During 8 sampling campaigns carried out over a period of two years, 72 samples, including
influent and effluent wastewater, and sludge samples from three conventional wastewater
treatment plants (WWTPs), were analyzed to assess the occurrence and fate of 43 pharmaceutical
compounds. The selected pharmaceuticals belong to different therapeutic classes,
i.e. non-steroidal anti-inflammatory drugs, lipid modifying agents (fibrates and statins),
psychiatric drugs (benzodiazepine derivative drugs and antiepileptics), histamine H2-
receptor antagonists, antibacterials for systemic use, beta blocking agents, beta-agonists,
diuretics, angiotensin converting enzyme (ACE) inhibitors and anti-diabetics. The obtained
results showed the presence of 32 target compounds in wastewater influent and 29 in
effluent, in concentrations ranging from low ng/L to a few mg/L (e.g. NSAIDs). The analysis of
sludge samples showed that 21 pharmaceuticals accumulated in sewage sludge from all
three WWTPs in concentrations up to 100 ng/g. This indicates that even good removal rates
obtained in aqueous phase (i.e. comparison of influent and effluent wastewater concentrations)
do not imply degradation to the same extent. For this reason, the overall removal was
estimated as a sum of all the losses of a parent compound produces by different mechanisms
of chemical and physical transformation, biodegradation and sorption to solid matter. The
target compounds showed very different removal rates and no logical pattern in behaviour
even if they belong to the same therapeutic groups. What is clear is that the elimination of
most of the substances is incomplete and improvements of the wastewater treatment and
subsequent treatments of the produced sludge are required to prevent the introduction of
these micro-pollutants in the environment.