Linear alkylbenzene sulfonates in the aquatic environment. Study of the analysis, sorption processes and sediment toxicity

The present PhD thesis focuses on the study of the sorption and bioavailability of linear alkylbenzene sulfonates (LAS) in relation to the characteristics of the compound and the system. The solid-phase microextraction technique (SPME) is initially tested and developed to analyze these anionic surfactants in different aquatic media. The SPME method is further applied in solubility and sorption studies. The sorption results have shown that the sorption of LAS compounds to sediments is dependent on both the organic carbon and the clay content of the sediment, and this correlation varies with the surfactant concentration in the media. Besides, the sorption of LAS at different salinities can be well predicted by the calcium concentration. Differences in the sorption affinity of the LAS constituents to sediment and humic acids were observed among the different LAS homologues and isomers, and this behavior could be well predicted by the fiber-water partitioning coefficients. In addition, sediment toxicity assays have shown that the toxicity of LAS to the marine mud shrimp Corophium volutator can be well predicted by the freely dissolved concentration in the pore water