Methomyl

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Details on sampling:

Samples were collected from the batches of test solution prepared at test initiation, and from two of the four replicate test chambers of the control and each test concentration at test termination (or when 100% immobility occurred within a treatment group) to measure concentrations of the test substance. Two sets of samples were collected at each interval. All samples were collected at mid-depth from the batch solutions and the test chambers and placed in glass scintillation vials containing 2.0 mL of methanol. One set was processed immediately for analysis. The second set was stored refrigerated for possible future analysis.

Vehicle:

yes

Remarks:

water

Details on test solutions:

Dilution water was adjusted to a pH of 7 using HEPES® buffer, thus creating the pH-adjusted dilution water used to prepare the primary stock, HEPES® buffer control and subsequent test solutions. A primary stock solution was prepared by mixing a calculated amount of test substance (0.0121 g) in 1000 mL of pH-adjusted dilution water at a nominal concentration of 12 mg a.s./L. The stock solution was sonicated in an ultra-sonic water bath for approximately 30 minutes and then stirred using a Teflon®-lined stir bar on a stir-plate for approximately 30 minutes. Aliquots of the primary stock solution were proportionally diluted with pH-adjusted dilution water to prepare the five test solutions at nominal concentrations of 1.3, 2.5, 5.0, 10 and 20 μg a.s./L. The solutions were stirred on a stir plate for approximately 30 minutes, and approximately 210 mL of solution was placed in each of four replicate test chambers per treatment group. The negative control solution was dilution water only, with a pH of 8.4. The HEPES® buffer control was pH-adjusted dilution water only and had a final pH of 7.1. The test solutions for the control groups and all treatment groups appeared clear and colorless after preparation, at test initiation and at test termination, with no visible precipitates, and had final pH values ranging from 7.1 to 7.2.

Test organisms (species):

Daphnia pulex

Details on test organisms:

TEST ORGANISM
- Common name: cladoceran
- Strain/clone: Daphnia pulex
- Source: obtained from cultures maintained by Wildlife International
- Age: Daphnid neonates used in the test were less than 24 hours old
- Feeding during test: not fed during the test

ACCLIMATION
The five adult daphnids used to supply neonates for the test were held 29 days prior to collection of the juveniles for testing and had each produced at least three previous broods. The adults showed no signs of disease or stress and no ephippia were produced during the holding period. At test initiation, the juvenile daphnids were collected from the cultures and indiscriminately transferred one and two at a time to transfer chambers until each chamber contained five daphnids. Each group of daphnids then was transferred to an indiscriminately assigned test chamber. All transfers were made below the water surface using wide-bore pipettes.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

140 mg/L (as CaCO3)

Test temperature:

20 ± 2°C

pH:

7.2-8.5

Dissolved oxygen:

≥8.0 mg/L

Conductivity:

309 μS/cm

Nominal and measured concentrations:

Nominal: 0, 1.3, 2.5, 5.0, 10, and 20 µg/L
Measured: 0, 1.4, 2.7, 5.5, 10, and 22 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250-mL glass beakers containing approximately 210 mL of test water. The depth of the test water in a representative chamber was 6.5 cm
- Aeration: not reported
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: well approximately 40 meters deep located on the Wildlife International site
- Total organic carbon: < 1 mg C/L
- Particulate matter:not reported
- Metals: 0- 35.8 mg/L
- Pesticides: < 6.3 µg/L
- Chloride:4.0 µg/L
- Alkalinity: 172-180 mg/L (as CaCO3)
- Ca/mg ratio: 35.8/13.8
- Conductivity: 338-365 μS/cm

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.8 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.7 µg/L

Nominal / measured:

meas. (TWA)

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

7.4 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Details on results:

There were observations of daphnids floating in all treatment groups during the course of the test. In the majority of cases, the daphnids appeared normal after being gently submerged. The observation of floating organisms did not follow a dose-response pattern and, therefore, was considered to be incidental to treatment. Organisms in the negative control and HEPES® buffer control groups were normal in behavior and appearance, with the exception of three lethargic organisms in the HEPES® buffer control group. Lethargic organisms were observed in the 2.7, 5.5, 10 and 22 μg a.s./L treatment groups, increasing in frequency as concentration increased. All organisms in the 5.5 and 10 μg a.s./L treatment groups were observed as immobile at the 24-hour observation interval. Percent immobility in the negative control and HEPES® buffer control groups and the 1.4, 2.7, 5.5, 10 and 22 μg a.s./L treatment groups was 5, 10, 0, 0, 15, 100 and 100%, respectively, at test termination. The 48-hour EC50 value was 6.8 μg a.s./L, with 95% fiducial limits of 5.5 to 10 μg a.s./L. The highest mean, measured concentration causing no immobility at test end was 2.7 μg a.s./L. The lowest mean, measured concentration causing 100% immobility was 10 μg a.s./L.

Reported statistics and error estimates:

48-hour EC50 based on mean measured concentrations was 6.8 µg/L with 95% confidence limits of 5.5-10 µg/L.
The no observed effect concentration was 2.7 µg/L

Mean Measured Concentration (mg/L)	Replicate	Number of Fish Immobilized/Number of Fish Alive(a)			Cummulative % Immobility
		3.5 hr	24 hr	48 hr	48 hr
Negative Control	A	0/5	0/5	1/5	5
	B	0/5	0/5	0/5
	C	0/5	0/5	0/5
	D	0/5	0/5	0/5
HEPES Buffer Control	A	0/5	0/5	0/5	10
	B	0/5	0/5	1/5
	C	0/5	0/5	1/5
	D	0/5	0/5	0/5
1.4	A	0/5	0/5	0/5	0
	B	0/5	0/5	0/5
	C	0/5	0/5	0/5
	D	0/5	0/5	0/5
2.7	A	0/5	0/5	0/5	0
	B	0/5	0/5	0/5
	C	0/5	0/5	0/5
	D	0/5	0/5	0/5
5.5	A	0/5	0/5	1/5	15
	B	0/5	0/5	0/5
	C	0/5	0/5	1/5
	D	0/5	0/5	1/5
10	A	0/5	5/5	5/5	100
	B	0/5	5/5	5/5
	C	1/5	5/5	5/5
	D	1/5	4/5	5/5
22	A	4/5	5/5	5/5	100
	B	3/5	5/5	5/5
	C	1/5	5/5	5/5
	D	5/5	5/5	5/5

Validity criteria fulfilled:

yes

Conclusions:

48-hour EC50 based on mean measured concentrations was 6.8 µg/L with 95% confidence limits of 5.5-10 µg/L.
The no observed effect concentration was 2.7 µg/L

Executive summary:

The toxicity of the test substance to the cladoceran (Daphnia pulex) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010. Daphnids were exposed to a geometric series of five test concentrations, a negative control (dilution water) and a HEPES® buffer control (dilution water adjusted to pH 7) for 48 hours under static conditions. Four replicate test chambers were maintained in each treatment and control group, with five daphnids in each test chamber for a total of 20 daphnids per concentration. Nominal concentrations were 0, 1.3, 2.5, 5.0, 10, and 20 µg/L. Measured concentrations were 0, 1.4, 2.7, 5.5, 10, and 22 µg/L.

 

The 48-hour EC50 based on mean measured concentrations was 6.8 µg/L with 95% confidence limits of 5.5-10 µg/L. The no observed effect concentration was 2.7 µg/L

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Lot: 16RLMX99
Purity: 100%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21°C

pH:

7.8-7.9

Dissolved oxygen:

7.9-8.2 mg/L

Nominal and measured concentrations:

Nominal: 0, 0.0010, 0.0018, 0.0032, 0.0056, 0.010, 0.018, 0.032, 0.056 and 0.10 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.017 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.01 mg/L

Nominal / measured:

meas. (not specified)

Reported statistics and error estimates:

48-hour EC50 based on mean measured concentrations was 0.017 mg/L with 95% confidence limits of 0.015-0.018 mg/L.
The no observed effect concentration was 0.0104 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hour EC50 based on mean measured concentrations was 0.017 mg/L with 95% confidence limits of 0.015-0.018 mg/L.
The no observed effect concentration was 0.0104 mg/L.

Executive summary:

The toxicity of the test substance to the daphnia magna was conducted according to OECD guideline 202 and Method C.2 of Commission Directive 92/69/EEC.  Twenty daphnids (2 replicates of 10 animals) were exposed to an aqueous solution of the test material at nominal concentrations of 0, 0.0010, 0.0018, 0.0032, 0.0056, 0.010, 0.018, 0.032, 0.056 and 0.10 mg/L for 48 hours under static test condition. The number of immobilized Daphnia were recorded after 24 and 48 hours.

The 48-hour EC50 based on mean measured concentrations was 0.017 mg/L with 95% confidence limits of 0.015-0.018 mg/L. The no observed effect concentration was 0.0104 mg/L.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic crustacea: Crayfish (Procambarus clarkii)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

140-144 mg/L (as CaCO3)

Test temperature:

22 ± 2°C

pH:

7.3 to 8.5

Dissolved oxygen:

≥ 6.3 mg/L

Conductivity:

354-357 μS/cm

Nominal and measured concentrations:

Nominal: 0, 1.9, 3.8, 7.5, 15, and 30 mg/L
Measured: 0, 2.1, 4.0, 7.6, 16, and 31 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

13.2 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

< 2.1 mg/L

Nominal / measured:

meas. (not specified)

Reported statistics and error estimates:

48-hour LC50 based on mean measured concentrations was 13.2 mg/L with 95% confidence limits of 5.5-53 mg/L.
The no observed effect concentration was < 2.1 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hour LC50 based on mean measured concentrations was 13.2 mg/L with 95% confidence limits of 5.5-53 mg/L.
The no observed effect concentration was < 2.1 mg/L.

Executive summary:

The toxicity of the test substance to the crayfish (Procambarus clarkii) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010. Crayfish were exposed to a geometric series of five test concentrations, a negative control (dilution water), and a HEPES® buffer control (dilution water adjusted to approximately pH 7) for 48 hours under static conditions. Two replicate test chambers were maintained in each treatment and control group, with 10 crayfish in each test chamber for a total of 20 per concentration. Nominal concentrations were 0, 1.9, 3.8, 7.5, 15, and 30 mg/L. Measured concentrations were 0, 2.1, 4.0, 7.6, 16, and 31 mg/L.

 

The 48-hour LC50 based on mean measured concentrations was 13.2 mg/L with 95% confidence limits of 5.5-53 mg/L. The no observed effect concentration was < 2.1 mg/L.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic arthropod: Mayfly (Neocloeon Triangulifer)

Test type:

static

Water media type:

freshwater

Limit test:

no

Hardness:

140 mg/L (as CaCO3)

Test temperature:

10 ± 2°C

pH:

7.2-8.4

Dissolved oxygen:

≥8.0 mg/L

Conductivity:

332 μS/cm

Nominal and measured concentrations:

Nominal: 0, 0.013, 0.025, 0.05, 0.10, 0.20 mg/L
Measured: 0, 0.014, 0.026, 0.05, 0.10, 0.21 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.11 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.026 mg/L

Nominal / measured:

meas. (not specified)

Reported statistics and error estimates:

48-hour LC50 based on mean measured concentrations was 0.11 mg/L with 95% confidence limits of 0.089-0.14 mg/L.
The no observed effect concentration was 0.0026 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hour LC50 based on mean measured concentrations was 0.11 mg/L with 95% confidence limits of 0.089-0.14 mg/L.
The no observed effect concentration was 0.0026 mg/L.

Executive summary:

The toxicity of the test substance to the mayfly (Neocloeon triangulifer) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010. Mayflies were exposed to a geometric series of five test concentrations, a negative control (dilution water), and a HEPES® buffer control (dilution water adjusted to approximately pH 7) for 48 hours under static conditions. Four replicate test chambers were maintained in each treatment and control group, with five mayflies in each test chamber for a total of 20 mayflies per concentration. Nominal concentrations were 0, 0.013, 0.025, 0.05, 0.10, 0.20 mg/L. Measured concentrations were 0, 0.014, 0.026, 0.05, 0.10, 0.21 mg/L.

 

The 48-hour LC50 based on mean measured concentrations was 0.11 mg/L with 95% confidence limits of 0.089-0.14 mg/L. The no observed effect concentration was 0.0026 mg/L.

Reference 5

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic arthropod: caddisfly (Chimarra atterima)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

144 mg/L (as CaCO3)

Test temperature:

10 ± 1°C

pH:

7.2-8.3

Dissolved oxygen:

≥8.9 mg/L

Conductivity:

355 μS/cm

Nominal and measured concentrations:

Nominal: 0, 5.1, 11, 25, 55, 120 mg/L
Measured: 0, 4.9, 11, 25, 55, 122 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

26 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

4.9 mg/L

Nominal / measured:

meas. (not specified)

Reported statistics and error estimates:

48-hour LC50 based on mean measured concentrations was 26 mg/L with 95% confidence limits of 20-34 mg/L.
The no observed effect concentration was 4.9 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hour LC50 based on mean measured concentrations was 26 mg/L with 95% confidence limits of 20-34 mg/L.
The no observed effect concentration was 4.9 mg/L.

Executive summary:

The toxicity of the test substance to the caddisfly (Chimarra atterima) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010. Caddisfly were exposed to a geometric series of five test concentrations, a negative control (dilution water), and a HEPES® buffer control (dilution water adjusted to approximately pH 7) for 48 hours under static conditions. Four replicate test chambers were maintained in each treatment and control group, with five caddisflies in each test chamber for a total of 20 per concentration. Nominal concentrations were 0, 5.1, 11, 25, 55, 120 mg/L. Measured concentrations were 0, 4.9, 11, 25, 55, 122 mg/L

 

The 48-hour LC50 based on mean measured concentrations was 26 mg/L with 95% confidence limits of 20-34 mg/L. The no observed effect concentration was 4.9 mg/L.

Reference 6

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

dimethylformamide

Test organisms (species):

other aquatic arthropod: stonefly (Soyedina carolinensis)

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

136 mg/L (as CaCO3)

Test temperature:

10 ± 1°C

pH:

8.1 to 8.4

Dissolved oxygen:

≥ 8.8 mg/L

Conductivity:

320 μS/cm

Nominal and measured concentrations:

Nominal: 0, 0.43, 0.94, 2.1, 4.5 and 10 mg/L
Measured: 0, 0.43, 0.99, 2.2, 4.7 and 10 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.62 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

< 0.43 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Reported statistics and error estimates:

48-hour LC50 based on mean measured concentrations was 0.62 mg/L with 95% confidence limits of 0.35-0.87 mg/L.
The no observed effect concentration was < 0.43 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hour LC50 based on mean measured concentrations was 0.62 mg/L with 95% confidence limits of 0.35-0.87 mg/L.
The no observed effect concentration was < 0.43 mg/L.

Executive summary:

The toxicity of the test substance to the stonefly (Soyedina carolinensis) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010. Larval-stage stoneflies were exposed to a geometric series of five test concentrations, a negative control (dilution water), and a solvent control (dimethylformamide) for 48 hours under flow-through conditions. Two replicate test chambers were maintained in each treatment and control group. Each test chamber contained two test compartments with 5 stoneflies in each test chamber for a total of 20 per concentration. Nominal concentrations were 0, 0.43, 0.94, 2.1, 4.5 and 10 mg/L. Measured concentrations were 0, 0.43, 0.99, 2.2, 4.7 and 10 mg/L.

 

The 48-hour LC50 based on mean measured concentrations was 0.62 mg/L with 95% confidence limits of 0.35-0.87 mg/L. The no observed effect concentration was < 0.43 mg/L.

Reference 7

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic crustacea: Freshwater Amphipod (Hyalella azteca)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

144 mg/L (as CaCO3)

Test temperature:

23 ± 2°C

pH:

7.2-8.6

Dissolved oxygen:

≥8.3 mg/L

Conductivity:

293 μS/cm

Nominal and measured concentrations:

Nominal: 0, 0.075, 0.15, 0.30, 0.60, 1.2 mg/L
Measured: 0, 0.08, 0.16, 0.32, 0.64, 1.3 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.37 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.08 mg/L

Reported statistics and error estimates:

48-hour LC50 = 0.37 mg/L with 95% confidence limits of 0.30-0.46 mg/L.
NOEC = 0.08 mg/L

Validity criteria fulfilled:

yes

Conclusions:

48-hour LC50 = 0.37 mg/L with 95% confidence limits of 0.30-0.46 mg/L.
NOEC = 0.08 mg/L

Executive summary:

The toxicity of the test substance to the freshwater amphipod (Hyalella Azteca) was conducted according to OECD guideline 202 and draft EPA OPPTS guideline 850.1010.  Amphipods were exposed to a geometric series of five test concentrations, a negative control (dilution water) and a HEPES buffer control (dilution water adjusted to pH 7) for 48 hours under static conditions. Four replicate test chambers were maintained in each treatment and control group, with five amphipods in each test chamber for a total of 20 amphipods per concentration. Nominal concentrations were 0, 0.075, 0.15, 0.30, 0.60, 1.2 mg/L. Measured concentrations were 0, 0.08, 0.16, 0.32, 0.64, 1.3 mg/L

 

The 48-hour LC50 based on mean measured concentrations was 0.37 mg/L with 95% confidence limits of 0.30-0.46 mg/L. The no observed effect concentration was 0.08 mg/L.

Reference 8

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other: Oligochaete (Lumbriculus variegatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

140 mg/L (as CaCO3)

Test temperature:

23 ± 2ºC

pH:

7.3-8.6

Dissolved oxygen:

≥7.9 mg/L

Conductivity:

342 μS/cm

Nominal and measured concentrations:

Nominal: 0, 63, 125, 250, 500, and 100 mg/L
Measured: 0, 65, 132, 262, 526, 1060 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

635 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Details on results:

The highest mean, measured test concentration causing no mortality at test end was 262 mg a.s./L. The lowest mean, measured test concentration causing 100% mortality at test end was 1060 mg a.s./L, the highest concentration tested.

All oligochaetes in the negative and the HEPES ® buffer control groups appeared normal throughout the test. All oligochaetes in the 65 mg a.s./L treatment group also appeared normal throughout the test, with no immobile oligochaetes or overt signs of toxicity observed, with the exception of one observation of an oligochaete appearing lethargic at test termination. There were observations of organisms tightly tangled together in a ball-like cluster in the 65 and 132 mg a.s./L treatment groups throughout the test. The organisms were gently separated from one another, and in the 65 mg a.s./L treatment groups appeared normal after being separated. This behavior is not considered treatment-related, as it is frequently noted in oligochaete cultures, and did not follow a dose-response in this study. After being separated, lethargic organisms in the 132 treatment groups were observed throughout the study. There were also observations of organisms with a broken or missing body segment in the 132 and 262 mg a.s./L treatment groups throughout the study. Oligochaetes reproduce via fragmentation, so it is not abnormal for an organism to be missing a body fragment, and these observations were not considered treatment related. Signs of toxicity observed among the oligochaetes in the 65, 132, 262, 526 and 1060 mg a.s./L treatment groups included lethargy. Percent mortality in the 65, 131, 262, 526 and 1060 mg a.s./L was 0, 0, 0, 25 and 100%, respectively.

Validity criteria fulfilled:

yes

Conclusions:

48-hr LC50 = 635 mg/L (95% confidence limits of 526 and 1060 mg/L)

Executive summary:

The oligochaete (Lumbriculus variegatus) was exposed for 48 hours under static conditions according to OECD guideline 202. Nominal concentrations were 0, 63, 125, 250, 500, and 100 mg/L. Measured concentrations were 0, 65, 132, 262, 526, and 1060 mg/L. Observations of mortality and clinical signs of toxicity were made periodically throughout the test. Mortality was defined as the lack of reaction by the test organism to a gentle stimulus. All clinical observations including abnormal behavior were noted. Observations were made approximately 2, 24 and 48 hours after test initiation.

 

The 48-hour LC50value was 635 mg/L, with 95% fiducial limits of 526 and 1060 mg/L. The highest mean, measured test concentration causing no mortality at test end was 262 mg/L. The lowest mean, measured test concentration causing 100% mortality at test end was 1060 mg/L.

Reference 9

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1020 (Gammarid Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-571
Purity: 99.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

Gammarus sp.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

140 mg/L (as CaCO3)

Test temperature:

18 ± 2°C

pH:

7.1-8.5

Dissolved oxygen:

≥ 7.7 mg/L

Conductivity:

335 μS/cm

Nominal and measured concentrations:

Nominal: 0, 0.094, 0.19, 0.38, 0.75, 1.5 mg/L
Measured: 0, 0.093, 0.19, 0.38, 0.76, and 1.5 mg/L

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.85 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.38 mg/L

Nominal / measured:

meas. (not specified)

Reported statistics and error estimates:

96-hour LC50 based on mean measured concentrations was 0.85 mg/L with 95% confidence limits of 0.71-1.004 mg/L.
The no observed effect concentration was 0.38 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

96-hour LC50 based on mean measured concentrations was 0.85 mg/L with 95% confidence limits of 0.71-1.004 mg/L.
The no observed effect concentration was 0.38 mg/L.

Executive summary:

The toxicity of the test substance to the freshwater amphipod (Gammarus pseudolimnaeus) was conducted according to draft EPA OPPTS guideline 850.1020. Amphipods were exposed to a geometric series of five test concentrations, a negative control (dilution water), and a HEPES® buffer control (dilution water adjusted to approximately pH 7) for 96 hours under static conditions. Four replicate test chambers were maintained in each treatment and control group, with 5 amphipods in each test chamber for a total of 20 per concentration. Nominal concentrations were 0, 0.094, 0.19, 0.38, 0.75, 1.5 mg/L. Measured concentrations were 0, 0.093, 0.19, 0.38, 0.76, and 1.5 mg/L.

 

The 96-hour LC50 based on mean measured concentrations was 0.85 mg/L with 95% confidence limits of 0.71-1.004 mg/L. The no observed effect concentration was 0.38 mg/L.

Reference 10

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-394
Purity: 98.35%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic crustacea: Mysidopsis bahia

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21.0-22.2 °C

pH:

7.9-8.2

Dissolved oxygen:

7.5-8.2 mg/L

Salinity:

16.2-17.5 ppt

Nominal and measured concentrations:

Nominal: 0, 0.10, 0.15, 0.20, 0.30, and 0.50 mg/L
Measured: 0, 0.13, 0.18, 0.25, 0.40, and 0.54 mg/L

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.22 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.32 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.13 mg/L

Reported statistics and error estimates:

96-hr LC50 of 0.22 mg/L, with a 95% confidence interval of 0.20-0.25 mg/L. (probit method)
48-hour LC50 of 0.32 mg/L, with a 95% confidence interval of 0.29-0.26 mg/L. (moving average method)

Validity criteria fulfilled:

yes

Conclusions:

96-hr LC50 of 0.22 mg/L, with a 95% confidence interval of 0.20-0.25 mg/L. (probit method)
48-hr LC50 of 0.32 mg/L, with a 95% confidence interval of 0.29-0.26 mg/L. (moving average method)
96-hr NOEC was estimated to be 0.13 mg/L.

Executive summary:

The acute toxicity of the test substance to mysid, Mysidopsis bahia, was conducted according the EPA OPP guideline 72-3. The test was performed under static unaerated conditions with five concentrations of the test material and a dilution water control. Nominal concentrations were set at 0, 0.10, 0.15, 0.20, 0.30, and 0.50 mg/L. Mean measured concentrations were 0, 0.13, 0.18, 0.25, 0.40, and 0.54 mg/L.

Exposure of mysids to the test material resulted in a 96-hr LC50 of 0.22 mg/L, with a 95% confidence interval of 0.20-0.25 mg/L. This value was determined via probit analysis method. The 96-hour no observed effect concentration (NOEC) was estimated to be 0.13 mg/L.

The 48-hour LC50 was determined to be 0.32 mg/L via moving average calculation method. The 95% confidence interval was 0.29-0.26 mg/L.

Reference 11

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA).

GLP compliance:

no

Specific details on test material used for the study:

INX-1179-238
Purity: 100%

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic crustacea: fiddler crab (Uca pugilator)

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21±1°C

Dissolved oxygen:

4.3-5.2 mg/L

Salinity:

25 o/oo

Nominal and measured concentrations:

Nominal: 0,1.2, 1.6, 2.1, 2.8, 3.7, 4.2, 5.6, 7.5, 10.0, and 12.0 mg/L

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

other: TL50

Effect conc.:

7.62 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

other: TL50

Effect conc.:

2.38 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1.6 mg/L

Reported statistics and error estimates:

24-hour TL50 = 7.62 mg/L with 95% confidence limits of 6.13-9.47 mg/L.
96-hour TL50 = 2.38 mg/L with 95% confidence limits of 1.97-2.83 mg/L.
The No effect level was 1.60 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

24-hour TL50 = 7.62 mg/L with 95% confidence limits of 6.13-9.47 mg/L.
96-hour TL50 = 2.38 mg/L with 95% confidence limits of 1.97-2.83 mg/L.
The No effect level was 1.60 mg/L.

Executive summary:

The toxicity of the test substance to the fiddler crab to the was measured in terms of the median tolerance limit (TL50), the concentration of the chemical in water which causes 50% response under the test conditions. The criteria utilized in this study was death. The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA). Nominal concentrations were set at 0,1.2, 1.6, 2.1, 2.8, 3.7, 4.2, 5.6, 7.5, 10.0, and 12.0 mg/L.

The 24-hour TL50 was 7.62 mg/L with 95% confidence limits of 6.13-9.47 mg/L. The 96-hour TL50 was 2.38 mg/L with 95% confidence limits of 1.97-2.83 mg/L. The No effect level was 1.60 mg/L.

Reference 12

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA).

GLP compliance:

no

Specific details on test material used for the study:

INX-1179
Purity: 100%

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Palaemonetes vulgaris

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21±1°C

Dissolved oxygen:

5.0-8.0 mg/L

Salinity:

25 o/oo

Nominal and measured concentrations:

Nominal: 0, 0.016, 0.037, 0.075, 0.160, 0.370, 0.490 mg/L

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

other: TL50

Effect conc.:

0.311 mg/L

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

other: TL50

Effect conc.:

0.196 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

other: TL50

Effect conc.:

0.049 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.016 mg/L

Reported statistics and error estimates:

24-hour TL50 = 0.311 mg/L with 95% confidence limits of 0.157-0.619 mg/L.
48-hour TL50 = 0.196 mg/L with 95% confidence limits of 0.123-0.313 mg/L.
96-hour TL50 = 0.049 mg/L with 95% confidence limits of 0.030-0.081 mg/L.
The No effect level was 0.016 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

24-hour TL50 = 0.311 mg/L with 95% confidence limits of 0.157-0.619 mg/L.
48-hour TL50 = 0.196 mg/L with 95% confidence limits of 0.123-0.313 mg/L.
96-hour TL50 = 0.049 mg/L with 95% confidence limits of 0.030-0.081 mg/L.
The No effect level was 0.016 mg/L.

Executive summary:

The toxicity of the test substance to the grass shrimp to the was measured in terms of the median tolerance limit (TL50), the concentration of the chemical in water which causes 50% response under the test conditions. The criteria utilized in this study was death. The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA). Nominal concentrations were set at 0, 0.016, 0.037, 0.075, 0.160, 0.370, 0.490 mg/L.

The 24-hour TL50 was 0.311 mg/L with 95% confidence limits of 0.157-0.619 mg/L. The 48-hour TL50 was 0.196 mg/L with 95% confidence limits of 0.123-0.313 mg/L. The 96-hour TL50 was 0.049 mg/L with 95% confidence limits of 0.030-0.081 mg/L. The No effect level was 0.016 mg/L.

Reference 13

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA).

GLP compliance:

no

Specific details on test material used for the study:

INX-1179-238
Purity: 100%

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

water

Test organisms (species):

Palaemonetes vulgaris

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21±1°C

Dissolved oxygen:

4.3-5.2 mg/L

Salinity:

25 o/oo

Nominal and measured concentrations:

Nominal: 0, 0.049, 0.065, 0.087, 0.140, 0.210, 0.320, 0.490, 0.750, 1.0, 1.2 mg/L

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

other: TL50

Effect conc.:

0.63 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

other: TL50

Effect conc.:

0.13 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.049 mg/L

Reported statistics and error estimates:

24-hour TL50 = 0.63 mg/L with 95% confidence limits of 0.45-0.90 mg/L.
96-hour TL50 = 0.13 mg/L with 95% confidence limits of 0.09-0.18 mg/L.
The No effect level was 0.049 mg/L

Validity criteria fulfilled:

yes

Conclusions:

24-hour TL50 = 0.63 mg/L with 95% confidence limits of 0.45-0.90 mg/L.
96-hour TL50 = 0.13 mg/L with 95% confidence limits of 0.09-0.18 mg/L.
The No effect level was 0.049 mg/L

Executive summary:

The toxicity of the test substance to grass shrimp was measured in terms of the median tolerance limit (TL50), the concentration of the chemical in water which causes 50% response under the test conditions. The criteria utilized in this study was death. The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods(APHA). Nominal concentrations were set at 0, 0.049, 0.065, 0.087, 0.140, 0.210, 0.320, 0.490, 0.750, 1.0, 1.2 mg/L.

The 24-hour TL50 was 0.63 mg/L with 95% confidence limits of 0.45-0.90 mg/L. The 96-hour TL50 was 0.13 mg/L with 95% confidence limits of 0.09-0.18 mg/L. The No effect level was 0.049 mg/L.

Reference 14

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA).

GLP compliance:

no

Specific details on test material used for the study:

INX-1179
Purity: 100%

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

other aquatic crustacea: mud crab (Neopanope texana)

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21±1°C

Dissolved oxygen:

5.0-8.0 mg/L

Salinity:

25 o/oo

Nominal and measured concentrations:

Nominal: 0, 0.16, 0.24, 0.49, 0.75, 1.20, and 2.10 mg/L

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

other: TL50

Effect conc.:

> 0.49 - < 0.75 mg/L

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

other: TL50

Effect conc.:

0.417 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

other: TL50

Effect conc.:

0.41 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.24 mg/L

Reported statistics and error estimates:

24-hour TL50 was >0.490 but <0.750 mg/L.
48-hour TL50 was 0.417 mg/L with 95% confidence limits of 0.225-0.772 mg/L.
96-hour TL50 was 0.410 mg/L with 95% confidence limits of 0.221-0.759 mg/L.
The No effect level was 0.240 mg/L.
The No effect level was 0.016 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

24-hour TL50 was >0.490 but <0.750 mg/L.
48-hour TL50 was 0.417 mg/L with 95% confidence limits of 0.225-0.772 mg/L.
96-hour TL50 was 0.410 mg/L with 95% confidence limits of 0.221-0.759 mg/L.
The No effect level was 0.240 mg/L.

Executive summary:

The toxicity of the test substance to the mud crab to the was measured in terms of the median tolerance limit (TL50), the concentration of the chemical in water which causes 50% response under the test conditions. The criteria utilized in this study was death. The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA). Nominal concentrations were set at 0, 0.16, 0.24, 0.49, 0.75, 1.20, and 2.10 mg/L.

The 24-hour TL50 was >0.490 but <0.750 mg/L. The 48-hour TL50 was 0.417 mg/L with 95% confidence limits of 0.225-0.772 mg/L. The 96-hour TL50 was 0.410 mg/L with 95% confidence limits of 0.221-0.759 mg/L. The No effect level was 0.240 mg/L.

Reference 15

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA).

GLP compliance:

no

Specific details on test material used for the study:

INX-1179
Purity: 100%

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

other aquatic crustacea: pink shrimp (Penaeus duorarum)

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21±1°C

Dissolved oxygen:

5.0-8.0 mg/L

Salinity:

25 o/oo

Nominal and measured concentrations:

Nominal: 0, 0.0037, 0.0049, 0.0075, 0.0140, 0.0280, and 0.0490 mg/L

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

other: TL50

Effect conc.:

> 0.049 mg/L

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

other: TL50

Effect conc.:

> 0.049 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

other: TL50

Effect conc.:

0.019 mg/L

Basis for effect:

mortality

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.007 mg/L

Reported statistics and error estimates:

24-hour TL50 > 0.049 mg/L
48-hour TL50 > 0.049 mg/L
96-hour TL50 = 0.019 mg/L with 95% confidence limits of 0.012-0.030 mg/L.
The No effect level was 0.007 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

24-hour TL50 > 0.049 mg/L
48-hour TL50 > 0.049 mg/L
96-hour TL50 = 0.019 mg/L with 95% confidence limits of 0.012-0.030 mg/L.
The No effect level was 0.007 mg/L.

Executive summary:

The toxicity of the test substance to the pink shrimp to the was measured in terms of the median tolerance limit (TL50), the concentration of the chemical in water which causes 50% response under the test conditions. The criteria utilized in this study was death. The test procedures used were generally in accordance with the Fish Bioassay procedures described in the 1970 edition of Standard Methods (APHA). Nominal concentrations were set at 0, 0.0037, 0.0049, 0.0075, 0.0140, 0.0280, and 0.0490 mg/L.

The 24-hour and 48-hour TL50s were > 0.049 mg/L. The 96-hour TL50 was 0.019 mg/L with 95% confidence limits of 0.012-0.030 mg/L. The No effect level was 0.007 mg/L.

Reference 16

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Methomyl technical
DPX-X1179-394
Purity: 98.35%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic mollusc: Eastern oyster, Crassostrea virginica

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

19.9-22.0 °C

pH:

7.6-7.9

Salinity:

30 ppt

Nominal and measured concentrations:

Nominal: 0, 0.6, 1.0, 1.5, 2.4 and 4 mg/L.
Measured: 0, 0.59, 1.1, 1.6, 2.6, and 4.2 mg/L.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4 mg/L

Reported statistics and error estimates:

48-hr EC50 of 4 mg/L, with a 95% confidence internal of 2.6-4.2 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

48-hr EC50 of 4 mg/L, with a 95% confidence internal of 2.6-4.2 mg/L.

Executive summary:

The acute toxicity of the test substance to embryos and larvae of the eastern oyster, Crassostrea virginica, was conducted according the EPA OPP guideline 72-3. The test was performed under static-unaerated conditions with five concentrations of the test material and a dilution water control. Nominal concentrations were set at 0, 0.6, 1.0, 1.5, 2.4 and 4 mg/L. Mean measured concentrations were 0, 0.59, 1.1, 1.6, 2.6, and 4.2 mg/L.

Oysters were produced by spawning conditioned oysters, combining the eggs and sperm, and using the resulting embryos for the toxicity test within 1 hour of spawning. Fertilization success was equal to 100% and all newly fertilized embryos were normal at the beginning of the study. Exposure of the oysters to the test material resulted in a 48-hr EC50 of 4 mg/L, with a 95% confidence internal of 2.6-4.2 mg/L.

Reference 17

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

DPX-X1179-394
Purity: 98.35%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

water

Test organisms (species):

other aquatic mollusc: eastern oyster, Crassostrea virginica

Test type:

flow-through

Water media type:

saltwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

21.2-23.7 °C

pH:

7.4-7.9

Dissolved oxygen:

6.5-7.6 mg/L

Salinity:

30 ppt

Nominal and measured concentrations:

Nominal: 0, 150 mg/L
Measured: 0, 140 mg/L

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 140 mg/L

Nominal / measured:

meas. (not specified)

Remarks on result:

other: no effects or lethality at the highest concentration tested

Details on results:

No sub-lethal effects were observed in any test vessel.

Validity criteria fulfilled:

yes

Conclusions:

96-hr EC50 > 140 mg/L (the highest concentration tested)

Executive summary:

The acute toxicity of the test substance on shell deposition by the eastern oyster, Crassostrea virginica, was conducted according the EPA OPP guideline 72-3. The test was performed under flow-through conditions with one concentration of the test material and a dilution water control. Nominal concentrations were set at 0 and 150 mg/L. Mean measured concentrations were 0 and 140 mg/L.

Exposure of the oysters to the test material resulted in a 96-hr EC50 > 140 mg/L, the highest concentration tested. No sub-lethal effects were observed.

Description of key information

Duration/Value Type	Species	Value	Guideline	Reliability
48-hr EC50	Daphnia pulex	0.0068 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr EC50	Daphnia magna	0.017 mg/L	OECD 202, EU Method C.2	1
48-hr LC50	crayfish	13.2 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr LC50	amphipod	0.37 mg/L	OECD 202, EPA OPPTS 850.1010	1
96-hr LC50	amphipod	0.85 mg/L	EPA OPPTS 850.1010	1
48-hr LC50	mayfly	0.11 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr LC50	caddisfly	26 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr LC50	stonefly	0.62 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr LC50	oligochaete	635 mg/L	OECD 202, EPA OPPTS 850.1010	1
48-hr EC50 96 -hr EC50	Mysid	0.32 mg/L 0.22 mg/L	EPA OPP 72-3	1
96-hr EC50	eastern oyster	> 140 mg/L	EPA OPP 72-3	1
48-hr EC50	eastern oyster	4 mg/L	EPA OPP 72-3	1
96-hr TL50	grass shrimp	0.13 mg/L	no guideline	2
48-hr TL50	grass shrimp	0.196 mg/L	no guideline	2
48-hr TL50	pink shrimp	> 0.049 mg/L	no guideline	2
48-hr TL50	mud crab	0.417 mg/L	no guideline	2
96-hr TL50	fiddler crab	2.38 mg/L	no guideline	2

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.007 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

0.22 mg/L

Additional information

Acute aquatic invertebrate tests were conducted in eight freshwater species and six marine species. The 48-h EC50 value in Daphnia magna is 0.017 mg/L. The EC50 values of freshwater species ranged from 0.0068 mg/L to 635 mg/L with the most sensitive species being the Daphnia pulex.  Marine species tested had 48 or 96-h EC50 values of ranging from 0.13 mg/L to > 140 mg/L. A 96-h EC50 value of 0.22 mg/L was observed in a guideline study in mysid and was chosen as the representative value for marine water invertebrates.  Both freshwater and saltwater aquatic invertebrates exhibited EC50s less than 1 mg/L.