PACs during wastewater treatment and in receiving waters – emerging issues

Pharmacologically active compounds (PACs) are emerging contaminants found in surface waters at ppt levels. Thousands of PACs are approved for human/veterinary use, although only a very small percentage of these compounds have been studied in the environment. Some of the most commonly used PACs are sold in hundreds of tonnes/year in the UK alone. PACs enter the environment mainly through insufficiently treated sewage, waste effluents from manufacturing processes, runoff and sludge (if used as fertiliser or transported to landfill). They are ubiquitous and persistent (due to their continuous introduction into the environment) with synergistic properties. PACs have also been detected in drinking water, which poses a direct risk to humans and raises the issue of contaminated water sources. The necessity of research into PACs is widely acknowledged and the need for action to further improve our understanding of risks posed by PACs is often highlighted.
The aim of this presentation is to discuss efficiency of different wastewater treatment processes in the removal of PACs and to raise awareness of two important but underreported issues relating to the presence and fate of PACs in wastewater and their ecotoxicity. These are: (i) the possibility of under-reporting of the measured concentrations of certain PACs due to lack of routine measurement of these compounds in solids and (ii) possibility of a significant under or overestimation of toxicity of chiral PACs and incorrect environmental risk assessment due to lack of data on enantiomer-specific fate of these compounds during wastewater treatment and in the environment.