Temporal variations and trends in loads of commonly used pharmaceuticals to large wastewater treatment plants in Sweden, a case study (Ryaverket)

Loads of individual commonly used analgesics (ibuprofen, diclofenac), antibiotics (sulfamethoxazole, trimethoprim), β-blockers (atenolol, metoprolol, sotalol, propranolol) and neuroleptics (carbamazepine, citalopram) to a large-scale operating wastewater treatment plant (WWTP) in Sweden (Ryaverket) were studied by monitoring concentrations and flows during a 9-year period (2006–2015). Variations in loads due to sampling and possible errors in chemical analyses were estimated to be below 40%. The variations in loads were analyzed and discussed in terms of the design of collecting wastewater system as an integrated part of the water treatment at the WWTP as well as the prescription and use of individual pharmaceuticals. Trend analysis in daily loads of individual pharmaceuticals indicated an increase for diclofenac, no significant changes for ibuprofen and metoprolol and a decrease for the other pharmaceuticals. The latter was ascribed to a decrease in their prescription and use. The increase in loads of diclofenac was ascribed to its growing topical use not requiring prescription. In view of future regulations by the EU, growing loads of diclofenac to WWTPs and its low removal rates in WWTPs may require an upgrade of WWTPs to achieve quality standards for diclofenac in receiving waters.