Liquid-liquid extraction as a simple tool to quickly quantify fourteen cytostatics in urban wastewaters and access their impact in aquatic biota.

ABSTRACT

Cytostatics are highly toxic pharmaceuticals used in the treatment of cancer. These substances are partially excreted by the human body after administration. The inefficient removal of some cytostatics in urban wastewater treatment plants (WWTPs) allows them to reach surface waters and consequently the aquatic biota. However, information about their occurrence in urban wastewaters is available only for certain active ingredients. A liquid-liquid extraction method coupled to liquid-chromatography-tandem mass spectrometry analysis was developed, allowing the identification and quantification of 14 cytostatics in wastewater samples, avoiding the use of expensive sorbents. Moreover, satisfactory cytostatics' recoveries were achieved when the new method was applied to wastewaters from a Portuguese WWTP average of (74 ± 21)% for the influents, (83 ± 22)% for secondary effluents, and (94 ± 24)% for tertiary effluents collected after UV treatment, except for imatinib. Doxorubicin, etoposide, megestrol and prednisone were completely eliminated in the first stage of the WWTP treatment (i.e. detected in the influents, but not in the effluents). Bicalutamide, capecitabine, cyclophosphamide, ifosfamide and mycophenolic acid were recalcitrant to UV radiation (i.e. detected in tertiary effluents), ifosfamide being the cytostatic most difficult to be removed (its concentration did not decrease from the entrance to the outlet of the WWTP). The risk at which aquatic organisms might be subjected, due to their exposure to cytostatics' concentrations 10-times lower than those found in the tertiary effluents, was estimated and it was verified that mycophenolic acid may represent a high risk. Although no risk was estimated for the other cytostatics, the risks associated to long-term and synergic exposure should not be ruled out.