Captan

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 December 2000 to 13 February 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Analytical purity: 95.2% (w/w)
- Batch number: 0133024
- Date of arrival: 8 December 2000
- Expiry date: 8 October 2002
- Storage conditions: room temperature, 20°C in the dark

Analytical monitoring:

yes

Vehicle:

yes

Test organisms (species):

Salmo trutta

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

180 mg CaCO3/L

Test temperature:

13.1 to 14.3 °C

pH:

7.8 to 8.5

Dissolved oxygen:

86 to 106 (% ASV)

Nominal and measured concentrations:

nominal concentrations of captan (dissolved in dimethylformamide):
13.7, 30.1, 66.1, 145 and 320 μg/L;
measured concentrations of captan (dissolved in dimethylformamide):
11.8, 26.5, 59.3, 126, 312 μg/L

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

93 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

13.7 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Sublethal observations / clinical signs:

Analysis of stock solutions and test media: Measured concentrations of captan in the stock solutions ranged from 91 to 102% of the nominal values. The results of the toxicity test are based on nominal concentrations of captan. The physical and chemical parameters of the test media remained at expected values during the study (pH 7.8 to 8.5, dissolved oxygen 83 to 106 % ASV, temperature 13.1 to 14.4°C and total hardness 176 to 182 mg CaCO3/L).

Toxicity and behaviour: At 320 μg/L, all fish exhibited hyperventilation within 15 minutes of exposure and were dead within four hours. At 145 μg/L, all fish were affected within two hours of exposure, exhibiting hyperventilation, darkened pigmentation and/or lethargy after four hours. After 24 hours, all fish were dead at 145 μg/L. At 66.1 μg/L, most fish exhibited hyperventilation within two hours of exposure and all were adversely affected after 24 and 48 hours Thereafter, some fish appeared to recover, with five fish exhibiting no adverse symptoms at 96 hours. At 30.1 μg/L, no adverse effects were observed during the first four hours of exposure but between 24 and 72 hours up to six fish exhibited hyperventilation and five of these had recovered and appeared normal after 96 hours. At 13.7 μg/L, all fish were normal for the first four hours of exposure and between 24 and 72 hours, up to three fish exhibited hyperventilation, but had fully recovered by 96 hours.

The results are summarised in Table 6.1.1 -1 and Table 6.1.1 -2.

6.1.1-1 Summary of sub-lethal effects of captan on brown trout following 96-hour exposure under static test conditions

Nominal captan concentration (μg/L)	Effects	Numbers affected (out of initial seven)
		0.25h	2h	4h	24h	48h	72h	96h
Control (water)	None exhibited	All fish appeared normal
Solvent control	None exhibited	All fish appeared normal
13.7	Hyperventilation	-	-	-	2/7	3/7	2/7	-
30.1	Hyperventilation	-	-	-	4/7	6/7	4/7	2/7
66.1	Hyperventilation	-	6/7	6/7	7/7	7/7	3/7	2/7
	Darkened pigmentation	-	-	-	-	-	1/7	-
	Lethargy	-	-	-	-	-	1/7	1/7
145	Hyperventilation	3/7	7/7	7/7	All dead
	Darkened pigmentation	-	2/7	2/7
	Lethargy	-	-	2/7
320	Hyperventilation	7/7	7/7	All dead
	Darkened pigmentation	-	4/7
	Lethargy	-	4/7

6.1.1-2 Summary of mortality of brown trout following 96-hour exposure to captan under static test conditions

Nominal captan concentration (μg/L)	Cumulative mortality (number out of seven)
	0.25 h	2 h	4 h	24 h	48 h	72 h	96 h
Control (water)	0	0	0	0	0	0	0
Solvent control	0	0	0	0	0	0	0
13.7	0	0	0	0	0	0	0
30.1	0	0	0	0	0	0	0
66.1	0	0	0	0	0	0	0
145	0	0	0	7	7	7	7
320	0	0	7	7	7	7	7

Validity criteria fulfilled:

yes

Remarks:

Criteria of OECD Method 203: Mortality of control: < 10%; dissolved, oxygen range > 60%, measured concentrations were within ± 20 % deviation from nominal concentrations, overall mortality over 7 d acclimatization prior to test initiation ≤ 10 % .

Conclusions:

The 96-hour LC50 of captan technical to brown trout under static test conditions was 98 μg/L (with 95% confidence limits of 66 to 145 μg/L). Adjusting for the purity of captan in captan technical (95.2 %), the 96-hour LC50 was 93 μg/L (with 95% confidence limits of 63 to 138 μg/L). The NOEC was less than 13.7 μg/L based on reversible toxic symptoms at 13.7 μg captan technical/L.

Executive summary:

A study was performed to assess the acute toxicity of captan Technical to brown trout (Salmo trutta) under static (no renewal) exposure conditions. A static exposure regime was selected in order to mimic a single application of the product in the environment; under these conditions it is unlikely that the exposure concentrations of captan would have been maintained during the study since captan is not stable in water, particularly at low concentrations and under alkaline conditions.

The study was conducted in accordance with EEC method Part C, Method 1 "Acute Toxicity for Fish" published in the regulation 440/2008 and the OECD Guideline for Testing of Chemicals No. 203 "Fish, Acute Toxicity Test”.

Groups of seven juvenile fish were exposed to captan Technical at nominal concentrations of 13.7, 30.1, 66.1, 145 and 320 µg/L (13.0, 28.7, 62.9, 138 and 305 µg a.i./l). The test substance was dissolved in dimethylformamide before being added to water (dechlorinated tap water, hardness ca. 180mg/L as CaCO₂).

The concentrations of captan in the solvent stock solutions, from which the test media were prepared, were verified using an HPLC method of analysis and an analytical standard of captan; the measured levels ranged between 91 and 102% of their nominal values. Attempts to develop a suitable analytical method to monitor the exposure concentrations in the aqueous media- during the test were unsuccessful. Consequently, the test results have been expressed in terms of their nominal values.

Observations of the fish were made after approximately 0.25, 2, 4, 24, 48, 72 and 96 hours of exposure.

After 96 hours, the highest nominal test concentration at which no mortality had occurred was 66.1 µg/l and the lowest at which there was 100% mortality was 145 µg/l. Sub-lethal, treatment-related effects were exhibited by the fish at all test levels, although five of the seven fish at 30.1 and 66.1 µg/L and all of the fish at 13.7 µg/L had recovered by the end of the test and appeared normal.

 

Based on these findings, the following values have been estimated:

Captan Technical:

96-hour LC50 value (95% c.l.):

98 (66 &145) µg/l

 

96-hour LC10 value (95% c.l.):

92 (57 &145) µg/l

 

Captan:

96-hour LC50 value (95% c.l.):

93 (63 &138) µg a.i./l

 

96-hour LC10 value (95% c.l.):

88 (54&138) µg a.i./l

 

c.l.: confidence limits.

Description of key information

Short-term toxicity to fish: LC50 (96h) = 93 µg/L (adjusting for the purity of captan in captan technical (95.2%)), (with 95% confidence limits of 63 to 138 µg/L) for Salmo trutta (OECD 203 (Fish Acute Toxicity Test)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

93 µg/L

Additional information

Acute toxicity on fish was determined with a study according to OECD guideline 203 in freshwater under static conditions. With a LC 50(96h) value of 93 µg/L on Salmo trutta fish was found to be the most sensitive species in aquatic system.

Based on the results captan is classified as acute toxic category 1 (H400) to fish.