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Effects Characterization Office of Pesticide Programs' Aquatic Life Benchmarks 

Office of Pesticide Programs' Aquatic Life Benchmarks 

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Introduction 

Relationship to Ambient Water Quality Criteria 

Use of Aquatic Life Benchmarks 

OPP Aquatic Life Benchmarks 

Footnotes 

Definitions 

References 

Introduction 

The aquatic life benchmarks (for freshwater species) provided in the table below are based on toxicity values reviewed by EPA and used in 

the Agency's most recent risk assessments developed as part of the decision-making process for pesticide registration. The Office of 

Pesticide Programs (OPP) in EPA relies on studies required under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as 

specified at 40 CFR Part 158, as well as a wide range of environmental laboratory and field studies available in the public scientific 

literature to assess environmental risk. Each Aquatic Life Benchmark is based on the most sensitive, scientifically acceptable toxicity 

endpoint available to EPA for a given taxon (for example, freshwater fish) of all scientifically acceptable toxicity data available to EPA. 

EPA's goal is to add to these benchmarks annually. 

Relationship to Ambient Water Quality Criteria 

Both OPP and EPA's Office of Water (OW) have responsibilities for evaluating aquatic toxicity data to assess the ecological effects of 

chemicals in surface water. Effects assessments under both program offices are developed with high quality data pursuant to parallel but 

somewhat different rigorously peer-reviewed assessment methods. 

OW uses aquatic toxicity data to develop ambient water quality criteria that can be adopted by states and tribes to establish water 

quality standards under the Clean Water Act. Criteria are available for roughly 16 pesticides. Procedures for deriving the criteria 

are described in Guidelinesa , and require, for acute criteria, that data be available for at least 8 families.

OPP uses aquatic toxicity data in ecological risk assessments for large numbers of pesticide registration decisions under FIFRA. 

OPP's procedures for effects assessment are described in the Overview Document b; and rely, at a minimum, on data for the most 

sensitive tested effects concentration for each taxon. 

Both the OW and OPP methods assess and characterize effects to protect aquatic communities. 

The table below provides aquatic toxicity benchmarks, a reference for the most recent risk assessment conducted by OPP for each

pesticide, and ambient water quality criteria, if available. 

Use of Aquatic Life Benchmarks 

EPA worked initially with the USGS to identify aquatic ecotoxicity benchmarks values from risk assessments developed by EPA for

individual pesticides during the recently completed re-registration program. The Overview Document and ecological risk assessments 

developed for individual pesticides provide useful information for understanding how these ecotoxicity benchmarks were developed and 

the uncertainties associated with each benchmark. Comparing a measured concentration of a pesticide in water with an aquatic life 

benchmark can be helpful in interpreting monitoring data, and to identify and prioritize sites and pesticides that may require further 

investigation. 

These aquatic benchmarks are extracted from the most recent publically available OPP risk assessment for the pesticide and are based on 

the most sensitive aquatic toxicity data of the distribution for each taxa. Benchmarks, developed for baseline risk assessments, are 

estimates of the concentrations below which pesticides are not expected to harm aquatic life. OPP may further refine a risk assessment 

based on the full distribution of toxicity data for a given species, using point estimates, species sensitivity distribution approaches, or 

probabilistic methods. 

OPP and OW are actively working together to harmonize the high quality, peer-reviewed scientific approaches that now underlie both 

programs. A harmonized approach will result in consistent tools and approaches for all stakeholder communities to use in ensuring the 

protection of aquatic ecosystems. 

Pesticides: Environmental Effects

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm

Last updated on Thursday, April 09, 2009

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OPP Aquatic Life Benchmarks (μg / L)

(freshwater)

Pesticide CAS 

number

Fish Invertebrates Nonvascular 

Plants

Vascular 

Plants

Office of Water 

Aquatic Life Criteria

Acute1 Chronic2 Acute3 Chronic4 Acute5 Acute6

Maximum 

Concentration 

(CMC)

Continuous 

Concentration

(CCC)

Acephate 9 30560191 416,000 5,760 550 150 > 50,000 — — —

Acetochlor 34256821 190 130 4,100.0 22.10 1.43 3.40 — —

Acetochlor

degradate

Ethanesulfonic 

acid (ESA) 8

— > 

90,000 — > 62,500 — 9,900.00 — — —

Acifluorfen 62476599 15,500 < 1,500 14,050 — > 265 189 — —

Acrolein 10, 13 107028 7 11.4 < 15.5 7.1 28 72 — —

Alachlor 15972608 900 187 1,600 110 1.64 2.3 — —

Alachlor

degradate

Ethane sulfonic 

acid

187022113 52,000 — 52,000 — — — — —

Alachlor

degradate

Oxanilic acid

184992444 47,500 — 47,500 — — — — —

Aldicarb 9 116063 26 0.46 10 1 > 5,000 — —

Aldicarb

sulfoxide 1646873 3,570 — 21.5 — — — — —

Aldicarb sulfone 21,000 — 140 — — — — —

Ametryn 834128 1,800 700 14,000 240 3.67 10 — —

Atrazine 7 1912249 2,650 65 360 60 1 37 — —

Atrazine

degradate

HA 8

2163680 > 1,500 — > 2,050 — > 10,000 — — —

Atrazine

degradate

DACT 8

— > 

50,000 — > 50,000 — —— —

Atrazine

degradate

DIA 8

— 8,500 — > 

63,000 — 2,500 — — —

Atrazine

degradate

DEA

— — — — — 1,000 — — —

Azinphos methyl

9 86500 0.18 0.055 0.08 0.036 — — — —

Azoxystrobin 13860338 235 147 130 44 49 3,400 — —

Benfluralin 8 1861401 34.85 1.9 10,540 15.5 > 100 — — —

Bensulide 10 741582 360 374 290 — 1,500 — — —

Bentazon 8 50723803 > 

50,000 — > 50,000 — 4,500 5,350 — —

Bromacil 314409 18,000 3,000 60,500 8,200 6.8 45 — —

Butylate 10 2008415 105 210 5,950 — — — — —

Carbaryl 9 63252 110 6.8 0.85 0.5 660 1,500 — —

Carbofuran 1563662 44 5.7 1.115 0.75 — — — —

Carboxin 5234684 600 — 42,200 — 370 670 — —

Captan 10 133062 13.1 16.5 4,200 560 320 > 12700 — —

Clopyralid 57754855 984,000 — 56,500 — — — — —

Chloropicrin 13 76062 < 8.49 — < 36 — — — — —

Chlorothalonil 1897456 5.25 3 1.8 0.6 6.8 630 — —

Chlorpyrifos 2921882 0.9 0.57 0.05 0.04 140 — 0.083 0.041

Coumaphos 10 56724 170 11.7 0.037 0.0337 — — — —

Cycloate 1134232 2,250 — 1,300 — — — — —

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Cypermethrin 52315078 0.195 0.14 0.21 0.069 — — — —

Dacthal (DCPA)

8 1861321 15,000 — 13,500 — > 11,000 > 11,000 — —

2,4-DB 11 94826 1,000 — 7,500 — 932 — — —

2,4-DB-DMAS 11 — 1,567 — 10,150 — — — — —

Diazinon 10, 13 333415 45 < 0.55 0.105 0.17 3,700 — 0.17 0.17

Diazinon

degradate

Oxypyrimidine 8

> 

50,500 — > 51,000 — > 109,000 — — —

Dicamba 8, 11 1918009 14,000 — 17,300 — 61 > 3,250 — —

Diclobenil 13 1194656 2,465 < 330 1,850 560 1,000 30 — —

Dicrotophos 141662 3,150 — 6.35 0.99 — — — —

Dimethenamid 163515148 3,150 300 6,000 1,020 14 8.9 — —

Dimethoate 9 60515 3,100 430 21.5 0.5 84 — — —

Disulfoton 9 298044 19.5 4 1.95 0.01 — — — —

Disulfoton

sulfone — > 4,600 — 17.5 0.14 — — — —

Disulfoton

sulfoxide 8 — 30,000 — 32 1.53 — — — —

Diuron 10 330541 355 26 80 160 2.4 — — —

Endosulfan 115297 0.42 0.11 2.9 0.07 — — 0.22 0.056

Endosulfan

sulfate 1031078 1.9 — — — — — — —

EPTC 759944 7,000 — 3,245 810 1,400 5,600 — —

Esfenvalerate 9 66230044 0.035 0.035 0.025 0.017 — — — —

Ethalfluralin 55283686 16 0.4 30 24 25 — — —

Ethoprop 13194484 150 24 22 800 8,400 — — —

Fenitrothion 122145 860 46 1.15 0.087 — — — —

Fenthion 8 55389 415.0 7.5 2.60 0.013 400 > 2,800 — —

Fluometuron 2164172 320 — 110 — 30 220 — —

Glyphosate 10 1071836 21,500 1,800 26,600 49,900 12,100 11,900 — —

Glyphosate

isopropylamine 

salt

38641940 42,450 — — — — — — —

Glyphosate

degradate

aminomethyl 

phosphoric acid 

(AMPA)

249,500 — 341,500 — — — — —

Hexazinone 51235042 137,000 17,000 75,800 20,000 7 37.4 — —

Imazapyr 8, 10 81334341 > 

50,000 43,100 50,000 97,100 11,500 18 — —

Imazamox 8 114311329 > 

59,500 — > 61,000 — > 40 11 — —

Imidacloprid 8 105827789 > 

41,500 1,200 35 1.05 > 10,000 — — —

Iprodione 8, 10 36734197 1,550 260 120 170 330 > 12,640 — —

Isoxaflutole 8 141112290 > 850 — > 750 — 110 4.9 — —

Isoxaflutole -

rpa202248 8 — > 

15,300 — > 29,800 — 5,000 75 — —

Lindane

(gamma HCH) 58899 0.850 2.9 0.500 54 — — 0.95 —

Linuron 9 330552 1,500 5.58 60 0.09 13.7 2.5 — —

Malathion 9 121755 0.295 0.014 0.005 0.000026 2,040 24,065 — —

Mancozeb 8018017 230 — 290 — 47 — — —

Maneb 12427382 21 — 60 — 13.4 — — —

Mancozeb and 

Maneb 

degradate

— > 

251,000 37,320 134,500 2 — — — —

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ETU 8

MCPA acid 11 94746 — — — — 300 170 — —

MCPA sodium 

salt 8, 11 — > 

34,000 — > 92,000 ——— — —

MCPA DMAS 11 — 48,000 12,000 41,000 11,000 160 130 — —

MCPA EHE 11 — 380 — 90 — 170 20 — —

MCPB 6062266 1,950 — 25,000 — 380 210 — —

MCPP-p acid 10 16484778 — — > 

45,500 50,800 — — — —

MCPP-p DMAS 8 6642394 > 

46,500 — — — 14 1,300 — —

Metam sodium 137428 25.6 — 27.5 254 590 — —

Metalaxyl 8 57837191 65,000 > 9,100 6,250 1,200 140,000 85,000 — —

Mefanoxam 8 70630170 > 

60,500 — 14,000 — — 77,000 — —

Methamidophos 8, 9 10265926 12,500 48.9 13 4.5 > 50,000 — — —

Methidathion 10 950378 1.1 6.1 1.5 0.66 — — — —

Methomyl 9 16752775 160 12 2.5 0.7 — — — —

Methiocarb 2032657 218 50 3.5 0.1 — — — —

Metribuzin 21087649 21,000 3,000 2,100 1.29 8.7 130 — —

Methoprene 40596698 380 48 165 51 — — — —

Methyl bromide 74839 1,950 100 1,300 — 2,200 — — —

Methyl

parathion 13 298000 925 < 10 0.485 0.25 15,000 18,000 — —

Methyl

paraoxon

950356 — — 1.15 1 — — — —

Metolachlor 51218452 1,600 1,000 550 1 8 21 — —

Metolachlor OA8 — > 

46,550 — 7,700 — 57,100 > 95,100 — —

Metolachlor ESA 8 — 24,000 — > 

54,000 — > 99,450 > 95,100 — —

Molinate 10 2212671 105 390 170 340 220 3,300 — —

Naled 300765 46 2.9 — 0.045 25 > 1,800 — —

Naled DDVP — 50 5.2 0.033 0.0058 — — — —

Napropamide 15299997 3,200 1,100 7,150 1,100 3,400 — — —

Norflurazon 8 27314132 4,050 770 > 750 1,000 9.7 58.2 — —

Oxydemeton

methyl 8, 9 301122 365 5 95 46 > 100,000 — — —

Oxyfluorfen 42874033 101.5 1.3 40 13 0.29 0.35 — —

Oryzalin 8 19044883 1,440 220 750 358 42 > 15.4 — —

Oxamyl 10 23135220 2,100 770 90 180 120 30,000 — —

Pebulate 1114712 3,150 — 3,315 — 230 1,800 — —

Pendimethalin 40487421 69 6.3 140 14.5 5.4 12.5 — —

Permethrin 16 52645531 0.395 0.0515 0.0106 0.0014 68 — — —

Phorate 8 298022 1.175 0.34 0.3 0.21 > 1,300 — — —

Phosmet 8 732116 35 3.2 1.0000 0.8 34 > 1,800 — —

Picloram 1918021 6,500 550 34,150 11,800 4,900 — — —

Pinoxaden 243973208 10,000 — — — 1,200 4,300 — —

Pinoxaden (NOA 

497854) 8 — > 

51,500 > 960 > 50,500 5,800 > 100,000 10,000 — —

Pinoxaden (NOA 

447204) 8 — > 

60,000 — > 60,000 — 95,600 > 93,500 — —

Profenofos 41198087 7.05 2 0.465 0.2 — — — —

Prometon 10 1610180 6,000 9,500 12,850 3,500 98 624 — —

Prometryn 7287196 1,450 — 9,295 1,000 1 11.8 — —

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Footnotes 

1 Benchmark = Toxicity value x LOC. For acute fish, toxicity value is generally the lowest 96-hour LC50 in a standardized test 

(usually with rainbow trout, fathead minnow, or bluegill), and the LOC is 0.5. 

2 Benchmark = Toxicity value x LOC. For chronic fish, toxicity value is usually the lowest NOEAC from a life-cycle or early life stage 

test (usually with rainbow trout or fathead minnow), and the LOC is 1. 

3 Benchmark = Toxicity value x LOC. For acute invertebrate, toxicity value is usually the lowest 48- or 96-hour EC50 or LC50 in a 

standardized test (usually with midge, scud, or daphnids), and the LOC is 0.5. 

4 Benchmark = Toxicity value x LOC. For chronic invertebrates, toxicity value is usually the lowest NOAEC from a life-cycle test

with invertebrates (usually with midge, scud, or daphnids), and the LOC is 1. 

5 Benchmark = Toxicity value x LOC. For acute nonvascular plants, toxicity value is usually a short-term (less than 10 days) EC50

(usually with green algae or diatoms), and the LOC is 1. 

6 Benchmark = Toxicity value x LOC. For acute vascular plants, toxicity value is usually a short-term (less than 10 days) EC50 

(usually with duckweed) and the LOC is 1. 

7 Chronic Aquatic Community Benchmark for Atrazine = 17.5 μg / L. 

Exceedance of this benchmark concentration, as an average for any 60-day period, could cause community-level effects based on 

changes in plant community diversity and indirect effects on fish and aquatic invertebrates. 

8 Because the underlying toxicity value is a "greater-than" value (such as >265,000), this benchmark may overestimate toxicity.

Propachlor 1918167 85 — 395 — 13.5 — — —

Propanil 709988 1,150 9.1 600 86 16 110 — —

Propargite 2312358 59 16 37 9 66.2 75,000 — —

Propetamphos 31218834 94 — 1.65 — — — — —

Propiconazole 60207901 425 95 2,400 — 93 4,828 — —

Propoxur 114261 1,850 — 5.5 — — — — —

Propyzamide 8, 9 23950585 36,000 7,700 > 2,800 600 > 4,000 1,180 — —

Resmethrin 10453868 0.14 0.32 1.550 — — — — —

Rotenone 10 83794 0.97 1.01 1.850 1.25 — — — —

Simazine 122349 3,200 960 500 2,000 36 140 — —

Sulfosulfuron 8 141776321 > 

45,000 100,000 > 48,000 102,000 400 1 — —

Tebuthiuron 34014181 53,000 9,300 148,500 21,800 50 135 — —

Telone 542756 540 — 45 70 7,900 20,000 — —

Telone

degradate

3-chloroacrylic 

acid

— 34,750 — 27,500 — 430 220 — —

Telone

degradate

3-chloroallyl 

alcohol

— 493 — 1,150 — 32,900 1,694 — —

Temephos 3383968 1,745 — 5 — — — — —

Terbacil 5902512 23,100 1,200 32,500 640 11 140 — —

Terbufos 10 13071799 0.385 0.64 0.1 0.03 — — — —

Thiobencarb 28249776 280 — 50 1 17 770 — —

Thiram 10 137268 21 530 105 170.6 140 1,600 — —

Tralkoxydim 8 87820880 > 3,750 — > 

87,000 2,100 7,700 2,600 — —

Triallate 2303175 600 38 45.5 13 120 2,400 — —

Triasulfuron 8, 10 82097505 > 

50,000 68,600 > 50,000 105,000 — — — —

Tribufos 78488 122.5 3.5 13.5 1.56 148 1,100 — —

Triclopyr 14 55335063 180 104,000 850 80,700 100 880 — —

Trifluralin 1582098 20.5 1.14 280 2.4 7.52 43.5 — —

Ziram 10 137304 9.7 101 24 39 67 370 — —

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9 The chronic benchmark is based on the acute toxicity value (which was lower than the lowest available chronic toxicity value),

and therefore may underestimate chronic toxicity. 

10 Although the underlying acute toxicity value is greater than or equal to the chronic toxicity value, the acute benchmark is lower 

than the chronic benchmark because acute and chronic toxicity values were multiplied by LOC values of 0.5 and 1, respectively. 

11 Original toxicity values are in micrograms of acid equivalents per liter. For 2,4-D and 2,4-DB, the toxicity values selected were 

the lowest available values for the acid or salt forms. For MCPA, acute toxicity values were the lowest for the acid, salt or ester 

forms, and chronic toxicity values were the lowest of the acid and salt forms. For Dicamba the toxicity values were the lowest of 

the acid or salt forms. (Selection was consistent with risk quotients in the cited USEPA references.) 

13 Because the underlying toxicity value is a "less-than" value (such as <1,500), this benchmark may underestimate toxicity.

14 The acute toxicity values were the lowest of the acid, salt or ester forms, and the chronic toxicity values were the lowest of the 

acid and salt forms of triclopyr. (Selection was consistent with risk quotients in the cited USEPA reference.) 

16 Toxicity values and benchmarks apply to permethrin. If monitoring data represent only the cis isomer of permethrin in water, 

comparison with benchmarks may underestimate potential toxicity. 

Definitions 

CCC = Criterion continuous concentration 

CMC = Criterion maximum concentration 

EC50 = 50 percent effect concentration

LC50 = 50 percent lethal concentration

LOC = level of concern 

NOAEC = no-observed-adverse-effects concentration 

μg/L = microgram per liter 

— = no benchmark available 

References 

aStephan, C.E, D.I. Mount, D.J. Hanson, J.H. Gentile, G.A. Chapman, and W.A. Brungs. 1985. Guidelines for Deriving Numerical National 

Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses. EPA PB85-227049. 

bU.S. EPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. Office of Prevention, Pesticides, 

and Toxic Substances. Office of Pesticide Programs. Washington, D.C. January 23, 2004. 

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