2-methylhydroquinone

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:

14.05.2018 - 22.06.2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1981

Deviations:

no

GLP compliance:

no

Remarks:

accredited by DAkkS

Analytical monitoring:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Caging of the fish was conducted in 40 l-glas pools under permananent ventilation at 20 +/- 5°C and a 12 h/12 h light-dark rhythm. The animals were fed daily.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

4 d

Test temperature:

see table 2

pH:

see table 2

Dissolved oxygen:

see table 2

Nominal and measured concentrations:

for nominal concentrations see table 2

Details on test conditions:

As pre-treatment the test organisms were transferred in a 15 l- glas pool 7 days before the start of the test. This pool contained a solution (see table 1 for the composition) where the test organisms were kept under equal conditions. Within this week, the mortality of the of the fishes was observed. Since no fish died in this week, the main test was carried out. Feeding of the fish was suspended 24 h before test start.
Before the start of the test, 6 10 l-glas pools were filled with 5 l of the solution (see table 1 for the composition) and ventilated for approx. 1 h in each case. Subsequently, the water was left for 12 h. Then, samples of methylhydroquinone in different concentrations (pools B - F) were added. Pool A was not exposed to the test item and was used as control sample. Next, 7 fishes from the pre-treatment pool were each placed in the sample solutions and kept at 20 +/- 2°C for 96 h without ventilation in a 12 h-12h light-dark rhythm. The measurement and documentation of oxygen content, pH-value, temperature and number of the fishes was conducted at 24 h intervals. Dead fishes were removed immediately.
The concentration range was determined in pre-tests by fish egg test according to OECD guideline.

Reference substance (positive control):

no

Key result

Duration:

4 d

Dose descriptor:

LC50

Effect conc.:

1.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

The value for the LC50 was calculated from the equation of the regression curve using measured values of the concentrations 0,9 mg/l and 1,6 mg/l.

Sublethal observations / clinical signs:

Table 2: Oxygen content, pH-value, temperature and number of the fishes in the control sample and test samples in the test period of 96 h

Test period [h]	parameter	concentration in mg/l
		0	0,5	0,9	1,6	2,9	5,2
0	oxygen content [mg/l]	8,87	8,87	8,86	8,84	8,82	8,92
	pH	7,51	7,45	7,53	7,52	7,51	7,52
	temperature [°C]	21,0	20,9	20,8	21,0	20,3	20,3
	number of living fishes	7	7	7	7	7	7
24	oxygen content [mg/l]	6,56	7,30	7,43	8,01	7,47	6,21
	pH	7,06	7,23	7,08	7,25	7,30	7,30
	temperature [°C]	21,2	18,8	18,9	19,0	21,1	20,6
	number of living fishes	7	7	7	0	0	0
48	oxygen content [mg/l]	6,08	6,01	6,10	/	/	/
	pH	7,07	7,09	7,16	/	/	/
	temperature [°C]	21,5	19,2	19,5	/	/	/
	number of living fishes	7	7	7	0	0	0
72	oxygen content [mg/l]	6,02	6,71	6,99	/	/	/
	pH	7,02	7,06	7,09	/	/	/
	temperature [°C]	21,5	19,8	19,7	/	/	/
	number of living fishes	7	7	7	0	0	0
96	oxygen content [mg/l]	6,24	4,42	4,66	/	/	/
	pH	7,10	6,92	7,01	/	/	/
	temperature [°C]	21,4	19,3	19,1	/	/	/
	number of living fishes	7	7	7	0	0	0
	mortality [%]	100	100	100	0	0	0

Validity criteria fulfilled:

yes

Remarks:

The validity of the test is given since all fishes have survived in the control samples and the oxygen content did not decrease 60% of the air saturation.

Conclusions:

The acute toxicity of methylhydroquinone to Danio rerio was investigated in a study according to OECD Test No. 203: Fish, Acute Toxicity Test. The 96 h LC50 was determined to be 1.20 mg/L.

Executive summary:

This study is based on OECD Guideline 203. 7 fishes (species: danio rerio) were exposed at 0 (control), 0.5, 0.9, 1.6, 2.9 and 5.2 mg/L (nominal), for 96 hours with measurement of mortality.

The 96-hour LC₅₀ for the test substance methylhydroquinone to danio rerio is 1.20 mg/L.

Description of key information

Based on a OECD 203-study, the 96-hour LC50 for the test substance methylhydroquinone to danio rerio is 1.20 mg/L as determined in a static freshwater test.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1.2 mg/L