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Achieving a Balance: Four Challenges for Canada in the Next Decade – Responding to environmental contaminants
Canadians are worried that environmental hazards are affecting the health of children (Ekos poll, September 2000: 93 percent). In the past quarter century, asthma has increased fourfold and is now the most common chronic illness in Canada. There has been a 25 percent increase in the incidence of childhood cancers. Allergies among children have also risen dramatically.
For several decades, governments have controlled the health risk of chemicals by examining substances one at a time and determining safe thresholds of exposure. The latest concern is over the effects of combinations of chemicals, ranging from pesticides to harmful air emissions to food additives. Individually, these chemicals may be at levels that pose no evident harm. In combination they may be unhealthy, particularly for children, whose bodies, brains, and immune systems are less developed and more vulnerable to contaminants.
Researchers now suspect that accumulated pollution and low-level exposure to several pollutants at once (also known as "total pollutant loads") have interactive and cumulative impacts on human health. Exposure may fall short of causing death or hospital admission, but still may affect large numbers of people. Ongoing exposure to low levels of pollution may result in permanent harm to healthy human function.
Immunological and neurological systems are particularly vulnerable in the unborn, young children, and the elderly. Impaired neurological function can cause learning disabilities and diminished intellectual capacity, while weakened immune systems make us more vulnerable to all disease.
Accumulation of environmental contaminants may be causing subtle but widespread damage to human health. More resources must be invested in researching and monitoring the combined effects of substances, especially with respect to neurological and immunological functioning.
We do not yet fully understand the impacts of individual toxic substances on human health, but we already face the additional complexities of trying to understand their cumulative and interactive impacts. Canada's standard-setting processes have not yet properly taken combined impacts into account.
Some scientists believe we need to radically change the way we think about managing these substances. We cannot wait for an entire generation of affected children to prove the worst expectations. Improving the environment to protect our children's physical health and intellectual capacity is not only a pragmatic precaution but a clear investment in our society and economy.
Our longevity and quality of life may depend on the development of comprehensive and coordinated research efforts to better understand the effects of total pollutant loads and a revamped regulatory approach to implement our new knowledge.
© 2013