Dibenzylbenzene, ar-methyl derivative

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study based on draft OSPAR protocol, GLP compliant

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

92

Principles of method if other than guideline:

Paris Commission (PARCOM) - Ring Test Protocol. A Sediment Bioassay Using an Amphipod Corophium sp (1993).

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The concentration of radioactivity in 4 subsamples (ca 0.1 g) of the sediment pre-mix was determined by combustion and liquid scintillation counting. The concentrations in the test vessels were calculated on a dry weight basis from the measured concentrations of radioactivity in the pre-mix and the weights of sediment used.

Details on sediment and application:

Sediment was collected from the same location as the Corophium and sieved to 500 µm using natural seawater.
A sediment pre-mix was prepared by adding 45.4 µg [14C]-DBT and ca 210 mg DBT, in acetone to ca 42 g of dry sediment. The acetone was removed under a stream of gaseous nitrogen. This prepared a nominal pre-mix concentration of ca 5000 mg [14C]-DBT.kg-1 sediment (oven dry basis).

Weighed amounts of wet sediment (ca 300 g in the range finding test, ca 900 g in the definitive test) were added to mixing containers, one at each concentration and a weighed amount of dry sediment pre-mix added to the centre of the sediment. Seawater
(100 ml.300 g-1 sediment) was added to each mixing container and the containers placed on a platform shaker at 150 rpm for ca 3 h. The mixed sediment from each container was then added to one test beaker (range finding test), or divided equally between 3 replicate test beakers (main test), per concentration and the sediment left to settle for ca 16 h. Alter the 16 h settling period, seawater was added to each beaker (ca 600 ml) to give a final volume of ça 850 ml and the contents allowed to settle for a further ca 24 h. Aeration was applied to the beakers for ca 24 h prior to the addition of Corophium.

The control sediment was prepared in the same manner as the test sediment. No sediment pre-mix was added to the wet sediment in the mixing container.

The concentration of [14C]-DBT in each test vessel was calculated from measurements of the concentration of total radioactivity in the sediment pre-mix.

Test organisms (species):

Corophium volutator

Details on test organisms:

Corophium volutator of length 5-8 mm were used for these studies, and were obtained from the Orkney Water Test Centre, Orkney on 16 January 1997. They were maintained in natural seawater collected from a site on the east coast of Scotland.

All Corophium were acclimatised to laboratory conditions for at least 5 days prior to commencement of the study. Only healthy, undamaged animais were used for the test.

Study type:

laboratory study

Test type:

static

Water media type:

saltwater

Type of sediment:

natural sediment

Limit test:

no

Duration:

10 d

Exposure phase:

total exposure duration

Test temperature:

15+/-1°C

pH:

8.0 +/- 0.1

Dissolved oxygen:

> 90%

Salinity:

34 %o

Nominal and measured concentrations:

Measured concentrations: see table below

Key result

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

119.3 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

45.1 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

Mortalities Recorded During the Definitive Test
(Sixty Animais per Concentration)


Time Measured Concentration of Test Material (mg.kg-1) -
0 11.2 23.0 45.1 89.0 179.5
10d 5* 3* 3+5* 3* 4+19* 6+37*
* = Not found in sediment

Validity criteria fulfilled:

not specified

Conclusions:

LC50-10d = 119.3 mg/kg dw, NOEC = 45.1 mg/kg dw

Executive summary:

Acute toxicity to Corophium volutator was carried out according to PARCOM ring test protocol (1993), sediment was spiked by 14C-dibenzyltoluene. Assessment of mortality after 10 days exposure was made and LC50 and NOEC derived.

Reference 2

Endpoint:

sediment toxicity: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study done according to ASTM standard, GLP compliant

Qualifier:

according to guideline

Guideline:

other: ASTM E1367-90, Standard Guide For Conducting 10 day Static Sediment Toxicity Tests with Marine and Estuarine Sediments.

GLP compliance:

yes

Remarks:

accredited by Norwegian Authority

Analytical monitoring:

no

Vehicle:

no

Details on sediment and application:

PREPARATION OF SPIKED SEDIMENT
- Sediment collected at an unpolluted site was used for preparing test sediments. The sediment is a muddy sand and was analysed for organic content and proportion silt for each test.
- 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 Ieft for a standstill for at least 2 hours. Then 300 ml of seawater was added to, and 10 animais were randomly selected for each beaker. A sample of the damp sediment was analysed for water content, and ail concentrations are calculated as mg kg-1 sediment dry weight.

Test organisms (species):

Corophium volutator

Details on test organisms:

Corophium volutator , from an unpolluted site in Bergen.
The test organisms were supplied as aduits (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

Water media type:

saltwater

Type of sediment:

natural sediment

Limit test:

no

Duration:

10 d

Exposure phase:

total exposure duration

Test temperature:

15 ± 1°C

pH:

From 8.1 (start) to 8.0 (end)

Dissolved oxygen:

From 93 (start) to 94 (end) % of saturation.

Salinity:

34 %o

Nominal and measured concentrations:

nominal

Details on test conditions:

The test was run in glass containers (600 ml) each containing 200 g of test sediment, app. 400 ml of seawater and 10 animais, 3 replicates for each concentration. The beakers were kept under continuous aeration at a temperature of 15 ± 1°C. pH and oxygen measurements were performed as indicated on the data sheet.

Reference substance (positive control):

yes

Remarks:

Fluoranthene

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

99.9 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 85.4 - 120

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

40.2 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The effect on the survival of Corophium volutator is expressed as the concentration of a product lethal to 50% of the test animais (LC50). The combined mortality per test concentration were used for caiculation. The 10 day LC50 value and the 95% confidence limit were calculated by using the standard PROBIT Analysis, National Swedish Environmental Protection Board (Version 2.3, 1990). This programme also calculate test concentrations lethal to 10% and 90% of the test animais.

Results with reference substance (positive control):

LC50-10d = 17.2 mg/kg dw

Validity criteria fulfilled:

yes

Remarks:

The validity criteria given in the test protocol are fulfilled, in that 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 foun

Conclusions:

LC50-10d = 99.9 mg/kg dw, NOEC = 40.2 mg/kg dw

Executive summary:

Acute toxicity to Corophium volutator was carried out according to ASTM standard, sediment was spiked by dibenzyltoluene. Assessment of mortality after 10 days exposure was made and LC50 and NOEC derived.

Description of key information

10-day acute toxicity reliable studies have been conducted on marine sediment reworker.

LC50s are about 110 mg/kg dw and NOECs about 42 mg/kg dw.

Key value for chemical safety assessment

EC50 or LC50 for marine water sediment:

110 mg/kg sediment dw

EC10, LC10 or NOEC for marine water sediment:

42 mg/kg sediment dw

Additional information

2 studies have been carried out on the marine sediment reworker Corophium volutator (mud shrimp), with exposure through sediment.

Both studies give very close results with resp.: LC50-10d = 99.9 mg/kg dw, NOEC = 40.2 mg/kg dw and LC50-10d = 119.3 mg/kg dw, NOEC = 45.1 mg/kg dw.

The average of the 2 studies results was retained to derive the PNEC sediment.

Nevertheless, from information available on production dry process and uses that are in closed systems, recovery of the used product for incineration, no exposure of sediment is expected.