Pesticide Registration and Regulation

Canadians are more and more health conscious and pay greater attention to diet, exercise and preventative medicine. A growing recognition of the nutritional attributes of fruits and vegetables has resulted in rapidly increasing consumption of fresh produce.

Despite these trends, many people are becoming concerned about the safety of eating fresh produce. Media reports abound on the issue of pesticide residues in food. Understandably, consumers react with fear when they read such reports. They wonder if the health benefits of increased consumption of fruit and vegetables are outweighed by the potential risk of ingesting pesticide residues.

The answers to these concerns are complex. They require a good understanding of the Canadian regulatory environment relating to food, and a perspective on making decisions involving risks and benefits.

Regulatory Approval of Pesticides

Few people realize that pesticides must undergo a rigorous regulatory clearance process by the government before being allowed for use. The proper use of pesticides is monitored through federal government evaluation programs which include residue testing.

Health Canada has the authority, under the Food and Drugs Act, for ensuring that all foods are fit for human consumption; that all foods are safe, clean and unadulterated. For the pesticides, this responsibility involves, for example, determining the safety and quantity of a pesticide residue that may be present in foods. Health Canada's Pest Management Regulatory Agency (PMRA) holds the responsibility for providing safe access to pest management tools, while minimizing risks to human and environmental health. Under the authority of the Pest Control Products Act the Agency is responsible for registering pesticides. This responsibility covers all aspects surrounding the sale and use of substances that claim to have a pest control use including safety to the producer, the consumer, the environment, and product effectiveness.

Before making a registration decision regarding a new pest control product, the PMRA conducts the appropriate assessment of the risks and value of the product specific to its proposed use. The risk assessment considers the inherent toxicity, persistence and bioaccumulative nature of the product, while addressing such key concerns as the degree to which humans and the target and non-target environments may be exposed, and the possible health hazards associated with the product. The value assessment may consider whether the use of the product contributes to pest management and whether the application rates are the lowest possible to effectively control the target pest.

Health Risk Assessment

An extensive battery of toxicity studies is required by pesticide manufacturers to determine the nature and extent of the hazard posed by a pest control product proposed for use in Canada. Long-term toxicity studies, carcinogenicity studies, reproductive and developmental toxicity studies are examples of the type of data required for evaluating the hazard on human health. If the assessment of the toxicity level of the chemical is unacceptable, the product is rejected. If the toxicity hazard is determined to be satisfactory, then an Acceptable Daily Intake (ADI) is established. The ADI is the amount of the residue that people can ingest daily, without causing harm. A large safety margin is applied to the animal toxicity data to determine the ADI.

The second component in the evaluation of the pesticide is to determine the amount of residue that may be present in foods. PMRA establishes a residue limit for the substance. A chemical residue limit is called a Maximum Residue Limit (MRL) for agricultural chemicals. Maximum residue limits are calculated so that the total consumption of the particular residue from all food sources will not exceed its ADI. Consideration is given as to how people consumer basic foods as well as processed foods, with particular emphasis on the patterns shown by segments of the population. For example, the dietary habits of infants, children, pregnant women, and older people are accounted for in the assessment process. Also, life-time exposures to chemicals are considered as a factor.

Assessment of limits is not a one-time process. It requires continual review, and the search for and analysis of new information.

Environmental Risk Assessment

Scientific data on the impact of a pesticide once it enters the environment are part of the information package required to support registration. In addition, provincial government experts and universities may be asked to participate in field trials or some other phase of the pesticide review process.

Value Assessment

Value assessment helps ensure that only those products that make a positive contribution to pest management are registered. This part of the process helps to minimize the risks associated with pest control products by eliminating unnecessarily high use-rates and by ensuring that even products of acceptable risk are approved for use only if their contribution to pest management is significant.

When the three-fold review is completed, the PIMRA either rejects the application or approves the pesticide for domestic, commercial, or restricted use. Once this "registration" occurs, pesticide use becomes a provincial responsibility. The provinces regulate who may use the pesticide, where it maybe sold and the specific conditions of sale. This responsibility usually falls to the provincial ministries of the environment.

Federal registration of a pesticide is renewed every five years. Ongoing surveillance of registered products, advances in analytical methods and improved evaluation processes provide a means to uncover environmental or health concerns, particularly with older products.

The pesticide approval process used in Canada is one of the toughest in the world and meets or exceeds the health standards established by the World Health Organization.

Monitoring Pesticide Residues

The Canadian Food Inspection Agency (CFIA) is responsible for monitoring agricultural and industrial chemical residues in foods. For pesticide residues, enforcement action is based on section 4(d) of the Food and Drugs Act, which states: "No person shall sell an article of food that is adulterated." Section B 15.002 of the Regulations defines a food as being adulterated if:

• 1) it contains any pesticide or derivative in excess of the established MRL, OR
• 2) where no MRL is established, the pesticide may not be present in an amount exceeding 0.1 parts per million.

The CFIA carries out the residue monitoring program, analysing about 11,000 food samples per year for agricultural and industrial residues. CFIA carries out several residue monitoring programs that operate under different sampling plans. Some of the sampling programs are "unbiased" to achieve statistical validity to the 95% confidence level. Other sampling programs are "biased" to capture violations in potential or suspected problem areas. Both domestic and imported foods are sampled in these monitoring programs.

When violations are found, The CFIA initiates punitive action. Depending upon the degree of hazard involved, this could involve a written warning, removal of food from retail outlets, seizure of stocks, rejection of imports, or legal prosecution. The incidence of violation is low. In 1996/1997 as part of its statistically unbiased sampling program, the CFIA found that 25% of the samples contained residues, however, only 1-2% were above the MRL. The CFIA will continue its residue monitoring program to provide further assurance of the safety of our supply of fresh produce. In addition, the PMRA conducts residue monitoring as part of its program to determine if pesticide manufacturers and end-users (producers) are meeting the conditions of registration.

Evaluating the Risks

Consumers lack perspective on the potential health risks surrounding pesticide use. Risk, the potential for harm, is present in all aspects of daily living. In particular, it must be understood that no human diet can be free of risk. What must be evaluated is the degree of risk involved in our food, and analysis of that risk in terms of potential benefits. Dr. Bruce Ames of the University of California has identified numerous natural compounds in our traditional diet that are carcinogenic to rodents. Plants develop their own poisons (natural pesticides) to fight off disease.

Consumers must learn to assess the risks inherent in our food supply. A crucial factor to remember is that the dose makes the poison. Excess intake of vitamin A can create toxic effects, yet a reasonable intake of this nutrient is essential for health. An Ad Hoc Panel on Pesticides and Cancer, convened by the National Cancer Institute of Canada, sat to examine the possible contribution of pesticide exposure to the development of human cancer. The Panel concluded that it was not aware of any definitive evidence to suggest that synthetic pesticides contribute significantly to overall cancer mortality. The Panel also concluded that it did not believe that any increased intake of pesticide residues associated with increased intake of fruits and vegetables poses any increased risk of cancer.

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