Fate of pharmaceuticals after applications of human urine-based fertilisers in long-term field experiments

International audience

English. Current agriculture is heavily dependent on the use of fertilisers derived from fossil resources.On the other hand, most of the nutrients in food are excreted in urine, mostly collected andmixed with wastewaters, whose management allows little recycling of these nutrients andleads to numerous environmental impacts. The direct use of human urine in agriculturewould enhance the recycling of their nutrients and develop a more circular management ofcrop fertilization as a cheaper and more sustainable source of nutrients than fossil-basedfertilisers. However, it may indirectly contribute to the dissemination of pharmaceuticals inthe environment.The objective of this work was to determine the concentrations of pharmaceuticals in humanurine-based fertilisers and in the receiving soils after one or several applications in Franceand in Denmark where the long-term effects of repeated use of different alternative fertilisersincluding human urine were studied since 2003 in the CRUCIAL field experiment.Fifty-nine molecules, including active compounds or metabolites of antibiotics (28), antiinflamatories(9), neuroleptics (5) were analysed by online SPE-UHPLC-MS-MS in urinebasedfertilisers (stored urines, fermented urines, Aurin®, Granurin®) and in soils after onespreading (France) and 18 spreading (Denmark). Caffein was also analysed as an anthropicmarker.Up to 11 and 20 molecules were found in stored urines, respectively. The concentrationsranged between 1 μg/L (e.g. carbamazepine, diclofenac) and 11 mg/L (acetaminophen) andfor some compounds were similar to published data. The concentrations varied dependingon the year and the origin of urine. In treated urine, only 4 to 8 compounds were at generallylower concentrations than in stored urine, as already shown. Salicylic acid, caffein and someanti-inflammatories were in all types of urine-based fertilisers. One month after one spreading,2 to 3 compounds were at very low concentrations in soil. In the CRUCIAL experiment, onlytwo compounds were quantified between 0.1 and 3 μg/kg DW in soils fertilised during 18years, i.e <6% of the total spread amount.Even though pharmaceutical concentrations in some urine-based fertilisers could be high,they were low in soils even after decades of urine fertilisation, indicating dissipation of themolecules in soil.