Benzenesulfonic acid, mono-C11-13-branched alkyl derivs.

Short-term toxicity to fish

Description of key information

In a 96 h acute toxicity study, Bluegill (Lepomis macrochirus) were exposed to C11.8 LAS (linear alkylbenzene sulfonate, an anionic surfactant) under static conditions. Nominal concentrations were not specified in the report. Measured concentrations were 79 % of nominal concentrations.

The 96 h LC50 value, based on measured concentration, was 1.67 mg a.i./L, with 95% CL 1.58 to 1.77 mg/L.  This toxicity study is classified as acceptable and satisfies the guideline requirement for the current USEPA OPPTS 850.1075 (1996) acute fish toxicity study.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1.67 mg/L

Additional information

In the key study, a 96 h acute toxicity study, Bluegill (Lepomis macrochirus) were exposed to C11.8 LAS (linear alkylbenzene sulfonate, an anionic surfactant) under static conditions. Nominal concentrations were not specified in the report. Measured concentrations were 79 % of nominal concentrations. The 96 h LC50 value, based on measured concentration, was 1.67 mg a.i./L, with 95% CL 1.58 to 1.77 mg/L. This toxicity study is classified as acceptable and satisfies the guideline requirement for the current USEPA OPPTS 850.1075 (1996) acute fish toxicity study.

In the first supporting study, groups of 10 carp or rainbow trout fry were exposed to various concentrations of LAS or BABS Na salt for 15 days in a semi-static experiment. The TLm value for fish for LAS was 1-2 mg/L. The TLm value for fish for BABS Na salt was 4-6 mg/L. BABS Na salt is two to three times less toxic to fish than LAS supporting the use of LAS data as worst case read across for BAB Acid.

In the second supporting study, the TLm values of BABS Na salt were tested against 11 species of fish. Two replicates of 10 fish were exposed to various concentrations from 0 -20 mg/L BABS Na salt for 4 days. The TLm values ranged from 7.4 - 22 mg/L.

In the third supporting study, six concentrations of LAS were tested in a 4-day flow-through study. Analytical monitoring was performed 4 times daily. 2 replicates of 10 fish from 5 different species were tested. Results show that BABS Na salt is two to four times less toxic to fish than LAS.

In the fourth supporting study, eight samples of sewage water were collected, and the bacteria that made up the inoculum was determined. Two test substances, LAS and BABS Na salt were then added, and the biodegradation of the substances followed for 168 hrs. At the times 0, 16, 24, 40, 48, 72, and 168 hrs, samples from the biodegradation tests were taken, and these samples were used in 24 -hr zebra fish acute toxicity experiments. Results of the toxicity tests show that LAS is more toxic than BABS.

In the fifth supporting study, a flow-through study, fathead minnow eggs were exposed to six to seven concerntrations of either LAS or BABS Na salt for 9 days. Results show that LAS is two to three times more toxic than BABS.

In the sixth supporting study, rainbow trout were exposed to various concentrations BABS Na salt for a period of 5 days. After exposure, some of the fish were sacrificed, and various blood parameters measured. Results show that the 96 -hr LC50 for fish was 2.58 mg/L, with death due to gill destruction.

Based on the data for linear and branched alkylbenzene sulfonates, linear structures are more toxic than branched structures. Therefore, data on linear materials, e.g., the chronic aquatic studies using LAS, are considered to be a worst case scenario.