Appendix I. Diagram/ Structure of Atrazine and Major Degradates and Metabolites Cl | C / \\ N N || | CH HN   C C   NH CH2 | \ // | ( CH3) 2 N CH3 Atrazine Atrazine Soil Degradates:

Cl Cl | | C C / \\ / \\ N N N N || | || | H2N   C C   NH CH2 CH NH   C C   NH2 \ // | | \ // N CH3 ( CH3) 2 N Deisopropylatrazine Deethylatrazine ( G 28279) ( G 30033)

OH | C / \\ N N || | CH HN   C C   NH CH2 | \ // | ( CH3) 2 N CH3 Hydroxyatrazine ( G 34048) OH OH | | C C / \\ / \\ N N N N || | || | H2N   C C   NHCH2 CHNH   C C   NH2 \ // | | \ // N CH3 ( CH3) 2 N Deisopropylhydroxyatrazine Deethylhydroxyatrazine ( GS 17792) ( GS 17794)

Cl OH | | C C / \\ / \\ N N N N || | || | H2N   C C   NH2 H2N   C C   NH2 \ // \ // N N Diaminochlorotriazine Diaminohydroxyatrazine ( G 28273) ( G 17791)

OH OH | | C C / \\ / \\ N N N N || | || | CH HN   C C   OH HO   C C   OH | \ // \ // ( CH3) 2 N N 2, 4 Hydroxy 6 isopropylamino s triazine Cyanuric Acid ( G 11957) Atrazine Photodegradates ( Burkhard and Guth, 1976):

Cl Cl | | C C / \\ / \\ N N N N || | || | H2N   C C   NHCH2 CH HN   C C   NH2 \ // | | \ // N CH3 ( CH3) 2 N Deisopropylatrazine Deethylatrazine ( G 28279) ( G 30033)

Cl OH | | C C / \\ / \\ N N N N || | || | H2N   C C   NH2 CH HN   C C   NHCH2 \ // | \ // | N ( CH3) 2 N CH3 Diaminochlorotriazine Hydroxyatrazine ( G 28273) ( G 34048) Major Mammalian Metabolites:

OH OH | | C C / \\ / \\ N N N N || | || | CH NH   C C   NH CH2 CH NH   C C   NH CH2 | \ // | | \ // | ( CH3) 2 N CH3 ( CH3) 2 N C = O | OH Hydroxyatrazine Ethanoichydroxyatrazine ( G 34048)

OH OH | | C C / \\ / \\ CH3 N N N N | || | || | CH NH   C C   NH CH2 CH NH   C C   NH2 | \ // | | \ // O = C N CH3 ( CH3) 2 N | OH Isopropanoichydroxytriazine Deethylhydroxyatrazine ( GS 17794)

OH OH | | C C / \\ / \\ N N N N || | || | H2N   C C   NH CH2 H 2N   C C   NH2 \ // | \ // N CH3 N Deisopropylhydroxyatrazine Diaminohydroxyatrazine ( GS 17792) ( GS 17791) Major Plant Metabolites:

O HO   C= O O O || | || || NH C CH2 CH2 CH NH2 HO   C HO   C | | | S CH2 CH C NH CH2 C   OH S CH2 CH NH C CH2 CH2 CH NH2 | || || | C O O C / \\ / \\ N N N N || | || | CH NH C C  NH CH2 CH NH C C  NH CH2 | \ // | | \ // | ( CH3) N CH3 ( CH3) N CH3 S( 4 Ethylamino 6 isopropylamino  L Glutamyl S( 4 ethylamino 2s triazino) Glutathione 6 isopropylamino 2 s triazino) L Cysteine O   CH3 O   CH2CH3 | | C C / \\ / \\ N N N N || | || | CH HN   C C   NHCH2 CH NH   C C  NH CH2 | \ // | | \ // | ( CH3) 2 N CH3 ( CH3) 2 N CH3 2 Methoxy 4 ethylamino 6 isopropylamino 2 Ethoxy 4 ethylamino 6 isopropylamino s triazine s triazine Appendix II. Environmental Fate and Transport Characterization Each individual guideline study is discussed separately. The chemical names and structures of atrazine and its degradation products are listed in Appendix 1.

Hydrolysis ( 161 1)

Based on the results of the hydrolysis study ( MRID 40431319), atrazine did not hydrolyze at pH 5, 7, and 9. It was concluded that hydrolysis is not an important degradation mechanism for atrazine.

Aquatic Photodegradation ( 161 2)

The study ( MRID 00024328) showed that [ 14C] atrazine degraded with a registrant calculated half life of 25 ± 2 hours in unbuffered aqueous solutions ( initial pH 6.8) that were irradiated with a 125 W mercury vapor lamp at 15oC; in unbuffered aqueous solutions sensitized with 1% acetone, the half life decreased to 4.9 ± 0.5 hours.

The study ( MRID 42089904) showed that in buffered solution at pH 7, atrazine did not appreciably degrade under natural sunlight conditions with a calculated half life of approximately 335 days from a rate constant of 1.72 x 10 4 hours 1. However, under artificial light irradiation with mercury arc lamp, atrazine degraded at a faster rate with a half life of approximately 17 hours. Due to the lack of a comparison of the mercury arc lamp with natural sunlight, and no UV VIS spectrum of atrazine in pH 7, the study is considered to be supplemental. For the purpose of risk assessment, the half life result of 335 days with natural sunlight should be considered. Information is requested on the intensity of the mercury arc lamp and the US VIS spectrum of atrazine in pH 7 for more accurate review.

Soil Photodegradation ( 161 3)

The study ( MRID 40431320) was investigated with both natural and artificial sunlight exposures. The results with artificial sunlight showed a half life of 5.3 days, when corrected with dark control, the half life was 7.4 days. With natural sunlight, the half life was determined to be 12 days.

The study ( MRID 42089905) was investigated with artificial sunlight exposure. The half life under non irradiated conditions was 267 days, and the half life under irradiated conditions was 38 days. The net half life attributable to photodegradation is 45 days.

Aerobic Soil Metabolism ( 162 1)

The study ( MRID 40431321) was considered supplemental. Based on the data of 94 days, the half life of atrazine in loam soil was calculated as 140 days. The main metabolites detected at all sampling times were G 30033 and G 28279, but the metabolite G 34048 was not detected until days 62 and 94. The second study ( MRID 40629303) was also considered supplemental. The calculated half life was 146 days under non sterile aerobic conditions and to be very slow under sterile conditions. The degradates identified were G 30033, G 28279, G 28273, G 34048, GS 17794, and GS 17792.

The third study ( MRID 00040663) with four Hawaiian soils was rejected due to several deficiencies: ( 1) no material balances, ( 2) soils were not completely characterized, ( 3) pattern formation and decline of degradates was not addressed, and ( 4) purity of the test substance was not reported.

For the similar deficiencies as the third study, the fourth study ( MRID 40431322) with a wet Tennessee soil was also rejected.

The study ( MRID 42089906) with atrazine applied on California loam soil showed an aerobic half life of approximately 146 days. The degradates identified were G 30033, G 28279, G 28273, and G 34048.

Anaerobic Soil Metabolism ( 162 2)

The study ( MRID 40431321) was considered supplemental. The calculated half life for atrazine under anaerobic conditions was about 159 days. The metabolites G 30033 and G 28279 were present at all sampling times in both soil extracts and supernatant water; G 28273 and G 34048 were also present, but not at all sampling times.

The half life value was not established in the second study ( MRID 40629303). The degradates identified were G 30033, G 28279, G 28273, and G 34048.

The study ( MRID 42089906) with atrazine applied on California loam soil showed that when flooded with water, atrazine degraded with a calculated half life of approximately 159 days. The degradates identified were G 30033, G 28279, G 28273, and G 34048.

Anaerobic Aquatic Metabolism ( 162 3)

The study ( MRID 40431323) is acceptable. The combined water/ sediment ( sandy clay) half life was calculated as 608 days ( 330 days in sediment; 578 days in water). Production of volatile materials was minimal. Bound residues increased with time, but leveled to about 10% of applied dose by month 12. About 70% of radioactivity in water and 4% in sediment was still associated with parent atrazine after 12 months. Metabolites were present at low levels ( G 30033, 4.7%; G 34048, 5%; and G 28279, 1.4%).

Mobility/ Adsorption/ Desorption ( 163 1)

Several studies ( MRID 00027134, 00116620, 00044017, 00098254, and 00105942) were unacceptable due to various deficiencies. The study ( MRID 40431324) was acceptable and partially contributed to fulfill data requirements for the mobility of atrazine. A batchequilibrium adsorption/ desorption was conducted with four different soils and four different concentrations of 14C label atrazine. The Kads constants ranged from 0.427 ( sand) to 2.030 ( loam soil). The Kdes constants ranged from 2.261 ( silty loam soil) to 14.90 ( sandy loam soil). Koc ranged from 55.0 ( sandy loam soil) to 135 ( loam soil) for the adsorption phase. These results indicated that atrazine was not strongly adsorbed onto soil particles and that desorption occurred readily.

A batch equilibrium adsorption/ desorption was conducted with four different soils and four different concentrations of 14C label G 28273 ( MRID 40431327). The Kads constants ranged from 0.108 ( sand) to 0.800 ( silty clay loam). The Kdes constants ranged from 1.172 ( silty clay loam) to 6.620 ( sandy loam). Koc ranged from 11.6 ( sandy loam) to 59.5 ( silt loam) for the adsorption phase. These results indicated that G 28273 was not strongly adsorbed onto soil particles and that desorption occurred readily.

A batch equilibrium adsorption/ desorption was conducted with four different soils and four different concentrations of 14C label G 28279 ( MRID 40431325). The Kads constants ranged from 0.225 ( sand) to 1.144 ( loam soil). The Kdes constants ranged from 1.784 ( silty loam) to 12.479 ( sand). Koc ranged from 35.1 ( sandy loam) to 82.3 ( silty loam) for the adsorption phase. These results indicated that G 28279 was not strongly adsorbed onto soil particles and that desorption occurred readily.

A batch equilibrium adsorption/ desorption was conducted with four different soils and four different concentrations of 14C label G 30033 ( MRID 40431328). The Kads constants ranged from 0.116 ( sand) to 0.963 ( silty clay loam). The Kdes constants ranged from 8.104 ( silty clay loam) to 12.87 ( silt loam). Koc ranged from12.8 ( sandy loam) to 66.5 ( silty loam) for the adsorption phase. These results indicated that G 30033 was not strongly adsorbed onto soil particles and that desorption occurred readily.

A batch equilibrium adsorption/ desorption was conducted with four different soils and four different concentrations of 14C label G 34048 ( MRID 40431326). The Kads constants ranged from 5.518 ( sand) to 22.26 ( silty clay loam). The Kdes constants ranged from 8.104 ( silty clay loam) to 12.87 ( silt loam). Koc ranged from 350 ( sand) to 680 ( silty loam) for the adsorption phase. These results indicated that G 34048 was the strongest adsorbed among the atrazine degradates.

In a series of studies ( MRID 40431329 to 40431334) with soil thin layer chromatography, only the degradate, hydroxyatrazine ( G 34048), showed low mobility, others ( atrazine, diaminochlorotriazine ( G 28273), deisopropylatrazine ( G 28279), and deethylatrazine ( G 30033) showed high mobility in the soil environment.

In a series reports ( MRID 41257901, 41257902, 41257904, 41257905, and 41257906), the adsorption/ desorption characteristics of atrazine, hydroxyatrazine ( G 34048), diaminochlorotriazine ( G 28273), deisopropylatrazine ( G 282279), and deethylatrazine ( G 30033) were addressed. The results are summarized in the tables below.

Sorption Coefficients of Atrazine and Its Main Degradates Soil Atrazine Diaminochloros triazine ( G 28273) Deisopropylatrazine ( G 28279) Deethylatrazine ( G 30033) Hydroxyatrazine ( G 34048)

Clay 2.46 ( 86.9) 1.56 ( 55.2) 2.73 ( 96.8) 1.10 ( 36.1) 389.6 ( 13797)

Sand 0.20 ( 38.5) 0.16 ( 30.7) 0.16 ( 30.4) 0.06 ( 12.2) 1.98 ( 374.2)

Sandy Loam 0.79 ( 70.4) 0.65 ( 57.9) 0.51 ( 45.2) 0.36 ( 31.8) 6.52 ( 583.3)

Loam 0.73 ( 155.3) 0.36 ( 76.0) 0.27 ( 58.1) 0.21 ( 44.9) 12.11 ( 2572.9) Number in parentheses refer to Koc values; Koc = Kads ÷ % O. C.; where % O. C. = % O. M. ÷ 1.7 Desorption Coefficients of Atrazine and Its Main Degradates Soil Atrazine ( G 30027) Diaminochloros triazine ( G 28273) Deisopropylatrazine ( G 28279) Deethylatrazine ( G 30033) Hydroxyatrazine ( G 34048)

Clay 9.12 ( 322.9) 7.. 80 ( 276.2) 12.36 ( 467.9) 8.14 ( 288.3) 515.89 ( 18271)

Sand 1.51 ( 285.5) Value indeterminable due to limited adsorption 9.02 ( 1704.2)

Sandy Loam 7.27 ( 650.5) 8.06 ( 721.0) 15.28 ( 1366.9) 11.19 ( 1001.1) 14.87 ( 1330.4)

Loam 4.76 ( 1011.5) 6.87 ( 1459.9) 6.98 ( 1484.2) 3.92 ( 833.3) 11.28 ( 22397.6) Number in parentheses refer to Koc values; Koc = Kdes ÷ % O. C.; where % O. C. = % O. M. ÷ 1.7 Adsorption/ Desorption Study: Soil Characteristics Soil Type Texture Bulk Density ( g/ cm 3) Organic Matter (%) pH Sand % Silt % Clay % CEC meq/ 100g Clay 1.22 4.8 5.9 25 33 42 24.3 Sand 1.65 0.9 6.5 96 2 2 1.8 Sandy Loam 1.28 1.9 7.5 63 20 17 6.1 Loam 1.57 0.8 6.7 44 47 9 4.3 The dealkylated degradates ( G 28273, G 28279, and G 30033) are more mobile than parent atrazine, but hydroxyatrazine ( G 34048) is the least mobile of the degradates. Atrazine, its dealkylated degradates, and hydroxyatrazine are very mobile in the sand soil, as shown by their low (< 2) adsorption coefficients ( Kads) and the low adsorption Koc values (< 500). In clay soil the adsorption coefficients and Koc values were higher for parent atrazine and the dealkylated degradates, but still fall below 5 and 500. However, adsorption of hydroxyatrazine was the strongest.

The results of the batch equilibrium adsorption/ desorption studies indicate that the dealkylated degradates are as likely ( or even more likely) to leach to ground water as parent atrazine. However, soil characteristics must be taken into account when assessing the leaching potential in an specific region. Terrestrial Field Dissipation ( 164 1)

The results of a field dissipation study with corn soil at Donaldsonville, Georgia ( MRID: 42165504) predicted a half life of 12.75 days with residues decreasing to less than 0.4 ppm on the 27 day sampling. AAtrex ® Nine O ® was applied at a rate of 4.4 lb a. i./ ac to a test corn plot of sandy loam soil on June 14, 1986. The residues of degradates G 34048. G 30033, and G 28279 found in the top 0 6" depth were significant lower (< 0.05 to 0.31 ppm) compared to the parent residues which ranged < 0.05 to 0.73 ppm. The leaching data for parent atrazine and metabolites at depths below 6 12" soil depth were generally below the screening level of 0.05 ppm.

The results of a field dissipation study with bare ground at Donaldsonville, Georgia ( MRID 42165505) predicted a half life of 38.52 days with residues decreasing to less than 0.5 ppm on the 451 day sampling. AAtrex ® Nine O ® was applied at a rate of 18.0 lb a. i./ ac to a field plot of unvegetated sandy loam soil on June 27, 1986. The residues of degradates G 34048. G 30033, and G 28279 found in the top 0 6" depth were significant lower (< 0.05 to 2.16 ppm) compared to the parent residues which ranged < 0.05 to 6.98 ppm. The leaching data for parent atrazine and metabolites at depths below 6 12" soil depth were generally below the screening level of 0.05 ppm.

The results of a field dissipation study with bare ground at Ripon, California ( MRID 40431336, 42165506) predicted a half life of 102.5 days. Atrazine ( 90% dry flowable) was applied at a nominal concentration of 18 lb ai/ ac to a field plot of unvegetated sandy loam soil in July 1986. In the 0 to 6 inch depth, atrazine was 4.75 ppm ( 4.75 ppm total residues) immediately after treatment, decreased to 1.05 ppm ( 1.20 ppm total) at 90 days, and 0.67 ppm ( 0.94 ppm total) at 120 days, increased to 5.31 ppm ( 6.24 ppm total) at 180 days, then decreased to 0.50 ppm ( 0.63 ppm total) at 267 days and 0.20 ppm ( 0.26 ppm total) at 358 days post treatment. The major degradates were G 34048. G 30033, and G 28279.

The results of a field dissipation study with bare ground at Hollandale, Minnesota ( MRID 40431337, 42165507) indicated a half life of 261 days. Atrazine ( 90% dry flowable) was applied at a nominal concentration of 20 lb ai/ ac to a field plot of unvegetated loam soil in July 1986. In the 0 to 6 inch depth, atrazine was 4.23 ppm ( 5.06 ppm total residues) immediately after treatment, increased to 10.15 ppm ( 11.66 ppm total) at 14 days, decreased to 5.34 ppm ( 6.75 ppm total) at 28 days, and was 2.90 ppm ( 4.88 ppm total) at 360 days post treatment. The major degradates were G 34048. G 30033, and G 28279.

The results of a field dissipation study with a corn soil at Hollandale, Minnesota ( MRID 40431339, 42165508) yielded a half life of 261 days. Atrazine ( 90% dry flowable) was applied at a nominal concentration of 4.4 lb ai/ ac to a field plot of loam soil planted to corn in July 1986. In the 0 to 6 inch depth, atrazine was 1.20 ppm ( 1.37 ppm total residues) immediately after treatment, increased to 1.40 ppm ( 1.59 ppm total) at 2 days, ranged from 0.48 to 1.00 ppm ( 0.90  1.17 ppm total) with no discernable pattern between 7 and 290 days, and was 0.37 ppm ( 0.91 ppm total) at 360 days post treatment. The major degradates were G 34048. G 30033, and G 28279. The results of a field dissipation study with corn soil in Ripon, California ( MRID 40431338, 42165509) indicated a half life of 58 days. Atrazine ( 90% dry flowable), applied at a nominal concentration of 3.96 lb ai/ ac to a field plot of sandy loam soil planted to corn in July 1986. In the 0 to 6 inch depth, atrazine was 1.15 ppm ( 1.15 ppm total residues) immediately after treatment, increased to 2.82 ppm ( 2.82 ppm total) at 7 days, decreased to 1.18 ppm ( 1.18 ppm total) at 14 days, decreased to 0.50 ppm ( 0.74 ppm total) at 60 days, and was 0.02 ppm ( 0.53 ppm total) at 358 days post treatment. The major degradates were G 34048. G 30033, and G 28279.

Forestry Field Dissipation ( 164 3)

A field dissipation half life of 87 days was estimated for exposed soil in a forestry study at Oregon City, Oregon ( MRID Nos: 40431340, 42041405). Atrazine ( 90% G) was applied aerially at 4 lb ai/ ac to 10 acres of an immature Douglas fir forest on April 4, 1985. In tree foliage samples, atrazine was 168.2  294.2 ppm immediately post treatment, 76.7  88.0 ppm at 7 days, 6.6  10.5 ppm at 29 days, and 1.6  3.2 ppm at 88 days post treatment. The registrantcalculated half life for atrazine in foliage was 13 days.

In leaf litter samples, atrazine was 73.1  114.2 ppm immediately post treatment, 21.8  27.9 ppm at 29 days, 7.2  8.1 ppm at 88 days, and 0.60  3.4 ppm at 364 days post treatment; the registrant calculated half life was 66 days. In soil ( 0 to 6 inch depth) that was not covered with leaf litter, atrazine concentration were variable with no discernible pattern, ranging from 0.075 to 4.3 ppm. G 30033 was isolated at up to 0.118 ppm. In the 6 to 12 and 12 to 18 inch soil depths, atrazine was < 0.05 to 0.432 ppm and < 0.05 to 0.110 ppm, respectively. In soil under leaf litter, atrazine concentration were variable in the 0 to 6 inch depth, ranging from 0.077 to 4.7 ppm, and were # 0.088 ppm in the 6 to 12 and 12 to 18 inch depths.

Long Term Terrestrial Field Dissipation ( 164 5)

The results of a long term field dissipation study with corn soil at Hollandale, Minnesota, ( MRID 40431339, 42089911) predicted a half life of 402 days with an r2 of 0.81. In the 0 6" soil samples, detectable residues of atrazine, G 30033, and G 34048 were found at 451, 510, 668, 847, 1032, 1211, and 1389 DAT ( days after treatment), and detectable residues of G 28279 were found at 451, 510, 668, 847, and 1032 DAT. In the 6 12" soil samples, detectable residues of atrazine were found at 510, 668, 847, 1032, and 1211 DAT, detectable residues of G 30033 were found at 668, 847, and 1032 DAT, and detectable residues of G 34048 were found at 451, 510, 668, 847, 1032, 1211, and 1389 DAT. The 12 18" soil samples produced no detectable residues of atrazine, G 28279, G 30033, or G 34048. No detectable residues of atrazine, G 28279, or G 30033 were found in the 18 24" soil samples; however, detectable residues of G 34048 were found at 1211 and 1389 DAT. In the 24 36" soil samples, no detectable residues of atrazine, G 28279, G 30033, or G 34048 were found.

The results of a long term field dissipation study with bare ground at Hollandale, Minnesota, ( MRID 40431337, 42089912) predicted a half life of 261 days with an r2 of 0.94. In the 0 6" soil samples, detectable residues of atrazine, G 30033, and G 34048 were found at 449, 498, 659, 839, 1020, 1200, and 1378 DAT, and detectable residues of G 28279 were found at 449, 498, 659, 839, and 1020 DAT. Detectable residues of atrazine and G 34048 were found in the 6 12" soil samples at 449, 498, 659, 839, 1020, and 1200 DAT, detectable residues of G 30033 were found at 449, 498, 659, 839, and 1200 DAT. In the 12 18" soil samples, detectable residues of atrazine were found at 449, 498, 659, 839, 1020, 1200, and 1378 DAT, no detectable residues of G 28279 or G 30033 were found, detectable residues of G 34048 were found at 449, 659, and 1200 DAT. In the18 24" soil samples, detectable residues of atrazine were found at 449, 498, 659, 839, and 1020 DAT, no detectable residues of G 28279 were found, detectable residues of atrazine were found only at 1020 DAT, detectable residues of G 28279 were found 449 and 498 DAT, detectable residues of G 30033 were only found at 498 DAT, and no detectable residues of G 34048 were found.

The results of a long term field dissipation study with corn soil at Ripon, California, ( MRID 40431338, 42089909) predicted a half life of 102 days with an r2 of 0.84. In the 0 6" soil samples, detectable residues of atrazine were found at 552 DAT, no detectable residues of G 30033 were found, and G 34048 were found at 460, 552, 726, 873, 1045 DAT samples. In the 6 12" soil samples, detectable residues of atrazine were found at 460 and 552 DAT, detectable residues of G 28279 and G 30033 were found only in the 460 DAT samples, and detectable residues of G 34048 were found at460, 552, 873, and 1045 DAT soils samples. At the 12 18" soil depth, detectable residues of atrazine were found at 460 DAT only, no detectable residues of G 28279 or G 30033 were found, and detectable residues of G 34048 were found in the 460, 552, and 873 DAT soil samples. In the 18 24" soil samples, detectable residues of atrazine and G 28279 were found in 460 and 552 DAT soil samples, no detectable residues of G 30033 were found, and detectable residues of G 34048 were found in the 460 and 873 DAT soil samples. No detectable residues of G 28279 were found in the 24 36" soil samples, while detectable residues of atrazine and G 30033 were found at 460 DAT, and residues of G 34048 were found at 460, 552, and 873 DAT.

The results of a long term field dissipation study with bare ground at Ripen, California, ( MRID 40431336, 42089910) predicted a half life of 110 days with an r2 of 0.92. In the 0 6" soil samples, detectable residues of atrazine and G 30033 were found only at 460 DAT, and detectable residues of G 34048 were found in 460, 552, and 837 DAT samples. No detectable residues of atrazine or G 28279 were found in the 6 12" soil samples, detectable residues of G 30033 were found only at 552 DAT, and detectable residues of G 34048 were found in the 460, 552, and 873 DAT soil samples. No detectable residues of atrazine, G 28279, or G 33033 were found in the 12 18" soil samples, while detectable residues of G 34048 were found in the 460, 552, and 873 DAT soil samples. In the18 24" soil samples, no detectable residues of atrazine, G 28279, or G 30033 were found, while detectable residues of G 34048 were found in the 460, 552, and 873 DAT soil samples. Detectable residues of atrazine, G 28279, G 30033, and G 34048 were found in the 24 36" soil samples for 460 DAT and residues of atrazine and G 34048 were also found at 873 DAT.

Bioaccumulation in Fish ( 165 4)

Based on an accepted study ( MRID: 40431344), total [ 14C] atrazine residues accumulated in bluegill sunfish with maximum bioconcentration factors of 7.7x, 12x, and 15x in edible tissues ( body, muscle, skin, skeleton), nonedible tissues ( fins, head, internal organs), and whole fish, respectively, during 28 days of exposure to uniformly ring labeled [ 14C] atrazineat 0.01 ppm in a flow through system. After 21 days of depuration, [ 14C] atrazine were 0.21 ppm in edible tissues, 0.38 ppm in nonedible tissues, and 0.28 ppm in whole fish; depuration rates were 74, 76, and 78%, respectively.

Spray Drift Data Requirements ( 201 1, 202 1)

The guidelines require data of droplet size spectrum and drift field evaluation. No atrazinespecific spray drift studies were reviewed. The registrant, Novartis, is a member of the Spray Drift Task Force ( SDTF). The SDTF has completed and submitted to the Agency a series of studies intended to characterize spray droplet drift potential due to various factors, including application methods, application equipment, meteorological conditions, crop geometry and droplet characteristics. EFED is currently evaluating these studies. After its review, the Agency will determine whether a reassessment is warranted of the potential risks from the application of atrazine to nontarget organisms.

Degradates Detected in Laboratory Studies There are two major types of degradates for atrazine. The first type of degradates are formed via dealkylation of the amino groups, for which mono and fully dealkylated degradates are known. The second type of degradates are formed by substitution of a chloro group by a hydroxy group in either parent or dealkylated degradates.

The following table provides a summary of atrazine degradates detected in the laboratory studies discussed above.

Major Degradates Photolysis in Water Photolysis on Soil Aerobic Soil Anaerobic Soil Anaerobic Aquatic Deethylatrazine G 30033 X X X X X Deisopropylatrazine G 28279 X X X X X Diaminochlorotriazine G 28273 X X X X Hydroxyatrazine G 34048 X X X X Deethylhydroxyatrazine GS 17794 X X Deisopropylhydroxyatrazine GS 17792 X X Appendix III. Submitted Environmental Fate and Transport Studies Balu, K. 1989. Atrazine: Summary of surface water monitoring data for atrazine. Laboratory Study No. EIR 89001. 484 p. Unpublished study prepared and submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41065205).

Balu, K. 1991. Responses to the EPA review of the field dissipation study on Aatrex Nine 0 for terrestrial uses on bareground, Hollandale, Minnesota: Supplement to EPA MRID Number 40431337. Lab. Project Number: ABR 91064. 50 p. Unpublished study prepared and submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165507).

Balu, K. 1991. Responses to the EPA review of the field dissipation study on Aatrex Nine 0 for terrestrial uses on bareground, Ripon, California: Supplement to EPA MRID Number 40431336. Lab. Project Number: ABR 91063. 110 p. Unpublished study prepared and submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165506).

Balu, K. 1991. Responses to the EPA review of the field dissipation study on Aatrex Nine 0 for terrestrial uses on corn, Hollandale, Minnesota: Supplement to EPA MRID Number 40431339. Lab. Project Number: ABR 91066. 49 p. Unpublished study prepared and submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165308).

Balu, K. 1991. Responses to the EPA review of the field dissipation study on Aatrex Nine 0 for terrestrial uses on corn, Ripon, California: Lab. Project Number: ABR 91065. 111 p. Unpublished study prepared and submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165509).

Balu, K. and P. W. Holden. 1996. Ciba/ State ground water monitoring study for atrazine and its major degradation products in the United States. Final Report. Ciba Study No. 174 91. 24 p. Unpublished study prepared by Waterborne Environmental, Inc. Leesburg, VA.; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 43934414).

Burkhard, N. and J. A. Guth. 1976. Photodegradation of atrazine, atraton and ametryne in aqueous solution with acetone as a photosensitizer. Pesticide Science 7( 1): 65 71. ( Also In: Unpublished submission received July 19, 1978 under 201 403; submitted by Shell Chemical Co., Washington, D. C.; CDL: 234469 C). ( MRID # 00024328).

Das, Y. 1989. Photodegradation of triazine( U) carbon 14 atrazine on soil under artificial sunlight. Lab. Project Number: 89070. 109 p. Unpublished study prepared by Innovative Science Services, Inc.; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42089905).

Forbis, A. 1986. Uptake, depuration, and bioconcentration and metabolite characterization of carbon 14 atrazine by bluegill sunfish ( Lepomis macrochirus): Laboratory Study No. 34737. 107 p. Unpublished study prepared by Analytical Bio Chemistry Laboratories, Inc.; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431344). Froelich, L., T. Bixler, C. Peake et al. 1982. Soil adsorption/ desorption characteristics of FMC 57020: M 4861. Unpublished study received Oct 1, 1982 under 279 EX 93; submitted by FMC Corp., Philadelphia, PA; CDL: 248476 D. ( MRID # 00116620).

Guy, S. 1987. Field dissipation on Aatrex Nine 0 for terrestrial uses on bareground in Donalsonville, GA: Lab. Project Number: 1641 86 71 01 21E 27. 317 p. Unpublished study prepared by Landis International and Others; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165505).

Guy, S. 1987. Field dissipation on Aatrex Nine 0 for terrestrial uses on corn in Donalsonville, GA: Lab. Project Number: 1641 86 71 01 06B 26. 325 p. Unpublished study prepared by Landis International and Others; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42165504).

Hardies, D. E. and D. Y. Studer. 1982. Soil thin layer chromatography of PPG 1292: BRC 22593. Unpublished study received April 5, 1982 under 2F2666; submitted by PPG Industries, Inc., Barberton, Ohio; CDL: 070755 J. ( MRID # 00098254).

Harris, C. I. 1967. Fate of 2 chloro s triazine herbicides in soil. J. Agric. Food Chem. 15( 1): 157 162. Also In: Unpublished submission received July 17, 1978 under 100 541; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 00027870).

Helling, C. S. 1971. Pesticide mobility in soils. II. Applications of soil thin layer chromatography. Soil Science Society of America Proceedings 35: 737 748. Also In: Unpublished submission received May 5, 1975 under 464 323; submitted by Dow Chemical U. S. A., Midland, Mich.; CDL: 221997 S. ( MRID # 00044017).

Klaine, S. 1987. Biotic and abiotic degradation of atrazine and three of its metabolites in a west Tennessee soil: Laboratory Study No. TX 431. 63 p. Unpublished study prepared by Memphis State University, Memphis, TN; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431322).

Leake, C., D. Lines and K. Tiffen. 1981. The leaching of NC 21 314 in four soil types using soil TLC: METAB/ 81/ 40. Unpublished study received July1, 1982 under 45639 EX 7; prepared by FBC Ltd., England; submitted by FBC Chemicals, Inc., Wilmington, DE; CDL: 070966 E. ( MRID # 00105942).

Nelson, D. and D. Schabacker. 1991. Summary report: Soil metabolism of carbon 14 atrazine and metabolite characterization/ identification: Lab. Project Number: 6015 185: ABR 91073. 321 p. Unpublished study prepared by Hazleton Labs America, Inc. ( MRID # 42089906).

Obien, S. R. and Green, R. E. 1969. Degradation of atrazine in four Hawaiian soils. Weed Science 17( 4): 509 514. ( Also~ In: Unpublished submission received July 19, 1978 under 201 403; submitted by Shell Chemical Co., Washington, D. C.; CDL: 234476 C) ( MRID # 00040663). Parshley, Thomas J. 1990. Letter: Atrazine technical, EPA Reg. No. 100 529: Additional information on adsorption/ desorption data: Soil series names. 3 p. Submitted by Ciba Geigy Corp., Greensboro, NC.

Rustum, A. 1987. Aerobic, aerobic/ anaerobic, and sterile soil metabolism of carbon 14 atrazine: Laboratory Study No. 6015 185. 133 p. Unpublished study prepared by Hazleton Laboratories America, Inc., Madison, WI; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431321).

Rustum, A. 1988. Aerobic, aerobic/ anaerobic, and sterile soil metabolism of 14C atrazine: Study No. HLA 6015 185. 165 p. Unpublished study prepared by Hazleton Laboratories America, Inc., Madison, WI; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40629303).

Saxena, A. M. 1987. Determination of the mobility of soil aged 14C atrazine residues by thinlayer chromatography: Laboratory Study No. HLA 6015 186. Unpublished study prepared by Hazleton, Laboratories America, Inc., Madison, WI; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431330).

Schabacker, D. 1991. Summary report: Aqueous photolysis of carbon 14 atrazine under natural and artificial light. Lab. Project Number: 12112 A: 12112 B. 185 p. Unpublished study prepared by Agrisearch Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 42089904).

Schofield, M. 1986. Combined field dissipation and aquatic non target organism accumulation Studies on Aatrex Nine O for forestry use at Oregon City, Oregon: Laboratory Study No. 32989. 135 p. Unpublished study prepared by Analytical Bio Chemistry Laboratories, Inc., Columbia, MO; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431340).

Spare, W. 1986. Determination of the hydrolysis rate constants of atrazine: Laboratory Study. No. 1236. 33 p. Unpublished study prepared by Agrisearch Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431319)

Spare, W. 1987. Anaerobic aquatic metabolism of atrazine: Laboratory Study No. 1231. 69 p. Unpublished study prepared by Agrisearch, Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID 40431323).

Spare, W. 1987. Photodegradation of atrazine on soil surfaces exposed to artificial and natural sunlight: Laboratory Study No. 1237. 68 p. Unpublished study prepared by Agrisearch Inc., Frederick, MD; Submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431320).

Spare, W. 1989. Adsorption/ desorption of 14C atrazine: Agrisearch Project No. 12174. 59 p. Unpublished study prepared by Agrisearch, Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41257901). Spare, W. 1989. Adsorption/ desorption of 14C G 28273: Agrisearch Project No. 12173. 55 p. Unpublished study prepared by Agrisearch Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41257904).

Spare, W. 1989. Adsorption/ desorption of 14C G 28279: Agrisearch Project No. 12170. 57 p. Unpublished study prepared by Agrisearch, Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41257905).

Spare, W. 1989. Adsorption/ desorption of 14C G 30033: Agrisearch Project No. 12169. 57 p. Unpublished study prepared by Agrisearch Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41257906).

Spare, W. 1989. Adsorption/ desorption of 14C G 34048: Agrisearch Project No. 12171. 57 p. Unpublished study prepared by Agrisearch, Inc., Frederick, MD; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 41257902).

Speth, Robert M. 1991. Responses to the EPA review of the atrazine forestry field dissipation study at Oregon City, Oregon. Supplement to MRID 40431340). Laboratory Project ID: ABR 91067. 45 p. Unpublished study prepared by Ciba Geigy Corp., Greensboro, NC.; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 420414050).

Talbert, R. E. and O. H. Fletchall. 1965. The adsorption of some s triazines in soils. Weeds 13: 46 52. ( Also In: Unpublished submission received July 19, 1978 under 201 403; submitted by Shell Chemical Co., Washington, D. C.; CDL: 234472 J). ( MRID # 00027134).

White, S. 1987. Field dissipation study on Aatrex Nine O for terrestrial uses on bareground, Hollandale, Minnesota: Laboratory Study No. 1641 86 71 01 21E 25. 356 p. Unpublished study prepared by Minnesota Valley Testing Labs, Inc., New Elm, MN; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431337).

White, S. 1987. Field dissipation study on Aatrex Nine O for terrestrial uses on bareground, Ripon, California: Laboratory Study No. 1641 86 71 01 21E 23. 300 p. Unpublished study prepared by Minnesota Valley Testing Labs, Inc., New Elm, MN; Submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431336).

White, S. 1987. Field dissipation study on Aatrex Nine O for terrestrial uses on corn, Hollandale, Minnesota: Laboratory Study No. 1641 86 71 01 06B 24. 372 p. Unpublished study prepared by Minnesota Valley Testing Labs, Inc., New Elm, MN; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431339).

White, S. 1987. Field dissipation study on Aatrex Nine O for terrestrial uses on corn, Ripon, California: Laboratory Study No. 1641 86 71 01 06B 22. 311 p. Unpublished study prepared by Minnesota Valley Testing Labs, Inc., New Elm, MN; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431338). Yu, W. C. 1986. Determination of adsorption/ desorption constants of atrazine: Laboratory Study No. 59 1A. 33 p. Unpublished study prepared by Cambridge Analytical Associates, Inc., Boston, MA; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431324).

Yu, W. C. 1986. Determination of adsorption/ desorption constants of G 28273: Laboratory Study No. 59 5A. Unpublished study prepared by Cambridge Analytical Associates, Inc., Boston, MA; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431327).

Yu, W. C. 1986. Determination of adsorption/ desorption constants of G 28279: Laboratory Study No. 59 6A. Unpublished study prepared by Cambridge Analytical Associates, Inc., Boston, MA; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431325).

Yu, W. C. 1986. Determination of adsorption/ desorption constants of G 30033: Laboratory Study No. 59 6A. Unpublished study prepared by Cambridge Analytical Associates, Inc., Boston, MA; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431328).

Yu, W. C. 1986. Determination of adsorption/ desorption constants of G 34048: Laboratory Study No. 59 7A. Unpublished study prepared by Cambridge Analytical Associates, Inc., Boston, MA; submitted by Ciba Geigy Corp., Greensboro, NC. ( MRID # 40431326). Appendix IV. Drinking Water Characterization The drinking water characterization is being reported in a separate report, entitled " Drinking Water Exposure Assessment for Atrazine and Various Chloro triazine and Hydroxy triazine Degradates." The conclusions and summary of results ( Chapter 10) are excerpted below.

10. Conclusions and Summary of Results 10.1) Atrazine concentrations in the PLEX and comparison to Office of Drinking Water MCL and short term HALs for atrazine Of the 21,241 ground, surface, and blend water source CWSs in 21 states with atrazine data in the PLEX database through 1998, 2,386 CWSs ( 11.2%) had one or more atrazine detections above limits of quantification ( LOQs) ( Table 4 2 which is Table 4.2 3 of MRID 450587 04). Of a total of 88,766 samples in the database, 8,685 ( 9.8%) had detections above the LOQs ( Table 4 2). The LOQs varied from 0.01 to 0.5 ug/ L, but were typically at 0.1 ug/ L ( Table 4 3 which is Table 3.2 6 of MRID 450587 04).

The population and % of the assessed population exposed to 1998, 1997, 1996, 1995, 1994, and 1993 annual mean atrazine concentrations > 3 ug/ L were 16,000 people ( 0.02%), 129,000 people ( 0.18%), 156,000 people ( 0.19%), 506,000 people ( 0.79%), 331,000 people ( 0.58%), and ( 76,500 people ( 0.17%), respectively. The assessed populations for 1998, 1997, 1996, 1995, 1994, and 1993 were approximately 79.9, 71.6, 82.3, 64.0, 57.1, and 45.0 million, respectively.

The # of CWSs and % of the assessed CWSs with 1998, 1997, 1996, 1995, 1994, and 1993 annual mean atrazine concentrations > 3 ug/ L were 4 CWSs ( 0.05%), 26 CWSs ( 0.31%), 73 CWSs ( 0.92%), 11 CWSs ( 0.14%), 95 CWSs 1.49%), and 19 CWSs ( 0.49%), respectively. The # of assessed CWSs in those years were 8548, 8300, 7944, 7909, 6395, and 3913 CWSs, respectively.

Of the 21,241 CWSs with atrazine data in the PLEX database, 182 CWSs had one or more annual mean atrazine concentrations > the MCL of 3 ug/ L during the 1993 1998 period ( Tables 4 1 and 4 2). Of those 182 CWSs, 81 are suppliers and 101 are purchasers. Of the 81 suppliers, 74, 5, and 2 have surface water, blend, and ground water sources, respectively. Of the 81 suppliers, 33 are in Illinois, 16 are in Missouri, 12 are in Kansas, 12 are in Ohio, 4 are in Kentucky, 2 are in Indiana, and one each are in North Carolina and Texas ( Table 4 2).

The highest atrazine concentration ( 42 ug/ L) reported in the PLEX database from 1993 through 1998 is well below the Office of Drinking Water short term HALs for atrazine of 100 ug/ L. However, because only one sample was collected per quarter/ CWS in the PLEX database, reported maximum atrazine concentrations in the PLEX database may often be substantially less than actual peak concentrations. Because the VMS ( on 100 surface water source CWSs) and the ARP surface water monitoring study ( on 175 surface water source CWSs) have substantially more time series data than the PLEX database, observed maximum atrazine concentrations in those studies for a given CWS should generally be closer to actual peak atrazine concentrations in the CWS than observed maximum atrazine concentrations for the same CWS in the PLEX database. However, the maximum reported atrazine concentrations in those studies ( 63.5 and 49.5 ug/ L) were still well below the Office of Drinking Water short term HALs for atrazine of 100 ug/ L.

10.2) Atrazine concentrations in the Rural Well Survey and comparison to Office of Drinking Water MCL and short term HALs for atrazine In the Rural Well Survey from September 1992 to March 1995, one sample was collected from each of 1505 wells and analyzed for atrazine, and various chloro triazine and hydroxytriazine degradates. The maximum, 99th percentile, and 95th percentile atrazine concentrations were 12.0, 2.4, and 0.87 ug/ L.

Eight wells ( out of the 1,505 wells sampled in the Rural Well Survey) had atrazine concentrations exceeding the MCL of 3 ug/ L. Because only one sample was collected from each well, it is not known how many if any of those 8 wells had annual mean atrazine concentrations exceeding 3 ug/ L. In the ARP ground water monitoring of 177 wells from May 1995 to March 1998, 2 of the 177 wells had a maximum annual mean atrazine concentration ( 14.3 and 4.97 ug/ L based on running annual means) > 3 ug/ L.

The highest atrazine concentration detected in the Rural Well Survey ( 12 ug/ L) was much less than the short term HAL of 100 ug/ L. However, because only one sample was collected per well in the Rural well Survey, the reported maximum atrazine concentration in the Rural Well Survey may be substantially less than the actual peak concentration. In the ARP ground water monitoring study of only 177 wells, but which included 12 samples/ well/ year over a 3 year period, one well had a maximum atrazine concentration ( 132 ug/ L) greater than the short term HAL of 100 ug/ L. However, the next highest atrazine concentration ( 11.0 ug/ L) was well below the HAL.

10.3) Regression estimated, annual mean and annual maximum total chloro triazine concentrations in the surface water portion of the PLEX database and comparison to HED subchronic chronic and acute DWLOCs.

The regression estimated, highest annual mean total chloro triazine concentration ( 17 ug/ L) for surface water source CWSs in the PLEX database from 1993 through 1998 is slightly below the sub chronic/ chronic HED DWLOC of 18 ug/ L for children and infants and well below the subchronic chronic HED DWLOC of 63 ug/ L for adults.

The assessed populations in the surface water portion of the Novartis PLEX database for 1998, 1997, 1996, 1995, 1994, and 1993 were approximately 44.0, 38.2, 41.5, 31.4, 24.0, and 23.9 million, respectively. The # of assessed surface water source CWSs in those years were 2494, 2132, 2547, 1699, 1700, and 1212, respectively.

The regression estimated, highest total chloro triazine concentration ( 59.8 ug/ L) for surface water source CWSsin the PLEX database from 1993 through 1998 is well below the single HED acute DWLOC of 298 ug/ L ( for pregnant women). In the PLEX database of atrazine data ( collected to comply with the monitoring requirements of the SDWA), the annual maximum reported atrazine concentration for a CWS also represents its annual maximum reported 3 month quarterly mean because only one sample is generally collected per quarter ( 3 months). Therefore, the EFED compared regression estimated annual maximum total chloro triazine concentrations to HED chronic as well as acute DWLOCs. The actual annual maximum quarterly mean for a CWS may be lower or higher than the annual maximum reported atrazine concentration for the CWS.

The population and the % of the assessed population exposed to estimated 1998, 1997, 1996, 1995, 1994, and 1993 annual maximum total chloro triazine concentrations > the lowest HED sub chronic/ chronic DWLOC of 18 ug/ L for children and infants were 1450 people ( 0.003%), 105,721 people ( 0.28%), 40,586 people ( 0.10%), 0 people ( 0.0%), 210,544 people ( 0.84%), and 184,092 people ( 0.77%), respectively. The assessed populations in the surface water portion of the Novartis PLEX database for 1998, 1997, 1996, 1995, 1994, and 1993 were approximately 44.0, 38.2, 41.5, 31.4, 24.0, and 23.9 million, respectively.

The # of CWSs and % of the assessed CWSs with 1998, 1997, 1996, 1995, 1994, and 1993 annual maximum total chloro triazine concentrations > the lowest HED sub chronic/ chronic DWLOC of 18 ug/ L for children and infants were 2 CWSs ( 0.08%), 9 CWSs ( 0.42%), 19 CWSs ( 0.75%), 0 CWSs ( 0.0%), 30 CWSs ( 1.77%), and 3 CWSs ( 0.25%), respectively. The # of assessed surface water source CWSs in those years were 2494, 2132, 2547, 1699, 1700, and 1212 CWSs, respectively.

The identities of, and populations served by CWSs with annual maximum total chloro triazine concentrations > the HED sub chronic/ chronic DWLOC of 18 ug/ L for children and infants can be obtained from the cumulative exceedence tables in Sub Appendix A 5.

The regression estimated, highest annual maximum total chloro triazine concentration ( 59.8 ug/ L) for surface water source CWSs in the PLEX database from 1993 through 1998 was slightly below the HED sub chronic/ chronic DWLOC of 63 ug/ L for adults.

10.4) Comparison of total chloro triazine and total hydroxy triazine concentrations in the Rural Well Survey to HED DWLOCs One well ( out of 1505 sampled in the Rural Well Survey) had a total chloro triazine concentration equaling the HED sub chronic/ chronic DWLOC of 18 ug/ L for the chronic exposure of children and infants, respectively. No wells had total chloro triazine concentrations exceeding the HED sub chronic/ chronic DWLOC of 18 ug/ L for children and infants, the HED sub chronic/ chronic DWLOC of 63 ug/ L for adults or the single HED acute DWLOC of 298 ug/ L for adult women.

The highest total hydroxy triazine concentration detected ( 7.66 ug/ L) was much less than the lowest HED chronic DWLOC of 99 ug/ L for children and infants. V  1 Appendix V. Documentation of Water Resource Modeling ( PRZM3 EXAMS & GENEEC)

Aquatic Exposure Assessment Modeling Approach For aquatic exposure assessment, the tier II refinement approach with PRZM ( Pesticide Root Zone Model) and EXAMS ( EXposure Analysis Modeling System) was simulated to generate the Estimated Environmental Concentrations ( EEC's).

The environmental fate data for atrazine used in the tier 2 refined modeling are summarized in the following Table . Input Parameters for PRZM ( version 3.12)

Variable ( units) Variable Description Input Value Source of Info/ Reference DWRATE( 1) 1 ( day 1) Dissolved phase pesticide decay rate in surface horizon DWRATE( 1) = DSRATE( 1)

4.748 x 10  3 Aerobic soil metabolism study ( GLN 162 1)

140 and 146 days DSRATE( 1) 1 ( day 1) Adsorbed phase pesticide decay rate in surface horizon DWRATE( 2) ( day 1) DWRATE( 3) ( day 1) Dissolved phase pesticide decay rate in 1st, and 2nd subsurface horizon DWRATE( 2) = DSRATE( 2)

4.359 x 10  3 DWRATE( 3) = DSRATE( 3)

4.359 x 10  3 Anaerobic soil/ anaerobic aquatic metabolism study ( GLN 162 2/ 3)

159 days DSRATE( 2) ( day 1) DSRATE( 3) ( day 1) Adsorbed phase pesticide decay rate in 1st and 2nd subsurface horizon KD( 1) KD( 2) KD( 3) ( cm3 gm 1 or mL g 1 or L kg 1) Pesticide partition or distribution coefficients for each horizon use KOC value of 87.78 to estimate KD at each horizon Mobility  Adsorption/ Desorption study ( GLN 163 1)

average of 86.9, 38.5, 70.4, and 155.3 DEPI ( cm) Incorporation depth Actual or pesticide label Product label V  2 TAPP ( kg ha 1) Application rate Maximum label rate Product label APPEFF ( decimal) Application efficiency 0.75 for aerial spray; 0.90 for ground spray. Product label; AGDRIFT2 DRFT Spray drift fraction 0.05 for aerial spray; 0.01 for ground spray. AGDRIFT2 Input Parameters for EXAMS ( Version 2.97.5)

Variable ( units) Variable Description Input Value Source of Info/ Reference HENRY ( atm m3mole 1) Henry's law constant 2.58 x 10  9 KBACW1 ( cfu/ mL) 1 hour 1 Bacterial biolysis in water column 9.89 x 10  5 twice of aerobic soil metabolism half life ( 146 x2)

KBACS1 ( cfu/ mL) 1 hour 1 Bacterial biolysis in benthic sediment 4.75 x 10  5 608 days KDP ( hour 1) Direct photolysis 1.72 x 10  4 335 days KBH ( mole 1 hour 1) KNH ( hour 1) KAH ( mole 1 hour 1) Base hydrolysis Neutral hydrolysis Acid hydrolysis 0.0 0.0 0.0 Stable KOC ( mL g 1 O. C.) Partition coefficient for organic carbon 87.78 average of 86.9, 38.5, 70.4, and 155.3 MWT ( g mole 1) Molecular weight 215.69 SOL ( mg L 1) Aqueous solubility 33 QUANT Reaction quantum yield for direct hydrolysis 0 VAPR ( torr) Vapor pressure 3 x 10 7 V  3 PRZM PRZM ( Version 3.12) relates pesticide movement to temporal variations of hydrology, agronomy, pesticide chemistry and meteorology. In order to run PRZM, four types of input data are needed: meteorology, soil, hydrology and pesticide chemistry. Except for the pesticide chemistry, the other three types of input data were adopted based on the standard scenarios established by the Water Quality Tech Team ( WQTT) of EFED.

Based on the rainfall records and crop productions, the modeling scenarios chosen to represent the high runoff potential are listed below:

Use Site/ Year MLRA* Soil Hydrologic Soil Group Corn Ohio ( 48' ~ 83') 111 Cardington Silt Loam C Sugarcane Louisiana ( 64'~ 83') 131 Sharkey Clay D Sorghum Kansas ( 48' ~ 83') 112 Dennis Silt Loam C * MLRA represents Major Land Resource Area, which are geographically associated land resource units ( USDA, 1981).

The meteorology parameters including precipitation, evaporation and air temperature were obtained from ORD, Athens Laboraotry. The soil properties including layer depth, soil texture class, soil composition ( i. e., percentage sand, silt, clay, and organic matter), bulk density, field capacity, wilting point, and available water for each selected soil were extracted from PIRANHA databases.

EXAMS The operation of EXAMS involved three types of data inputs: Environment, Load and Chemical. The standard Georgia farm pond data file was used to describe the Environment data input. The P2E C1. D( X) [ where " X" representing a two digit number from 48 to 83, or 64 to 83], files generated by PRZM were used as the Load data input. The Chemical data input was created based on the E. Fate profile of atrazine.

EXAMS was run using data from 36 years using Mode 3 which used monthly environmental data and the daily pulse loads of runoff and spray drift. For each year simulated, the maximum annual peak, 96 hour average, 21 day average, 60 day average, 90 day average values, and the annual mean were extracted from the EXAMS output file REPORT. XMS with the TABLE20. EXE post processor. The 10 year return EECs ( or 10% yearly exceedance EECs) of corn, sugarcane, and sorghum listed in the Table below were calculated by linear interpolation between the third and fourth largest values by the program TABLE20. EXE.

Results  Aquatic EECs V  4 The refined tier II approach with PRZM/ EXAMS was implemented. The upper tenth percentile concentration values, expressed in ppb ( ug/ L), are summarized below. The results of three uses, corn, sugarcane, and sorghum, were based on the standard scenarios provided by the Water Quality Tech Team ( WQTT) to predict reasonable high exposure values, i. e., soils with high runoff potential and heavy rainfall amounts.

Use Peak 96 hr average 21 d average 60 d average 90 d average Corn 38.24 38.02 37.18 35.50 34.16 Sugarcane 205.10 204.10 202.20 198.10 194.20 Sorghum 72.70 72.31 70.64 67.74 65.86 The modeling results indicate that atrazine does have the potential to move into surface waters, especially for sugarcane use.

The post processor, LOAD. EXE, was used to estimate the chemical contributions of runoff, erosion and spray drift to the standard farm pond. The results expressed as percentages are tabulated below:

Percent of Pesticide Loadings from Different Sources to the Standard Pond Use Runoff Erosion Spray Drift Corn 55.03% 3.47% 41.50%

Sugarcane 99.15% 0.85% 0.01%

Sorghum 71.80% 5.29% 22.91%

The erosion losses were the smallest among the three components, except for sugarcane use scanario. Most of the atrazine losses to aquatic environments are from runoff. Therefore, any mitigation approaches should focus on reducing chemical runoff. V  5 V  6 ATRAZINE USE ON CORN WATER COLUMN DISSOLVED CONCENTRATION ( PPB) YEAR PEAK 96 HOUR 21 DAY 60 DAY 90 DAY YEARLY 1948 13.680 13.580 13.260 12.610 12.080 6.926 1949 14.140 14.060 13.880 13.320 13.190 10.440 1950 15.760 15.680 15.400 14.960 14.560 11.290 1951 23.380 23.250 22.760 21.830 21.200 15.030 1952 20.560 20.490 20.140 19.440 18.970 15.590 1953 29.880 29.730 29.300 28.060 27.050 19.430 1954 22.840 22.720 22.230 21.710 21.140 18.160 1955 19.090 19.010 18.790 18.220 18.000 15.290 1956 20.920 20.820 20.500 19.740 19.020 15.070 1957 32.860 32.720 32.200 30.610 29.410 20.940 1958 38.210 37.980 37.120 35.310 33.860 25.720 1959 37.370 37.200 36.610 35.180 33.910 27.120 1960 27.500 27.360 27.060 26.420 25.730 22.390 1961 27.630 27.470 26.840 25.580 24.640 20.060 1962 28.280 28.150 27.530 26.390 25.530 20.650 1963 25.710 25.580 25.240 24.330 23.520 19.600 1964 21.240 21.170 20.820 20.250 19.650 16.620 1965 20.510 20.420 19.980 19.010 18.450 14.920 1966 18.040 17.960 17.740 17.040 16.480 13.550 1967 30.050 29.900 29.490 28.380 27.460 18.950 1968 47.490 47.380 46.480 44.190 42.650 30.330 1969 43.270 43.080 42.260 40.680 39.310 32.090 1970 31.790 31.660 31.230 30.330 29.360 25.740 1971 28.230 28.100 27.580 26.680 26.080 21.600 1972 31.520 31.370 30.980 30.390 29.460 22.600 1973 25.110 25.010 24.570 23.860 23.370 20.090 1974 38.300 38.100 37.330 35.930 34.730 24.720 1975 27.160 27.040 26.580 26.280 25.750 22.750 1976 23.580 23.450 22.950 22.300 21.890 18.560 1977 19.460 19.380 19.020 18.390 18.120 15.750 1978 21.450 21.350 21.020 20.770 20.220 15.880 1979 20.200 20.090 19.640 18.900 18.530 15.320 1980 30.210 30.110 29.910 28.800 27.760 19.970 1981 30.530 30.360 29.820 28.610 27.920 22.190 1982 29.040 28.910 28.290 27.060 26.140 21.380 1983 24.270 24.140 23.910 23.410 23.120 19.420 Upper 10th 38.237 38.016 37.183 35.496 34.156 26.154 Percentile MEAN OF ANNUAL VALUES = 19.337 STANDARD DEVIATION OF ANNUAL VALUES = 5.287 UPPER 90% CONFIDENCE LIMIT ON MEAN = 20.642 V  7 V  8 ATRAZINE USE ON SUGARCANE WATER COLUMN DISSOLVED CONCENTRATION ( PPB) YEAR PEAK 96 HOUR 21 DAY 60 DAY 90 DAY YEARLY 1964 57.960 57.690 56.610 54.640 53.220 40.190 1965 87.580 87.270 86.000 83.530 81.670 63.870 1966 133.000 132.000 131.000 128.000 126.000 98.030 1967 103.000 103.000 102.000 99.860 98.170 79.370 1968 83.860 83.640 83.320 81.640 80.150 64.630 1969 119.000 119.000 118.000 116.000 114.000 88.150 1970 76.900 76.760 76.190 75.860 75.000 61.140 1971 85.600 85.320 84.500 83.870 82.530 64.820 1972 88.110 87.850 87.220 85.570 84.230 67.330 1973 97.760 97.450 96.430 94.080 92.280 72.340 1974 102.000 102.000 101.000 98.940 96.890 76.860 1975 143.000 143.000 141.000 137.000 134.000 105.000 1976 163.000 162.000 161.000 159.000 156.000 123.000 1977 175.000 174.000 172.000 169.000 166.000 131.000 1978 126.000 126.000 125.000 124.000 122.000 98.470 1979 155.000 155.000 154.000 150.000 146.000 115.000 1980 229.000 229.000 227.000 220.000 216.000 168.000 1981 208.000 207.000 205.000 201.000 197.000 157.000 1982 172.000 171.000 170.000 168.000 165.000 132.000 1983 179.000 178.000 177.000 172.000 169.000 134.000 Upper 10th 205.100 204.100 202.200 198.100 194.200 154.700 Percentile MEAN OF ANNUAL VALUES = 97.010 STANDARD DEVIATION OF ANNUAL VALUES = 35.121 UPPER 90% CONFIDENCE LIMIT ON MEAN = 108.774 V  9 V  10 ATRAZINE USE ON SORGHUM WATER COLUMN DISSOLVED CONCENTRATION ( PPB) YEAR PEAK 96 HOUR 21 DAY 60 DAY 90 DAY YEARLY 1948 50.720 50.410 49.010 46.270 44.190 21.970 1949 38.890 38.690 38.080 36.510 35.360 31.360 1950 32.120 31.940 31.560 30.860 30.210 26.320 1951 39.050 38.820 38.120 37.420 36.160 27.780 1952 66.370 65.950 64.290 60.950 58.370 39.860 1953 48.530 48.280 47.310 46.190 44.890 40.210 1954 34.520 34.350 34.090 33.460 33.020 29.870 1955 26.390 26.240 25.620 25.270 24.940 22.820 1956 23.430 23.310 22.760 22.200 21.590 19.080 1957 27.430 27.270 27.000 25.740 24.820 19.470 1958 23.490 23.370 22.830 21.960 21.510 18.600 1959 21.910 21.780 21.530 21.120 20.830 17.390 1960 26.250 26.140 25.560 24.690 23.900 18.820 1961 41.740 41.490 40.480 39.400 38.310 27.360 1962 64.500 64.110 63.410 60.600 58.330 41.460 1963 62.780 62.390 60.740 57.330 55.260 45.510 1964 48.410 48.170 47.260 45.690 44.840 41.030 1965 38.640 38.440 37.980 36.700 35.710 31.830 1966 40.540 40.310 39.390 37.540 36.360 29.680 1967 43.540 43.290 42.440 41.200 40.160 31.790 1968 37.350 37.160 36.290 34.420 33.420 29.770 1969 41.670 41.430 40.520 38.860 37.650 29.820 1970 60.560 60.200 59.150 56.200 53.950 38.740 1971 46.830 46.590 45.990 44.210 42.660 37.700 1972 34.560 34.360 33.620 32.650 32.020 29.550 1973 58.390 58.050 56.980 54.830 52.810 37.050 1974 100.000 99.840 97.310 91.840 88.580 60.470 1975 82.780 82.440 81.330 77.590 74.640 64.500 1976 55.640 55.560 55.250 54.460 53.760 47.640 1977 52.650 52.410 51.200 48.460 46.600 39.210 1978 47.580 47.330 46.240 43.870 42.320 36.220 1979 56.810 56.490 55.300 53.680 51.700 39.190 1980 75.400 75.050 73.280 69.150 66.500 48.800 1981 71.540 71.140 69.510 67.140 65.590 54.300 1982 69.750 69.380 68.410 65.320 62.780 52.210 1983 46.710 46.650 46.380 45.720 45.120 39.610 Upper 10th 72.698 72.313 70.641 67.743 65.863 52.837 Percentile MEAN OF ANNUAL VALUES = 35.194 STANDARD DEVIATION OF ANNUAL VALUES = 11.797 UPPER 90% CONFIDENCE LIMIT ON MEAN = 38.105 VI  1 Fig. USGS 1992 Lake/ Reservoir Misc. maxima cumul. exceed. curves 0 2 4 6 8 10 12 14 0 20 40 60 80 100 120 % of lakes/ res w. maximum >= Y Max. concentration ( ug/ L)

Atrazine DEA DIA APPENDIX VI. Lake and Reservoir Monitoring Studies and Data Plots USGS 1992 1993 Study of 76 Mid Western Reservoirs ( USGS Open File Report 96 393):

The USGS sampled the outflows from 76 mid western reservoirs 8 times ( approximately once every two months) from April 1992 through September 1993 ( USGS Open File Report 96 393). The samples were analyzed for a number of pesticides and pesticide degradates including atrazine, de ethyl atrazine ( DEA), and de isopropyl atrazine ( DIA). The reservoirs were selected from a list of approximately 440 reservoirs in 11 mid western states. The locations of the reservoirs are shown below. Information about the sampled reservoirs is supplied in table.

The sampling frequency was inadequate for EFED to provide an atrazine, time series for the reservoirs. However, EFED generated 1992 and 1993 cumulative exceedence curves of maximum annual atrazine, DEA, and DIA concentrations versus the % of reservoirs with equal or greater annual maximum concentrations. VI  2 Fig. USGS 1993 Lake/ Reservoir Misc. maxima cumul. exceed. curves 0 2 4 6 8 10 12 0 20 40 60 80 100 120 % of lakes/ res w. maximum >= Y Max. concentration ( ug/ L)

Atrazine DEA DIA VII  1 APPENDIX VII. Stream and River Monitoring Studies and Data Plots USGS 1989 1990 Reconnaissance Study of Mid Western Streams ( USGS Open File Report 93 457):

In 1989, the USGS collected one " pre application" sample, one " post application" sample and one " Fall" sample from 52, 129, and 143 mid western streams, respectively, across 10 states. In 1990, the USGS collected one " pre application" sample, and one " post application" sample from 52 and 50 mid western streams, respectively, across 10 states. " Pre application" samples were generally collected in March or April before the applications of various herbicides. " Postapplication samples were collected during May or June during the first runoff event following the bulk of herbicide applications. " Fall" samples were generally collected in October or November.

The samples were analyzed for a number of pesticides including atrazine, DEA, and DIA. The number of samples collected at each site ( 1 3 depending upon the site) was not adequate for EFED to generate atrazine, DEA, and DIA time series curves. However, EFED generated 1989 pre application, post application, and Fall cumulative exceedence curves of atrazine, DEA, and DIA concentrations versus the % of sites with equal or greater concentrations. EFED also generated 1990 pre application and post application cumulative exceedence curves for those chemicals.

USGS 1990 1992 Study of 9 Mid western Rivers/ Streams ( USGS Open File Report 94 396):

The USGS sampled each of 9 mid western rivers/ streams several hundred times from April 1990 through July 1990. Samples were manually collected 1 2 times per week and automatically collected during runoff events either at several hour intervals or in response to changes in flows. During runoff events, 2 4 samples were typically collected at different times on the same day. The samples were analyzed for a number of pesticides including atrazine. Using the same sampling methodology in the Spring/ Summer of 1991, the USGS collected additional samples from 2 of the 9 rivers/ streams ( the Iroquois River in IL and the Sangamon River in IL) from April 1991 through March 1992 The number of sites sampled ( 9) and the number of years sampled ( 1 2) were too low for EFED to generate cumulative exceedence curves from the data. However, EFED did generate two sets of atrazine time series curves from the data. In one set of atrazine time series curves, EFED plotted the average of the atrazine concentrations in all of the samples collected on the same day during a runoff event. In the other set of atrazine time series curves, EFED plotted the maximum atrazine concentration in all of the samples collected on the same day during a runoff event.

USGS April 1991 to September 1992 Study of the Mississippi River Basin ( USGS Open File Report 93 657): VII  2 The USGS sampled 8 sites within the Mississippi Basin from April 1991 through September 1992. Three of the sampling sites were on the Mississippi River. The other 5 sampling sites were on other rivers within the Mississippi Basin. Two samples were collected per week from May 6 to July 15, 1991. One sample was collected every two weeks from November 1991 through February 1992. One sample was collected per week during all other periods of the study ( April 1991, July 15, 1991 October 30, 1991 and March 1992 July 1992). The samples were analyzed for a number of pesticides including atrazine.

The number of sites sampled ( 8) and the number of years sampled ( 1) were too low for EFED to generate cumulative exceedence curves from the data. However, EFED did generate atrazine time series curves from the data.

USGS 1994 1995 Reconnaissance Study of Mid Western Streams ( USGS Open File Report 98 181):

In 1994, the USGS collected one " pre application" sample, and one " post application" sample from 52 and 50 mid western streams, respectively, across 8 states. In 1995, the USGS collected one " post application" sample from 50 mid western streams across 7 states. " Pre application" samples were generally collected in March or April before the applications of various herbicides. " Post application" samples were collected during May or June during the first runoff event following the bulk of herbicide applications.

The samples were analyzed for a number of pesticides including atrazine, DEA, and DIA. The number of samples collected at each site ( 1 2 depending upon the site) was not adequate for EFED to generate atrazine, DEA, and DIA time series curves. However, EFED generated 1994 and 1990 pre application and post application cumulative exceedence curves of atrazine, DEA, and DIA concentrations versus the % of sites with equal or greater concentrations. EFED also generated 1995 post application cumulative exceedence curves for those chemicals. VIII  1 Figure 13. Surface Water Monitoring Results for Atrazine in the Chesapeake Bay's Tidal Rivers Maximxum Concentrations by Site and Year ( 1977  1993)

0 5 10 15 20 25 30 35 0 10 20 30 40 50 60 70 80 90 100 Exceedence % % Sites w/ Atrazine Concs >= Y Atrazine Concs ( ug/ L) * Reductions in Fish & Invertebrate Population Estimated to Occur at 23 µ g/ L * Reduction in Primary Productivity & Macrophytes Estimated to Occur at 9.1 µ g/ L * Reduction in Macrophytes Likely to Occur at 4 µ g/ L APPENDIX VIII. Chesapeake Bay Monitoring Data on Atrazine Levels IX  1 APPENDIX IX. Documentation of Terrestrial Fate Residue Model and Data The model of Hoerger and Kenega ( 1972), as modified by Fletcher et al. ( 1994) was used to estimate pesticide concentrations on selected avian or mammalian food items. This model predicts the maximum concentrations that may occur immediately following a direct application at 1 lb ai/ A. For 1 lb ai/ A applications, peak concentrations ( i. e., Day 0) on short grass, tall grass, broadleaf plants, and fruits are predicted to be as high as 240, 110, 135, and 15 ppm, respectively. The residue monitoring on which this model was based, did not include insects. However, based on similar surface area to volume ratio between insects and some plant parts, the predicted maximum concentration for broadleaf plants and fruits are used to represent maximum concentrations that may occur on small and large insects, respectively. Linear extrapolation is then used to estimate maximum terrestrial EEC's for single applications at application rates other than 1 lb ai/ A. For example, a single application at 4 lbs ai/ A would result in peak concentrations of 960 for short grass, 440 ppm for tall grass, 540 ppm for broadleaf foliage and small insects, and 60 ppm for fruits and large insects. If multiple applications are permitted, the peak terrestrial EECs resulting from subsequent applications are estimated by summing the maximum EEC predicted for the last application with the remaining concentrations predicted for the previous application( s). After application, residues on food items are predicted to decline according to a first order exponential model. If the maximum initial concentration is C0 and the half life for the exponential dissipation of the active ingredient is t1/ 2, the remaining concentration at time t is given by the following formula:

C Ce t t t =   0 2 1/ 2 ln The general formula for the peak EEC ( Cpeak) following multiple applications is:

C Ce peak i n In t =

  0 1 1 2 1/ 2 ( ) ln where C0 is the maximum initial concentration after one application, I is the interval in days between applications, n is the number of applications, and t1/ 2 is the half life of the active ingredient.

The initial concentration, half life, number of applications, interval between treatments, and length of simulation are variable. The current Fate Model has two limitations: 1) for more than two applications, only one time interval can be designated for a run; and 2) between treatments per fate run ( i. e., two or more treatment intervals can not be used per run). Four examples of Fate Model printouts follow; one each for short grass, foliage and small insects, long grass, and fruits, seeds and large insects.

The data tables used in the risk assessment for sugarcane, corn and sorghum are presented below. IX  2 DAILY PESTICIDE RESIDUE LEVELS  MAXIMUM. SUGARCANE USE RATE SINGLE APPLICATION AT 4 LB AI./ A ON SHORT GRASS Chemical name  Atrazine Initial concentration ( ppm)  960 Half life  17 Length of simulated ( day)  160 DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) 0 960 46 147.1362 92 22.5511 1 921.6448 47 141.2576 93 21.6501 2 884.822 48 135.6139 94 20.78511 3 849.4704 49 130.1957 95 19.95467 4 815.5313 50 124.9939 96 19.15742 5 782.9481 51 120 97 18.39.202 6 751.6668 52 115.2056 98 17.6572 7 721.6352 53 110.6027 99 16.95173 8 692.8035 54 106.1838 100 16.27446 9 665.1237 55 101.9414 101 15.62424 10 638.5498 56 97.8685 102 15 11 613.0376 57 93.95834 103 14.4007 12 588.5447 58 90.20439 104 13.82534 13 565.0304 59 86.60042 105 13.27297 14 542.4556 60 83.14045 106 12.74267 15 520.7826 61 79.81871 107 12.23356 16 499.9757 62 76.6297 108 11.74479 17 480 63 73.56808 109 11.27555 18 460.8224 64 70.62878 110 10.82505 19 442.411 65 67.80693 111 9.977337 20 424.7352 66 65.09783 112 9.578712 21 407.7656 67 62.49695 113 9.578712 22 391.4741 68 60 114 9.196009 23 375.8334 69 57.6028 115 8.828598 24 360.8176 70 55.30138 116 8.475866 25 346.4017 71 53.0919 117 8.137228 26 332.5618 72 50.9707 118 7.812118 27 319.2749 73 48. 93425 119 7.5 28 306.5188 74 46.97917 120 7.200348 29 294.2724 75 45.10219 121 6.91267 30 282.5152 76 43.3002 122 6.636485 31 271.2278 77 41.57022 123 6.371336 32 260.3913 78 39.90935 124 6.116781 33 249.9878 79 38.31484 125 5.872396 34 240 80 36.78403 126 5.637774 35 230.4112 81 35.31439 127 5.412525 36 221.2055 82 33.90347 128 5.196277 37 212.3676 83 32.54891 129 4.988669 38 203.8828 84 31.24847 130 4.789353 39 195.737 85 30 131 4.598002 40 187.9167 86 28.8014 132 4.414299 41 180.4088 87 27.65069 133 4.237933 IX  3 42 173.2009 88 26.54595 134 4.068614 43 166.2809 89 25.48535 135 3.906059 44 159.6374 90 24.46713 136 3.75 45 153.2594 91 23.48958 137 3.600173 Maximum residue  960 Average residue  149.0321 IX  4 DAILY PESTICIDE RESIDUE LEVELS  MAXIMUM. SUGARCANE USE RATE SINGLE APPLICATION AT 4 LB AI./ A ON BROADLEAF FOLIAGE Chemical name  Atrazine Initial concentration ( ppm)  540 Half life  17 Length of simulated ( day)  100 DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) 0 540 46 82.7641 92 12.68499 1 518.4252 47 79.45738 93 12.17818 2 497.7124 48 76.2828 94 11.69162 3 477.8271 49 73.23506 95 11.2245 4 458.7364 50 70.30907 96 10.77605 5 440.4084 51 67.5 97 10.34551 6 422.8126 52 64.80314 98 9.932172 7 405.9198 53 62.21404 99 9.53535 8 389.7019 54 59.72839 100 9.154381 9 374.1321 55 57.34204 10 359.1842 56 55.05104 11 344.8336 57 52.85157 12 331.0564 58 50.73997 13 317.8296 59 48.71274 14 305.1313 60 46.7665 15 292.9402 61 44.89802 16 281.2363 62 43.1042 17 270 63 41.38205 18 259.2126 64 39.72869 19 248.8562 65 38.1414 20 238.9136 66 36.61753 21 229.3682 67 35.15453 22 220.2042 68 33.75 23 211.4063 69 32.40157 24 202.9599 70 31.10702 25 194.851 71 29.86419 26 187.066 72 28.67102 27 179.5921 73 27.52552 28 172.4168 74 26.42578 29 165.5282 75 25.36998 30 158.9148 76 24.35636 31 152.5656 77 23.38325 32 146.4701 78 22.44901 33 140.6182 79 21.55209 34 135 80 20.69102 35 129.6063 81 19.86435 36 124.4281 82 19.0707 37 119.4568 83 18.30876 38 114.6841 84 17.57727 39 110.1021 85 16.875 40 105.7031 86 16.20079 41 101.4799 87 15.55351 42 97.42548 88 14.9321 43 93.53301 89 14.33551 44 89.79606 90 13.76276 45 86.20841 91 13.21289 Maximum residue  540 Average residue  131.6416 IX  5 DAILY PESTICIDE RESIDUE LEVELS  MAXIMUM. CORN & SORGHUM USE RATES SINGLE APPLICATION AT 2 LB AI./ A ON SHORT GRASS Chemical name  Atrazine Initial concentration ( ppm)  480 Half life  17 Length of simulated ( day)  100 DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) 0 480 46 73.56808 92 11.27555 1 460.8224 47 70.62878 93 10.82505 2 442.411 48 67.80693 94 10.39255 3 424.7353 49 65.09783 95 9.977337 4 407.7657 50 62.49695 96 9.578709 5 391.4741 51 60 97 9.196009 6 375.8334 52 57.60279 98 8.828598 7 360.8176 53 55.30137 99 8.475866 8 346.4017 54 53.0919 100 8.137228 9 332.5618 55 50.9707 10 319.2749 56 48.93425 11 306.5188 57 46.97917 12 294.2724 58 45.1022 13 282.5152 59 43.30022 14 271.2278 60 41.57023 15 260.3913 61 39.90936 16 249.9878 62 38.31485 17 240 63 36.78404 18 230.4112 64 35.31439 19 221.2055 65 33.90346 20 212.3676 66 32.54891 21 203.8828 67 31.24848 22 195.737 68 30 23 187.9167 69 28.8014 24 180.4088 70 27.65069 25 173.2009 71 26.54595 26 166.2809 72 25.48535 27 159.6374 73 24.46713 28 153.2594 74 23.48958 29 147.1362 75 22.5511 30 141.2576 76 21.6501 31 135.6139 77 20.78511 32 130.1957 78 19.95467 33 124.9939 79 19.15742 34 120 80 18.39201 35 115.2056 81 17.6572 36 110.6028 82 16.95173 37 106.1838 83 16.27446 38 101.9414 84 15.62424 39 97.8685 85 15 40 93.95833 86 14.4007 41 90.20439 87 13.82534 42 86.60042 88 13.27298 43 83.14046 89 12.74267 44 79.81872 90 12.23356 45 76.6297 91 11.74479 Maximum residue  480 Average residue  117.0147 IX  6 DAILY PESTICIDE RESIDUE LEVELS  MAXIMUM. CORN & SORGHUM USE RATES SINGLE APPLICATION AT 2 LB AI./ A ON BROADLEAF FOLIAGE Chemical name  Atrazine Initial concentration ( ppm)  270 Half life  17 Length of simulated ( day)  100 DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) DAY RESIDUE ( PPM) 0 270 46 41.38205 92 6.342496 1 259.2126 47 39.72869 93 6.089091 2 248.8562 48 38.1414 94 5.845812 3 238.9136 49 36.61753 95 5.612252 4 229.3682 50 35.15453 96 5.388024 5 220.2042 51 33.75 97 5.172756 6 211.4063 52 32.40157 98 4.966087 7 202.9599 53 31.10702 99 4.767675 8 194.851 54 29.86419 100 4.577191 9 187.066 55 28.67102 10 179.5921 56 27.52552 11 172.4168 57 26.42578 12 165.5282 58 25.36999 13 158.9148 59 24.35637 14 152.5656 60 23.38325 15 146.4701 61 22.44901 16 140.6182 62 21.5521 17 135 63 19.86435 18 129.6063 64 19.0707 19 124.4281 65 18.30876 20 119.4568 66 17.57727 21 114.6841 67 16.875 22 110.1021 68 16.20079 23 105.7031 69 15.55351 24 101.4799 70 14.9321 25 97.42548 71 14.33551 26 93.53301 72 13.76276 27 89.79606 73 13.21289 28 86.20841 74 13.21289 29 82.7641 75 12.68499 30 79.45739 76 12.17818 31 76.28281 77 11.69162 32 73.23506 78 11.2245 33 70.30908 79 10.77605 34 67.5 80 10.34551 35 64.80315 81 9.932172 36 62.21405 82 9.53535 37 59.72839 83 9.154381 38 57.34204 84 8.788632 39 55.05104 85 8.4375 40 52.85156 86 8.100393 41 50.73997 87 7.776756 42 48.71274 88 7.466048 43 46.76651 89 7.167754 44 44.89803 90 6.881379 45 43.1042 91 6.606445 Maximum residue  270 Average residue  65.8208 X  1 APPENDIX X. Terrestrial Plant Exposure Formulae Calculating EECs for terrestrial plants inhabiting dry areas adjacent to treatment sites Unincorporated ground application: Runoff = maximum application rate ( lbs ai/ A) x runoff value Drift = maximum application rate x 0.01 Total Loading = runoff ( lbs ai/ acre) + drift ( lbs ai/ A)

Incorporated ground application: Runoff = [ maximum application rate ( lbs ai/ A) ÷ minimum incorporation depth ( cm.)] x runoff value Drift = maximum application rate x 0.01 ( Note: drift is not calculated if the product is incorporated at the time of application.) Total Loading = runoff ( lbs ai/ A) + drift ( lbs ai/ A)

Aerial, airblast, forced air, and chemigation applications: Runoff = maximum application rate ( lbs ai/ A) x 0.6 ( 60% application efficiency assumed) x runoff value Drift = maximum application rate ( lbs ai/ A) x 0.05 Total Loading = runoff ( lbs ai/ A) + drift ( lbs ai/ A)

Calculating EECs for terrestrial plants inhabiting semi aquatic low lying areas Unincorporated ground application: Runoff = maximum application rate ( lbs ai/ A) x runoff value x 10 acres Drift = maximum application rate x 0.01 Total Loading = runoff ( lbs ai/ A) + drift ( lbs ai/ A)

Incorporated ground application: Runoff = [ maximum application rate ( lbs ai/ A)/ minimum incorporation depth ( cm)] x runoff value x 10 acres Drift = maximum application rate x 0.01 ( Note: drift is not calculated if the product is incorporated at the time of application.) Total Loading = runoff ( lbs ai/ A) + drift ( lbs ai/ A)

Aerial, airblast, and forced air applications: Runoff = maximum application rate ( lbs ai/ acre) x 0.6 ( 60% application efficiency assumed) x runoff value x 10 acres Drift = maximum application rate ( lbs ai/ A) x 0.05 Total Loading = runoff ( lbs ai/ A) + drift ( lbs ai/ A) XI  1 Appendix XI. Ecological Effects Characterization a. Toxicity to Terrestrial Animals I. Birds, Acute and Subacute An acute oral toxicity study using the technical grade of the active ingredient ( TGAI) is required to establish the toxicity of atrazine to birds. The preferred test species is either mallard duck ( a waterfowl) or bobwhite quail ( an upland gamebird). Results of this test are tabulated below.

Avian Acute Oral Toxicity Surrogate Species % ai LD50 ( mg/ kg) Probit Slope Toxicity Category MRID No. Author/ Year Study Classification1 Northern bobwhite quail ( Colinus virginianus) 14 day old chicks; 8 day test Tech. 940 slope 3.836 Slightly toxic 00024721 Fink 1976 Core Mallard Duck ( Anas platyrhynchos) 6 months old; 14 day test 76 % 80 WP > 2,000 slope none Practically non toxic 00160000 Hudson, Tucker & Haegle 1984 Supplemental ( only 3 birds) ( formulation)

Ring necked Pheasant ( Phasianus colchicus) 3 months old; 14 day test 76 % 80 WP > 2,000 slope none Practically non toxic 00160000 Hudson, Tucker & Haegle 1984 Supplemental ( formulation)

Japanese Quail ( Coturnix c. japonica) 50 60 days old; 14 day test Tech. 4,237 slope > 6 Practically non toxic 00024722 Sachsse and Ullman 1974 Supplemental ( species not native)

1 Core ( study satisfies guideline). Supplemental ( study is scientifically sound, but does not satisfy guideline)

Since the lowest LD50 is in the range of 501 to 2,000 mg/ kg, atrazine is categorized as slightly toxic to avian species on an acute oral basis. According to Hudson et al. ( 1984), signs of intoxication in mallards first appeared 1 hour after treatment and persisted up to 11 days. In pheasants, remission of signs of intoxication occurred by 5 days after treatment. Signs of intoxication included weakness, hyper excitability, ataxia, tremors; weight loss occurred in mallards. The guideline requirement ( 71 1) is fulfilled ( MRID 00024721).

Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in various compartments of the environment. Minor atrazine degradates include deethylatrazine, deisopropylatrazine and diaminochlorotriazine. Acute mammalian LD50 values available for deethylatrazine and deisopropylatrazine are both more toxic than the parent atrazine. Therefore, a special ( 70 1) acute oral test with the upland gamebird ( preferably northern bobwhite) are required to address the concern for these three degradates. The requirement ( 70 1) has not been fulfilled. XI  2 Two subacute dietary studies using the TGAI are required to establish the toxicity of atrazine to birds. The preferred test species are mallard duck and bobwhite quail. Results of these tests are tabulated below.

Avian Subacute Dietary Toxicity Surrogate Species % ai 5 Day LC50 ( ppm) 1 Toxicity Category MRID No. Author/ Year Study Classification Northern bobwhite ( Colinus virginianus) 9 days old chicks 99.0 > 5,000 ( no mortality) Practically non toxic 00022923 Hill et al. 1975 Core Northern bobwhite ( Colinus virginianus) young adults Tech. > 10,000 Practically non toxic unknown  Gulf South Gough & Shellenberger 1972 Supplemental ( Adult birds & no raw data)

Ring necked pheasant ( Phasianus colchicus) 10 days old chicks 99.0 > 5,000 ( no mortality) Practically non toxic 00022923 Hill et al. 1975 Core Japanese Quail ( Coturnix c. japonica) 7 days old chicks 99.0 > 5,000 ( 7 % mortality at 5,000 ppm) Practically non toxic 00022923 Hill et al. 1975 Supplemental ( species not native)

Mallard duck ( Anas platyrhynchos) 10 days old ducklings 99.0 > 5,000 ( 30 % mortality at 5,000 ppm) Practically non toxic 00022923 Hill et al. 1975 Core 1 Test organisms observed an additional three days while on untreated feed.

Since the LC50 values are greater than 5,000 ppm, atrazine is categorized as practically nontoxic to avian species on a subacute dietary basis. The time to death was Day 3 for the one Japanese quail and Day 5 for three mallard ducks ( J. Spann at Patuxent Wildlife Center, 1999, personal communication). The guideline requirement ( 71 2) is fulfilled ( MRID 00022923).

Subacute dietary studies using a typical end use product ( TEP) may be required on a case bycase basis to establish the toxicity of atrazine formulations to birds. The preferred test species are mallard duck and bobwhite quail. Results of these tests are tabulated below.

Formulation Avian Subacute Dietary Toxicity Surrogate Species % ai Form 5 Day LC50 ( ppm ai) 1 Probit Slope Toxicity Category MRID No. Author/ Year Study Classification Northern bobwhite ( Colinus virginianus) ( 6 weeks old) 76 80 WP 5,760 slope 3.252 Practically non toxic 00059214 Beliles & Scott 1965 Supplemental ( birds too old)

Mallard duck ( Anas platyrhynchos) 76 80 WP 19,560 slope 1.807 Practically non toxic 00059214 Beliles & Scott 1965 Core for 80W formulation 1 Test organisms observed an additional three days while on untreated feed.

Since the LC50 values are greater than 5,000 ppm, atrazine is categorized as practically nontoxic to avian species on a subacute dietary basis for the 80W formulation. In the mallard study, a highly noticeable weight loss and emaciated birds were found at all test levels ( 1,000 to XI  3 32,000). No additional data is required under guideline requirement 71 2 for atrazine formulations at this time.

Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in various environmental compartments. Acute mammalian LD50 values available for deethylatrazine and deisopropylatrazine, minor degradates, are both more toxic than the parent atrazine. Special ( 70 2) oral dietary tests for these degradates with waterfowl ( preferably mallard duck) and upland gamebird ( preferably northern bobwhite) are reserved pending the results of acute oral toxicity tests on these degradates. The requirement ( 70 2) is reserved.

ii. Birds, Chronic Avian reproduction studies using the TGAI are required for atrazine, because the following conditions are met: ( 1) birds may be subject to repeated or continuous exposure to the pesticide, especially preceding or during the breeding season, ( 2) the pesticide is stable in the environment to the extent that potentially toxic amounts may persist in animal feed, ( 3) the pesticide is stored or accumulated in plant or animal tissues, and/ or, ( 4) information derived from mammalian reproduction studies indicates reproduction in terrestrial vertebrates may be adversely affected by the anticipated use of the product. The preferred test species are mallard duck and bobwhite quail. Results of these tests are tabulated below.

Avian Reproduction Surrogate Species/ Study Duration % ai NOEC/ LOEC ( ppm ai) Statistically sign. ( p= 0.05) LOEC Endpoints MRID No. Author/ Year Study Classification Northern bobwhite ( Colinus virginianus) 20 weeks 97.1 NOAEC 225 LOAEC 675 NOAEC < 75 LOAEC 75 29 % red. in egg production 67 % incr. in defective eggs 27 % red. in embryo viability 6 13 % red. in hatchling body wt. 10 16 % red. in 14 day old body wt. 8.2 % red. in 14 day old body wt. ( after recovery period)

6.7 18 % red. in 14 day old body wt. 42547102 Pedersen & DuCharme 1992 Core Mallard duck ( Anas platyrhynchos) 20 weeks 97.1 NOAEC 225 LOAEC 675 NOAEC 75 LOAEC 225 49 % red. in egg production 61 % red. in egg hatchability 12 17 % red. in food consumption 9 13 % red. in food consumption ( During 3 of 11 biweekly periods) 42547101 Pedersen & DuCharme 1992 Core In the bobwhite study, the reproductive endpoints were measured after a 3 week recovery period. A statistically significant effect during the recovery period was a 700 percent increase in the number of defective eggs at 675 ppm compared to controls; the number of defective eggs was consistent with the number of defective eggs during the treatment period at 675 ppm. Bobwhite and mallard tests show similar toxic effects on reduced egg production and embryo viability/ hatchability. In an 8 day LC50 test with adult Japanese quail, the quail fed atrazine had XI  4 reduced food consumption, lost body weight and egg production stopped after 3 days of exposure ( Sachsse and Ullman, 1975; MRID 00024723). The guideline requirement ( 71 4) is fulfilled for both avian species ( MRID 42547101, 42547102).

Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in various environmental compartments. Minor degradates were deethylatrazine, deisopropylatrazine and diaminochloro s triazine. Subchronic mammalian toxicity values available for deethylatrazine, deisopropylatrazine, hydroxyatrazine and diaminochlorotriazine indicate greater or equal toxicity compared to the parent atrazine in 10 day pregnancy tests, 13 week dog dietary tests, 1 year dog dietary tests and 2 year carcinogenicity tests. The requirement for avian reproductive tests with degradates are reserved pending the acute oral and dietary test results. The requirement ( 70 4) for degradates is reserved.

iii. Mammals, Acute Wild mammal testing is required on a case by case basis, depending on the results of lower tier laboratory mammalian studies, intended use pattern and pertinent environmental fate characteristics. In most cases, rat or mouse toxicity values obtained from the Agency's Health Effects Division ( HED) substitute for wild mammal testing. The acute toxicity values cited in HED's one liners are reported below.

Mammalian Toxicity Surrogate Species % ai Test Type Toxicity Value Affected Endpoints MRID No./ Author Laboratory mouse ( Mus musculus) ?? Acute oral 1,750 mg/ kg LD50 ( mortality) Weed Sci. Assoc. 1967 Laboratory rat ( Rattus norvegicus) Tech. Acute oral 1,869 mg/ kg LD50 ( mortality) 00230303 Ciba Geigy 1975 Laboratory rat ( Rattus norvegicus) Tech. Acute oral 2,030 mg/ kg LD50 ( mortality) 00231466 Instituto di Ricerche Laboratory rat ( Rattus norvegicus) 95 Acute oral 2,850 mg/ kg LD50 ( mortality) 00027097 Consultox Lab. Ltd.

Laboratory rat ( Rattus norvegius) ?? Acute oral 3,080 mg/ kg LD50 ( mortality) Weed Sci. Assoc. 1967 Laboratory mouse ( Mus musculus) Tech. Acute oral 3,992 mg/ kg LD50 ( mortality) 00230303 Ciba Geigy 1977 FORMULATIONS:

Laboratory rat ( Rattus norvegicus) 85.5 Acute oral  female male 1,180 mg/ kg 1,317 mg/ kg LD50 ( mortality) 00249196 Stillmeadow Inc. 1980 Laboratory rat ( Rattus norvegicus) 85.5 90 W Acute oral 1,440 mg/ kg LD50 ( mortality) 00000527 Industry Bio Test 1971 Laboratory rat ( Rattus norvegicus) 85.5 Acute oral 1,992 mg/ kg LD50 ( mortality) 00000847 Hill Top Research, Inc. Mammalian Toxicity Surrogate Species % ai Test Type Toxicity Value Affected Endpoints MRID No./ Author XI  5 Laboratory rat ( Rattus norvegicus) 76 80 WP Acute oral > 1,520 mg/ kg < 1,900 mg/ kg LD50 ( mortality) 00046159 WIL Res. Lab. 1978 Laboratory rat ( Rattus norvegicus) 76 Acute oral  male 2,147 mg/ kg LD50 ( mortality) 00240852 Industrial Bio Test 1974 Laboratory rat ( Rattus norvegicus) Atratol 8P Acute oral 3,100 mg/ kg ( as product) LD50 ( mortality) 00234490 Food & Drug Res. 1977 Laboratory rat ( Rattus norvegicus) 76 80 W Acute oral 3,876 mg/ kg LD50 ( mortality) 00230305 Industrial Bio Test 1965 Laboratory rat ( Rattus norvegicus) 51.0 Acute oral  female male 546 mg/ kg 729 mg/ kg LD50 ( mortality) 00245364 Food & Drug Res. Lab.

Laboratory rat ( Rattus norvegicus) 44.3 Aatrex Acute oral  female male 2,437 mg/ kg 2,038 mg/ kg LD50 ( mortality) 00000519 Not listed Laboratory rat ( Rattus norvegicus) 43 Flowable Acute oral 830 mg/ kg LD50 ( mortality) 00000522 Not listed Laboratory rat ( Rattus norvegicus) 42.0 Acute oral 811 mg/ kg LD50 ( mortality) 00002041 Bio/ Dynamics Inc. 1976 Laboratory rat ( Rattus norvegicus) 40.8 Acute oral  female male 224 mg/ kg 738 mg/ kg LD50 ( mortality) 00242662 Raltech Sci. Serv. 1980 Laboratory rat ( Rattus norvegicus) 40.8 Acute oral  female male 432 mg/ kg 690 mg/ kg LD50 ( mortality) 00000537 WIL Res. Lab. 1978 Laboratory rat ( Rattus norvegicus) 40.8 Acute oral  female male 439 mg/ kg 769 mg/ kg LD50 ( mortality) 00246393 Toxigenics, Inc 1981 Laboratory rat ( Rattus norvegicus) 40.8 Acute oral  female male > 694 mg/ kg 775 mg/ kg LD50 ( mortality) 00243485 Cosmopolitan Safety Evalutation, Inc 1980 Laboratory rat ( Rattus norvegicus) 40.8 Acute oral 1,306 mg/ kg LD50 ( mortality) 00253726 Bio/ Dynamics Inc. 1984 Laboratory rat ( Rattus norvegicus) 40.8 Atrazine 4L Acute oral  female male 1,918 mg/ kg 1,705 mg/ kg LD50 ( mortality) 00241725 Cosmopolitan Safety Evaluation, Inc An analysis of the results indicate that atrazine and its formulations range from 224 to 3,992 mg/ kg which categorized atrazine as moderately to slightly toxic to small mammals on an acute oral basis. Initial symptoms, piloerection and decreased activity, were reported as early as 30 minutes posttreatment. Other signs of toxicity include salivation, lacrimation, muscular weakness, tremor ataxia, diarrhea, adrenal degradation, congested lungs, and degeneration of kidneys and adrenal glands. Matching toxicity values for males and females in most cases ( i. e., 7 out of 9 studies) indicate that females are more sensitive to atrazine than male rats. Atrazine does not appear to be dermally toxic to adult rats and rabbits; dermal LD50 values are greater than 2,000 mg/ kg. Atrazine generally causes corneal opacity which clears by day 7. The need for mammalian acute toxicity is fulfilled. XI  6 Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in various compartments of the environment. Therefore, a special ( 70 3) acute oral test with small mammals is required to address degradate concerns.

Degradate Mammalian Acute Oral Toxicity Surrogate Species/ Study Duration % ai Test Type Toxicity Value Affected Endpoints MRID No.

Laboratory rat ( Rattus norvegicus) 95.7 % Deethylatrazine ( G 30033) Acute oral  female male 668 mg/ kg 1,881 mg/ kg LD50 ( mortality) signs within 30 minutes died within 24 48 hours 43012302 Laboratory rat ( Rattus norvegicus) Tech. Deisopropylatrazine ( G 28279) Acute oral  female male 810 mg/ kg 2,290 mg/ kg LD50 ( mortality) signs within 0.5 48 hours died within 6 48 hours 43012301 Acute mammalian oral toxicity data are available for two degradates, deethylatrazine and deisopropylatrazine. The female LD50 values are more toxic to laboratory rats than technical grade values for the parent pesticide, atrazine. These degradates have LD50 values between 501 and 2,000 mg/ kg which indicates that these degradates are slight toxicity orally. As with atrazine, the female toxicity values for the degradates indicate greater toxicity than for male rats. The requirement ( 71 3) for these two degradates are fulfilled, but the requirement ( 70 3) has not been fulfilled for the major degradate, hydroxyatrazine.

iv. Mammals, Chronic Wild mammal reproduction testing is required on a case by case basis, depending on the results of lower tier laboratory mammalian studies, intended use pattern and pertinent environmental fate characteristics. Atrazine is persistent and initial residue levels exceed acute toxicity values. Usually mammalian chronic data are rat and/ or mouse toxicity values are obtained from the Agency's Health Effects Division ( HED) and substitute for wild mammalian testing. HED reproductive and systematic toxicity values are reported below.

Mammalian Subchronic and Reproduction Toxicity Surrogate Species/ Study Duration % ai NOAEL/ LOAEL ( ppm ai) Statistically sign. ( p= 0.05) LOEC Endpoints MRID No. Author/ Year Study Classification Laboratory Rat ( Rattus norvegicus) 2 Generation Dietary Tech. NOAEL 50 LOAEL 500 NOAEL 50 LOAEL 500 red. adult body weight and red. adult food consumption red. pup body weight in second generation 40431303 Ciba Geigy 1987 Minimum Laboratory Rat ( Rattus norvegicus) 2 Yr Carcinogenicity 98.9 NOAEL 10 LOAEL 70 NOAEL 70 LOAEL 500 incr. carcinomas for females ( adenomas & fibroadenomas)

red. mean adult body weight 00158930 American Biogenics Corp. 1986 Minimum Laboratory Rat ( Rattus norvegicus) 2 Yr Carcinogenicity 97 NOAEL 70 LOAEL 400 red. adult body weight gain 42204401 Hazleton Lab. 1992 Minimum Mammalian Subchronic and Reproduction Toxicity Surrogate Species/ Study Duration % ai NOAEL/ LOAEL ( ppm ai) Statistically sign. ( p= 0.05) LOEC Endpoints MRID No. Author/ Year Study Classification XI  7 Laboratory Rat ( Rattus norvegicus) Fed for 14 days 97.4 NOAEL 100 LOAEL 200 reduced estrogen levels 41570901 Hazelton Lab. 1990 Supplementary Laboratory rat ( Rattus norvegicus) Dosed on Days 6  15 97.4 NOAEL 100 LOAEL 500 increased fused sternebrae 1 & 2 43012308 Ciba Geigy 1992 Guideline Laboratory rat ( Rattus norvegicus) Dosed on Days 6  15 95.7 NOAEL 100 LOAEL 500 NOAEL 500 LOAEL 2,000 17 % red. adult body weight gain incr. in fused sternebrae 1 & 2 incr. poor ossification of fifth toe 43013209 Ciba Geigy 1992 Guideline Laboratory rat ( Rattus norvegicus) Dosed on Days 6 15 ? 96.7 NOAEL 200 LOAEL 1,400 red. body weight gain delayed ossification 40566301 Ciba Geigy 1984 Minimum Dog   Beagle ( Canis sp.) 13 Week Feeding Tech. NOAEL < 200 LOAEL 200 red. body weight in males 00163339 WARF Institute 1997 Supplementary Dog   Beagle ( Canis sp.) 1 Year Feeding 97 NOAEL 150 LOAEL 1,000 increases in deaths, cachexia, ascite decr. body weight & food consumption irregular heart beat, incr. heart rate, incr. cardiac lesions 40431301 41293800 Ciba Geigy 1987 Minimum New Zealand Rabbit ( Lepis sp.) 96.3 NOAEL 33 LOAEL 165 NOAEL 165 LOAEL 2,475 red. body weight gain and red. food consumption.

incr. resorptions, red. fetal body weights and delayed ossification of appendages 00143008 40566301 Ciba Geigy 1984 Supplemental Minimum Laboratory mice ( Mus musculus) 22 Month Oncology batch 84180 2 NOAEL 300 LOAEL 1,500 23.5 % red. male body weight 11 % red. female body weight incr. incidence of cardiac thrombi in females 40431302 Ciba Geigy 1987 Guideline The above mammalian chronic studies provide adequate toxicity data on chronic and reproductive effects. HED has concluded there is evidence that atrazine is associated with endocrine disruption. Direct measurements of norepinephrine, dopamine, and GnRH, and of serum hormones such as certain steroid hormones and luteinizing hormone, as well as changes in estrous cycling and histomorphic changes in hormone responsive tissues, indicate neuroendocrine disruption. The need for chronic mammalian toxicity data is fulfilled.

Degradates: The major atrazine degradate, 2 hydroxyatrazine, forms a large percentage of the recoverable pesticide in various environmental compartments. Several subchronic and chronic toxicity studies for atrazine degradates and/ or metabolites are summarized in the table below for deethylatrazine, deisopropylatrazine, diaminochlorotriazine and hydroxyatrazine. XI  8 Degradate Mammalian Subchronic and Reproduction Toxicity Surrogate Species/ Study Duration % ai NOAEL/ LOAEL ( ppm ai) Statistically sign. ( p= 0.05) LOAEL Endpoints MRID No. Author/ Year Study Classification Laboratory rat ( Rattus norvegicus) Fed for 14 days assumed to be 98.2 Diaminochlorotriazine ( G 28273) NOAEL < 100 LOAEL 100 200 red. LH and prolactin levels red. estrogen, LH, prolactin and progesterone 41570901 Hazleton Lab. 1990 Supplemental Laboratory rat ( Rattus norvegicus) Diet for 13 weeks 95.7 Deethylatrazine ( G 30033) NOAEL 50 LOAEL 500 red. in female body weight red. in food efficiency for male and female rats 43012306 Ciba Geigy 1991 Acceptable Guideline Laboratory rat ( Rattus norvegicus) Diet for 13 weeks 96.7 Deisopropyltriazine ( G 28279) NOAEL 50 LOAEL 500 red. in body weights and red. body weight gains in males and females 43012305 Ciba Geigy 1992 Core Guideline Laboratory rat ( Rattus norvegicus) Diet for 13 weeks 98.2 Diaminochlorotriazine ( G 28273) NOAEL 10 LOAEL 100 NOAEL 100 LOAEL 250 Estrous cycle effects in female rats red. body weight gain in males and females Week 12 43012307 Ciba Geigy 1991 Core Guideline Laboratory rat ( Rattus norvegicus) Diet for 13 weeks 97.1 Hydroxyatrazine ( G 34048) NOAEL 100 LOAEL 300 renal effects  high urine output with low S. G. red. hematopoietic parameters in both sexes 41293501 Ciba Geigy 1989 Minimum Dog   Beagle ( Canis sp.) 13 Week Feeding 95.7 Deethylatrazine ( G 30033) NOAEL 100 LOAEL 1,000 red. body weight & weight gain in males and females; red. heart to brain weight; normocytic/ normochromic anemia, paroxysmal atrial fibrillation and right atrial wall hemorrhagic inflammation with angiomatous hyperplasia 43012304 Ciba Geigy 1992 Core Minimum Dog  Beagle ( Canis sp.) 14 Week Feeding 96.7 Deisopropylatrazine ( G 28279) NOAEL 100 LOAEL 500 red. body weight, weight gain and food consumption in females red. organ to brain weight for heart, testes, prostrate glands in males 43012303 Ciba Geigy 1992 Core Minimum Dog   Beagle ( Canis sp.) 1 Year Feeding 98.7 Diaminochlorotriazine ( G 28273) NOAEL 5 LOAEL 100 1 of 8 females had tremors 41392401 Ciba Geigy 1990 Minimum Laboratory rat ( Rattus norvegicus) Dosed on Days 6 15 95.7 Deethylatrazine ( G 30033) NOAEC 5 LOAEC 25 Development: NOAEL 25 LOAEC 100 red. body weight; weight gain and food consump.

Fused sternebrae 1 & 2 Poor ossification of digit 5 43013209 Ciba Geigy 1992 Acceptable Guideline Laboratory rat ( Rattus norvegicus) Dosed on Days 6 15 97.4 Deisopropylatrazine ( G 28279) NOAEL 5 LOAEL 25 Development: NOAEL 5 LOAEL 25 red. maternal body weight, weight gain & food consumption fused sternebrae 1 and 2. poor ossification at 100 ppm 43012308 Ciba Geigy 1992 Core  Guideline Degradate Mammalian Subchronic and Reproduction Toxicity Surrogate Species/ Study Duration % ai NOAEL/ LOAEL ( ppm ai) Statistically sign. ( p= 0.05) LOAEL Endpoints MRID No. Author/ Year Study Classification XI  9 Laboratory rat ( Rattus norvegicus) Dosed on Days 6 15 98.2 Diaminochlorotriazine ( G 28273) NOAEL 500 LOAEL 3000 Development: NOAEL 50 LOAEC 500 red. body weight gain and food consumption incr. resorption of embryos incr. unossified bones 41392402 Ciba Geigy 1989 Minimum Laboratory rat ( Rattus norvegicus) Dosed on Days 6 15 97.1 Hydroxyatrazine ( G 34048) NOAEL 500 LOAEL 2,500 Development: NOAEL 500 LOAEL 2500 decr. mother's food consumption red. young body weight incr. delay in ossification of skull bones 41065202 42873702 Ciba Geigy 1989 Minimum Laboratory rat ( Rattus norvegicus) 2 yr Carcinogenicity 97.1 Hydroxyatrazine ( G 34048) NOAEL 10 LOAEL 25 incr. in accumulation of interstitial matrix in the kidney in females only 43532001 Ciba Geigy 1995 Reserved Laboratory rat ( Rattus norvegicus) 2 yr Carcinogenicity 97.1 Hydroxyatrazine ( G 34048) NOAEL 25 LOAEL 200 incr. in urinary tract effects in both sexes 42662901 Ciba Geigy 1993 Supplemental Comparison of various subchronic and chronic toxicity levels for the following degradates ( deethylatrazine, deisopropylatrazine, diaminochlorotriazine and hydroxyatrazine) with atrazine data suggest that the toxicity of these degradates are equal to or slightly more toxic to laboratory rats and beagles than atrazine. The degradate studies typically show similar types of toxic effects seen in atrazine tests. The mammalian chronic studies provide adequate data on chronic and reproductive effects of degradates.

v. Reptile Eggs Atrazine was tested on eggs of the turtle, red eared slider ( Pseudemys elegans) and the American alligator ( Alligator mississippiensis) to determine if atrazine produced endocrine effects on the sex of the young ( Gross, 2001). The turtle and alligator eggs were placed in nests constructed of sphagnum moss treated with 0, 10, 50 100 and 500 Fg/ L for 10 days shortly after being laid. The test temperatures, 27.3EC for the turtle and 32.8E for alligators, were temperatures which normally yield all male young. No adverse effects were found. Analysis of the embryonic fluids indicated that no atrazine was present in the eggs at the detection limit ( 0.5 Fg/ L). Under these conditions, atrazine does not appear to be an endocrine disruptor. The nonguideline study is classified as supplemental and provides useful information on the potential effects of atrazine on endocrine mediated pathways ( MRID 455453 03 and 455453 02).

vi. Insects A honey bee acute contact study using the TGAI is required for atrazine because its widespread use on corn and other crops that need insect pollination will result in honey bee exposure. Results of this test are tabulated below. XI  10 Nontarget Insect Acute Contact Toxicity Surrogate Species % ai LD50 ( Fg/ bee) Toxicity Category MRID No. Author/ Year Study Classification Honey bee ( Apis mellifera) Tech. 96.69 ( 4.79% dead) relatively non toxic 00036935 Atkins et al. 1975 Core Test results indicate that atrazine is categorized as relatively non toxic to bees on an acute contact basis. The guideline ( 141 1) is fulfilled ( MRID 00036935).

A honey bee toxicity of residues on foliage study using the typical end use product is not required for atrazine because the acute contact honey bee LD50 is greater than 0.11 Fg/ bee. The guideline requirement ( 141 2) is fulfilled ( MRID 00036935).

vii. Terrestrial Field Testing No field tests have been required, because atrazine shows low toxicity to birds, mammals and insects.

b. Toxicity to Freshwater Animals I. Freshwater Fish and Amphibia, Acute Two freshwater fish toxicity studies using the TGAI are required to establish the toxicity of atrazine to fish. The preferred test species are rainbow trout ( a coldwater fish) and bluegill sunfish ( a warmwater fish). Results of these tests are tabulated below.

Freshwater Fish Acute Toxicity Surrogate Species/ Static or Flow through test % a. i. 96 hour LC50 ( ppb) ( measured/ nominal) Probit Slope Toxicity Category MRID No. Author/ Year Study Classification Rainbow trout ( Oncorhynchus mykiss) Static test 98.8 5,300 ( nominal) slope  2.723 moderately toxic 00024716 Beliles & Scott 1965 Core Brook trout ( Salvelinus tontinalis) Flow through test 94 6,300 4,900 ( 8 day test) not specified moderately toxic 00024377 Macek et al. 1976 Supplemental ( 52 gram fish & no raw data)

Fish from the Nile River Chrysichthyes auratus Static renewal  daily 150 mg/ L CaCO3; 22EC 96 6,370 ( not specified) moderately toxic 45202911 Hussein, El Nasser & Ahmed 1996 Supplemental ( non native sp.; 26 gram fish; no raw data)

Bluegill sunfish ( Lepomis macrochirus) Flow through test 94 > 8,000 6,700 ( 7 day test) ( not specified) moderately toxic 00024377 Macek et al. 1976 Supplemental ( 6.5 gram fish & no raw data)

Tilapia 38 grams ( Oreochromis niloticus) Static renewal  daily 150 mg/ L CaCO3: 22EC 96 9,370 ( not specified) moderately toxic 45202911 Hussein, El Nasser & Ahmed 1996 Supplemental ( non native sp.; 38 gram fish; no raw data) Freshwater Fish Acute Toxicity Surrogate Species/ Static or Flow through test % a. i. 96 hour LC50 ( ppb) ( measured/ nominal) Probit Slope Toxicity Category MRID No. Author/ Year Study Classification XI  11 Fathead minnow ( Pimephales promelas) 24 Hour renewal test 94 15,000 ( nominal) 15,000 ( 5 day test) slightly toxic 00024377 Macek et al. 1976 Supplemental ( no raw data)

Carp ( Cyprinus carpio) Semi static test 93.7 18,800 ( nominal) slope not reported slightly toxic 45202913 Neskovic et al. 1993 Supplemental ( no raw data)

Fathead minnow juvenile ( Pimephales promelas) Flow through test; 52 mg/ L CaCO3 97.1 20,000 ( measured) Slope  6.889 slightly toxic 42547103 Dionne 1992 Core Bluegill sunfish ( Lepomis macrochirus) Static test 98.8 24,000 ( nominal) no slope slightly toxic 00024717 Beliles & Scott 1965 Core Brown trout ( Salmo trutta) 1.9 gr. Static Renewal  daily pH 6; 10EC; 11 mg/ L CaCO3 ?? 27,000 ( nominal) slightly toxic 45202909 Grande, Anderson & Berge 1994 Supplemental ( no raw data; slight aeration & purity unknown)

Zebrafish ( Brachydanio rerio) ?? 37,000 (???????) slightly toxic ????????? Korte & Greim 1981 Supplemental ( article unavailable)

Bluegill sunfish ( Lepomis macrochirus) Static test 100 57,000 ( nominal) slightly toxic 00147125 Buccafusco 1976 Core Goldfish ( Carassius auratus) Static test 98.8 60,000 ( nominal) Slope  2.695 slightly toxic 00024718 Beliles & Scott 1965 Supplemental ( not an acceptable species)

The lowest fish LC50 value falls in the range of > 1  10 ppm, hence atrazine is categorized as moderately toxic to freshwater fish on an acute basis. The guideline requirement ( 72 1) is fulfilled ( MRID 00024716, 00024717, 000147125).

The following table presents fish toxicity data for formulated products.

Freshwater Fish and Amphibian Acute Toxicity Surrogate Species/ Flow through or Static % ai formul. 96 hour LC50 ( ppb) ( measured/ nominal) Toxicity Category MRID No. Author/ Year Study Classification Black Bass  fry ( Micropterus salmoides) Static test; 20EC 78 mg/ L hardness 80 80 W 12,600 ( nominal) slope  5.86 slightly toxic 45227717 R. O. Jones 1962 Supplemental ( 48 hours; limited raw data)

Channel Catfish yolk sac ( Ictalurus punctatus) Static test; 23.3 25.8EC 78 mg/ L hardness 80 80 W 16,000 ( nominal) slope  3.36 sightly toxic 45227717 R. O. Jones 1962 Supplemental ( limited raw data) Freshwater Fish and Amphibian Acute Toxicity Surrogate Species/ Flow through or Static % ai formul. 96 hour LC50 ( ppb) ( measured/ nominal) Toxicity Category MRID No. Author/ Year Study Classification XI  12 Bluegill Sunfish fry ( Lepomis macrochirus) Static test; 25 27EC 78 mg/ L hardness 80 80 W 20,000 ( nominal) no slope slightly toxic 45227717 R. O. Jones 1962 Supplemental ( limited raw data)

American Toad  larvae ( Bufo americanus) Flow through test 40.8 4L 10,700 late stage 26,500 early stage ( nominal) slightly toxic 45202910 Howe et al. 1998 Supplemental ( no raw data)

Northern Leopard Frog larvae ( Rana pipiens) Flow through test 40.8 4L 14,500 late stage 47,600 early stage ( nominal) slightly toxic 45202910 Howe et al. 1998 Supplemental ( no raw data)

Coho Salmon ( Oncorhynchus kisutch) Renewal daily; 144 hr 40.8* AAtrex Liquid > 18,000 25 % mortality ( measured) slightly toxic 45205107 Lorz et al. 1979 Supplemental ( no LC50 value & 12 17 months old)

Rainbow trout ( Onchorhynchus mykiss) Flow through test 40.8 4L 20,500 ( nominal) slightly toxic 45202910 Howe et al. 1998 Supplemental ( no raw data)

Channel Catfish ( Ictalurus punctatus) Flow through test 40.8 4L 23,800 ( nominal) slightly toxic 45202910 Howe et al. 1998 Supplemental ( no raw data)

Rainbow trout ( Oncorhynchus mykiss) Static test 43 Liquid 24,000 ( unknown) slightly toxic 40098001 Mayer & Ellersieck 1986 Supplemental ( no raw data)

Bluegill sunfish ( Lepomis macrochirus) Static test 43 Liquid 42,000 ( unknown) slightly toxic 40098001 Mayer & Ellersieck 1986 Supplemental ( no raw data)

* Percent a. i. assumed based on description as a liquid formulation, AAtrex.

All toxicity values for the atrazine formulation are > 10 and 100 ppm, therefore this atrazine product is classified as slightly toxic.

Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in aquatic environmental compartments. Therefore, acute fish testing with bluegill and rainbow trout are required to address degradate concerns. The requirement for special degradate tests ( 72 1) has not been fulfilled.

ii. Freshwater Fish, Chronic A freshwater fish early life stage test using the TGAI is required for atrazine because the enduse product is expected to be transported to water from the intended use site, and the following conditions are met: the pesticide is intended for use such that its presence in water is likely to be continuous and recurrent; an aquatic acute EC50 is less than 1 mg/ L ( i. e., Chironomus tentans LC50 0.72 ppm); and the pesticide is persistent in water ( i. e., half life greater than 4 days). The preferred test species is rainbow trout. XI  13 Freshwater Fish Early Life Stage Toxicity Surrogate Species/ Study Duration/ Flow through or Static Renewal % ai NOAEC/ LOAEC Fg/ L ( ppb) ( measured or nominal) Statistically sign. ( p= 0.05) Endpoints Affected MRID No. Author/ Year Study Classification Rainbow trout ( Oncorhynchus mykiss) 86 days, flow through 50 mg/ L CaCO3 Tech. NOAEC 410 LOAEC 1,100 ( measured) sign. delays in hatching @ 1,100 and 3,800 Fg/ L sign. red. wet wt. at 30 & 58 days @ 1,100 & 3,800 Fg/ L sign. red. dry wt. @ 3,800 Fg/ L 58.8 % mortality @ 3,800 Fg/ L at swim up 45208304 Whale et al. 1994 Invalid ( DMSO used as solvent, which aids in transport of chemicals across cell membranes)

Rainbow trout embryo larvae ( Oncorhynchus mykiss) 27 days; flow through 80 WP Hardness 50 mg/ L: LC50 660 LC01 29 Slope 1.2 Hardness 200 mg/ L: LC50 810 LC01 77 Slope 1.38 % normal survival 50/ 200 mg/ L 19 Fg/ L  94 98 54  88 90 54 **  68 74 5,020 **  10 9 50,900 **  0 0 45202902 Birge, Black & Bruser 1979 Supplemental ( short test; no raw data for statistical analyses)

Channel catfish embryo larvae ( Ictalurus punctatus) 8 days; flow through 80 WP Hardness 50 mg/ L: LC50 220 Slope 0.977 Hardness 200 mg/ L: LC50 230 Slope 0.84 highly teratogenic in all tests; no results for soft water 420 Fg/ L  16% terata 830 Fg/ L  47 % terata 46,700 Fg/ L  86 % terata 45202902 Birge, Black & Bruser 1979 Supplemental ( short test; no raw data for statistical analyses)

Zebrafish ( Brachydanio rerio) 35 Days; pH 8; 27+ 1EC Flow through test Hardness 24 mg/ L 98 NOAEC 300 LOAEC 1,300 ( measured) 35 Day LC50 890 Slope 1.25 2  3 % sign. incr. in edema 45 62 % mortality 45202908 Gorge & Nagel 1990 Supplemental ( no raw data)

In addition to survival of rainbow trout and catfish embryo larvae, Birge et al. ( 1979) also reported that " Atrazine was highly teratogenic in all tests." The frequency of teratogenicity was reported for channel catfish in hard water and included in the table above; no data on frequency was reported for soft water or for rainbow trout. ( MRID # 45202902). The guideline requirement ( 72 4) for a fish early life stage test is fulfilled by four fish life cycle tests with rainbow trout, bluegill and fathead minnows ( listed below).

Degradates: The major atrazine degradate, hydroxyatrazine, forms a large percentage of the recoverable pesticide in aquatic environmental compartments. Therefore, a special fish early life stage test ( 72 4) is reserved to address degradate concerns, pending the results of acute fish tests.

A freshwater fish life cycle test using the TGAI is required for atrazine because the end use product is expected to be transported to water from the intended use site and studies of other organisms indicate that the reproductive physiology of fish may be affected. The preferred test species is fathead minnow. Results of four fish life cycle tests are tabulated below; the fish full life cycle guideline requirement ( 72 5) is fulfilled by the brook trout study ( MRID 00024377). XI  14 Freshwater Fish Life Cycle Toxicity Surrogate Species/ Study Duration/ Flow through or Static Renewal % ai NOAEC/ LOAEC Fg/ L ( ppb) ( measured or nominal) Statistically sign. ( p= 0.05) Endpoints Affected MRID No. Author/ Year Study Classification Brook trout ( Salvelinus frontinalis) 44 weeks, flow through 94 NOAEC 65 LOAEC 120 ( measured) 7.2 % red. mean length 16 % red. mean body weight 00024377 Macek et al. 1976 Core Bluegill sunfish ( Lepomis macrochirus) 6 18 months, flow through 94 NOAEC 95 LOAEC 500 ( measured) LOAEC based on loss of equilibrium in a 28 day test conducted at the same lab. 00024377 Macek et al. 1976 Supplemental ( Low survival in the controls)

Fathead minnow ( Pimephales promelas) 39 weeks; flow through 97.1 NOAEC < 150 LOAEC 150 ( measured) 6.7 % red. in F1 length 22 % red. in F1 body wt. ( sign. diff. from neg. control) 42547103 Dionne 1992 Supplemental ( Failed to identify a NOAEC)

Fathead minnow ( Pimephales promelas) 43 weeks, static renewal 94 NOAEC 210 LOAEC 870 ( measured) LOAEC based on 25% mortality in a 96 hour test conducted at the same lab. 00024377 Macek et al. 1976 Supplemental ( High mortality in control adults)

iii, Sublethal Effects, Fish and Amphibians Fish:

Adult largemouth bass ( Micropterus salmoides) were exposed to nominal concentrations of technical grade atrazine ( purity 97.1%) at 0, 25, 35, 50, 75, and 100 Fg/ L for 20 days to determine the potential effects on endocrine mediated functions ( Wieser and Gross, 2002) . Additionally, bass were exposed to commercial grade ( purity 42.1%) atrazine at 100 Fg/ L. After 20 days, plasma concentrations of estradiol, 11 ketotestosterone, testosterone, and vitellogenin ( a protein that serves in yolk formation) were measured. Female bass treated with 100 Fg/ L formulated atrazine contained significantly higher plasma estradiol and exhibited plasma vitellogenin roughly 37 times greater ( 260 Fg/ ml) than controls ( 7 Fg/ ml). Male bass treated with 100 Fg/ L formulated atrazine contained significantly lower plasma 11 ketotestosterone. While not statistically significant, plasma testosterone ( 286 pg/ ml) was lower than controls ( 433 pg/ ml) and plasma vitellogenin ( 42 Fg/ ml) was 7 times greater than control ( 6 Fg/ ml). Although there was considerable variability in plasma vitellogenin levels, atrazinetreated fish appeared to have elevated plasma vitellogenin relative to controls. at 50 and 100 Fg/ L of atrazine. Plasma 11 ketotestosterone was significantly lower in fish exposed to atrazine concentrations greater than 35 Fg/ L. Treatment of fish with commercial grade atrazine resulted in a significant increase in plasma estradiol in female fish and a significant decrease in 11 ketotestosterone in male fish. Although not statistically significant, plasma vitellogenin in both female and male fish appeared to be increased in fish treated with technical and commercial grade atrazine.

Although high variability confounds this study's ability to resolve the effects of atrazine on plasma steroids and vitellogenesis, the study has demonstrated that technical grade atrazine affects plasma 11 ketotestosterone in males and that the formulated product affects plasma XI  15 estradiol in females. The non guideline study is classified as supplemental and provides useful information on the potential effects of atrazine on endocrine mediated pathways. ( MRID 45622304). Furthermore, previous studies with commercial atrazine showed increased plasma vitellogenin levels and decreased plasma testosterone levels at concentrations greater than 50 Fg/ ml ( Gross et al. 1997; Grady et al. 1998).

Effects on behavior were found to be significant ( p < 0.0001) in zebrafish ( Brachydanio rerio) following 1 week exposures at 5 to 3125 Fg/ L atrazine ( Steinberg et al., 1995). Fish exposed to atrazine for 1 week showed a pronounced preference ( p < 0.0001) for the dark part of the aquarium compared to the control. Since no significant difference were found between the effects at the various test concentrations ( 5Fg/ L: 79%; 25Fg/ L: 85%; 125 Fg/ L: 83%; 625 Fg/ L: 81%; 3125 Fg/ L: 81%), these changes in swimming behavior appears to be threshold effects. After 4 weeks at the above exposures, 15 to 24 percent more of the treated fish preferred dark habitats than did the controls. The authors concluded that atrazine probably has an effect on the sensory organs and the nervous system at atrazine concentrations commonly found in surface waters. ( MRID # 45204910).

Saglio and Trijase ( 1998) measured 5 behavioral activities in goldfish following 24 hour exposures to 0.5, 5 and 50 Fg/ L atrazine. A number of behavioral measurements were statistically significant ( p < 0.05) from controls, but in most instances the significance was inconsistent and failed to show a dose related effect. The only behavioral effect showing a consistent, dose related effect was reduction in grouping ( i. e., significant at 5 Fg/ L ( 31% reduction) and 50 Fg/ L ( 39% reduction). Other behaviors with statistically significant effects were surfacing at 5 Fg/ L ( 341% increase), burst swimming at 0.5 and 50 Fg/ L ( 1.00 and 2.25 units, respectively, the controls showed no effect). Following the introduction of skin extract, 5 Fg/ L of atrazine significantly ( p < 0.05) reduced sheltering ( 81%) and grouping ( 60%), but these effects showed no consistency with effects at 0.5 and 50 Fg/ L. This study shows that a 24 hour exposure at 5 Fg/ L atrazine significantly affected aspects of swimming, positioning in water column, increased number of mouth openings at the surface, and social behaviors. ( MRID # 45202914).

Fischer Scherl et al. ( 1991) reported acute and chronic atrazine induced alterations in the rainbow trout kidneys affecting renal corpuscles, renal tubules, and renal interstitium. Additionally, the accumulation of cellular debris in Bowman's space affects glomerular filtration. Compared to control fish, chronic 28 day exposures at 5, 10 and 20 Fg/ L almost obliterated Bowman's space due to a proliferation of podocytes with their epithelial foot processes forming tight and intensive connections. The most conspicuous feature was the thickening of the glomerular basement membrane, with formation of so called spikes. In some glomerula sub endothelial humps, electron dense deposits attached to glomerular basement membrane, have been detected. In some instances, moderate electron dense material and membranous structures were deposited in Bowman's space. At higher chronic concentrations ( 40 and 80 Fg/ L) renal corpuscles appeared hypercellular and enlarged due to a proliferation of podocytes and mesangial cells. Also, the amount of membrane bound vesicles with varying electron dense contents had increased in the urinary space of renal corpuscles. Fibrillar XI  16 structures and fibrocytes were found around Bowman's capsule indicating beginning periglomerular fibrosis. Acute 96 hour exposures at 1.4 and 2.8 mg/ L caused a more pronounced obliteration of Bowman's space due to the proliferation of mesangial cells and more renal corpuscles were affected. Increasing amounts of cellular debris accumulated in Bowman's space. Simultaneously, epithelial cells of the parietal layer of Bowman's capsule displayed an increased number of lysosomes and swollen mitochondria. Also, the number of glomerular endothelial cells exhibiting vacuolar degeneration increased. Furthermore, light microscopy shows minor alterations to renal tubules, but electron micrographs revel considerable changes. First, obvious alterations of tubules appeared at 10 Fg/ L. Basilar labyrinth was dilated and irregularly arranged. The mitochondria were electron dense and showed club shaped ends of circular structure. At 40 Fg/ L, part of the endoplasmic reticulum appeared foamy and fragments of endoplasmic reticulum were heavily distended. At 80 Fg/ L in proximal and distal tubular epithelia lysis of the cytoplasm with formation of vacuoles and vesicles and condension of mitochondria was prominent. In many tubular epithelia, only remnants of the former parallelarranged tubular system were present, mitochondria were swollen, lysosomal structures as well as a vacuolization of the cytoplasm were detectable. In proximal tubules, lysomes had increased in number and size. At acute exposures ( 1,400 and 2,800 Fg/ L), tubular structural lesions similar to those described at 80 Fg/ L were present, but a distinctly higher number of renal tubules was affected. Extensive cytoplasmic vacuolization was evident and the parallel arrangement of the basilar labyrinth was completely lost, some mitochondria were dark and condensed. Tubules of the basilar labyrinth appeared foggy, partly involving mitochondria. Except for an increase in cells with mitotic figures at concentrations of 5, 10, 20 Fg/ L, no conspicuous alterations in basic interstitial architecture could be detected. Beginning at 40 Fg/ L, a loosening of the hemopoietic tissue was evident. Cells, preumably macrophages, phagocytizing material had increased in number. In addition to these effects, sinusendothelial cells were severely damaged at a concentration of 80 Fg/ L. They separated from the basement membrane and exhibited numerous vesicular and lysosomal structures as well as swollen degenerating mitochondria. Alterations in renal interstitium were considerable at acute exposures with 1,400 and 2,800 Fg/ L. Interstitial tissue was loosened and a state of spongiosus was indicated. Numerous macrophages were present. Nuclei of interstitial cells were pyknotic or karyorhectic, mitochondria were swollen and the cytoplasm displayed lytic areas. Cell boundaries in some parts of the interstitium were lost. Cell organelles were scarce, but lysosomal structures abundant. ( MRID # 45202907)

Davies et al. ( 1994) exposed three fish species to 0.9, 3.0, 10, 50 and 340 Fg/ L atrazine for a period of 10 days and measured effects on growth and properties of various tissues, such as blood, muscle and liver. Statistically significant ( p < 0.05) effects occurred at levels as low as 0.9 and 3.0 Fg/ L. The most sensitive, consistent statistically significant effect was with the species Galaxias maculatus at 10 Fg/ L ( i. e., 144% increase in muscle RNA/ DNA levels), and the DNA levels were significantly reduced 25%. In Pseudaphritis urvillii consistent significant effects were found on glutathione ( GSH) in the liver at 50 Fg/ L ( 24% reduction) and 340 Fg/ L ( 13% reduction). Consistent, significant effects with rainbow trout were found at 50 and 340 Fg/ L ( i. e., reductions of 15% and 14%, respectively, in protein levels in muscle); and at 350 Fg/ L ( 159% reduction in growth and a 23% increase in glucose levels) ( MRID # 45202904). XI  17 Alazemi et al. ( 1996) reported gill damage to a freshwater fish; the damage was characterized by the presence of breaks in the gill epithelium at 500 Fg/ L which developed into deep pits at 5,000 Fg/ L.

Hussein et al. ( 1996) exposed two important Rile River fish ( Oreochromis niloticus and Chrysichthyes auratus) to 3,000 and 6,000 Fg/ L atrazine for up to 28 days. Fish exposed to these concentrations showed some clinical signs such as rapid respiration and increased rate of gill cover movements; slower reflexes and swimming movements; reduction in feeding activities; loss of equibrium and death. These signs were more pronounced in C. auratus than O. niloticus. About 25 percent of the treated fish had abdominal swelling ( ascites) in the two species. Abnormal behavior could be attributed to the effect of atrazine on CNS and cardiovascular system. Exposure to 3,000 and 6,000 Fg/ L resulted in significant ( p < 0.01) decreases in the number of red blood cells ( RBC), hemoglobin and haematocrit levels compared to controls in both species. While the data appear to show clear differences from controls, these conclusions could not be verified from the data given in the article . The authors also reported significant ( p < 0.01) changes in mean corpuscular volume ( MCV), mean corpuscular hemoglobin ( MCH), and mean corpuscular hemoglobin ( MCHC), serum components, and brain and serum AChE levels. While some of these measurements also appear to show clear differences between 3,000 and 6,000 Fg/ L and the controls, such as brain and serum AChE, whether the effects are significantly different than the controls could not be confirmed from the data presented in the article. ( MRID # 45202911).

Neskovic et al. ( 1993) exposed carp to atrazine concentrations of 1,500, 3,000 and 6,000 Fg/ L and found biochemical changes in the activity of some enzyme activity levels in serum and some organs. Alkaline phosphatase levels were significantly ( p < 0.05) higher in serum at all test levels than in controls. Alkaline phosphatase levels were lower, but not significantly ( p< 0.05) less than control levels in the heart, liver and kidneys at all test levels. The greatest drop in alkaline phosphatase activity was found in the liver and ranged from 26.1% ( 1,500 Fg/ L) to 50.2% ( 6,000 Fg/ L). Somewhat weaker effects were found on glutamic oxaloacetic ( GOT) in the liver and kidney ( p < 0.1). No statistically significant ( p < 0.01) effects were found on glutamic pyruvic transaminase ( GPT). Histopathological effects include damage to gills ( > 1,500 Fg/ L), liver ( almost normal at 1,500 Fg/ L and vacuolization of hepatocytes at > 3,000 Fg/ L), kidney ( more or less normal at 3,000 Fg/ L and with tubular epithelium and intertubular tissue degradation at 6,000 Fg/ L) and intestine ( slightly greater lymphocyte infiltration and stronger mucous secretion at 6,000 Fg/ L) ( MRID # 45202913).

In addition, effects on reproductive function of Atlantic salmon ( Salmo salar) were reported by Moore and Waring ( 1998) when mature male Atlantic salmon ( Salmo salar L.) parr exposed to nominal concentrations of 0.5, 5, 10, and 20 Fg/ L. Measured exposure concentrations in the study were 0.04, 3.6, 6.0 and 14.0 Fg/ L and represented 8, 72, 60, and 70 percent of nominal concentrations, respectively. There appears to be uncertainty about actual exposure concentrations, since the water samples were collected only after the test period and the authors concluded that atrazine in the water samples suffered rapid degradation as the result of an unavoidable delay in being analyzed. 1Tavera Mendosa, L., S. Ruby, P. Brouseau, M. Fournier, D. Cyr, and D. Marcogliese. 2002a. Response of amphibian tadpole ( Xenopus laevis) to atrazine during sexual differentiation of the testis. Environmental Toxicology and Chemistry 21( 3): 527 531.

2Tavera Mendosa, L., S. Ruby, P. Brouseau, M. Fournier, D. Cyr, and D. Marcogliese. 2002b. Response of amphibian tadpole ( Xenopus laevis) to atrazine during sexual differentiation of the ovary. Environmental Toxicology and Chemistry 21( 6): 1264 1267.