The significance of hazardous chemicals in wastewater treatment works effluents

► 70 priority chemicals were determined in 162 wastewater treatment works' effluents representing medium sized works in the UK. ► All substances selected for analysis were detected in sewage effluents. ► Levels of many priority chemicals in effluent exceeded water quality standards. ► After dilution with river water some chemicals will still exceed standards. ► A prioritised list of chemicals is provided for further consideration and possible remedial action.