Tuesday, March 13, 2012

Buffer Paradox

Why is the science about buffers so poor (see email below), and yet they are proposed with calculated precision as a solution for all manner of pollutants? For such a "well accepted" remedy to pollution, you'd think there would be all sorts of data about the effectiveness of buffers to clean up metals, pesticides, herbicides, and other chemicals.

The answer is that, outside of their use by planners and wetland scientists, buffers have no reputation as a remedy for pollution. That's why they have been studied so little. No one in the venerable fields of ecotoxicology or fate & transport would propose a buffer as the primary solution to contamination. If buffers were effective as a remedy, then to clean up Hanford, Love Canal, Times Beach, or the Duwamish, all we would have to do is put a buffer around them and call it a day.

There is plenty of data about the ecotoxicology and fate & transport of thousands of potential contaminants. If there is nary a mention about buffers in that scientific literature, it is probably for the same reason there is no mention of buffers as a solution to AIDS: buffers have no relevance to the problem.

Buffers simply are not useful as a remedy for authentic pollution problems. From my perspective, they are a planning gimmick. If we want buffers, we should have them for aesthetic or public policy reasons.


From: Paul Adamus <adamus7@comcast.net>
Date: September 29, 2011 9:29:01 AM PDT
To: Shireene Hale <shireeneh@sanjuanco.com>
Subject: Alderton comments - reply


Sorry I could not reply to this before the meeting.  Janet Alderton raises some good points with regard to the minimum width of buffer that should be allowed - in the specific case of protecting functions of the wetlands of lowest importance from low-intensity development where the potential for pollutant transport is low.

I concur with her observation that there is almost no published peer-reviewed literature on the adequacy or inadequacy upland buffers for removal of soluble pollutants such as nitrate within the width category of 0 to 82 feet (0- 25m).  As Mayer et al.  (2007) noted, "Effectiveness was not related to buffer width when analyzing buffers within width categories."  [emphasis added].   I chose a 15 foot threshold based not on nitrate removal, but on removal of runoff-borne sediment because published literature amply demonstrates that vegetated buffers of even less than 15 feet are effective for filtering that from runoff.  I do not suggest that sediment is necessarily a good proxy for nitrate, but it is the only data we have.  Note that the 15 foot minimum we proposed is close to the 25 foot minimum buffer width for protecting wetlands recommended by the Washington Department of Ecology.  However, unlike our approach, Ecology's buffer width recommendation does not explicitly address situations where potential for pollutant transport is low, as is the only case where our 15 foot buffer would be applied.

I also concur with Janet Alderton's observation that the removal of nitrate might not be a good proxy for removal of other soluble pollutants such as some surfactants.  However, there is essentially no literature on the effectiveness of buffers for reducing surfactants, so we are forced to adopt a best-available science approach based only on nitrate and sediment removal.


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