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Archive: Copper ban pending again in California, USA

In favor of coating manufacturers, the California state senator Christine Kehoe has abruptly halted her long-fought effort to ban the use of copper antifouling paint on recreational boats in the state of California. She has withdrawn the bill, which would have prohibited manufacturers from selling recreational vessels with copper-based bottom paint in California after 2014 and recreational boat owners from using or applying copper-based paint after 2018.

Kehoe has been pushing hard on the bill with the support of the Port of San Diego and San Diego Coastkeeper. Marina bays in the area have been seriously impacted by excessive copper concentrations in the water body, primarily from hull antifouling paints.

Kehoe’s measure easily passed the state Senate in June 2011, on the heels of a similar ban in Washington State that was signed into law the month before. However, the California bill ran aground in the state Assembly, fueled by fierce opposition from boating groups and the American Coatings Association (ACA), which represents coating manufacturers. Although the ban would have applied only to recreational vessels, ACA feared the measure would set a bad precedent that could affect other marine coatings of professional use. ACA and the boating groups also contend that today’s non-copper-based antifouling paints are not as effective or sufficiently available as copper-based biocide antifouling coatings which are doubted by Japanese paint manufacturers in special. In August 2011, Kehoe quietly decided to hold off on the bill until this summer, to allow more time for the parties to work out a compromise. In a letter of May 30 to supporters and ACA, she cited studies now underway that could affect the science underpinning the measure:

Given some of the outstanding issues highlighted in your letter, such as the near-completion of the U.S. Environmental Protection Agency’s marine Biotic Ligand Model for copper and the hull cleaning study requested of the marine coatings industry by the Department of Pesticide Regulation, I agree with you that it makes sense to defer the bill until some of these essential items are completed in 2013.” Still, the copper problem will require answers. Water quality in coastal waters and marina bays nationwide is being hard hit by copper and other metals in hull paints. In California, all of San Diego’s eight marina basins have been found to suffer from overloading of copper, virtually all of which is caused by passive leaching of the copper from antifouling coatings and periodic hull cleaning by divers, state and federal officials say.

“Gale Filter, executive director of San Diego While the environmental NGO Coastkeeper states that the problem is not going to go away told the Union-Tribune. On the other hand, Hopewell believes that EPA’s Biotic Ligand Model may well show that the copper threat to waters has been overstated. BLM is a relatively recent method of calculating metal toxicity using 10 water chemistry parameters. BLM “could fundamentally change how we define copper-impaired waters,” Hopewell said.

Earlier this month, ACA submitted comments to the U.S. Environmental Protection Agency (EPA), urging the agency to expeditiously adopt the Biotic Ligand Model (BLM) for saltwater. The BLM has been a long standing standard for measuring copper in freshwater environments which has now been adapted to marine waters. A few U.S. marinas have been seeking to reduce copper in marinas using caps, or so called Total Maximum Daily Loads (TMDL).

A recent study by the Port of San Diego has indicated that using the BLM to measure copper in the Shelter Island Yacht Basin may allow the body of water to meet the TMDL without any statutory restrictions on hull coatings.

The BLM focuses on the fact that copper leached form antifouling paint as copper-ion is toxic and effective against aquatic organisms but is labile and complexed to suspended mater in short time. When inactivated by complexation it is readily sinking into the sediment. The weak points of this model are variable parameters like organic content, hardness, pH and salinity which influence the complexation process. In addition the fate of copper compounds in the sediment regarding remobilization is quite different according currents, tidal exchange of water bodies and biogeochemical cycles.

Since the U.S. marine coatings industry replaced tributyl tin (TBT) in antifouling coatings with more environmentally friendly copper-based coatings nearly a decade ago, there have been questions about the effect of copper coatings in U.S. ports. As such, measures have arisen in some states that would seek to ban copper antifouling coatings for recreational vessels.

In its comments to EPA, ACA noted that preliminary results using the BLM for saltwater in places such as the Shelter Island Yacht Basin in San Diego demonstrate very little to no toxicity in the water column. This is a very different result than using the current method designed by the EPA in the 1970s. The BLM is actually the most favored model available for assessing site-specific water quality in saltwater and ACA encouraged EPA to adopt this model and advocate for its use across the United States, arguing that using the best available science will aid the states in making the right public policy decisions.


Paint Square News, June 2012






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