LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
LOEC = 1.0 mg/L
Analytic Monitoring: Yes [ ]; No [ ]; ? [X]
Method: ASTM. 1984. Standard Practice for Conducting Toxicity Tests with
Microalgae, Draft #7, Philadelphia, PA. Algae were exposed to the test
material for four days, after which cell counts were made. The EC50 value
was calculated using the method of Larson and Schaefer. Assumed 1 x 10 4
cells/mL because ASTM protocol, but not reported.
GLP: Yes [ ]; No [X]; ? [ ]
Test Substance: C11.8 LAS; MW = 345; technical grade LAS from P&G
Remarks: The first significant effect concentrations were
between 0.5 and 1.0 mg/L. Mean test temperature was 23.6 (21.2-25.6 °C).
Total mean water hardness was 137 mg/L as CaCO3. The pH range was 6.8
to 7.2. Mean dissolved oxygen was 9.1 mg/L. Results of the laboratory
studies were compared with enclosure studies conducted with natural
phytoplankton assemblages. Concentrations in the enclosures that first
altered community structure were found to be between 27 and 108 mg/L.
The EC50 value reported represents the lowest acute value for algal species
for which a report or publication was available. This is a key study for
aquatic toxicity to algae (see SIAR Tables 10 and 12).
Reference: 1) Lewis, M.A. 1986. Comparison of effects of surfactants on freshwater
phytoplankton communities in experimental enclosures and on algal
population growth in the laboratory. Environ. Toxicol. Chem. 5:319-332.
2) Lewis, M.A. and Hamm, B.G. 1986. Environmental modification 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
(b)
Species: Selenastrum capricornutum and Scenedesmus subspicatus
Endpoint: Biomass [ ]; Growth rate [X ]; Other [ ]
Results: ErC50 values ranged from 29 to 35.5 for S. capricornutum (two records)
ErC50 values ranged from 82 to 163 mg/L for S. subspicatus (three records)
Test Substance: C10-13 LAS (CAS #68411-30-3)
Remarks: A total of 13 algae studies originally were reviewed by HERA in 2004. Eight
of these studies were rejected because
the test material was not commercial LAS, the study deviated
significantly from standard protocols, or non-standard endpoints were
measured. The remaining five studies were evaluated for reliability and
the results reflect the range of acute ErC50 values obtained for the two
most commonly tested algal species. These studies are tabulated and
discussed further in the SIAR and SIAP in a weight-of-evidence
approach. A robust summary for the study with the lowest acute ErC50
value was prepared (see Lewis 1986 above).
Reference: HERA-LAS team, May 2004; see SIAR Annex 2.
Reliability: 4 Not assignable. This study is given a reliability score of 4 because it is
a summary evaluation of a series of studies conducted by other
researchers.
(c)
Species: Chlamydomonas reinhardi, Chlorella kessleri, Microcystis sp., Plectonema
boryanum, Scendesmus subspicatus, Selenastrum sp. (algae)
Results: NOEC (C. reinhardi) = 12 mg/L (1 record)
NOEC (C. kessleri) = 3.5 mg/L (1 record)
NOEC (Microcystis sp.) = 0.80 mg/L (4 records)
NOEC (P. boryanum) = 15 mg/L (1 record)
NOEC (S. subspicatus) = 7.7 mg/L (4 records)
UNEP PUBLICATIONS 188