1) Ethylene glycol is a colourless, odourless, relatively non-volatile liquid. It is widely used as an anti-freeze and deicing agent. It is also used as an ingredient in inks found in ink pads and ballpoint pens. It is used as solvent in the paint and plastics industry, and is used to produce polyester fibres. It is an intermediate in the manufacture of polyethylene terephthalate (PET). It has been used is some cosmetics but this was a very minor use.
2) Ethylene glycol has been approved for use in the US as an 'Antifreeze, deactivator for all pesticides used before crop emerges from soil and in herbicides before or after crop emerges'. As it is not an active ingredient it has not been reviewed by JMPR. I do not know of its use elsewhere in pesticides. I know of no use such as suggested, i.e. to make the pesticide visible when it is used.
3) As with all chemicals, the risks associated with its use depend on the exposure level. Ethylene glycol is of low acute toxicity. The effects of exposure to large amounts of ethylene glycol are mostly a consequence of its metabolism to acidic products, including oxalic acid. Intoxication with ethylene glycol results first in effects on the brain (central nervous system), with feelings of tiredness, seizures and unconsciousness, metabolic acidosis with disturbances of acid-base balance, followed by effects on the heart and lungs (increased heart rate, high blood pressure, tissue damage), and finally renal damage, due to crystallisation of the metabolite calcium oxalate in the urine, leading to renal failure. Repeated exposure to high doses, below those causing acute intoxication as above, can lead to renal damage and renal failure. Less severe effects in the liver may also be seen at these doses. Low doses, even on repeated exposure do not cause any harm. There is minimal risk from use of the chemical as recommended, or from exposure to products that contain ethylene glycol, unless there is intentional or accidental intoxication. There is no additional risk from mixing ethylene glycol with pesticides, as long as the formulation is used as recommended.
4) The closely related compound, diethylene glycol, has been added illegally on occasion to wine, to increase its 'body' and sweetness. Although this is potentially toxic, the WHO International Programme on Chemical Safety estimated that to be harmful 28 bottles of wine per day would need be consumed for two weeks. There is no evidence that ethylene glycol has been used in this way, but given that it has similar characteristics to diethylene glycol, including a sweet taste, such misuse is a possibility.
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