Drugs of abuse in the watercycle
For about half a decade it is known that illicit drugs can be found in wastewater and in source waters (especially in surface waters) used for preparation of drinking water. This morning I presented the results of research KWR has done together with several other laboratories all over Europe on the occurrence and fate of illicit drugs in the water cycle.
The IWA organisation took me by surprise when asking me this morning to chair the session in which my presentation was scheduled. Consequently, I was allowed to announce myself, keep my own time (and permitting myself to talk slightly longer than scheduled) and prepare questions for myself (just in case ….).
Drinking water processing used in the Netherlands removes the great majority of drugs of abuse that are indeed present in source waters taken in from rivers. Sewage treatment plants are the major sources of illicit drugs observed in river water, and wastewater treatment processes only partly remove these from influents. Concentration data from illicit drugs can in fact be used to estimate drug consumption in the population connected to the sewer.
In the afternoon the theme ‘illicit drugs’ was continued by Gernot Kayser from Germany who introduced the use of enzymes extracted from fungi as a means of transformation of drugs of abuse in sewage waters. Rather than removing, these enzymes transform the drugs, mostly by oxidation or demthylation. When asked how many fungi (mushrooms) would have to be cultivated for large scale practices the answer was: “We are not that far yet and still need to find out.”
The theme of illicit drugs will be continued at the IWA congress during a special workshop on Thursday morning chaired by Annemarie van Wezel from KWR and myself.
Pim de Voogt