Jean Cottam

An ever increasing number of Canadian municipalities are now protected by pesticide bylaws and Québec Pesticide Code, by-passing our faulty federal pesticide regulatory system, which relies on undisclosed data provided by the industry and the US Environmental Protection Agency (EPA).

Both the EPA and Health Canada’s Pest Management Regulatory Agency (PMRA) have been criticized for their lenient pesticide registration criteria regarding their proposed re-registration of 2,4-Dichlorophenoxyacetic Acid (2,4-D). On February 21, 2005 the PMRA released the “Proposed Acceptability for Continuing Registration” (PACR) document pertaining to non-agricultural use of 2,4-D. The deadline to comment on the document was Earth Day (April 22).

Agent Orange
2,4-D, mixed with other phenoxy herbicides and one of the most widely used weed-killers, was a component of Agent Orange used to defoliate trees in Vietnam. The other component, 2,4,5-T, was banned following a serious industrial accident involving the escape of a toxic dioxin 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD) in Seveso near Milan, Italy, in 1976. (The nature and role of dioxins will be discussed later on in this column.)

Individual Vietnamese are now suing Monsanto and Dow Chemical, the manufacturers of Agent Orange. US veterans who had suffered serious health effects, often passed onto offspring, fought for and obtained compensation, in contrast to Australian Vietnam War participants who received nothing. The Royal Australian Commission looking into the Australian veterans’ claims was influenced by Monsanto and the latter was hostile to Dr. Lennart Hardell, a reputable Swedish oncologist representing these veterans. The industry now blames the toxicity of Agent Orange on the banned ingredient, 2,4,5-T.
EPA under attack
The EPA’s 2,4-D assessment came under attack by Washington’s Beyond Pesticides et al, including Québec’s Coalition for Alternatives to Pesticides (CAP). Of concern is poor understanding of child exposure, as well as the scientifically indefensible use of the exceptionally insensitive species (rat) on which to base the human health risk assessment. Moreover, the EPA is requested to consider the aggregate toxicity of all phenoxy herbicides in 2,4-D product formulations; to cancel all registered use of Weed and Feed products [they are incompatible–the fertilizer to be used over the whole lawn, the herbicide intended for spot treatment]; to withhold re-registration until the risk of dioxin production is removed and all information is received, assessed and opened for public comment; and to use the weight of evidence and classify 2,4-D as a Class C ‘possible human carcinogen.’ (It is currently classified as a Class D, a neutral category.)

2.4-D to be banned in Québec
2,4-D, one of the 22 pesticide active ingredients to be banned across the Province of Québec, was put on the Québec list, because it was found to be a risk by the International Agency for Research on Cancer (IARC), reporting to the World Health Organization. There is likely to be a secret “formulant” in 2,4-D, called an “inert” element in the United States, which is added to make the herbicide more potent or easier to use. Some formulants are considered carcinogenic by the IARC.

The label
The PMRA claims that a registered pesticide does not pose an “unacceptable risk” if label directions are followed. (A “label” may consist of thirty pages.) This means that we, our children, our pets, our environment are at risk of harm when label directions are not followed. Moreover, it is impossible to monitor every usage across Canada. We have already seen that most professional applicators do not even protect themselves adequately when applying pesticides on lawns. One may ask: “what is unacceptable risk and to whom?” Moreover, is any risk justified where at stake is control of harmless weeds?

In Canada it is illegal to advertise that a pesticide is “safe.” Yet, contradicting the provisions of the Pest Control Products Act, the PMRA released an “Information Note” stating that “2,4-D can be used safely on lawns and turf.” The chemical lawn care industry took advantage of this statement in advertising the alleged safety of their product and opposing pesticide bylaws.

Epidemiology neglected
According to Dr. Meg Sears (MEng, PhD) of the Coalition for Healthy Ottawa (see, the PMRA specifically attacked the report on human epidemiology prepared by the OCFP (Ontario College of Family Physicians), criticizing both the report’s incomplete data (the PMRA had denied the OCFP access to some of this data), and the well-accepted process of systematic literature review pursued by the OCFP. It seems that the PMRA has a predilection for questionable rat studies–yet rats have genes for detoxification of chemicals lacking in people.

The PMRA’s “Independent Science Advisory Panel” were of the opinion that childhood cancer merited more study, but the PMRA found this too difficult and instead relied on animal studies that do not demonstrate carcinogenicity. However, in the PMRA’s response to this author’s Environmental Petition, the PMRA went even further by stating that proven carcinogenicity in animals was not necessarily indicative of human cancer.

Reproductive Problems
The PMRA declared 2,4-D was “safe” before receiving a reproductive study from the Industry Task Force II on 2,4-D Research Data. Yet 2,4-D has been found in semen and blood, and was linked in open literature to reproductive problems and gender imbalances.

Neurological Impairment
The PMRA declared 2,4-D “safe” before receiving developmental neurotoxicity studies from the industry. Yet lawn pesticides have been linked, among other things, to Alzheimer’s and Parkinson’s diseases, autism and ADHD (attention deficit hyperactivity disorder). Neurological impairment has been noted as a possibility on the pesticide label for professional applicators, without such warning being provided on product intended for homeowners who themselves apply the herbicide.

“2,4-D may cause severe irritation to the eyes. Prolonged breathing of 2,4-D may cause caughing, burning, dizziness or temporary loss of muscle coordination. Other possible effects include fatigue, muscle weakness or nausea. Treat symptomatically.”

Dioxins not monitored
In the manufacture of 2,4-D, chlorinated dioxins are inevitably formed during the manufacturing process. Dioxins persist in the environment, may cause cancer, harm neurological development, impair reproduction, disrupt the endocrine system and alter immune function. The PMRA relies on the manufacturer's testing of 2,4-D to monitor dioxins; however since 1983 no such monitoring has been carried out and the recent PMRA announcement stated that required dioxin data had not yet been provided by the industry.

PMRA and dioxins
According to Canada's Environmental Protection Act (CEPA), dioxins with 2 or more chlorine atoms (chlorines) are targeted for virtual elimination. Dr. Meg Sears says that dioxins with 2 and 3 chlorines will be the predominant contaminants in 2,4-D. However, the PMRA is only asking for analyses of dioxins with 4 or more chlorines (made famous by the Seveso, Italy, disaster in 1976). Thus, the PMRA is in contravention of the CEPA. Moreover the pending analyses will be carried out on five samples picked by the industry and analyzed for the industry. (Low temperature samples with little contamination will doubtless be chosen.) In Canada no monitoring of “of-the-shelf” product nor of of the presence of herbicide-related dioxins in the environment, including streams, rivers and lakes, is being pursued. Dr. Sears concludes that the sporadic contamination by dioxins could be an important contributing factor of the inconsistent epidemiological evidence of the diverse morbidity linked to pesticide use.

Chemicals not considered
2,4-D herbicide products take the form of various salts and esters. Among these products, the diethanolamine (DEA) salt is particularly toxic, and was explicitly excluded from the review. Yet it can be found in many Weed and Feed type products. As a rule, 2,4-D is mixed with other pesticides and ingredients and the overall toxicity is not considered.

Breakdown product
No break-down product toxicities were mentioned by the PMRA. The bad odour that emanates from storage or use of lawn pesticides is the smell of the first such product, 2,4-dichlorophenol, which is very toxic yet not even mentioned in the review of 2,4-D by the PMRA.

Scientific Process
Important gaps in relevant information do exist. For example, reproduction and neurotoxicity studies required by the PMRA were not submitted by the industry, and cancer due to children’s exposure will not be considered. Child cancer merited special studies, but this proved too difficult; instead animal studies were used exclusively.

Secret industry studies
According to Dr. Sears, using industry-provided, secret studies that are not open for peer review and reliance upon reviews by self-interested parties, rather than pursing a systematic review of primary literature, are problematic. Canada does not track pesticide sales or use, and has no adverse effects reporting system.

Dr. Sears concludes that, “ rather than illuminating risks, the PMRA has been derelict in its duty to compile relevant information and to weigh it dispassionately. The report is at best premature,
since all relevant data was not in hand.” The PMRA’s “Proposed Acceptability for Continuing
Registration” (PACR) contradicts Canada’s Environmental Protection Act (CEPA) and does not meet the desired ethical, accuracy and transparency standards. “Well-executed science may illuminate the nature and magnitude of risks, but it can neither define an ‘acceptable risk’ nor ensure ‘safety’.”


K. Jean Cottam

This email address is being protected from spambots. You need JavaScript enabled to view it.

Tags: Jean Cottam