EEA Technical report No 8/2011 provides a comprehensive overview of hazardous substances in Europe’s fresh and marine waters.
The document should provide a starting point, or refresher, for all those who are concerned with the disposal or treatment of drug wastes and the presence of drug residues in treatment outflows and natural waters.
Wastewater treatment processes do not remove pharmaceutical residues:
Whilst household and industrial wastewater treatment has been implemented progressively across Europe, the process does not remove all hazardous substances, with household and industrial chemicals and pharmaceuticals, for example, being detected in treated effluent that is subsequently discharged to surface waters (Ashton et al., 2004; Gros et al., 2010; HELCOM, 2010; Miège et al., 2009; Reemtsma et al., 2006).
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Inevitably, we must take care in disposal and take every reasonable attempt to keep pharaceuticals out of the wasterwaters. However, ‘reasonable’ is open to debate though common sense suggests that chasing the occasional discarded tablet or an empty syringe, even 1,000 empty syringes, is a futile undertaking. It is not reasonable to propose that such measures are likely to make any appreciable difference; the chance of success is infinitesimally small.
The release of human medicines to freshwater occurs through various routes. After administration, they are absorbed, metabolised and then excreted to a sewer system – often only slightly transformed or even unchanged. In addition, despite take-back schemes, unused medicines are often disposed of improperly via the sink or toilet. Typically incomplete removal techniques at urban wastewater treatment plants (Heberer, 2002; Miège et al., 2009; Reemtsma et al., 2006) mean that drug residues or their transformation products are found in treated effluent discharged to receiving waters (e.g. Ashton et al., 2004; Gros et al., 2010) and, as a consequence, in the receiving waters themselves.
The presence of pharmaceuticals in groundwater can also derive from other sources, such as sewer leakage (Ellis, 2006) and landfill leachates (as a result of disposal via domestic waste) (Ahel and Jelicic, 2001).
Following use in livestock treatment, veterinary drugs and any metabolites may be released to soil directly, by animals at pasture, or indirectly, through the application of animal manures and slurries to land as a fertiliser (Boxall et al., 2003 and 2004). Veterinary medicines that are released to soil may subsequently be transported to surface waters via run-off or field drains (Burkhard et al., 2005; Kay et al., 2005) or leach to groundwaters (Blackwell et al., 2007). Another important route of input of livestock medicines to water bodies is wash-off from impervious farmyard surfaces. In aquaculture treatments, the drug is often added directly to the aquatic environment.
Section 2.8.4, page 19
EEA Technical report No 8/2011 makes particularly interesting reading and puts into context the problem of pharmaceutical residues in water supplies. The problems are, as noted above, each and every one of those sources noted so many times before on the Clinical Waste Discussion Forum, and no others.
The architects of this report, summarising current research opinion, do not identify the routine disposal of clinical wastes as a significant source of wastewater contamination. Though this is no reason to relax source segregation of wastes and the specific incineration of bulk pharmaceutical wastes, regulators should take heed and focus their attention more effectively on matters that will make a difference.
see also Pharmaceutical discharges from ATT treatment wastewaters