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Pharmaceuticals and recently also illicit drugs have been recognised as emerging environmental contaminants due to their potential environmental impact: frequent occurrence, persistence and risk to aquatic life and humans. This manuscript is part one of the two-part study aiming to provide a better understanding and application of environmental data not only for environmental aims but also to meet forensic objectives. An attempt to use wastewater data is made in order to verify patterns of the usage of drugs (in particular illicit) in local communities. The average usage of cocaine in South Wales was estimated at 0.9 g day(-1) 1000 people(-1), which equals 1 tonne of this drug used or disposed of to sewage annually in Wales. The calculated usage of amphetamine denoted 2.5 g day(-1) 1000 people(-1) and is suspected to be an overestimate. Because no analysis of enantiomers of amphetamine was undertaken, no distinction between amphetamine's legal and illicit usage could be made.

This manuscript is part two of a two-part study aiming to provide a better understanding and application of environmental data not only for environmental aims but also to meet forensic objectives. In this paper pharmaceuticals were investigated as potential chemical indicators of water contamination with sewage. The monitoring program carried out in Wales revealed that some pharmaceuticals are particularly persistent and/or ubiquitous in contaminated river water and therefore might be considered as potential conservative or labile wastewater indicators. In particular, these include some anti-inflammatory/analgesics, antiepileptics, beta-blockers, some H2-receptor antagonists and antibacterial drugs.

A 5-month monitoring program was undertaken in South Wales in the UK to determine the fate of 55 pharmaceuticals, personal care products, endocrine disruptors and illicit drugs (PPCPs) in two contrasting wastewater plants utilising two different wastewater treatment technologies: activated sludge and trickling filter beds. The impact of treated wastewater effluent on the quality of receiving waters was also assessed. PPCPs were found to be present at high loads reaching 10kgday(-1) in the raw sewage. Concentrations of PPCPs in raw sewage were found to correlate with their usage/consumption patterns in Wales and their metabolism. The efficiency of the removal of PPCPs was found to be strongly dependent on the technology implemented in the wastewater treatment plant (WWTP). In general, the WWTP utilising trickling filter beds resulted in, on average, less than 70% removal of all 55 PPCPs studied, while the WWTP utilising activated sludge treatment gave a much higher removal efficiency of over 85%. The monitoring programme revealed that treated wastewater effluents were the main contributors to PPCPs concentrations (up to 3kg of PPCPsday(-1)) in the rivers studied. Bearing in mind that in the cases examined here the WWTP effluents were also major contributors to rivers' flows (dilution factor for the studied rivers did not exceed 23 times) the effect of WWTP effluent on the quality of river water is significant and cannot be underestimated.