Assessing the aquatic hazard of some branched and linear nonionic surfactants by biodegradation and toxicity

Abstract

An aquatic hazard assessment was conducted for branched and linear nonionic surfactants using toxicity and biodegradation measurements. Four nonionic alcohol ethoxylate surfactants with different degrees of branching (ranging from 0.1, essentially linear, to 4.0 internal methyl groups per hydrophobe) were evaluated for neat surfactant toxicity, degradation in laboratory sewage treatment units, and aquatic toxicity of treated effluents. Acute testing with neat surfactants showed ranges for EC50s of 1.3 to 11.6 mg/L for Daphnia, 1.6 to 6.1 mg/L for Pimephales promelas (fathead minnow), and 1.5 to 11.4 mg/L for Microtox®. Chronic testing of algae showed NOECs of 1 to 10 mg/L and maximum acceptable toxicant concentrations (MATCs) of 0.8 to 14.2 mg/L. Seven‐day chronic estimation tests showed MATCs of 0.6 to 41.4 mg/L for Pimephales promelas and 1 to 14 mg/L for Daphnia. Effluents collected from treatment units receiving a 50‐mg/L surfactant feed at 25°C showed no acute toxicity to either Daphnia or fathead minnows, with the exception of a unit containing nonylphenol ethoxylate. Chronic effluent toxicity was greatest in effluent from the nonyl‐phenol ethoxylate unit and least in the effluent from the linear alcohol ethoxylate unit. Chronic toxicity of the highly branched C13 alcohol ethoxylate effluent was greater than that for the linear alcohol ethoxylate unit effluent.

Toxicity of nonionic surfactants

“…Helenius and Simons [16] and Dorn et al [17] indicated that the Triton surfactants can solubilise the lipid bilayer membrane by integration into the cell membrane while the Tween series can also be incorporated into bacterial membranes these products are ineffective in solubilising membrane lipids. Liwarska-Bizukojc et al [3] also indicated that non-ionic surfactants were more toxic than the anionic surfactants to three aquatic organisms: gastropod Physa acuta, crustacean Artemia salina and alga Rapidocelis subcapitata.…”

Effects of a nonionic surfactant (C14–15AE‐7) on aquatic invertebrates in outdoor stream mesocosms

“…In retrospect, it is, perhaps, not very surprising in light of the known sensitivity of fish species to surfactants. Fish and invertebrates are affected by surfactants through disruption of respiratory processes at the gill membrane [2,4]. Because Simuliidae have a highly branched pair of thoracic gills [14], we suggest that, in a similar manner, the gill membranes of simuliid larvae are probably disrupted by surfactants.…”

“…Large volumes of surfactants are produced annually, with over 15.2 million metric tons of surfactants used worldwide in 1987 [1,2]. These compounds constitute a large portion of a variety of cleaning products, including detergents, personal care products, and household cleaning agents [3].…”

Endocrine disruptors in the environment (IUPAC Technical Report)

“…Owing to the widespread use of APEs as detergents and their water dispersal properties, discharge to the environment-to the compartment water-occurs mainly from industrial effluents, STPs, and septic tanks [169][170][171]. Depending on legal regulations, usage, or voluntary bans, and agreements with industry in Europe, the main sources may be different in different countries.…”