Effect-directed analysis: a powerful tool for the surveillance of aquatic systems

The advantages of combined approaches for the evaluation of drinking-water quality, such as effect-directed analysis (EDA) consisting of biological and chemical analytical methods are illustrated in this work by comparing a classical and EDA approach applied to samples from China and Germany. The China samples contain polycyclic aromatic hydrocarbons, alkylanilines, chloroanilines, chloronitrobenzenes, chlorobenzothiazoles, chloroalkylphosphates, as well as pesticides ((4-chloro-2-methylphenoxy)ethanoic acid, metolachlor, atrazine, and the insect repellent N,N-diethyl-3-toluamide) in concentrations between 1 and 1000 µg L-1. The toxicity profiles of two River Elbe samples and one sewage-treatment-plant sample, as determined by the luminescent bacteria test, selectively reflect the contamination background: the first profile only possesses two out of eight fractions well above the significance level of 10% inhibition, in the second profile, all but one fraction lie well above this level, exhibiting also a much higher total toxicity in each fraction as compared with the latter sample. In the third example, all fractions are far above the significance level and show a much higher total toxicity, but also the profile shifts towards less polar fractions.