Chemical evaluation of contaminants in wastewater effluents and the environmental risk of reusing effluents in agriculture

Due to increasing interest in reusing wastewater in water-deficient regions, we suggest environmental risk assessment (ERA) as a suitable tool to evaluate potential risks from trace pollutants in irrigation water. We propose a simple method for screening environmental risks associated with reusing wastewater, which can predict potential risks in terrestrial ecosystems based on the concentration of pollutants in the effluent to be reused.This method was tested in a case study including 27 priority and emerging pollutants found in effluents from two Spanish wastewater-treatment plants (WWTPs). The results showed that secondary effluents from these Spanish WWTPs were likely to cause adverse effects, due particularly to the presence of some pharmaceuticals and heavy metals.A need for effective tertiary treatment prior to reuse of wastewater effluents in agriculture is highlighted.