Link to 2.2.7 Pesticides Teaching Resources
Link to Problems for Discussion

Pesticides


There is an estimated 300 000 deaths annually from pesticide self-poisoning in the Asia-Pacific region. The great majority of deaths are caused by three classes of pesticide: organophosphorus compounds, paraquat, and aluminium phosphide. Organochlorine pesticides were once important causes of fatal poisoning but their replacement by organophosphorus insecticides in agricultural practice has reduced the number of deaths they cause. There are numerous other pesticides in use globally – many of them appear to be relatively harmless after overdose.
There are several other relatively new classes of pesticides for which we currently have very little human toxicity data. Many of them are likely to be relatively harmless to humans in self-poisoning.

Syndromes from Pesticide poisoning


Significant acute exposure to insecticides or herbicides usually results in one of several clinical syndromes:
1. Cholinergic over-activity or crisis (OPs, carbamates)
2. Seizures (organochlorines, N-phenylpyrazoles)
3. Multiorgan failure or lung fibrosis (dipyridyls)
4. Muscle damage producing renal damage (chlorphenoxy compounds)
5. Methaemoglobinaemia (propanil)
6. Effects of the surfactant (probably true for glyphosate, in particular)
7. Aspiration pneumonia
8. No effect (some newer classes of pesticides)

Classes of Pesticides


2.2.7.1 Fumigants and Sterilants
2.2.7.2 Fungicides
2.2.7.3 Herbicides
2.2.7.4 Insecticides and repellents
2.2.7.5 Rodenticides
2.2.7.6 Other (eg, molluscides)

Expanded List of Pesticides


Dawson AH, Eddleston M, Senarathna L, Mohamed F, Gawarammana I, et al. 2010 Acute Human Lethal Toxicity of Agricultural Pesticides: A Prospective Cohort Study. PLoS Med 7(10): e1000357. doi:10.1371/journal.pmed.1000357


see EPA Recognition and Management of Pesticide Poisoning
OECD ChemPortal provides as searchable link to information about chemicals
Health Canada provides data on risk assessment of many important chemicals