Cosmetic Use of Pesticides

This was submitted to the BC Ministry of Environment in response to its call for public input in pesticide policy and possible new regulations
My Background
I’m an environmental scientist with a PhD in wildlife toxicology and 39 years of post‐university experience. I’m a registered professional biologist (RPBio) in British Columbia, and a member of the Society of Environmental Toxicology and Chemistry (SETAC), among other professional societies. I spent 21 years with Environment Canada, mostly managing pollution assessment programs with the Environmental Protection Service. My last post before early retirement was head of the Wildlife Toxics group at the Canadian Wildlife Service. Currently I consult on a variety of environmental science issues for resource development corporations and provincial and national governments and intergovernmental agencies. Besides my PhD dissertation[1], I have about 100 publications in scientific journals, government technical reports and peer‐review conference proceedings, the majority of which involve contaminants and toxicology. The list is available on‐line (www.SciWrite.ca).
“Approved” pesticides that were later found to be harmful and were banned
When I worked for the Environmental Protection Service, my colleague in the next office was on a federal‐provincial committee that reviewed and approved or rejected (rarely) pesticide applications. He also supervised the ocean dumping program and chaired the committee that approved or rejected ocean disposal applications. I often noticed that his committees would approve applications for pesticides that, based on the scientific literature, were dangerous to people and/or the environment. In some cases, my own group did the research that showed toxicity to indicator organisms, or to benthic communities in the marine environment. When I asked him about this, he would reply to the effect that, “Since it is approved for this use by Agriculture Canada, we can’t deny the application.” Nevertheless, many of the pesticides that he and other officials approved were later banned when more research revealed that they were, in fact, dangerous. Here are some examples:

1. In 1971 while pruning apple trees in the Okanagan, the orchard owner and I were discussing a recently announced ban on consumption of fish from the Okanagan Lake because of high mercury levels[2]. The orchardist didn’t believe that mercury was a problem and thought that mercury had always been there naturally, but had only been discovered in the fish because scientists had developed the analytical capability. He complained that he would be made to stop using mercury‐based pesticides on his apples because of this. In a later conversation, I asked him why he didn’t graze his horses in the orchard, where grass was plentiful. “I used to,” he said. “But they kept dying. The vet said it was mercury poisoning.”
2. Tributyl tin (TBT) was approved for use as an anti‐foulant on ship hulls, but in 1988 the nascent salmon farming industry began using it on their nets. My group discovered this by finding that nearby oyster farms were experiencing high mortalities and deformed growth typical of TBT poisoning[3]. The oysters and the fish produced by the salmon farms had TBT at levels exceeding Health Canada guidelines for pesticides. Agriculture Canada then banned TBT for use on fish nets; subsequently, TBT use was greatly restricted for use on boat hulls[4].
3. My group found high levels of ideopathic (pre‐cancerous) lesions in fish from Vancouver Harbour associated with polynuclear aromatic hydrocarbons (PAH)[5], several of which are known to be carcinogenic at extremely low (ppb range) concentrations. The sources were many, and included creosote used to protect wood pilings from decay and attack by marine organisms. Meanwhile, Environment Canada was issuing ocean dumping permits that specified a 25 ppm limit for “hydrocarbons” and many of the dumping applications were for sediments from Vancouver Harbour that were heavily contaminated with PAH[6]. The “hydrocarbon” limit was intended to protect marine organisms from ordinary oil and grease, not PAH. My colleague and his committee members felt powerless to reject applications for high PAH because it was a “hydrocarbon.” After about three years, as my group and others accumulated scientific information, new guidelines for PAH were developed nationally and internationally that were much more restrictive and include chemical testing at low ppb detection limits, followed by biological testing if detected.[7] No material with 25 ppm PAH would be approved today anywhere in the world today. Health advisories against fish consumption were issued, and under the “Green Plan” we got $5 million for a federal‐provincial‐municipal plan to clean up Vancouver Harbour.
4. Creosote had many other uses, including protection of railroad ties and fence posts. As a result of the above and other new data[8], creosote was banned in BC.
5. 2,4,5‐T (“Agent Orange” used to defoliate Vietnam during the Vietnam War: 2,4,5‐trichlorophenoxy cetic acid) was used in paint, and a 1984 spill of it from a paint plant into Nicomecl River killed fish all the way down to Boundary Bay[9, 10]. We found that some of the dead fish and crabs were contaminated with dioxin (the most toxic synthetic chemical known), a contaminant in the 2,4,5‐T formulation. This was first measurement of dioxin in Canada.[11]
6. During 1985–1990 my group at Environment Canada discovered that dioxins were produced by pulp mills and were contaminating marine fish at levels that threatened health of consumers[12, 13]; our colleagues monitoring freshwater systems found the same with interior pulp mills. Wood chips from sawmills that used various formulations of 2,4,5‐T, PCP (pentachlorophenol) and related compounds as anti‐fungal pesticides were one of the sources of dioxin in the pulping process. Eagles, herons and ospreys feeding in these environments were accumulating dioxins at high enough levels to affect reproduction[14-16]. Dioxins also appeared in river otters and mink[17]. Jointly with Health Canada and Fisheries and Oceans Canada, we closed about 170,000 ha of marine fishing areas near pulp mills, imposed similar restrictions downstream from mills on interior rivers, and issued health advisories against consuming marine and freshwater fish and shellfish from these areas. PCP and 2,4,5‐T were ultimately banned in BC and new regulations for pulp mill effluent and for dioxins in any effluent were brought in nationally, becoming effective in 1992.
7. While managing the Wildlife Toxics group at the Canadian Wildlife Service (CWS), people often brought in ducks, geese, swans, hawks, and eagles that were dying or dead from pesticide poisoning[18, 19]. The documentation that we and others provided[20, 21] resulted in the national banning of four pesticides by Agriculture Canada in 1997.
8. DDT was banned in Canada in 1971, but remained in widespread use in the Okanagan for about another four years[2]. In the mid‐1990s biologists at CWS found that worms and other soil invertebrates were taking up DDT and its metabolites DDD and DDE and transferring these to songbirds and quail at levels high enough to affect reproductive performance[22-25]. Anecdotally, the toxicologist directing the study mentioned that the soil at one orchard had such high DDT levels that it would have qualified as a “special waste” under provincial regulations; ironically, this orchard was certified organic. Modelling of uptake showed that peregrine falcons feeding on orchard birds would also be adversely affected[26].

Even “safe” pesticides kill non-target organisms
The environment and humans in British Columbia are safer because of the above achievements, but they are a warning that we do not know everything we need to know about environmental and human health safety of pesticides. More nasty surprises are in store for us. What we do know is enough to warrant caution for the use of pesticides for cosmetic purposes. For example, studies have shown that 2,4‐D (a common herbicide for dandelions and other broad‐leafed plants that is chemically related to 2,4,5‐T) on lawns kills earthworms and other soil organisms that are necessary for full health of the soil ecosystem. Some “approved” insecticides that people put on their lawns (e.g., to kill leatherjacket grubs) also alter the soil ecology and remain toxic for long enough to kill or affect the reproductive performance of songbirds that consume them.

Some people are more sensitive than others
Walking around the neighbourhood, I notice that commercial yard care companies, after treating lawns with pesticides, put in signs saying that the treated lawns are safe for kids and pets. This is simply not true. Toxicity testing can show lack of effects, but can never prove safety. Such signs should never be allowed. Some people are more sensitive to pesticides than others. For example, I learned early in life that I’m allergic to mercury, which in the 1950s was used as an antibiotic in bandages (remember those red pads with mercurochrome or merthiolate?). Mercury has been banned for such uses for half a century. Here’s another example: in 1981, while wearing a wool jacket, I sprayed my cherry and apple trees with an approved insecticide from the hardware store. Then I picked up my three‐year-old son. Within an hour, his cheek where it brushed that wool jacket broke into a rash that persisted for some weeks. This was chloracne, a potentially serious skin condition caused by organohalogens and other common components of pesticides. My son later showed other skin sensitivities; for example, guava juice repulsed him and when spilled on his chest caused raised red welts to form. This doesn’t mean that the natural compounds in guava juice should be banned, but proves what toxicologists already know, that some people are more sensitive than others and have adverse physical reactions to compounds that are otherwise completely safe. No one can guarantee that such people will not be exposed to pesticides used on a lawn.

Conclusion

For these reasons, I do not believe that because a pesticide has passed Agriculture Canada’s toxicity testing, it is necessarily safe for use around people. Nor does it guarantee that approved pesticides will not harm non‐target organisms in the environment. Therefore I support a complete ban on cosmetic pesticides made from synthetic organic compounds.
I would not, however, recommend proscribing elements such as sulfur (good for fungus on roses) and elemental compounds such as ferrous sulfate for moss control as “pesticides,” or any fertilizers. I would not support a blanket ban on all pesticides, but would recommend that non‐cosmetic use in urban and suburban environments be permitted in cases of infestation or disease, that only certified people may apply them, and signs must be stalled informing the public that pesticides have been applied without comment on safety. People can decide for themselves whether to walk on the grass or not.
Lee E. Harding, PhD, RPBio, January 13, 2010
References
For brevity, the 26 references cited in this paper are not included here. Please contact me if you would like a copy with the reference list.