Letter Concerning EPA Proposed Rule on Coal Fired Power Plants

from Dr. David Dow of East Falmouth

Letter to the Editor:

I received an email recently from the Union of Concerned Scientists expressing their concern on the costs/benefits analysis for hazardous chemicals released from power plants.  Since I have long been concerned about the mercury contamination of fish in Ashumet Pond where there are consumption alerts for women of child bearing age and children, I decided to submit comments through the federal register as a retired marine scientist from the Fisheries Lab in Woods Hole and grassroots environmental activist living on Cape Cod.  The comment period on: EPA-HQ-OAR-2018-0794-0001 closes on April 17, 2019.

The concern for these MATS (Mercury and Air Toxics Standard) under the Clean Air Act (CAA) is that the benefits will be more limited and the costs exaggerated, so that mercury will no longer considered a  toxic chemical requiring remediation and/or pollution treatment controls by the power plants.  In Ashumet Pond the airborne mercury is methylated in the anaerobic portions of the sediments and this methyl mercury bioaccumulates through the food chain leading to levels of health concern in the fish species targeted by recreational anglers.  Much of this airborne mercury comes from coal-fired power plants in the midwest. The recently discovered perfluorinated chemicals (PFOS and PFOA) in the Ashumet Valley Plume may pose similar threats. One source of PFOS/PFOA is the former fire training area at Joint Base Cape Cod


Another player in this story is “phosphorus pollution” from septic systems and the former Joint Base Cape Cod wastewater treatment plant which has effected water quality and plant/animal habitats within Ashumet Pond. 

This has lead to low dissolved oxygen levels in the bottom waters and increased the anaerobic conditions in the sediments which can enhance the bacterial action that methylates mercury.  Fortunately the US Geological Survey and JBCC Air Force Civil Engineer Center developed a permeable reactive barrier of iron particles in sand to intercept “P” from the wastewater treatment plant and added alum to the sediment in deep portions of the pond to reduce “P” loading from the sediments.  This has helped to restore water quality and improve conditions for swimmers and other recreational users of the pond.

When I worked at the Fisheries Lab in Woods Hole, I participated in an EPA-lead Waquoit Bay Watershed Ecological Risk  Assessment (ERA) project which identified nutrients as the major human stressors in the watershed. Nitrogen was important in Waquoit Bay which is impacted by septic systems in Falmouth, Mashpee and Sandwich which will have to be addressed by some type of joint Comprehensive Wastewater Management Plan.  For Ashumet Pond “phosphorus” was the pollutant of concern and is being studied by the US Geological Survey and UMass- Dartmouth leading to remediation efforts by AFCEC/USGS.  This scientific research and monitoring have influenced policy and regulatory action by US EPA Region 1 and Massa. Department of Environmental Protection.  These two nutrients also influence the periodic Summer cyanobacterias blooms which produce toxins which can impact mussels and other filter feeders.  Thus we need to consider more holistic approaches to address these environmental challenges.

Thus EPA Headquarters proposal to alter the cost/benefit rules underlying mercury (and other toxic chemicals) and small particulate matter emanating from coal fired power plants needs to consider far field effects like those described above for Ashumet Pond.  Many power plants have tall smoke stacks, so that the airborne contaminants can travel long distances to impact other regions of the country which have to fund the remediation costs.  A lot of the airborne nitrogen pollution on Cape Cod comes from the regional airshed.  It is unknown for PFAS chemicals how much of it comes from airborne exposure routes. 

Thus from my perspective as a retired scientist/grassroots environmental activist, the  CAA needs to be strengthened rather than weakened by US EPA. There is wisdom in the adage about a pound of prevention being more effective than a ton of cure.  EPA has a new perspective on federalism in which they want reduce national environmental mandates that diminish business development, but if states/grassroots entities want to pursue such endeavors they should pay for them.  A good example being the CWMPs to reduce “N” loading from septic systems which could cost Cape Cod residents  $ 4-7 billon over the next 20-30 years.

Dr. David Dow

East Falmouth, Ma.

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