I have no problem with applying the PP as originally developed in the 1970s in Germany – as a risk management tool, not a scientific tool. But this means that risks need to be balanced against consequences of actions or lack thereof. In addition to potential consequences that might mediate against treatment noted above, a particularly powerful consequence is the perception that treatment obviates individual responsibility to control waste inputs into, for instance, public sewage systems (e.g., chemicals used in the garden and for other purposes). Source control is a highly effective approach to contaminant

and harm reduction that can obviate, in appropriate circumstances, if properly implemented and ‘sold’ to citizens, expensive higher levels of treatment and associated environmental effects. But if citizens are paying higher taxes for treatment that has been sold Cyclopamine order and/or mandated as solving a pollution problem, they will have no incentive to practice source control – the treatment is taking care of everything: out of sight, out of mind. And sometimes politicians, managers, activists believe that ‘the end justifies the means’. They blindly believe that treatment is necessary Doramapimod chemical structure and will do anything to implement it. Let me give you an example. In the mid-1980s in Puget Sound (WA, USA), Region 9 of the USEPA was pushing for the City of Seattle to move from primary to secondary sewage treatment.

At that time there was a great deal of publicity regarding lesions in bottom-living fish due to pollution. The lesions were in fact due to historic sediment chemical contamination, not to the

then-current sewage discharges. However, USEPA linked the fish lesion and sewage upgrade issues. At the same time I and others had completed a report for the US Department of Commerce building on the current status of chemicals in Puget Sound and projecting future status. One of many components of this report examined the effects of increased levels of sewage effluent treatment and noted that this would not resolve the issue of fish lesions. As one might imagine, when this report came to the attention pentoxifylline of USEPA they were not pleased. In fact, all copies of that report (several hundred had been printed) were destroyed at their request and it only exists as a citation, not as an actual document (Quinlan et al., 1985). Please do not think that I am universally against treatment, far from it. The “dead zones” noted above certainly required treatment, for example. So too do contaminant inputs into drinking water sources. And there are other cases that require treatment. But we tend to forget (or ignore) the fact that sometimes treatment occurs naturally without human intervention. Among the ecosystem services that Nature provides at no cost are, under appropriate conditions, regulating services – of water quality.