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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other:
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Title:
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 3. Sublethal effects on soil invertebrates.
Author:
Holmstrup, M. and Krogh, P.H.
Year:
2001
Bibliographic source:
Environmental Toxicology and Chemistry 20:1673-1679

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: Draft ISO/WD 16387 protocol
Qualifier:
according to
Guideline:
ISO 11268-2 (Effects of Pollutants on Earthworms. 2. Determination of Effects on Reproduction)
Deviations:
yes
Remarks:
limited cocoons Comparable to ISO 11268-2, but with only weight measurement
Principles of method if other than guideline:
Adult E. albidus (10) were placed in soil containing the test substance for 21 days. The adults were removed, and the cocoons incubated in the soil for another 21 days. The juveniles were then counted.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
C10-13 LAS was obtained as an aqueous sodium salt solution with an active matter concentration of 16.1% (w/w), average molecular weight = 342 g/mol, distribution of the linear alkyl chains: C10 14%, C11 34%, C12 31%, and C13 21%; average alkyl chain length = C11.6

Sampling and analysis

Analytical monitoring:
not specified

Test substrate

Vehicle:
not specified
Details on preparation and application of test substrate:
Earthworm tests: For the reproduction tests, 1 kg dry weight of soil was carefully mixed with 160 mL of LAS solution using an electric mixer and filled into plastic pots. For the growth test with juvenile A. caliginosa, 60 g dry weight of soil were mixed with 9.6 mL of LAS solution with a spatula and filled into 160-mL polyethylene beakers with perforated lids for ventilation.
Enchytraeid test: Forty grams dry weight of soil were mixed with 6.4 mL of LAS solution and filled into 160-mL beakers with perforated lids for ventilation.

Test organisms

Test organisms (species):
other: Enchytraeus albidus, Aporrectodea caliginosa, Aporrectodea longa
Animal group:
annelids
Details on test organisms:
For the growth test with juvenile A. caliginosa (2-3 weeks old),

Study design

Study type:
other: no data
Substrate type:
other: Sandy, agricultural soil
Limit test:
no
Post exposure observation period:
21 days (28 days for A. caliginosa and A. longa growth tests)

Test conditions

Details on test conditions:
Earthworm tests: The six treatments consisted of one control and five concentrations of LAS and these treatments were randomly assigned to the experimental units. After 24-hour equilibration of the test soil, 3 (rather than 10) earthworms were added to closed containers with perforated lids for ventilation. Approximately 5 g per worm were added after the test animals had been introduced. The containers were then incubated for 21 days in darkness and the contents were later wet sieved through a 1-mm mesh. Water content was adjusted after 14 days. For the growth test with juvenile, six treatments consisted of one control and five concentrations of LAS and these treatments were randomly assigned to the experimental units. After 24-hour equilibration of the test soil, one earthworm was added to each container. The beakers were incubated for 28 days in darkness and then the earthworms were recovered and their guts were cleared. The surviving animals were dried for 24 hours and their dry weight was recorded to the nearest 0.1 mg. The examination of the effects on growth of A. longa used the same method except the test period was 42 days.
Enchytraeid: After 24-hour equilibration of the test soil, 10 adult E. albidus were added to each container and incubated in darkness for 21 days. After incubation, the surviving adult animals were removed from the soil. Now only containing cocoons, the soil was incubated in the beakers for another 21 days to allow development and hatching of the juveniles. After this period, the soil containing juveniles was stained with Bengal red, and water was added to facilitate counting of the juveniles.
Nominal and measured concentrations:
Enchytraeid: The test concentrations were not provided but can be estimated from Figure 5 to be 0, 20, 40, 80, 200 and 400 mg/kg with the numbers of adults surviving per replicate to be approximately 10, 10, 10, 10, 9, and 6, and the numbers of juveniles per replicate (reproduction) to be approximately 77, 50, 37, 21, 0, and 0, respectively.
Reference substance (positive control):
not specified

Results and discussion

Effect concentrations
Key result
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
6.2 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: E. albidus
Details on results:
. It should be noted that these studies report worst case exposures due to the use of a sandy test soil and the fact that LAS was added as an aqueous solution to the soil. In addition, too few replicates were used for the ECx approach (e.g., <5 controls) and several key deviations from draft protocols limited the reliability of endpoints for some studies (e.g., A. caliginosa and A. longa cocoon production). Nominal concentrations were derived from tables and figures since actual values were not found in the text.

Any other information on results incl. tables

The following table shows the results of all tests.  All values are nominal LAS concentrations in mg/kg dry weight.

Species

Parameter

NOEC

LOEC

LC10 or EC10

LC50 or EC50

Relia-bility Rating

Rationale for Reliability Rating

Enchytraeus albidus

Survival, adults

Reproduction

198

20

397

40

194

6

430

41

1

1

Draft ISO/WD 16387 protocol

Aporrectodea caliginosa

Survival, adults

Cocoon production

Survival, juveniles

Growth, juveniles

278

>793

>397

278

793

>793

>397

397

329

14

>397

105

535

129

>397

354

2

3

2

2

Comparable to

ISO 11268-2

Deviations; limited cocoons

Comparable to ISO 11268-2, but with only weight measurement

Aporrectodea longa

Survival, adults

Cocoon production

Survival, juveniles

Growth, juveniles

278

>793

397

79

793

>793

793

278

329

27

296

84

535

137

517

349

2

3

2

2

Comparable to

 ISO 11268-2

Deviations; limited cocoons

Comparable to ISO 11268-2, but with only weight measurement

Folsomia fimetaria

Survival, adults

Reproduction

>793

278

>793

278

>793

85

>793

424

1

1

Comparable to  ISO 11267

Hypogastrura assimilis

Reproduction

79

278

99

421

1

Comparable to  ISO 11267

Hypoaspis aculeifer

Survival, adults

Reproduction

>793

278

>793

793

>793

82

>793

236

2

2

No guideline available

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 21-day EC10 to E. albidus was 6.2 mg/kg dry weight.
Executive summary:

Adult E. albidus (10) were placed in soil containing the test substance for 21 days. The adults were removed, and the cocoons incubated in the soil for another 21 days. The juveniles were then counted. The 21-day EC10 to E. albidus was 6.2 mg/kg dry weight.