Surfactants in sediments

There is a general paucity of literature data dealing with surfactants monitoring in sediments using specific methodologies. The only surfactants for which a consistent data set already exists are Linear Alkylbenzene Sulphonate (LAS) and Nonyl Phenol Ethoxylate (NPE). Concentrations of LAS and NPE, have in fact been monitored in both fresh water and marine sediments and were generally found to range from 0 to 5.0 mg/kg. Higher levels were reported only for some sediments collected close to untreated or inadequately treated sewage effluent discharges. This paper reviews the existing monitoring data for these surfactants in sediments and also reports the preliminary results of a recent monitoring programme carried out on the bottom sediments of the main watercourse in Italy, the river Po, using HPLC methodologies. For the first time, attention has been focused not only on LAS but also on Alcohol Ethoxylate (AE). To our knowledge this is the first example of a concentration-specific estimate of AE in sediments. These results will be discussed and compared with the limited toxicity information which is available on benthic organisms.