Captan

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 February to 13 March 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

other: Guideline 202, Part II, Daphnia sp Reproduction Test (adopted April 1984) is used in this study, not the update OECD 211. OECD Test Guidelines for Testing of Chemicals are reviewed in the light of scientific progress.

Version / remarks:

1984

Deviations:

no

Principles of method if other than guideline:

Deviations to OECD 202 (1984): The Daphnia were individually separated for addition to the test vessels. The test method is equivalent or similar to OECD 211.

GLP compliance:

yes

Specific details on test material used for the study:

- Physical state: white powder
- Analytical purity: 90.0 % (w/w)
- Batch number: RS309
- Date of arrival: 8 June 1990
- Storage conditions: room temperature

Analytical monitoring:

yes

Details on sampling:

10 replicate vessels, each containing one Daphnia were employed for the control, solvent control and each concentration of the substance. These daphnia were termed the P0 generation.

Vehicle:

yes

Details on test solutions:

- Chemical name of vehicle: dimethylformamide
- The test solutions were prepared on the day of use, and were renewed every third day.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Age at study initiation: < 24 hours old
- Method of breeding: defined diet of algae (Chlorella vulgaris) and yeast

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Hardness:

total hardness approx. 173 mg CaCO3/L

Test temperature:

20 ± 1 °C

pH:

8.0 - 8.4

Dissolved oxygen:

9.3-9.5 mg/L

Nominal and measured concentrations:

nominal concentrations (dissolved in dimethylformamide): 0.32, 0.56 and 1.0 mg/L

Key result

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality: Number of living offspring produced per surviving parental animal {for Daphnia magna, TG 211}

Remarks:

based on the reduction in offspring and body length recorded at 1.0 mg/L.

Analysis of solutions: Measured concentrations of captan in the stock solutions ranged from 91 to 100% of the nominal values. The analytical results are therefore calculated based on dilution of the stock solution and the toxicity results are based on nominal values. The physical and chemical parameters of the test solutions remained at expected values during the study.

Toxicity, reproduction and body length: No symptoms other than mortality and no dead offspring were observed. The results are summarised in Table 6.1.4 -1

Table 6.1.4-1 Summary of effects of captan on Daphnia magna following 21-day exposure

Captan concentration1 (mg/L)	Adult mortality after 21 days (%)	Mean total offspring/ parent	Mean adult body length (mm)
Water only	0	212 (100)	4.84 (100)
Solvent control	10	199 (94)	4.79 (99)
0.32	0	195 (92)	4.76 (98)
0.56	0	184 (87)	4.77 (99)
1.0	10	171^2	4.67^2(96)

¹Nominal concentrations.

²Significantly different from water and/or solvent control at P = 0.05.

Figures in parenthesis are % of control values.

 

Validity criteria fulfilled:

yes

Remarks:

OECD 211: the mortality of the parent animals (female Daphnia) does not exceed 20% at the end of the test; the mean number of live offspring produced per parent animal surviving at the end of the test is > 60

Conclusions:

The 21-day EC50 of captan to Daphnia magna under semi-static conditions was greater than 1.0 mg/L. The NOEC was 0.56 mg/L based on the reduction in offspring and body length recorded at 1.0 mg/L.

Executive summary:

The chronic toxicity of captan technical to Daphnia magna was determined. Due to the rapid hydrolysis of captan in aqueous conditions the results have been expressed as nominal concentrations. The methods were based on those described In the relevant OECD method 202 (1984) equivalent to OECD 211, modified by individually separating the Daphnia.

The test organism was the freshwater crustacean, Daphnia magna Straus, obtained from continuous laboratory cultures at the ICI Group Environmental Laboratory. Daphnia <24 hours old, obtained from a Single culture vessel, were used for testing. Ten replicate vessels, each containing one Daphnia were employed for the control, solvent control and each concentration of test substance.The duration of the test was 21 days. There were no mortalities in the control and nominal test concentrations of 0.32 and 0.56 mg/L after 21 days. In the solvent control and nominal concentration of 1.0 mg/L, there was 10% mortality during the test. The 21-day EC50 of captan to Daphnia magna under semi-static conditions was greater than 1.0 mg/L.

The mean number of offspring produced by the control and solvent control were significantly different (P = 0.05, t-test, one-sided). Therefore, the treatments were compared with the solvent control only. The no observed effect concentration (NOEC) for reproduction is 0.56 mg/L (nominal).

The length of the surviving P₀ Daphnia at the end of the test at nominal concentrations up to and including 0.56 mg/L mean length was not significantly reduced. Therefore the no observed effect concentration (NOEC) for length is 0.56 mg/L (nominal).

Description of key information

Long-term toxicity to aquatic invertebrates, 21-day, Daphnia magna under semi-static conditions: EC50 > 1.0 mg/L, NOEC = 0.56 mg/L (based on reduction in offspring and body length, OECD Guideline No 202 (1984) equivalent to OECD Guideline No 211 (1998)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

0.56 mg/L

Additional information

Long-term toxicity to Daphnia was determined according to OECD 202 (1984) (similar to OECD 211 (1998)). Up to a concentration of 1.0 mg/L captan no symptoms other than mortality and no dead offspring were observed. The no observed effect concentration (NOEC) for reproduction is 0.56 mg/L (nominal) due to significant offspring reduction in respect to control groups at 1.0 mg/l concentration.