by
Larry Pynn and Darah Hansen
The B.C. forests ministry has produced a map of thousands of trees that the public and loggers are urged to avoid due to arsenic residue from the application of a pine-beetle pesticide no longer used in Canada.
Monosodium methanearsenate, or MSMA, was widely used in B.C.'s northern and Interior regions from the mid-1980s until 2004 with assurances at the time that the pesticide, sold under the trade name Glowon, posed little threat to the environment or to human health.
By 2005, MSMA was no longer in use in Canada after the manufacturer allowed its permit to expire.
In 2006, the U.S. Environmental Protection Agency announced its intention to not re-register MSMA as an organic arsenic pesticide because it posed a cancer risk due to its potential to "transform to a more toxic inorganic form of arsenic in soil with subsequent transport to drinking water." MSMA continues to be sold in the U.S.
In 2008, published research by Environment Canada researchers in Delta warned that management practices such as the application of MSMA and large-scale salvage logging had the "potential to limit woodpecker populations" through direct toxicity, loss of food sources, and loss of habitat.
Tim Ebata, a provincial forests health specialist, said in an interview Wednesday that despite such concerns, he had no evidence of any appreciable environmental or public risk associated with use of the pesticide to fight the pine beetle's spread in the province's commercial forests.
In the U.S., MSMA is used in various products for cotton as well as turf, including on golf courses, home lawns, school yards, and athletic fields.
Ebata said the province is showing "due diligence" by conducting a representative analysis of wood from treated trees as well as untreated trees, shrubs and soils to determine current arsenic levels. Results are expected in early 2009.
No tests are planned in surrounding streams, he added, because the pesticide was not applied within 10 metres and because "arsenic doesn't move that readily in soil because it binds to the soil particles and to the tree tissues."
The ministry used MSMA as part of B.C's effort to stop the spread of the mountain pine beetle. Individual trees were girdled with an axe and injected with the pesticide to kill the beetles and the trees.
The pesticide proved a safe and cost-effective alternative to cut-and-burn methods, Ebata said, although the spread of the pine beetle across much of the province ultimately proved unstoppable.
Mapping of the trees is close to completion, and can be viewed along with other background information at www.for.gov.bc.ca/hfp/health/MSMA.htm#links. Local forests district offices also have information.
Mapping shows concentration of the chemical in the northern and southern Interior regions, including Fort St. James, Prince George, Kamloops, and the Okanagan.
Ebata said anyone travelling in the areas should be able to identify the treated trees by the axe scars as well as flagging tape, paint, or waterproof tags.
The provincial action is in response to a Forest Practices Board report in 2004 that recommended, in part, the ministry track MSMA-treated trees to ensure they are not harvested or milled. The board found MSMA was used near human habitation and that treated trees were subsequently logged and milled within a year.
Dr. Josette Wier, a former pediatrician from France now living in Smithers, said she has been fighting the use of MSMA since 2000 and puts much of the blame on Health Canada for allowing the sale of such products in Canada without adequate long-term studies on human and environmental health impacts.
"We just don't know what we're doing," Wier said from Toronto, where she is attending a Canadian Cancer Society conference on the link between cancer and pesticides.Vancouver Sun
