Environmental monitoring for linear alkylbenzene sulfonate, alcohol ethoxylate, alcohol ethoxy sulfate, alcohol sulfate, and soap

An extensive monitoring program was executed jointly by the Dutch Soap Association (NVZ) and the Dutch authorities. Flow proportional samples of raw, settled, and treated sewage from seven representative municipal sewage treatment plants were collected over three consecutive days. The samples were analyzed for detergent surfactants, including linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), alcohol ethoxylated sulfate (AES), alcohol sulfate, (AS) and soap, using state-of-the-art analytical methods. All surfactants were removed by more than 99% during sewage treatment. The concentrations of the surfactants in the treated sewage averaged 39 mu g/L for LAS, 6.2 mu g/L for AE, 65 mu g/L for AES, 5.7 mu g/L for AS, and 174 mg/L for soap. These measured surfactant concentrations form the basis for the exposure element of the aquatic risk assessment for the surfactants studied. In addition, the field studies indicated that in-sewer removal can play a significant role in reducing the concentrations of surfactants entering the sewage treatment plant.