Editor:

Re: Debate over health, pesticides, Oct. 2

I am honorary Canadian observer on the U.S. Pesticide Working Group.

To say, as Dr. Hepworth does, that Health Canada’s 350-plus toxicologists are top-notch health and environmental professionals is highly misleading (it is possible, however, that some of them are capable professionals whose talents are being wasted).

Scientists at Health Canada’s Pest Management Regulatory Agency (PMRA) are almost entirely limited to examining rat data provided by the industry. Rats have a life span of only three years and may survive exposures to toxic substances humans cannot. Toxicological rat studies have a very limited applicability to humans.

On the other hand, PMRA’s epidemiology (human science) is very weak. Independent scientists do provide this agency with numerous epidemiological reports. However, there is no mechanism to search and review pesticide literature systematically and no bibliographies are compiled – each report that happens to come across someone’s desk is examined on its own, and if a single report by itself does not overturn the agency’s decision then it is put in the “disregard” file.

Yet, it is epidemiology that has convincingly linked the common herbicide 2,4-D to various types of cancer, impaired child development, Parkinson’s, and immunological and reproductive harms.

When herbicides are used in combinations, these combinations go untested even though a synergistic (reinforcing) effect is suspected. A ready-to-use synthetic chemical consists of the “active” and secret “inert” (formulant) portions, and the latter may constitute as much as 90-99 percent of the chemical. This untested “inertness” is now being questioned.

Moreover, applying these chemicals responsibly, according to the label, protects only the applicator, but does not alter their inherent toxicity, especially their adverse effect on the health of young children. It is thus highly misleading to suggest, as Dr. Hepworth does, that Health Canada pesticide evaluations are characterized by strict health and safety standards.

There is thus no justification whatsoever for the inessential use of these toxic chemicals.

K. Jean Cottam, Ottawa