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

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.

Assessment of alcohol ethoxylate surfactants and fatty alcohols mixtures in river sediments and prospective risk assessment.

A feasible and relatively readily available analytical method was adapted for the assessment of alcohol ethoxylates (AE) and fatty alcohols (FA) in sediments. This study illustrates the simultaneous measurement of 38 of 114 possible alcohol ethoxylate ethoxymers (AE) and fatty alcohols (FA) found in commercially important AE products. We predicted toxicity for all identified fractions, as well as the total mixture toxicity, relative to three exposure scenarios via sewage treatment plants (STP) for these widely used chemicals in consumer products and hence generate a preliminary environmental risk screening for AE and FA in sediments. The method is based on derivatization of solvent or solid-phase extracts with 2-fluoro-N-methylpyridinium p-toluenesulfonate (Pyr+). The derivatized extracts were analyzed with liquid chromatography/mass spectrometry (LC/MS) operating in the positive ion electrospray mode. The extraction efficiency of AE and FA in three different sediments of varying composition was evaluated with spike-recovery studies, ranging from 64% to 80%. The detection limits for individual ethoxymers typically ranged from 1 to 5 ngg(-1)on a dry weight basis. The mean limit of detection (LOD) was 6 ngg(-1)and the median LOD was 3 ngg(-1). AE and FA in sediments were found to be stable for two weeks if preserved with 3% (v/v) formalin and stored at 4-6( composite function)C. Based on equilibrium partitioning, background concentrations of AE and FA were predicted to be below concentrations known to elicit chronically toxic effects. Total worst case mixture toxicities for all AE ethoxymers combined with FA were predicted to result in a risk quotient less than 0.6. Activated sludge treatment (STP) significantly reduced the release of total AE and FA by four-fold, suggesting that the total mixture risk quotient would be < 0.15 for sediment dependent organisms.