Benzyltoluene

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From the 10th to the 20th September, 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The documentation is too limited for a full quality assessment of the study.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

ASTM E1367 (10-day Static Sediment Toxicity Test (Media: Sediment-marine))

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

PHYSICO-CHEMICAL PROPERTIES (according to the SDS)
- Vapour pressure: 0.34 Pa at 20°C

Analytical monitoring:

no

Remarks:

Analytical monitoring is not required by ASTM 1367 standard.

Vehicle:

yes

Details on sediment and application:

Natural seawater was used for dilution water. The sediment was a muddy sand and was analysed for organic content and proportion silt for each test.
The test substance has low solubility in water. Each concentration was prepared by dissolving the product in 20 ml of acetone, this solution was added to 100 g pre-dried sediment. After the acetone had dried off in a fume hood, the sample was added to 500 g of damp sediment in a plastic bucket. 350 ml of sea-water was added, and the bucket was shaken for 3 hours. The sediment was then divided into three beakers and left for a standstill for at least 2 hours. Then 300 ml of seawater was added to, and 10 animals were randomly selected for each beaker.
A sample of the damp sediment was analysed for water content, and all concentrations are calculated as mg kg-1 sediment dry weight.
Characteristics of the sediment used for testing:
- Organic content: 1.94%
- Silt fraction: 1.17%

Test organisms (species):

Corophium volutator

Details on test organisms:

The test organisms were supplied as adults (4-8 mm in size) and were held in aerated seawater at 15°C. A small amount of natural seaweed was used for feeding.

Study type:

laboratory study

Test type:

static

Type of sediment:

natural sediment

Limit test:

no

Duration:

10 d

Exposure phase:

total exposure duration

Post exposure observation period:

None reported

Hardness:

No data

Test temperature:

15 +/- 1°C

pH:

Initial measured constant pH was 8.1; final measured pH ranged from 7.9 to 8.0

Dissolved oxygen:

Initial measured dissolved oxygen ranged from 86 to 93%; final measured dissolved oxygen ranged from 92 to 97%

Salinity:

The salinity of the seawater used was 3.4%.

Ammonia:

No data

Nominal and measured concentrations:

Tested concentrations were 0, 129, 232, 403, 730 and 1254 mg/kg dry weight (nominal).

Details on test conditions:

The test was run in glass containers (600 ml) each containing 200 g of test sediment, approximately 400 ml of seawater and 10 animals, 3 replicates for each concentration. The beakers were kept under continuous aeration at a temperature of 15 ± 1°C.

Reference substance (positive control):

yes

Remarks:

fluoranthene

Key result

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

331 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 229 - 379 mg/kg sediment dw

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

129 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

10 d

Dose descriptor:

LC10

Effect conc.:

194 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 149 - 229 mg/kg sediment dw

Details on results:

- Mortality of test animals at end of exposure period: 1/51 specimen was dead

Results with reference substance (positive control):

- Results with reference substance valid? no data
- Relevant effect levels: LC50 = 17.2 mg/kg sediment dw (13.4 - 20.7)
- Other:
LC 10 = 8.41 mg/kg sediment dw (4.7 - 11.3)
LC 90 = 35.3 mg/kg sediment dw (28.8 - 49.5)

Reported statistics and error estimates:

The 10 day LC values and the 95% confidence limits were calculated by using the standard PROBIT Analysis, National Swedish Environmental Protection Board (Version 2.3, 1990).
NOEC are calculated by using the computer programme InStat 2.01.

Table 1: Marine amphipod mortality rate in the 10-day study

Tested Concentration [mg/kg sediment dry weight]	Mortality rate throughout the 10-d study period (Number of individuals)
Control	1/51
129	0/30
232	7/30
403	20/30
730	29/30
1254	30/30

Validity criteria fulfilled:

yes

Remarks:

the dissolved oxygen concentration at the end of the test was greater than or equal to 60 %, and the percentage mortality in the controls were less than 15%. The sediment used is found to be within accepted limits for organic content and silt fraction.

Conclusions:

LC50 and NOEC values of Jarylec C100 after a 10-day exposure of test substance on marine amphipod, Corophium volutator, were found to be 331 and 129 mg/kg sediment dw, respectively.

Executive summary:

The toxicity of the test item on marine amphipod, Corophium volutator (mud shrimp) was assessed according toASTM E1367-90, Standard Guide For Conducting 10 day Static Sediment Toxicity Tests with Marine and Estuarine Sediments.

The test was performed with 10 specimen per vessel in seawater, exposed at the nominal following concentrations: 0, 129, 232, 403, 730 and 1254 mg/kg dry weight, following dissolution of the test substance in acetone. The test concentrations of the test item were not analytically monitored.

LC50 and NOEC values of the test item after a 10-day exposure were found to be 331 and 129 mg/kg sediment dw, respectively.

The method was applied with respect to its quality criteria :

The dissolved oxygen concentration at the end of the test was greater than or equal to 60 %.

The percentage mortality in the controls were less than 15%.

The sediment used is found to be within accepted limits for organic content and silt fraction.

Description of key information

The toxicity of the test item on Corophium volutator was assessed according to ASTM E1367-90.Th

e test was performed with 10 specimen per vessel in seawater, exposed at the nominal following concentrations: 0, 129, 232, 403, 730 and 1254 mg/kg dry weight, following dissolution of the test substance in acetone. The test concentrations of the test item were not analytically monitored.

LC50 of the test item after a 10-day exposure was 331 mg/kg sediment dw.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:

331 mg/kg sediment dw