Occurrence and hazard screening of alkyl sulfates and alkyl ethoxysulfates in river sediments

Abstract

Alkyl sulfates (AS) and alkyl ethoxysulfates (AES) are High Production Volume (HPV) 'down-the-drain' chemicals widely used globally in detergent and personal care products, resulting in low levels (ng to microg L(-1) range) ultimately released to the environment via wastewater. These surfactants have a strong affinity for sorption to sediments. However, data regarding the fate and effects following release into the environment has not been reported. Sediment samples from both normal exposed and presumably low exposed locations (background) were analyzed to determine the levels of AS/AES. The method used in this study shows broad applicability across various sediment types and the most common congeners of AS/AES. The combined levels of AS/AES detected in the two presumed lower exposed sites ranged from 0.025 and 0.034 microg g(-1) on a dry weight (dw) basis while the presumed higher exposed site had combined levels of AS/AES of 0.117 microg g(-1) (dw) based on triplicate analyses. Results indicate that detectable levels of AS/AES can be found in sediments in the environment at these three sites that are below the concentrations expected to produce significant adverse ecological effects for individual homologues and the whole mixture, the hazard screening for these three sites had PEC(porewater)/PNEC(total mixture) ratios of 0.007-0.024. However, further investigation of potential effects and risk assessment is warranted.