Pesticide inputs from the sewage treatment plant of Agrinio to River Acheloos, western Greece: occurrence and removal

This work reports the occurrence and the removal of a wide spectrum of pesticides in municipal wastewaters from the Agrinio region, Greece. Analytical determination was carried out by means of solid-phase extraction followed by gas chromatography equipped with flame thermionic and mass spectrometric detection. The herbicides atrazine, alachlor, isoproturon, and s-metolachlor and the insecticides diazinon, methidathion, fenthion and chlorpyriphos, were more frequently detected in influent and effluent samples while they were also detected in river samples. Isoproturon and diazinon showed the highest concentrations in influent samples that reached concentrations up to 2,328 and 1,486 ng L(-1), respectively. Secondary treatment and cumulative removal rates for herbicides and insecticides ranged between 23-91%, 21- > 99% and 36- > 99%, 38- > 99%, respectively. The data demonstrate that there are significant levels of pesticides entering river waterways.