QSAR Modelling of the Toxicity of some Technical Non‐ionic Surfactants towards Fairy Shrimps

Abstract

Abstract The toxicity of a number of non‐ionic surfactants towards Thamnocephalus platyurus (sweet water fairy shrimp) has been examined. The measurements have been performed with the use of so‐called Toxkits, and the results have been expressed both as a mean LC 50 value for each of the surfactants, and with a relative scale estimated using of multi dimensional scaling (MDS). An algorithm is shown in matlab code, with which it is possible to perform MDS on a difference matrix with a lot of systematically missing values. The thus obtained results have been combined with the physico‐chemical data for the surfactants, and QSAR models have been estimated for the toxicity (log(LC 50 )) of the surfactants. The physico‐chemical properties with the main influence on the models were the hydrophilic‐lipophilic‐balance (HLB), the hydrophobicity (log P), the critical micellar concentration (CMC) and the number of carbon atoms in the hydrophobic part (C) of the surfactant.