort has also been made to enter information to EIIS on incident reports received prior to establishment of current databases. Incident reports are not received in a consistent format ( e. g., states and various labs usually have their own formats), may involve multiple incidents involving multiple chemicals in one report, and may report on only part of a given incident investigation ( e. g., residues). While some progress has been made in recent years, both in getting incident reports submitted and entered, there has never been the level of resources assigned to incidents that there has been to the tracking and review of laboratory toxicity studies, for example.

Incidents entered into EIIS are categorized into one of several certainty levels: highly probable, probable, possible, unlikely, or unrelated. In brief, " highly probable" incidents usually require carcass residues, substantial ChE inhibition in avian and/ or mammalian species, and/ or clear circumstances regarding the exposure. " Probable" incidents include those where residues were not available and/ or circumstances were less clear than for " highly probable." " Possible" incidents include those where multiple chemicals may have been involved and it is not clear what the contribution was of a given chemical. The " unlikely" category is used, for example, where a given chemical is practically nontoxic to the category of organism killed and/ or the chemical was tested for but not detected in samples. " Unrelated" incidents are those that have been confirmed to be not pesticide related.

Incidents entered into the EIIS are also categorized as to use/ misuse. Unless specifically confirmed by a state or federal agency to be misuse, or there was very clear misuse such as intentional baiting to kill wildlife, incidents would not typically be considered misuse. Data entry personnel often do not have a copy of the specific label used in a given application, and would not usually be able to detect a variety of label specific violations, for example.

Of the 11 reports in the database, all but one incident alleges that pyrethrins caused damage to non target terrestrial plants; one study ( described below) associates pyrethrin use with effects in fish. No incidents were assigned a certainty index of 4 ( highly probable). In addition, most of these incidents involved formulated products containing a very low concentration of pyrethrins and a high percentage of " inert" ingredients. The Agency does not consider pyrethrin ( or the synergist PBO) to have phytotoxic properties and assumes that the reported toxicity to terrestrial plants after application of a formulation may be the result of inerts or other circumstances associated with the application.

Although incidents associated with pyrethroid exposure to aquatic systems has resulted in kills to aquatic organisms ( e. g., pyrethrin, cypyrethrin) only one possible incident is recorded with the Agency for pyrethrin ( noted below).

However, the number of documented kills in EIIS are believed to be a very small fraction of total  99 mortality caused by all pesticides. Mortality incidents must be seen, reported, investigated, and have investigation reports submitted to EPA to have the potential for entry into the database. Incidents often are not seen, due to scavenger removal of carcasses, decay in the field, or simply because carcasses may be hard to see on many sites and/ or few people are systematically looking. Poisoned birds may also move off site to less conspicuous areas before dying. Incidents seen may not get reported to appropriate authorities capable of investigating the incident because the finder may not know of the importance of reporting incidents, may not know who to call, may not feel they have the time or desire to call, may hesitate to call because of their own involvement in the kill, or the call may be long distance and discourage callers, for example. Incidents reported may not get investigated if resources are limited or may not get investigated thoroughly, with residue analyses, for example. Also, if kills are not reported and investigated promptly, there will be little chance of documenting the cause, since tissues and residues may deteriorate quickly. Reports of investigated incidents often do not get submitted to EPA, since reporting by states is voluntary and some investigators may believe that they don't have the resources to submit incident reports to EPA. An effort has also been made to enter information to EIIS on incident reports received prior to establishment of current databases. Although many of these have been added, the system is not yet a complete listing of all incident reports received by EPA.

In addition, there are a number of uncertainties associated with the data that are reported. Incident reports are not received in a consistent format ( e. g., states and various labs usually have their own formats), may involve multiple incidents involving multiple chemicals in one report, and may report on only part of a given incident investigation ( e. g., residues). While some progress has been made in recent years, both in getting incident reports submitted and entered, there has never been the level of resources assigned to incidents that there has been to the tracking and review of laboratory toxicity studies, for example. This adds to the reasons cited above for why EPA believes the documented kills are but a fraction of total mortality caused by pyrethrins.

a. Incidents Involving Aquatic Organisms One incident involving several fish killed in a small pond was investigated in Stanly County, NC on May 5, 1994. A homeowner noticed that several fish in the pond were dead and asked the NC Department of Agriculture to investigate. It was determined that there were several possible causes of the fish kill. On April 30, 1994, the complainant's dog, which had recently been treated with flea powder containing pyrethrins, jumped into the pond, possibly releasing pyrethrins to the water and resulting in the fish kill. While a mixture of herbicides ( 2,4 D, Weedone 638, and glyphosate) was applied to land adjacent to the pond, the application date was reported as May 10, five days after the dead fish began to appear in the pond. No information is available regarding applications prior to the incident and it is unlikely that the herbicides were responsible for the fish kill. Three weeks after the herbicides were applied, analysis of the pond water and surrounding vegetation gave negative results ( presumably for the sprayed herbicides and pyrethrins).

b. Incidents Involving Terrestrial Organisms Although the Agency believes that the pyrethroid in general are non phytotoxic, the incident ( certainty index score = 3) noted for pyrethrin occurred in Kootenai County, ID on August 25, 1999, and involved damage to 12 of 14 rose bushes, sunflowers, and several other plants that were treated with an insecticide containing pyrethrins and piperonyl butoxide. All other incidents of plant or crop damage associated with pyrethrin uses were listed as possible ( certainty index score = 2). The Agency assumes that toxicity  100 may have been related to inerts in the formulation or other circumstances related to application.

Table 38. Incident reports involving pyrethrins in chronological order.

Location and incident # Date Organisms involved Certainty indexa Descriptionb NC I003826 024 5/ 4/ 1994 Aquatic organisms 2 Fish from a pond died after possible contamination with pyrethrins WI I007155 181 5/ 9/ 1994 Terrestrial plants 2 A complaint alleged the loss of 10,000 peppers as a result of spraying with Pyrenone Crop Spray TN I007340 671 5/ 13/ 1998 Terrestrial plants 2 Damage to an edible crop may have occurred following application of Ortho Tomato and Vegetable Insect Killer TX I007340 672 5/ 14/ 1998 Terrestrial plants 2 Damage to ornamentals may have occurred following application of Ortho Tomato and Vegetable Insect Killer GA I007340 700 5/ 26/ 1998 Terrestrial plants 2 Damage to edible crops may have occurred following application of Ortho Tomato and Vegetable Insect Killer WI I008693 046 4/ 29/ 1999 Terrestrial plants 2 Damage to plants may have occurred following application of Ortho RosePride Rose and Flower Insect Killer CA I008693 047 4/ 21/ 1999 Terrestrial plants 2 Damage to about 12 bushes may have occurred following 2 applications of Ortho RosePride Rose and Flower Insect Killer ID I009262 095 8/ 24/ 1999 Terrestrial plants 3 Damage to roses, snapdragons, sunflowers, occurred following the application of insecticide containing pyrethrins.

No location I009825 002 8/ 31/ 1999 Terrestrial plants 2 Damage to unspecified plants, occurred following the application of insecticide containing pyrethrins. Table 38. Incident reports involving pyrethrins in chronological order.

Location and incident # Date Organisms involved Certainty indexa Descriptionb  101 FL I009916 023 2/ 1/ 2000 Terrestrial plants 2 Damage to about 6 or 7 roses may have occurred following applications of Ortho RosePride Rose and Flower Insect Killer WI I010017 017 3/ 7/ 2000 Terrestrial plants 2 Damage to ornamentals occurred 2 weeks following the application of Ortho RosePride Rose and Flower Insect Killer aCertainty index scoring reflects the likelihood that the pesticide was responsible for the alleged damage. Highly probable ( 4); Probable ( 3); Possible ( 2); Unlikely ( 1); Unrelated ( 0). b All events are related to exposure from formulated products that contain pyrethrins + piperonyl butoxide.