7 February, 2014. Pesticides are less necessary at latitudes far from the Equator, as fewer pests survive. So Canada would not have reason to use the same battery of chemicals as in the tropics. Not quite. The Ottawa government and Health Canada have supported the necessity to allow multiple pesticides that have long been banned elsewhere, e.g., in the European Union. Now the government has agreed to review 23 pesticides again.
Two NGOs, Ecojustice and the David Suzuki Foundation, filed lawsuits against the government last year. According to the law, the authorities are required to review chemicals that are banned in any other member of the Organisation for Economic Co-operation and Development (OECD). The Canadian Pest Management Regulatory Agency quietly responded at the end of 2013 by posting a message that the 23 pesticides would now be reviewed. The decision has just received attention this week.
The decision involves 5 pesticides known to be neurotoxic. Carbaryl – used in some flea collars and domestic bug killers and also for protecting a variety of crops against insect pests. 2,4-D – a herbicide used in agriculture and also as weed killer in gardens. Diazinon – used for insect control on various crops and ear tags on cattle. Dichlorvos – used for insect control inside buildings. Pentachlorophenol – a wood preservative.
All of these substances present risks to human health, may contaminate drinking water, or cause ecological damage. However, toxic effects on the human brain is not commonly listed for these 5 compounds as a main reason for concern.
Why not? First all, cancer risk and ecological harm are often sufficient to to restrict the uses of a product. Second, the documentation on neurotoxicity and chemical brain drain is usually weak. For 18 of the 23 compounds, no information has been found on their possible adverse effects on human brains, at least not yet. Does this mean that the compounds are safe for developing brains? Of course not. For some of the pesticides, laboratory studies have clearly shown that the compounds are toxic to nerve cells and brains, although usually in rats, mice, and cell cultures.
When reviewing the pesticides in current use, the Canadian government should also consider the need to protect the developing brains of the next generation of Canadians.