A predictive approach seems useful to identify pharmaceuticals in the environment and give an idea of overall levels of contamination, so as to restrict monitoring to those molecules most likely to be contaminants. We propose an approach based on two parts. The first is to rank the molecules according to the predicted environmental loads; the second is to refine the list by analysing the pharmaceuticals in sewage treatment plants (STPs) and comparing the concentrations with levels previously measured in surface water. This approach identified a restricted group of priority pollutants (ofloxacin, furosemide, atenolol, hydrochlorothiazide, carbamazepine, ibuprofen, spiramycin, bezafibrate, erythromycin, lincomycin and clarithromycin) in the aquatic environment in Italy, for further studies and monitoring.