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Pharmaceuticals and Personal Care Products in the Canadian Environment: Research and Policy Directions

5.2 Drinking Water Treatment

Although existing research and new analytical capabilities have detected certain PPCPs in raw drinking water sources, they have generally been found in orders of magnitude below any daily therapeutic dose. Concerns have, however, arisen over potential health effects related to the consumption of drinking water including antibiotic resistance and unknown potential long term chronic effects caused by the intake of mixtures of PPCPs in low concentrations to individuals during sensitive life stages.

Generally where research is underway in this area in Europe and the U.S., it is frequently in the context of better understanding the removal of EDCs during centralized water reclamation/reuse processes. In the Great Lakes, a number of partners have assessed, and continue to investigate, the occurrence of pharmaceuticals and endocrine disrupting chemicals in the Detroit River, and the effectiveness of ozone in degrading these compounds (see Jasim summary in section 3.3).

Reviews of the science are less plentiful here though von Gunten et al. (2006) provide a recent summary of the state of knowledge on the removal of PPCPs during drinking water treatment:

  • The raw water of waterworks using surface water is likely to be contaminated by many pharmaceuticals whereas the presence of pharmaceuticals in groundwater is rather unlikely. Depending on the water treatment, finished drinking water might contain pharmaceuticals at very low concentrations;
  • Ozonation, activated carbon, and nanofiltration are very efficient treatment processes for the removal of PPCPs. Treatment trains using these advanced techniques are effective to prevent drinking water contamination by most pharmaceuticals;
  • Waterworks that treat groundwater have short treatment lines if any, frequently consisting only of disinfection with e.g. chlorine or UV; these processes are inadequate to eliminate most polar pharmaceuticals;
  • Iodinated contrast media are among the compounds found most often in drinking water, since they generally persist after activated carbon treatment as well as oxidation processes such as ozonation. The only options to guarantee a complete elimination are nanofiltration, reverse osmosis and activated carbon filtration with frequent renewal or regeneration;
  • Only in a very few cases do the concentrations of pharmaceuticals in drinking water exceed the maximum European concentration level of 0.1 µg/L required for individual pesticides;
  • Even if the highest concentration of individual pharmaceuticals reported for drinking water is considered for the assessment of effects on humans, based on the current knowledge, adverse effects via the consumption of drinking water are very unlikely.
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