Identification of cytotoxic compounds in European wastewaters during a field experiment

Two short term bioluminescence inhibition assays based on Vibrio fischeri (Microtox ® and ToxAlert ® 10 tests) were used for the estimation of the cytotoxicity of several European wastewaters from Germany, Spain and Sweden during a field experiment carried out in Berlin (Germany) organised by the Environment and Climate program of the European Commission. The various effluents, freshly collected and transported immediately to Berlin, were tested for their cytotoxic potential and were characterised by an analytical protocol involving the use of sequential solid phase extraction (SSPE) followed by liquid chromatography-mass spectrometry (LC-MS). The bioluminescence tests showed a relatively high sensitivity concerning cytotoxic effects. Besides the wastewater samples of a cement industry (K1 to K3), the effluents of all industrial plants demonstrated a high cytotoxic impact on test bacteria. The highest toxicity was observed in the tannery raw effluent from Sweden and Spain (SW1 and BAR1, respectively). Cytotoxicity was investigated in different wastewater samples of two sewage treatment plants (STP) receiving the raw tannery wastewaters of Sweden and Spain mixed with domestic wastewaters and industrial effluents of a German manufacturing plant. A substantial decrease on the inhibition from 70–80% down to 15–20% was observed when analysing the untreated influent versus the treated effluent of both STPs, respectively. In addition, genotoxicity with the umu-assay (DIN 38415T3, ISO FIS/DIS13829) was also performed and high genotoxicity was observed when analysing the same untreated wastewater samples that showed the highest bioluminescence inhibition with V. fischeri with a good correlation between both tests. The analytical protocol applied for the evaluation of the toxicity tests involves the use of SSPE using C18 and polymeric cartridges (Isolute ENV+) followed by ion pair-electrospray-mass spectrometry (IP-ESI-MS) and by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). By this protocol different analytes including non-ionic (polyethoxylates) surfactants, ionic (linear alkyl benzene-sulfonates) surfactants, phenols, benzene-sulfonates and naphthalene-sulfonates were determined. Combination of this previously developed methodology with toxicity measurements allowed to detect different groups of pollutants responsible for the toxicity of the studied wastewaters. Evidence of the existence of a correlation between th