Detergenty pochodzące ze ścieków w środowisku przyrodniczym

Jedną z największych grup substancji syntetycznych wprowadzanych do środowiska przyrodniczego stanowią substancje powierzchniowo czynne. Największe ilości detergentów znajdują się w wodach powierzchniowych i w glebach. Syntetyczne środki powierzchniowo czynne trafiają do środowiska przede wszystkim wraz ze ściekami i osadami ściekowymi.

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One of the biggest group of anthropogenic synthetic substances in the environment are surfactants. Sewage treatment plants do not ensure the ultimate biodegradation of surfactants. Incomplete, primary degradation products are not well known yet, and can be far by more toxic than precursors. In consequence of incomplete degradation and sorption, considerable amount of surfactants and derivatives are introduced with effluents and sludge to surface waters and soils. Biodegradation rate under environmental conditions is slower, where specific microbial community and adaptation period is required. Strong sorption of surfactants to sediments and soil cause a delay of biodegradation of pollutants. Sorption is positively correlated with clay content, organic matter (especially humic substances) and calcium carbonate content. Even for easily-degradable detergents the half-live time can be two times longer in heavy soils, and there often occurs refractory surfactant pool, not available for bioconversion processes. The toxicity of detergents is not very high, but the exposure to a small concentration over a long time can be dangerous because of bioaccumulation risk. One of the best investigated examples is endocrine-disrupting activity of alkylphenols as a product of incomplete degradation of polyethoxylated alkylphenols. In soils toxic concentrations of surfactants occurs rare, and the main part of pollutants is immobilised. The risk of sewage sludge utilisation seems low but agricultural way of waste incineration requires a careful dosage and continuos monitoring of pollutants fate in the environment.