Captan

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 January to 19 March 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Deviations:

yes

Remarks:

The fish were slightly smaller (mean length 34 mm) than recommended (50 ± 10 mm) but this is not considered to have affected the validity of the study.

GLP compliance:

yes

Specific details on test material used for the study:

- Physical state: white powder
- Analytical purity: 90% (w/w)
- Batch number: RS309/H
- Date of arrival: 8. June 1990
- Storage conditions: in the dark, room temperature

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

solvent: dimethylformamide

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Hardness:

34.0 to 47.0 mg/L as CaCO3

Test temperature:

15.0 to 15.3 °C

pH:

7.29 to 8.12

Dissolved oxygen:

9.0 to 10.0 mg/L

Conductivity:

115.4 to 160.4 µS/cm

Nominal and measured concentrations:

nominal concentrations: 100, 56, 32, 18, 10, 5.6 µg/L
measured concentrations: 82, 56, 31, 16, 9.6, 5.2 µg/L

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

56 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

21 d

Dose descriptor:

LC50

Effect conc.:

75 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 61 - 100

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

75 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 61 - 100

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

75 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 63 - 96

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

75 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 63 - 96

Duration:

4 d

Dose descriptor:

LC50

Effect conc.:

75 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 63 - 96

Details on results:

There were no mortalities attributable to captan in the dilution water and solvent controls or in the nominal concentrations of 56 μg/L or less during the 21 day exposure.

Analysis of solutions: Mean measured concentrations of captan in the solvent stock solutions ranged from 82 to 100% of the nominal values based on calculated values from each respective solvent stock solution. The results are, therefore, presented as nominal values. The physical and chemical parameters of the test solutions remained at expected values during the study (pH 7.3 to 8.1 for all treatments).

Toxicity and behaviour: No treatment-related symptoms of toxicity apart from mortality were observed. There was no treatment-related effect on fish weight or length. The results are summarised in Table 6.1.2 -1.

Table 6.1.2-1 Summary of effects of captan on rainbow trout following 21-day exposure

Captan Concentration (μg/L)^1	Cumulative mortality (%)		Mean fish weight (g)		Mean fish length (mm)
	14 days	21 days	14 days	21 days	21 days
Water only	0	0	2.39	2.57	54.2
Solvent only	0	0	2.42	2.74	54.4
5.6	10	10	2.60	2.86	56.7
10	0	0	2.19	2.61	54.0
18	0	0	2.53	2.78	56.5
32	10	10	2.76	3.23	58.1
56	0	0	2.38	2.67	55.0
100	100	100	TD	TD	TD

¹Nominal concentrations.

TD = test terminated.

Validity criteria fulfilled:

yes

Remarks:

Criteria of OECD 204: mortality in controls did not exceed 10 % at the end of the test, measured concentrations of captan in the solvent stock solutions ranged from 82 to 100% of the nominal values, dissolved oxygen (over all mean) 9.7 mg/L

Conclusions:

The 21-day LC50 of captan to the rainbow trout under flow-through conditions was 75 μg/L. The NOEC was 56 μg/L based on the mortality recorded at 100 μg/L. The 4, 7, 10 and 14-day LC50 values were also 75 μg/L.

Executive summary:

The 21 day LC50 of captan to rainbow trout (Salmo gairdneri) was determined in freshwater. A dynamic (flowthrough) system was used to determine the 4.7,10,14 and 21 day LC50 values. Rainbow trout (Salmo gairdneri, also known as Oncorhynchus mykiss) a freshwater species, was selected as the test organism.

The bioassay test method used in this study was based on OECD Guideline Number 204. The nominal test exposure concentrations used in this study were 100, 56, 32, 18, 10 and 5.6 µg of captan technical per litre, together with a dilution water and solvent control. Each test concentration was run unreplicated without aeration. The anlyses to determine the levels of captan technical were done by high performance liquid chromatographic method. Samples of all new stock solutions were analysed to confirm nominal values.

Observations of mortalities and symptoms of toxicity were made daily. Mortalities were recorded daily and symptoms of toxicity were recorded on days 4,7,10, 14 and 21. The LC50 value was calculated at various time intervals by the ICI Group Environmental Laboratory computer program "LC50" using Stephan´s method. The results were calculated by using the moving average angle method.

The general symptoms of toxicity noted in this study were quiescence, weakness, loss of balance, dark discolouration and slow respiration. However, these symptoms were exhibited by only a single fish in the nominal 32 µg/L exposure concentration and were considered not to be dose related.

The LC50 values and 95% confidence intervals are shown below as µg of captan technical per litre based on nominal concentrations. Calculation method: Moving average angle

Time: 4 day, LC50: 75 µg/L, 95% confidence interval: 63- 96

Time: 7 day, LC50: 75 µg/L, 95% confidence interval: 63- 96

Time: 10 day, LC50: 75 µg/L, 95% confidence interval: 63- 96

Time: 14 day, LC50: 75 µg/L, 95% confidence interval: 61- 100

Time: 21 day, LC50: 75 µg/L, 95% confidence interval: 61- 100

There were no mortalities attributable to captan technical in the dilution water and solvent controls or in the nominal concentrations of 56 µg/L or less during the 21 day exposure. The single mortalities in the nominal exposure concentrations of 32 and 5.6 µg/L were considered to have been random and not due to any effect of captan.

The no observed effect concentration (NOEC) of captan (based on mortalities and symptoms of toxicity) was therefore determined to be 56 µg/L on the basis of nominal concentrations. The threshold level of both lethal and observed effect was determined at 100 µg/L (nominal concentration). The lowest nominal concentration at which there was 100% mortality was 100 µg/L.

Description of key information

Longterm toxicity to fish (rainbow trout): LC50 (21 day) = 75 µg/l, NOEC (21 day, mortality) = 56 µg/l, OECD 204.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

56 µg/L

Additional information

Long-term toxicity to fish was determined according to OECD 204. For rainbow trout under flow-through conditions LC50 (21 day) = 75 µg/l and NOEC (21 day, mortality) = 56 µg/l were found. Increased exposure time (21 days) for rainbow trout did not increase toxicity (21-day LC50 = 0.075 mg/L) compared to the acute value (96-hour LC50 = 0.056 mg/L), under flow-through test conditions.

According to regulation 1272/2008 captan is classified as acute toxic in aquatic systems category 1 (H400).