2,4-dihydroxybenzoic acid

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02.04.2018-09.05.2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

no

Remarks:

accredited by DAkkS

Test material

Test material information

Constituent 1

Reference substance name:

2,4-dihydroxybenzoic acid

EC Number:

201-946-9

EC Name:

2,4-dihydroxybenzoic acid

Cas Number:

89-86-1

Molecular formula:

C7H6O4

IUPAC Name:

2,4-dihydroxybenzoic acid

Test material form:

solid

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

yes

Remarks:

test samples diluted in water

Details on test solutions:

The test vessels contained a final volume of 10 mL (2,4-dihydroxybenzoic acid stock solution and dilution water). For each dilution stage and a control solution (contains only water) 4 30 mL-test tubes with 5 daphniae each were prepared. The test tubes were covered with Kapsenberg caps and left for 48 h. Incubation was performed at room temperature (20-22°C) in a 12 h/12 h light-dark rhythm without feed portion. The daphnia mobility was checked and documented after 24 h and 48 h.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna Straus

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20-22°C

pH:

7,2 (+/-0,3)

Dissolved oxygen:

8,6 (+/-0,2) in the beginning of the test
7,6 (+/-0,2) in the end of the test

Salinity:

dilution water:
25 ml 0,08 M CaCl2-solution
+ 25 ml 0,02 M MgSO4-solution
+ 25 ml 0,03 M NaHCO3-solution
+ 25 ml 0,003 M KCl on 1 l deionised water

Conductivity:

606 μS/cm (dilution water)

Nominal and measured concentrations:

0 and 100 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 3

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 4

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

A daphnia is assessed as immobile provided that it did not move independently or after slight swinging within 15 s. Other effects of the test substance on daphniae like coloration or special stress behaviour were not observed.

Any other information on results incl. tables

Table 1: Mobility of Daphnia magna Straus at different concentrations of 2,4-dihydroxybenzoic acid

concentration [mg/l]	Mobility of Daphnia magna after
	24 h		48 h
	Amount	%	Amount	%
0	20	100	18	90
100	20	100	20	100

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Reference samples did not fall below 90% daphnia mobility. Oxygen content at the test end was always above 3 mg/L.

Conclusions:

In a limit test according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test), a 48 h EC50 > 100 mg/L and a 48 h NOEC > 100 mg/L were determined for the toxicity of 2,4-dihydroxybenzoic acid on daphnia magna.

Executive summary:

The acute toxicity of 2,4-dihydroxybenzoic acid to Daphnia magna was investigated in a limit test according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The endpoint examined was immobilization. The daphnids (20 animals/concentration) were exposed to a nominal concentration of 100 mg/l of 2,4-dihydroxybenzoic acid.

The 48 h EC₅₀ and NOEC were determined to be >100 mg/L.

The testing/validity criteria laid down in the OECD guideline 202 are fulfilled. This study is regarded as reliable without restriction.