The significance of different health institutions and their respective contributions of active pharmaceutical ingredients to wastewater

Active pharmaceutical ingredients (APIs) have been frequently found in the environment. It is, however, still not quite clear who is mainly responsible for API emissions. Hospitals have been considered to be the main contributing point sources for wastewater (WW) discharge of APIs. However, recent studies have shown that the contribution of hospitals to the input of APIs into the aquatic environment is quite low. Due to demographic change and the increase of psychiatric diseases, health institutions (HIs) such as psychiatric hospitals and nursing homes are likely to be important sources as well, but no data is available in this respect. This study aims to assess the impact of HIs and to provide a methodology to measure their respective contributions. Drawing on pharmaceutical consumption data for the years 2010, 2011, and 2012, this study identified API usage patterns for a psychiatric hospital (146 beds), a nursing home (286 inhabitants), and a general hospital (741 beds), the latter of which comprises three separate locations. All the HIs are located in two sub-regions of a county district with about 400,000 citizens in southwestern Germany. A selection of neurological drugs was quantified in the sewer of these facilities to evaluate the correlation between consumption and emission. The API contribution of HIs was assessed by comparing the specific consumption in the facilities with the consumption in households, expressed as the emission potential (I_EP). The study shows that the usage patterns of APIs in the psychiatric hospital and the nursing home were different from the general hospital. Neurological drugs such as anticonvulsants, psycholeptics, and psychoanaleptics were mainly consumed in the psychiatric hospital and the nursing home (74% and 65%, respectively). Predicted and average measured concentrations in the effluent of the investigated HIs differed mostly by less than one order of magnitude. Therefore, the consumption-based approach is a useful method to assess usage patterns of APIs in HIs and to predict their respective contributions to WW. The national contribution of HIs on total WW discharge of APIs compared to households was very low. Only the results for the sedative clomethiazole in general hospitals as well as the antidepressant moclobemide and the antipsychotic quetiapine for the nursing homes were found to deserve some attention. The regional comparison showed that in sub-regions with a comparably higher density of HIs, the allocated facilities could be seen as point sources emitting particular APIs. However, in general, the bulk of the consumed pharmaceuticals to WW discharge has to be attributed to households.