Bis(4-methylbenzoyl)peroxide

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed under GLP according to protocol. It was reviewed in the HPV program and recorded in the OECD SIDS dossier as reliability 1.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Nominal and measured concentrations:

Nominal: 3.0, 5.1, 8.7, 15 25, 43 and 72 mg/L

Reference substance (positive control):

not specified

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

42 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Conclusions:

This study is reliable. It is performed according to OECD guideline 202 under GLP and it was reviewed during the HPV process. The calculated endpoints are adequate for C&L and risk assessment purposes.

Executive summary:

For daphnids, Daphnia magna, an acute toxicity of p-toluic acid was 48 h EC₅₀of 42 mg/L (MOE, 2003). A static test was conducted, twenty daphnids per test concentration were exposed at the concentrations of 3.0, 5.1, 8.7, 15 25, 43 and 72 mg/L nominal of the chemical together with a blank control group. The exposure concentrations were kept throughout the test period; the mean measured concentrations of p-toluic acid (geometric mean) of each treatment were 2.9, 4.8, 8.3, 14, 24, 41 and 70 mg/L, respectively, and the measured concentrations showed at the start and end of test were ranged 94.6 - 97 % of nominal and 95.3 - 98.2 % of nominal, respectively.The exposure was conducted without pH adjustment however pH was decreased to 4.9 at the highest concentration of 70 mg/L due to the test substance property. At the lower concentrations of the chemical pH was not changed significantly from that of dilution water. At the control and up to 14 mg/L (mean measured concentration) no immobilization was observed for 48 hr. At the highest concentration of 70 mg/L all daphnids were immobilized. Based on mean measured concentration the 48 h EC50 of 42 mg/L was calculated by using the probit analysis. At the concentration 41 mg/L (pH was 6.9 - 7.6) 8 of 20 individuals (40 %) of daphnids were immobilized, therefore the value of LC50 indicate a true toxicity of this chemical instead of a low pH effect, however at high concentrations a pH effect should be present. Then, the test is regarded as high reliability because no deviations from the OECD Test Guideline 202 occurred.

Description of key information

For daphnids, Daphnia magna, an acute toxicity of p-toluic acid was 48 h EC₅₀of 42 mg/L (MOE, 2003). A static test was conducted, twenty daphnids per test concentration were exposed at the concentrations of 3.0, 5.1, 8.7, 15 25, 43 and 72 mg/L nominal of the chemical together with a blank control group. The exposure concentrations were kept throughout the test period; the mean measured concentrations ofp-toluic acid(geometric mean) of each treatment were 2.9, 4.8, 8.3, 14, 24, 41 and 70 mg/L, respectively, and the measured concentrations showed at the start and end of test were ranged 94.6 - 97 % of nominal and 95.3 - 98.2 % of nominal, respectively.The exposure was conducted without pH adjustment however pH was decreased to 4.9 at the highest concentration of 70 mg/L due to the test substance property. At the lower concentrations of the chemical pH was not changed significantly from that of dilution water.At the control and up to 14 mg/L (mean measured concentration) no immobilization was observed for 48 hr. At the highest concentration of 70 mg/L all daphnids were immobilized. Based on mean measured concentration the 48 h EC50 of 42 mg/L was calculated by using the probit analysis. At the concentration 41 mg/L (pH was 6.9 - 7.6) 8 of 20 individuals (40 %) of daphnids were immobilized, therefore the value of LC50 indicate a true toxicity of this chemical instead of a low pH effect, however at high concentrations a pH effect should be present.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

42 mg/L

Additional information

Due to rapid hydrolysis of 895-85-2 (see van Dam, 2014), the aquatic results of p-toluic acid are considered most relevant.