Comparison of predicted and measured concentrations of selected pharmaceuticals, fragrances and hormones in Spanish sewage

A review of consumption and excretion rates of 17 pharmaceuticals, two musk fragrances and two hormones by the Spanish population in 2003 was performed. For that purpose, three different models were used: (i) extrapolation of the per capita use in Europe to the number of inhabitants of Spain for musk fragrances; (ii) annual prescription items multiplied by the average daily dose for pharmaceuticals and; (iii) excretion rates of different groups of population for hormones. This information enabled the prediction of the expected concentrations (PEC) entering sewage treatment plants (STPs), which were subsequently compared with the measured environmental concentrations (MEC) in raw sewage. Annual drugs consumption in Spain ranges from few kilograms (Oxazepam and 17α-ethinylestradiol) to several hundred of tons (Ibuprofen). The quantities of musks used accounts for 110–450 kg d−1 and the total amount of hormones excreted daily reaches almost 1 kg d−1. 12 out of 21 selected substances were predicted to be present in raw sewage influent at concentrations greater than 100 ng l−1 and these predicted concentrations fitted with the measured values for half of them (Carbamazepine, Diazepam, Ibuprofen, Naproxen, Diclofenac, Sulfamethoxazole, Roxithromycin, Erythromycin and 17α-ethinylestradiol).