A limitation of the Microtox{reg_sign} test for toxicity measurements of nonionic surfactants

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1897/1551-5028(1996)015<1034:SCALOT>2.3.CO;2· OSTI ID:268008

Sherrard, K B; Marriott, P J; McCormick, M J ^[1]; Millington, K ^[2]

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1. Royal Melbourne Inst. of Tech. (Australia). Dept. of Applied Chemistry
2. CSIRO, Belmont (Australia). Div. of Wool Technology

Qualitative and quantitative analysis of the components of wastewaters is a necessary step towards determining the nature of aqueous effluents. However, toxicity levels of the effluents and receiving waters should also be determined to obtain a more comprehensive understanding of the effects the discharges may have on aquatic environments. The Microtox{reg_sign} test was successfully used to measure EC50 values of nonionic polyethoxylate surfactants. However, toxicity measurements of real samples that contain surfactants above a particular concentration, termed the critical toxicity concentration (CTC) are not valid. These samples require dilution before the test is performed, and because the relationship between toxicity and concentration is not linear above the CTC, the EC50 cannot be extrapolated back to give the toxicity of the original concentrated sample and a true estimation of toxicity is therefore not possible. This phenomenon may be related to the minimum surface tension requirement of the bacteria or other physical properties of the surfactant such as the tendency to assemble at interfaces and surfaces and the tendency to form micelles.

• Sponsoring Organization: USDOE
• OSTI ID: 268008
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 7 Vol. 15; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOASSAY
BIOLOGICAL INDICATORS
CHEMICAL EFFLUENTS
PHOTOSYNTHETIC BACTERIA
SENSITIVITY
SURFACTANTS
WASTE WATER
WATER POLLUTION