Pesticides and Aquatic Animals: A Guide to Reducing Impacts on Aquatic Systems

Authors: Louis A. Helfrich, Extension Specialist, Fisheries and Wildlife Sciences, Virginia Tech; Diana L. Weigmann, Director, Office of Science, Engineering, and Technology, Carson City, Nevada; Patricia Hipkins, Virginia Pesticide Programs, Department of Entomology, Virginia Tech; and Elizabeth R. Stinson, Virginia Department of Game and Inland Fisheries, Blacksburg, Virginia.

Publication Number 420-013, June 1996

Pesticides and Aquatic Animals: Tables

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Introduction

The tables provided give toxicity information for many of the common pesticides used in and near aquatic ecosystems. Acute effects are those that occur rapidly in animals following a single dose or single exposure to a chemical. Death is the acute effect most commonly used in toxicity testing. The acute toxicity of chemicals toxic to aquatic animals usually is reported as a LC50 value. The LC50 value is the concentration of a chemical in water (usually milligrams/liter or ppm, parts per million) that can kill 50 percent of the test animals in a given period of time. An exposure time of 24, 48, or 96 hours is given. The more toxic the pesticide, the lower its LC50 value will be.

The toxicity of pesticides to aquatic animals is influenced by many factors. These include the species, age, sex, and condition of an animal, water temperature, and the pesticide formulation. As a result, several LC50 values can exist for the same chemical.

Aquatic toxicity data for ready-to-use pesticides is not generally available. Tables 3, 4, and 5 provide acute toxicity data of technical (manufacturing) grade pesticide active ingredients. However, the actual toxicity of a pesticide is dependent on the formulation, and its use dilution. Acute toxicity information for fish was gathered from five primary references marked with an * in the following suggested publications list. The lowest (most toxic) value is reported.

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Table 1

Relative effectiveness off aquatic herbicides for the control of selected water weeds.

Plant Species Copper Sulfate Dichlobenil Diquat Endothal K Fluridone Glyphosate

Algae

Filamentous Good Good - - - -

Chara Good Good - - - -

Nitella Good Good - - - -

Submersed Plants

Bladderwort - Good Good - Excellent -

Coontail - Excellent Excellent Excellent Excellent -

Elodea - Excellent Excellent - Good -

Watermilfoil - Good Excellent Excellent Good -

Parrotfeather - Fair Excellent Excellent Good -

Hydrilla - Fair Good Good Excellent -

Pondweed - Excellent Good Excellent Excellent -

Slender Naiad - Excellent Excellent Excellent Excellent -

Southern Naiad - Good Good Poor Good -

Floating Plants

Duckweed - - Excellent Poor Excellent -

Watermeal - - Fair - Fair -

Emersed Plants

Bullrush - - - - Poor Good

Cattail - - Good -< td valign=top>Fair Excellent

Spatterdock - Good - - Good Excellent

Water lilly - - - - Good Excellent

Watershield - - - - Excellent -

Plant Species	Copper Sulfate	Dichlobenil	Diquat	Endothal K	Fluridone	Glyphosate
Algae
Filamentous	Good	Good	-	-	-	-
Chara	Good	Good	-	-	-	-
Nitella	Good	Good	-	-	-	-
Submersed Plants
Bladderwort	-	Good	Good	-	Excellent	-
Coontail	-	Excellent	Excellent	Excellent	Excellent	-
Elodea	-	Excellent	Excellent	-	Good	-
Watermilfoil	-	Good	Excellent	Excellent	Good	-
Parrotfeather	-	Fair	Excellent	Excellent	Good	-
Hydrilla	-	Fair	Good	Good	Excellent	-
Pondweed	-	Excellent	Good	Excellent	Excellent	-
Slender Naiad	-	Excellent	Excellent	Excellent	Excellent	-
Southern Naiad	-	Good	Good	Poor	Good	-
Floating Plants
Duckweed	-	-	Excellent	Poor	Excellent	-
Watermeal	-	-	Fair	-	Fair	-
Emersed Plants
Bullrush	-	-	-	-	Poor	Good
Cattail	-	-	Good	-< td valign=top>Fair	Excellent
Spatterdock	-	Good	-	-	Good	Excellent
Water lilly	-	-	-	-	Good	Excellent
Watershield	-	-	-	-	Excellent	-

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Table 2

Waiting period (days) before using water after application of aquatic herbicides.

Herbicide Irrigation Fishing Livestock Swimming

Fluridone (Sonar) 30 0 0 0

Glyphosate (Rodeo) 0 0 0 0

Copper sulfate 0 0 0 0

Diquat 14 turf 5 0 14 1
Endothal:

Aquathal K 14 3 14 1

Aquathal G 7 3 14 1

Dichlobenil 90 90 - -

Herbicide	Irrigation	Fishing	Livestock	Swimming
Fluridone (Sonar)	30	0	0	0
Glyphosate (Rodeo)	0	0	0	0
Copper sulfate	0	0	0	0
Diquat	14 turf 5	0	14	1
Endothal:
Aquathal K	14	3	14	1
Aquathal G	7	3	14	1
Dichlobenil	90	90	-	-

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Table 3

Toxicity to fish of commonly used herbicides.

Toxicity Classification	LC₅₀(mg/L*)	Toxicity Classification	LC₅₀(mg/L*)
super	< 0.01	slight	11 - 100
extreme	0.01 - 0.10	minimal -	> 100
High	0.11 - 1.0	nontoxic	-
moderate	1.1 - 10	*1 mg/L = 1 part per million (ppm)

Chemical Name	Commonly Used Trade Name	Toxicity Classification	Rainbow trout^b	bluegill^b
			96-houraLC₅₀(mg/L)
acetochlor	Harness, Surpass	high	0.5	1
acifluorfen	Blazer	slight	17	31
alachlor	Lasso, Micro-Tech, Partner	moderate	2	3
ametryn	Evik	moderate	9	4
atlazine	AAtrex	moderate-slight	5	16
benefin	Balan	extreme	0.08	0.06
bensulide	Betasan	high	0.7	0.8
bentazon	Basagran	minimal	109	116
bromacil	Hyvar	slight	56-75 (48hr)	71 (48hr)
bromoxynil	Buctril	extreme	0.1	0.06
butylate	Sutan	moderate	4	7
chlorimuron	Classic	slight-minimal	50	> 100
Clomazone	Command	slight	19	34
copper (chelated) complex	K-Tea, Komeen	high-moderate	0.2 4^d	1 - 8^d
copper sulfate	bluestone	moderate-high	0. 1^d	0.8 - 7^d
2,4-D	Aqualeer, Weedar, Weedestroy	slight-high	1 - 100^C	> 100
2,4-DB	Butoxone, Butyrac, Embutox	moderate	2	8
DCPA	Dacthal	minimal-nontoxic	-	> 100
dicamba	Banvel, Clarity, Vanquish	slight	135	135
dichloberlil	Casoran, Norosac	slight-moderate	> 18 (48h, guppy)	> 6
diclofop	Hoelon	high	0.25	0.54
diquat	Aqua-clear, Diquat, Weedtrine	slight-moderate	10	115
diuron	Karmex	moderate	6	6
endothall	Aquathol, Hydrothol	high	0.14	0.94
EPTC	Eptam, Eradicane, Shortstop	slight	19	27
fluazifop-p-butytl	Fusilade	moderate	5.4	-
fluometuron	Cotoran, Meturon	slight	47	96
fluridone	Sonar	slight	12	l6
fosarnine	Krenite	minimal	415	278
glyphosate	Roundup, Rodeo	slight	38^c	120^c
hexazinone	Velpar	minimal	320	370
"inert" dyes	Aquashade	-	-	-
irnazapyr	Arsenal,Chopper, Contain	minimal	> 100	> 100
lactofen	Cobra	moderate	3.7	2.1
linuron	Lorox, Linex	slight	16	16
metolachlor	Dual, Pennant	moderate-slight	2	15
metribuzin	Lexone, Sencor	slight	42	80
napnpamide	Devrinol	moderate-slight	9	20
naptalam	Alanap	slight-minimal	76	354
nofflurazon	Solicam, Zorial	moderate	6	200 (catfish)
oryzalin	Surflan	moderate	3	3
oxadiazon	Ronstar	high	9 (carp)	0.9
oxyfluorfen	Goal	high	0.4	0.2
paraquat	Gramoxone	slight	15	13
pendimethalin	Prowl, Stomp	high	0.1	0.2
picloram	Tordon	moderate-slight	3.1	13.5
prometryn	Caparol, Cotton-Pro	moderate	3	10
propanil	Stam	moderate	3	4
simazine	Princep	moderate-slight	3	16
sulfometuron	Oust	slight	13	13
tebuthiuron	Spike	minimal	144	112
terbacil	Sinbar	slight-minimal	46	103
triclopyr	Garlon, Pathfinder	minimal	117	148
trifluralin	Treflan	Super-extreme	0.01 (young trout)	0.02 (young bluegill)
vernolate	Vernam	moderate	10	8

a Toxicity values are determined by 96h exposure time unless otherwise specified

b Toxicity values are for rainbow trout and bluegill sunfish unless otherwise specified

c Toxicity depends on formulation

d Toxicity depends on pH - more toxic in water with low alkalinity

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Table 4

Toxicity to fish of commonly used insecticides, miticides, and nematicides

Toxicity Classification	LC₅₀(mg/L*)	Toxicity Classification	LC₅₀(mg/L*)
super	< 0.01	slight	11 - 100
extreme	0.01 - 0.10	minimal -	> 100
High	0.11 - 1.0	nontoxic	-
moderate	1.1 - 10	*1 mg/L = 1 part per million (ppm)

Chemical Name	Commonly Used Trade Name	Toxicity Classification	Rainbow trout^b	bluegill^b
			96-houraLC₅₀(mg/L)
abamectin	Affirm, Avid	super-extreme	0.003	0.01
acephate	Orthene, Monitor, Payload	minimal	>1000	20.50
aldicarb	Temik	high-moderate	0.9	1.5
azinphos-methyl	Guthion	extreme	0.003	0.004
Bacillus thuringiensis	Dipel, Thuricide,Vectobac	minimal	> 1,000	-
bendiocarb	Dycarb, Ficam, Turcam	high	-	0.4
cabaryl	Sevin	moderate	1.3	10
carbofuran	Furadan	high	0.3	0.2
chlorpyrifos	Killmaster II, Brodan, Eradex	super-extreme	0.003	0. 01
cypermethrin	Ammo, Cynoff, Fury	super	0.0008	0.002
diazinon	Diazinon	moderate-slight	2.6	16
diflubenzuron	Dimilin	minimal	-	>100
dimetlsoate	Cygon	moderate	6.2	6
disulfoton	Di-Systom	high-moderate	1.9	0.3
endosulfan	Thiodan	super	0.001	0.001
esfenvalerate	Asana	super	0.0003	0.0003
esfenvalerate	Ectrin, Pydrin	super	0.004	-
ethoprop	Mocap	moderate-slight	13.8	2.1
fluvalinate	Mavrik	super	0.003	0.0009
fonofos	Dyfonate	extreme-super	0.02	0.007
lindane	Lindane	super-extreme	0.002	0.03
malathion	Cythion	extreme	0.07	0.02
methamidophos	Monitor	slight	25	34
methidathion	Supracide	extreme-super	0.01	0. 002
methiocarb	Mesurol	high	0.6	0.2
methomyl	Lannate	high-moderate	3.4	0.8
methoxychlor	Methoxychlor	extreme	0.01	0.03
methyl parathion	Penncap-M	high-moderate	2.8	1.0
naled	Dibrom	high-moderate	0.2	2. 2
oxamyl	Vydate	moderate	4.2	5. 6
oxydemeton-methyl	Metasystox-R	moderate-slight	4	11
parathion	Parathion, Paraspray	extreme-high	0.8	0. 02
permethrin	Ambush, Pounce	super	0.003	0.005
phorate	Holdern,Thimet	super-extreme	0.01	0.001
phosmet	Imidan	extreme	0.02	0.02
propoxur	Baygon	moderate	6.6	3.7
pyrethrin	Various	extreme	-	0.04
resmethrin	Scourge	super	0.002-0.0003	0.003 -0.0008
rotenone	Rotenone, Rotacide	extreme	0.03	0.02
temephos	Abate	extreme-slight	0.2 - 3.5	1.4 - 21.8
terbufos	Counter	super-extreme	0. 01	0.004
tetrachlorvinphos	Rabon	high	-	0.5
trichlorfon	Dylox, Proxol	extreme-high	0.07	0.2

a Toxicity values are determined by 96h exposure time unless otherwise specified

b Toxicity values are for rainbow trout and bluegill sunfish unless otherwise specified

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Table 5

Toxicity to fish of commonly used fungicides.

Toxicity Classification	LC₅₀(mg/L*)	Toxicity Classification	LC₅₀(mg/L*)
super	< 0.01	slight	11 - 100
extreme	0.01 - 0.10	minimal -	> 100
High	0.11 - 1.0	nontoxic	-
moderate	1.1 - 10	*1 mg/L = 1 part per million (ppm)

benomyl	Benlate,	high	0.2	0.2
captan	Agrox, Captan, Captec	extreme-moderate	0.06	0.12
carboxin	Vitavax	high-moderate	> 0.1	1.2
chlorothalonil	Bravo, Daconil,Terlanil	high	0.3	0.3
coppersutfate	Basicop,Bluestone	high-moderate	0.14	0.8-7.3^d
fenarimol	Rubigan	high	2	0.9
fosetyl -Al	Aliette	minimal	428	-
iprodione	Rovral	moderate	4	6
mancozeb	Dithane, Fore, Manzate	high-moderate	2 (48h)	1
maneb	Maneb, Manex	high-moderate	2 (48h)	1
metalaxyl	Ridomil	minimal	> 100	> 100
metiram	Polyram	high-slight	1	85 (carp)
PCP	Pentachlorophenol	high	0.2 (48h)	-
PCNB	Terraclor	high	0.6	0.1
propiconazole	Alamo, Orbit,Banner, Tilt	high-moderate	0.9	1.3
thiophanate-methyl	Topsin	moderate	9.4	-
thiram	Thiram, Spotrete	high-moderate	0.1	0.2
triadimefon	Bayleton	slight	14	11
triforine	Funginex	minimal	> 1000	> 1000
vinclozolin	Ronilan, Ornalin	slight-minimal	53	130 (guppy)
ziram	Ziram	moderate	5 (5h, goldfish)	-

a Toxicity values are determined by 96h exposure time unless otherwise specified

b Toxicity values are for rainbow trout and bluegill sunfish unless otherwise specified

c Toxicity depends on formulation

d Toxicity depends on pH - more toxic in water with low atkalinity

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