Prescription and illegal drugs in the watercycle
This morning there were two interesting sessions on prescription drugs and illegal drugs. Shane Snyder pointed out that the issue of occurrence of pharmaceuticals in waste and drinking water has been known for decades, and concentrations have decreased continuously. Several authors have shown the big gap between the very low concentrations occurring in water and the higher concentrations that may pose a risk for human health. Yet a high percentage of the population in several US cities do not drink water directly from the tap. So, while no risks of these compounds can be shown, authorities now oblige water utilities to monitor whole series of these compounds. After my presentation an engaged discussion on interventions started. The audience agreed that additional treatment at sewage treatment plants is preferred above additional drinking water treatment, as all kinds of benefits to environmental quality and food quality are gained then and the concentration of substances to be treated is higher.
The second session focused on illegal drugs. Methods applied were discussed by Alexander van Nuijs, especially the uncertainties in the back calculation of concentrations of illegal drugs in raw sewage water to consumption by the population. Kevin Thomas presented the 19 cities study on drugs consumptions as measured via sewage monitoring. One of the discussion points afterwards was on the ethics of measuring in human excrements. It might not be desirable to perform measurements aon relatively small populations. An example was given of an attempt to monitor use of illegal drugs on marine oil platforms, which eventually was not performed because the workers thought their privacy had to be protected.
Annemarie van Wezel