Pesticide: Any substance intended for prevailing, repelling, attracting any pest including unwanted plant as animal during production transport and processing of food and animal food.
Residue: Residue is a term applied when any pesticide applied to soil, plant or broadcasted in soil and due to the physico- chemical parameters (environmental parameter) it is subjected to change in chemical form. Thus some toxic substances remains as such or its metabolites. Residue is a reminenant of the chemical including its degraded products with a span of time or time factor when exposed to environment including degraded products of adjuvant.
In environment pesticide residue obtained from plants. Out of which 20% remains on plant and 80% fall in soil and when you irrigate the crop and then soluble amount go into water and this leached water is collected at some place and it will pollute ground water.
When fodder Alpha-alpha is grown for the fodder purpose and given to animals, then in milk of those animals residues of organochlorine pesticide are found and are lipophilic in nature which causes harm. When Pesticide 25kg a i/ha applied, residue after harvest of crop is found in PPM.
Pesticide residue is major problem in chlorinated and organophosphorus compounds, as they are not easily degraded. In chlorinated hydrocarbon bio-magnification occurs i.e., pesticide residue goes into the soil then into water and enter in organism or in food chain these molecules get accumulated in fats and therefore their concentration increases. Which has long term effect like teratogenic (birth defect), carcinogenic effect which is seen particularly in birds whereby thickness of shell is reduced. Sometimes lethal mutation also occurs.
A concern more specific to pesticides is any danger attached to chronic regular intake of small quantities as residues in our food. Like radioactivity, pesticide levels decrease with time along a hollow curve. If half the pesticide has gone in 5 days, the ¼ will still be there after 10 days, 1/8 after 15 days, 1/16 after 20days, and so on. Great alarm followed the discovery in the 1940s that post-mortems of, for example, accident victims revealed measurable quantities of DDT in the body fat of nearly all inhabitants of developed countries and that no restaurant meal could be found free of DDT residues in such countries. The alarm was heightened by the linear increase of these DDT residues in body fat year after year. However, it could later be shown that man eventually attained a plateau level of about 10 parts per million (ppm) DDT in body fat, and that thereafter further intake was balanced by elimination from the body. More modern pesticides also lead to residues in our food, but are much more quickly broken down and lost from our bodies.