2,5-di-tert-pentylhydroquinone

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

Study period:

11 May 1980 to 13 May 1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study similar to OECD 202. No analytical determinations of the test substance.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

: no analytical determinations of the test substance

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

not applicable

Vehicle:

yes

Details on test solutions:

- vehicle: nanograde acetone
- dilution water: ABC well water
- maximum concentration of vehicle (=solvent control): 3.2 mg/L
- compound was found to form a floating white precipitate

Test organisms (species):

Daphnia magna

Details on test organisms:

- source: in-house culture
- adult Daphnids were fed a suspension of trout chow and alfalfa (PR-11) daily, until 24 hours prior to testing

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

255 mg/L CaC03 (measured in well water, not measured during test)

Test temperature:

20 ± 1 °C

pH:

7.8 in control at start of test
8.3-8.4 in all treatments at end of test

Dissolved oxygen:

9.2 mg/L in control at start of test
8.7-8.8 mg/L in all treatments at end of test

Salinity:

not applicable

Nominal and measured concentrations:

nominal concentrations: control, solvent control, 0.32, 0.56, 1.0, 1.8, 3.2 mg/L
measured concentrations: no analytics performed

Details on test conditions:

- photoperiod: 16:8, light:dark
- test vessels: 250-mL glass beakers
- test volume: 200 mL
- n° replicates: 2
- 10 Daphnids per vessel
- Daphnids were < 24 hours old
- range-finding test:
* concentrations: 0.1, 1.0, 10 mg/L
* results: after 24 hours 8 dead organisms in 10 mg/L, after 48 hours 8 and 10 dead organisms in 1.0 and 10 mg/L, respectively
- temperature, dissolved oxygen and pH were measured in the control only at the start of the test, and measured in all other treatments after 48 hours

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.91 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95 % CL: 0.78-1.1 mg/L

Details on results:

Percent mortality after 24h: 0% in control, control+acetone, 0.32, 0.56 and 1.0 mg/L; 35% in 1.8 mg/L; 95% in 3.2 mg/L.
Percent mortality after 48h: 0% in control, control+acetone and 0.32 mg/L; 10% in 0.56 mg/L; 55% in 1.0 mg/L; 100% in 1.8 and 3.2 mg/L.
The test substance formed a floating white precipitate.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

Binomial, moving average and probit tests were performed when appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

Reliable study (Klimisch 2) reporting an LC50(48h) of 0.91 mg/L for Daphnia magna. The test compound was found to form a floating white precipitate.

Executive summary:

The acute toxicity of Santovar A t o Daphnia magna was assessed using the methods outlined by the Commitee on Methods for Toxicity Tests with Aquatic Organisms. Water quality parameters of temperature, dissolved oxygen and pH were measured at the termination of the test and were within acceptable limits.

 

The results of the 48 hour static Daphnia magna toxicity study are summarized below.

Compound                             48-hour LC50 (95% C.I.)

Santovar A                            0.91 (0.78-1.1) mg/l

 

The no effect level observed for Santovar A was 0.32 mg/l after 48 hours.

Description of key information

A 48-h static exposure of Daphnia magna resulted in an LC50 value of 0.91 mg/L (ABC Laboratories, 1980, AB-80-395). The organisms were exposed to Santovar A, according to a test protocol which was similar to OECD 202 guideline, and mortality was observed. The LC50 value was derived based on nominal concentrations as no analytical measurements were performed.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.91 mg/L

Additional information

The only relevant study identified for the short-term toxicity to aquatic invertebrates was the study of Forbis and Boudreau by ABC Laboratories (1980, AB-80-395). As this study was found reliable with restrictions, its outcome can be used as key value.