o-cresol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

equivalent or similar to guideline

Guideline:

other: NEN 6501 (1976): Toxicity test to Daphnia sp.

Principles of method if other than guideline:

The sensitivity of Daphnia magna in short-term tests has been tested in comparison with Daphnia pulex and Daphnia cucullata. Additionally, the reproducibility of the method was tested.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

Daphnia sp.

Details on test organisms:

The daphnids were cultured as described by ten Berge (1978). The short-term (LC50.48 h) and reproduction toxicity experiments with Daphnia magna were carried out in analogy to the concept rules of the Dutch Standardization Institute (Adema, 1978); the short-term tests
with Daphnia pulex and Daphnia cucullata in the same way as the experiments with Daphnia magna. The age of Daphnia cucullata however deviated: instead of animals < 1 day, 11 ± 1 day old organisms were used in view of the required size.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 +/- 1°C

Duration:

48 h

Dose descriptor:

LC50

Remarks:

Daphnia magna

Effect conc.:

15.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: Overall Mean value

Duration:

48 h

Dose descriptor:

LC50

Remarks:

Daphnia pulex

Effect conc.:

9.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: Mean value

Duration:

48 h

Dose descriptor:

LC50

Remarks:

Daphnia cucullata

Effect conc.:

16.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: Mean value

The single results (48h-LC50 in mg/l) of each test and laboratory are shown in the table:

	Daphnia magna	Daphnia pulex	Daphnia cucullata
Lab I	9.8	10.8
	8.6	8.5
mean	9.2	9.6
Lab II (exp.1)	23.8		17.4
	23.1		15.5
mean	23.5		16.4
Lab II (exp.2)	15.1
	14.0
mean	14.5

Validity criteria fulfilled:

not specified

Conclusions:

The acute toxicity of o-cresol to Daphnia pulex was determined in 3 different laboratories. The tests were carried out according to a Dutch standard method which is similar to OECD 202 . The lowest mean-value for the 48h-EC50 of 1 laboratory was reported to be 9.6 mg/l.

Executive summary:

The acute toxicity of o-cresol to Daphnia pulex was determined in a static immobilization test after an exposure period of 48 h. The test was carried out in analogy to a Dutch standard method which is similar to OECD 202. In 3 laboratories, duplicate samples with each 25 individuals of <1 day old daphnids were exposed to the test solutions. Analytical confirmation of exposure levels was not performed. The lowest nominal EC50 was reported to be 9.6 mg/l.

Description of key information

The lowest EC50 value was reported to be 9.6 mg/l. Acute toxicity of o-cresol to Daphnia pulex was determined in a static immobilization test after an exposure period of 48 h.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

9.6 mg/L

Additional information

Short term toxicity of o-cresol towards various species of aquatic invertebrates was assessed in several experiments.

For risk assessment purposes, only the most reliable and sensitivity study is considered.

The lowest toxicity value was obtained in an acute toxicity test of o-cresol to Daphnia pulex, determined in a static immobilization test after an exposure period of 48 h. The test was carried out in analogy to a Dutch standard method which is similar to OECD 202. In 3 laboratories, duplicate samples with each 25 individuals of <1 day old daphnids were exposed to the test solutions. Analytical confirmation of exposure levels was not performed. The lowest nominal EC50 was reported to be 9.6 mg/l.