The occurrence of anticancer drugs in the aquatic environment - a Lebanese case study

Compared to other countries in the Middle East and North Africa region, Lebanon is considered the richest in water resources. However, due to inadequate water management, Lebanese water resources are under stress. Water pollution is one of the main problems causing major concerns. The contamination of Lebanese surface water originates predominantly from the discharge of untreated municipal and industrial wastewater. Reports revealed that 58% of the population is connected to sewerage systems, with most wastewater collection systems not safely managed. The remainder uses on-site sanitation or discharges untreated wastewater into water streams. This suggests that almost 90% of the generated wastewater in Lebanon is released without treatment into the aquatic environment.

Previous studies in Lebanon were mainly focused on heavy metals and microbiological analysis. Following the increase in cancer rates in Lebanon, this thesis aimed to assess the occurrence of six anticancer drugs estimated to be the most administered in Lebanon, in addition to platinum that could emerge from platinum-based drugs in samples collected from wastewater treatment plants, sewage outfalls and surface water.

As reported in the literature, SPE-LC-MS/MS and ICP-MS were the most adopted techniques for analysing the selected compounds. For this reason, analytical methods were developed and validated for detecting the anticancer drugs and the total dissolved platinum in Lebanese environmental samples. Trace concentrations of 5-fluorouracil, methotrexate, cyclophosphamide, and platinum were identified in rivers, wastewater influents and effluents, and sewage outfalls at concentrations ranging from 1 to 305 ng/l. These drugs alone will not cause significant effects on the aquatic biota at the levels detected. Nevertheless, wastewater effluents can contain other hazardous elements that can contribute to toxicity towards the aquatic environment. A pilot study was conducted, where the acute toxicity of two sewage outfalls was assessed with Daphnia pulex according to the OECD and USEPA guidelines. Results suggested that samples induced acute toxicity as toxic units ranged between 1.3 and 2.5.

Considering the results obtained throughout this thesis, deficiencies in waste management and wastewater treatment were revealed, and urgent action needs to be taken to avoid the deterioration of the Lebanese aquatic ecosystem. On a national and international level, wastewater generated from hospitals should be regarded as hazardous waste and pre treated on-site with advanced technologies before it is merged with municipal wastewater.