By LUMA MUHTADIE
Globe and Mail Update
May 11, 2004
Ottawa must make drastic changes to the way it evaluates the safety of pesticides and conduct large-scale study on the effects of chronic exposure to the chemicals on the health of Canadians, environmental groups say.
The Sierra Club of Canada and the Coalition for Alternatives to Pesticides (CAP) say a U.S. government study that found traces of pesticides in the blood and urine of nearly all 9,282 of the subjects it tested is a clarion call for the Canadian government.
"Everyone who has seen the study is asking 'is this the same in Canada?'" said Andrea Peart, director of health and environment at the Sierra Club. "The issue is no one is even checking. We don't know."
The study, done by the U.S. Centers for Disease Control, analyzed the so-called "pesticide body burden" – the amount that remained in the subjects' body as a result of exposure to 34 pesticides – and the long-term health effects.
The body burden of two pesticides – chlorpyrifos, an insecticide more commonly known by its commercial name Dursban, and methyl parathion – far exceeded the thresholds established as acceptable by the U.S. government.
"And we don't even have thresholds in Canada," Ms. Peart noted.
On average, subjects showed traces of 13 pesticides in their blood and urine, according to the CDC study.
Adult women, including those of child-bearing age, were found to have the highest measured body burden levels for three of the six pesticides explored in a class known as organochlorines.
Many pesticides in this class can cross the placenta and cause harm during fetal development, including reduced infant birth weight and disruption of neurological development during infancy, potentially leading to learning disabilities and other neurobehavioural problems.
In his own group's study, Michel Gaudet of the Quebec-based CAP, tested the levels of pesticide metabolites in his family and discovered his wife had the highest levels, followed by his youngest daughter.
Children are known to be particularly vulnerable to pesticides because of their low body mass to skin ratio (pesticides can be absorbed through the skin), immature immune systems, and over exposure – children eat drink and breathe more air per kilogram of body weight than do their adult counterparts.
The CDC study also found that Mexican Americans, many of whom work in the agricultural industry, had significantly higher concentrations of five pesticide metabolites in their blood and urine, including lindane and DDT, which hasn't been used in the United States since the government banned it in 1971.
The Canadian government banned DDT in 1969, but lindane, an organochlorine insecticide whose uses in agriculture and on pets have been banned, remains available in shampoos used on children and adults to treat lice.
Ms. Peart said the fact that a comparable study hasn't been commissioned in Canada represents "a failure on the part of the Canadian government."
The Sierra Club and CAP are urging Health Canada to spearhead a nationwide double-blind study that looks at the pesticide body burdens in Canadians.
They are also asking Ottawa to rethink the current approach to evaluating the toxicity of pesticides.
In Canada, the effects of pesticides are measured and evaluated individually, but they do not consider the way several pesticides can interact and exert synergistic effects in the body.
"Pesticides are volatile chemicals," Ms. Peart said. "We don't live in labs. We are not exposed to pesticides one at a time, we are exposed to many."
The two groups say Canada should ban all persistent, bio-accumulative pesticides – those stored in fatty tissue – because they recycle in the food chain and persist in the environment.
The report follows an Ontario College of Family Physicians study released last month on the chronic effects of pesticide exposure in the home, garden and workplace.
After reviewing 12,000 international studies conducted between 1990 and 2003, the college found "consistent evidence of the health risks to patients with exposure to pesticides," citing brain cancer, prostate cancer, kidney cancer, pancreatic cancer and leukemia among other acute illnesses.
They found no evidence to support the notion that some pesticides are less dangerous than others, saying different types simply have different effects on health.
http://www.globeandmail.com/servlet/story/RTGAM.20040511.wpest0511/BNStory/National/
© 2004 Bell Globemedia Publishing Inc. All Rights Reserved.
