Benzenesulfonic acid, 4-C15-16-sec-alkyl derivs.

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

see read-across document

Reason / purpose for cross-reference:

read-across source

Analytical monitoring:

yes

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

>= 105 mg/kg sediment dw

Basis for effect:

biomass

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

81 mg/kg sediment dw

Basis for effect:

biomass

Details on results:

LAS half-life in aerobic sediment was approximately 20 days. This is shorter than studies conducted in the same sediment without worms (half-life of 38 days), most likely due to increased bioturbation due to worm activity.

There was a loss of between 15 and 78% of the LAS radioactivity over the duration of the test, which was attributed to mineralization of LAS by the worms and microorganisms present in the sediment (biodegradation).  Results are therefore based on the average of day 0 and day 28 measured sediment concentrations.  All results are shown in the following table.

                                    

	Sediment Concentration (mg/kg dw)
Survival/Reproduction Endpoint	NOEC	LOEC	EC20	EC50
Based on nominal values	100	150	90	136
Based on measured day 0 values	136	170	131	164
Based on mean of days 0 & 28 values	81	110	73	105
Biomass Endpoint
Based on nominal values	100	150	108	144
Based on measured day 0 values	136	170	146	166
Based on mean of days 0 & 28 values	82	110	102	109

Validity criteria fulfilled:

yes

Conclusions:

The 28-day EC50 is >= 105 mg/kg sediment dw.

Executive summary:

This study determined the toxicity to sediment dwelling organisms. Samples of natural sediment were spiked with test substance at concentrations of 50, 75, 100, 150, 300, and 600 mg/kg/dry weight. 10 test organisms of species Lumbriculus variegatus were then added. Exposure lasted 28 days, at which time the organisms were observed for survival and biomass. The test substance half-life in aerobic sediment was approximately 20 days. The EC50 was >= 105 mg/kg sediment dw.

Reference 2

Endpoint:

sediment toxicity: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

see read-across document

Reason / purpose for cross-reference:

read-across source

Analytical monitoring:

yes

Key result

Duration:

3 d

Dose descriptor:

other: EC10

Effect conc.:

275 mg/kg sediment dw

Basis for effect:

growth rate

Key result

Duration:

3 d

Dose descriptor:

NOEC

Effect conc.:

200 mg/kg sediment dw

Basis for effect:

growth rate

Details on results:

The test was regarded as valid as the fertility of the test organisms in the control was ¿ 80%.

	Nominal Sediment Concentration (mg/kg dw)
Test Parameter	NOEC	LOEC	EC10	EC30
Growth	200	300	275
Fertility	200	300		258
Egg Production	100	200		125

Validity criteria fulfilled:

yes

Conclusions:

The 3-day EC10 was 275 mg/kg sediment dw based on growth rate.

Executive summary:

This study determined the toxicity to sediment dwelling organisms. Samples of natural sediment were spiked with concentrations of 10, 50, 100, 200, 300, 400, 500, 750 and 1000 and controls. 10 test organisms of species Caenorhabditis elegans were then added. Exposure lasted 3 days, at which time the organisms were observed for survival and reproduction. The EC10 was 275 mg/kg sediment dw based on growth rate.

Reference 3

Endpoint:

sediment toxicity: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Followed guideline with minor deviation, well documented, non GLP.

Justification for type of information:

see read-across document

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test a (no sediment present)

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

4.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test a (w/sediment). Estimated from graph.

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test b (no sediment present)

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test b (w/sediment: sand-silt)

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test b (w/sediment: sand)

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: test b (w/sediment: silt)

Key result

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

319 mg/kg sediment dw

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: sediment spiked with LAS

Key result

Duration:

24 d

Dose descriptor:

LOEC

Effect conc.:

993 mg/kg sediment dw

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Remarks on result:

other: Sediment spiked with LAS

Key result

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

> 1 - < 4.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: survival of newly hatched larvae

Details on results:

- Mortality of test animals at end of exposure period: In the egg hatchability assay, at the lowest exposure level 1.5 % mortality was observed. At 4.7 mg/L and above, 100% mortality was observed. For details see Table 1 under "Any other information on results incl. tables"
- Total mass of test animals at beginning of test: Not reported
- Changes in body weights of live adults: Not reported
- No. of offspring produced: Not reported
- No. of emerged male and female midges (per vessel and per day): Not reported
- No. of pupae failing to emerge (per vessel and per day): Not reported
- Percent emergence per test concentration: See Tables 2,3,4 under "Any other information on results incl. tables"
- Mean development rate of fully emerged midges: Not reported
- Mean individual dry weight of larvae: Not reported
- Morphological abnormalities: Not reported
- Behavioural abnormalities: Not reported

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Chi-square analyses used for significant differences among treatments and variance homogeneity were applied to numbers of larvae and unhatched egg - Probit analysis used to calculate EC50 values for each data set in chronic assay

Table 1. Effects of LAS upon Chironomus egg hatching success and survival of newly hatched larvae

Average measured concentration (mg/L)	Egg hatching success (%)	Survival (%)
0.0	100	91
1.0	100	88.5
4.7	100	0^a
9.4	100	0^a
18.9	100	0^a

a Significantly  different from control value (p < 0.05)

72 hr (acute) test.

Table 2. Chronic toxicity of LAS to Chironomus: Effect of sediment

Details of this experiment are in a graph in the publication.

Table 3. Chronic toxicity of LAS to Chironomus: Effect of substrate

Overlying water concentration (mg/L; nominal)	Emergence of winged adults (%)
	No substrate	Sand	Sand-silt	Silt
0	80	100	100	100
1.5	80	100	100	85
3	75	95	100	85
6	40^a	95	75^a	75
12	5^a	0^a	20^a	0^a

a Significantly different(p< 0.05) from respective control value

Table 4. Partitioning and chronic effects of LAS to Chironomus: Sediment-spiked experiment

Surfactant sediment Concentrations (ppm; mean ± SE)	Interstitial water (lW)	overlying water (OW)	% Emergence
993±225	15.2 ± 2.7	1.69±0.12	73^a
319 ± 23	15.0 ± 1.4	1.05 ± 0.Q7	90
146 ± 18	7.7±1.1	0.59 ± 0.05	90
42 ± 5	1.5 ± 0.3	0.35 ± 0.01	90
8 ± 2	0.2 ± 0.0	0.32 ± 0.01	95
0(control)	0	0	98

a Significantly different(p< 0.05) from control value

Validity criteria fulfilled:

yes

Conclusions:

The effect of C12 LAS (linear alkylbenzene sulfonate) on midge was evaluated in acute and chronic tests. The 24-day chronic NOEC was 2.4 mg/L, based on emergence. The 72-hour acute LC50 was between 1.0 and 4.7 mg a.i./L, based on survival of newly hatched larvae.

Executive summary:

A sediment toxicity test of LAS (linear alkylbenzene sulfonate) was conducted following the OECD 218 guideline, using the midge Chironomus riparius.  All results are based on the measured concentration of the test substance. The LAS had an average alkyl chainlength of 11.9, and was comprised of C10 -C14 alkyl chains.

In an egg hatchability semi-static assay (acute test), midge eggs were exposed to a range of LAS concentrations in water and were monitored for hatching success and posthatch survival. No significant reduction in egg hatching was observed at the highest concentration tested (18.9 mg/L). However, significant reduction in the survival of the newly hatched larvae occurred at 4.7 mg/L. The 72h LC50 was between 1.0 and 4.7 mg/L, based on survival of newly hatched larvae.

In the partial life cycle bioassay in a flow-through sediment/water test system (chronic test), percentages of winged adults emerging after continuous exposure of larvae and pupae to a range of LAS concentrations were determined. Exposure concentrations in sediment, interstitial water and overlying water were monitored by 14C liquid scintillation counting. The effect of LAS level in the water column was determined in a total of 6 chronic toxicity tests. The NOECs from these tests were 2.4 -3.0 (without sediment), and 3.0 -6.0 (with sediment). The effect of LAS on Chironomus was also evaluated in an experiment using sediment spiked with LAS. In this test, the NOEC of sediment-spiked LAS was 319 mg/kg sediment (dry weight basis). The normalized NOEC is 2.87 mg/L for C11.6 LAS (van de Plassche et al., 1999).

Description of key information

Three sediment toxicity studies are available using LAS (read across).

Studies were conducted with Lumbriculus variegatus, Caenorhabditis elegans and Chironomus ripariu. The NOECs from the studies ranged from 81 mg/kg sediment (dry weight basis) to 319 mg/kg sediment (dry weight basis).

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

81 mg/kg sediment dw

Additional information

Three sediment toxicity studies are available using LAS (read across). The first study (Comber et al. 2006) determined the toxicity to sediment dwelling worms. Samples of natural sediment were spiked with test substance at concentrations of 50, 75, 100, 150, 300, and 600 mg/kg/dry weight. Ten test organisms of species Lumbriculus variegatus were then added. Exposure lasted 28 days, at which time the organisms were observed for survival and biomass. The test substance half-life in aerobic sediment was approximately 20 days. The EC50 was ≥ 105 mg/kg sediment dry weight. The NOEC was 81 mg/kg sediment dry weight. The second study (Comber et al. 2006) consisted of samples of natural sediment spiked with concentrations of 10, 50, 100, 200, 300, 400, 500, 750 and 1000 mg/kg dw mg/kg dw and controls. Ten test organisms of the nematode species Caenorhabditis elegans were then added. Exposure lasted 3 days, at which time the organisms were observed for survival and reproduction. The NOEC for egg production was 100 mg/kg sediment dw, the NOEC for fertility was 200 mg/kg sediment dw and the EC10 for growth was 275 mg/kg sediment dw. In the final toxicity study (Pittinger et al. 1989; The Procter & Gamble Company 1986; van de Plassche et al 1999), which was conducted following the OECD 218 guideline, the midge Chironomus ripariu, was exposed to C11.9 LAS for 24 days. This actually consisted of a series of separate tests. In an egg hatchability semi-static assay (acute test), midge eggs were exposed to a range of LAS concentrations in water and were monitored for hatching success and posthatch survival. No significant reduction in egg hatching was observed at the highest concentration tested (18.9 mg/L). However, significant reduction in the survival of the newly hatched larvae occurred at 4.7 mg/L. The 72 hour LC50 was between 1.0 and 4.7 mg/L, based on survival of newly hatched larvae. In the partial life cycle bioassay in a flow-through sediment/water test system (chronic test), percentages of winged adults emerging after continuous exposure of larvae and pupae to a range of LAS concentrations were determined. Exposure concentrations in sediment, interstitial water and overlying water were monitored by 14C liquid scintillation counting. The effect of LAS level in the water column was determined in a total of six chronic toxicity tests. The NOECs from these tests ranged from 2.4 to 3.0 (without sediment), and 3.0 to 6.0 (with sediment). The effect of LAS on Chironomus was also evaluated in an experiment using sediment spiked with LAS. In this test, the NOEC of sediment-spiked LAS was 319 mg/kg sediment (dry weight basis). The normalized NOEC is 2.87 mg/L for C11.6 LAS.