Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

RA_CAS 61789-86-4_OECD209: EC50(3h) > 10000 mg/L, NOAEC(3h): 10000 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:
10 000 mg/L
EC10 or NOEC for microorganisms:
10 000 mg/L

Additional information

Information referring to the toxicity of Benzenesulfonic acid, mono-C20-24 (even)-sec-alkyl derivs., para-, sodium salts (generic name: C20 -24 sodium sulfonate) to microorganisms is not available. However, a study has been conducted to assess the potential environmental impact and waste control for calcium-sulfonate read-across substance (CAS 61789-86-4), whereby the testing procedure was in accordance to OECD Guideline 209 (Goodrich, 1994). The testing strategy incorporates the potential effect of new materials on aerobic microorganisms associated with the biological treatment of wastewater. The assessment was based on the potential of a material to inhibit the metabolism of these microbes, as indicated by the microbes consumption of oxygen. This test methodology is not definitive but rather a screening mechanism for the rapid assessment of a material's potential impact. As a screening tool, the assessment of the inhibitory effect on the oxygen consumption of microorganisms within a microbe population not previously exposed to industrial wastes represents a "worst case" scenario. The test duration was a three-hour exposure period to the test material followed by up to ten minutes for the measurement of oxygen consumption. The study design comprised five nominal exposure concentrations: 1, 10, 100, 1000 and 10000 mg/L, a duplicate control group; and an assessment of the sensitivity of the inoculum used in the test to a reference toxicant (3,5- dichlorophenol). The activated sludge respiration test passed the quality control criteria for an acceptable test. The EC50 calculated for the reference toxicant was 13.0 mg/L, within the acceptable range of 5 to 30 mg/L. The two control replicates produced oxygen consumption rates within the required 15 % of each other, 27 and 29 mg O2/L x h. The respiration rates of the sludge-associated microbes exposed to the five nominal concentrations of the test substance were 24.0, 24.6, 25.3, 26.7, and 28.1 mg O2/L x h. respectively. The calculated No Observed Adverse Effect Concentration (NOAEC) for 3 hours based on inhibition compared to the control was calculated to be equal to 10000 mg/L. The EC50 (3h)was > 10000 mg/L.