LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Reliability: 2 Valid with restrictions. Non-standard length of study, therefore not
included in SIAR Table 12A.
(s)
Type of Test: Static [X]; semi-static [ ]; flow-through [ ]
Open-system [X]; closed-system [ ]; not stated [ ]
Species: Microcystis aeruginosa (algae)
Exposure Period: 96 hours
Effect Criteria: Growth rate
Results: EC50 = 0.9 mg/L
Analytic Monitoring: Yes [ ]; No [X]; ? [ ]
Method: The test species was cultured following the procedures of USEPA 1971.
Temperature was maintained at 24 ± 2°C. Water chemistry was
determined at least once during each test according to Standard
Methods (APHA 1985). EC50 values were calculated using the method of
Larson and Schaeffer (1982) or graphical interpolation.
GLP: Yes [ ]; No [X]; ? [ ]
Test Substance: C12 LAS; average molecular weight = 345
Remarks: Mean hardness was 137 mg/L as CaCO3, pH range was 6.8-7.2, and the mean
dissolved oxygen was 9.1 mg/L. Comparison was also made to in situ
studies conducted in which lake water was bottled and suspended in Lake
Acton (Ohio) for 3 hour periods. The mean 3-h EC50 (photosynthesis) for the
in situ studies was 3.4 mg/L (0.5-8.0 mg/L). The NOEC normalized by van
de Plassche et al. (1999) to C11.6 LAS was 0.35 mg/L. Using the acute to
chronic ratio calculation (documented in Annex 3 of the LAS SIAR), the
EC50/3 for Microcystis is 0.3 mg/L. This is a critical study for this SIDS
endpoint.
Reference: Lewis, M.A. and Hamm, B.G. 1986. Environmental modifications of the
photosynthetic response of Lake Plankton to surfactants and significance to a
laboratory-field comparison. Wat. Res. 20:1575-1582.
Reliability: 2 Valid with restrictions
(t)
Type of Test: Static [ ]; semi-static [ ]; flow-through [ ]
Open-system [ ]; closed-system [ ]; not stated [X]
Species: Plectonema boryanum (algae); strain 597
Exposure Period: not stated
Effect Criteria: Growth rate
Results: NOEC = 20 mg/L
LOEC = 30 mg/L
Analytic Monitoring: Yes [ ]; No [ ]; ? [X]
Method: LAS concentrations of 1, 5, 10, 15, 20 and 30 mg/L were prepared in
Deionized, sterilized double-distilled glass water. Algae were grown
in Bold’s medium.
GLP: Yes [ ]; No [X]; ? [ ]
Test Substance: C11.2 LAS
Remarks: Growth rate was reduced at 30 mg/L concentrations of LAS as indicated by
spectrophotometer readings and dry weight. The NOEC normalized by van
de Plassche et al. (1999) to C11.6 LAS was 15 mg/L.
Reference: Dhaliwal, A.S., Campione, A., and Smaga, S. 1977. Effect of linear
alkylbenzene sulfonate (C11.2 LAS) on the morphology and physiology of
Plectonema boryanum and Chlamydomonas reinhardi. J. Phycol. 12:18.
Reliability: 4 Not assignable This study was given a reliability score of 4 because the
document reviewed was an abstract. However, these data were considered
reliable as part of a weight-of-evidence approach in the analysis conducted
by van de Plaasche et al. (1999).
UNEP PUBLICATIONS 197