The biodegradation of surfactants in the environment

Abstract

The possible contamination of the environment by surfactants arising from the widespread use of detergent formulations has been reviewed. Two of the major surfactants in current use are the linear alkylbenzene sulphonates (LAS) and the alkyl phenol ethoxylates (APE). These pass into the sewage treatment plants where they are partially aerobically degraded and partially adsorbed to sewage sludge that is applied to land. The biodegradation of these and a range of other surfactants both in wastewater treatment plants and after discharge into natural waters and application to land resulting in sewage sludge amended soils has been considered. Although the application of sewage sludge to soil can result in surfactant levels generally in a range 0 to 3 mg kg(-1), in the aerobic soil environment a surfactant can undergo further degradation so that the risk to the biota in soil is very small, with margins of safety that are often at least 100. In the case of APE, while the surfactants themselves show little toxicity their breakdown products, principally nonyl and octyl phenols adsorb readily to suspended solids and are known to exhibit oestrogen-like properties, possibly linked to a decreasing male sperm count and carcinogenic effects. While there is little serious risk to the environment from commonly used anionic surfactants, cationic surfactants are known to be much more toxic and at present there is a lack of data on the degradation of cationics and their fate in the environment.

Mixture toxicity of three toxicants with similar and dissimilar modes of action to Daphnia magna

“…The additivity of AChE inhibitors has been shown previously in experiments with cladocerans (Norbergking et al, 1991). LAS is one of the most frequently used anionic surfactants (Scott and Jones, 2000). It is known to be toxic to aquatic organisms (Lewis, 1991;Kusk and Petersen, 1997;Tanaka and Nakanishi, 2001).…”

Distinct expression and activity profiles of largemouth bass (Micropterus salmoides) estrogen receptors in response to estradiol and nonylphenol

“…NP is a microbial breakdown product of NP polyethoxylates (NPEs) that are most commonly found in industrial non-ionic surfactants and also used in the production of plastics, textiles, paints, emulsifiers, paper products, and cosmetics (Scott & Jones 2000, Sabik et al 2003. It is estimated that more than 500 000 tons of NPEs are used annually (Scott & Jones 2000) with O60% entering the environment via sewage outflows (White et al 1994, Nimrod & Benson 1996, Canadian 2000.…”

Preparation of Date Seed Activation for Surfactant Recovery

“…Another source of surfactants contamination comes from surfactants dispersants for fuel oil spillages. These surfactants are resistant to bio-degradation by bacteria and have a toxic effect upon breakdown [3]. Synthetic surfactants also do not biodegrade sufficiently in the treatment plant, even when they are left for a long time [4].…”