Agricultural effluents include the process of flowing of insecticides and other chemicals used in agriculture along with water.
Soil erosion due to defective agricultural systems also supports it. At present, fertilizers, pesticides and insecticides and biotic killing chemicals are being used for increasing agricultural productivity.
Their discovery and use are important for the present age. Many chemicals like sulphur, copper and lime have been in use for destroying harmful insects, for control of crop diseases since many years.
Chemical materials for destroying insects include the following five types:
Different types of chemicals are used for making these materials which get mixed with irrigation water. Among them are poisonous elements like mercury, calcium, lead, arsenic, nickel, manganese, chlorine, boron etc. all of which have harmful effects on man as well as animals.
In the present times, sewerage farms are being developed from water mixed with urban effluents and vegetables are being cultivated there. Unfortunately, fungus, bacteria, harmful insects and non-carbonic elements are polluting the vegetables, which have a poisonous effect. Labourers working on sewerage farms also face health risk, because living amidst polluted water makes them suffer from skin diseases, breathing problems and digestive problems.
During irrigation of sewerage farm, groundwater becomes polluted due to infiltration of water underground. This can have a harmful effect on trees, plants and biotic organisms. Excessive irrigation results in salinity in soil, while excess water brings existing salts and alkalinity from lower layer to surface and makes the soil sterile.
Fertilizers used in agriculture, mainly nitrates phosphates, urea etc. also cause pollution because of imbalanced use of these fertilizers flow away with water and pollute it. This water also develops algae. Useful bacteria in soil (Azotobacter, Azospirillum, Azolla) are greatly affected by groundwater pollution, resulting in deterioration of its agricultural productive capacity.
In most of the chemicals used in agriculture, poisonous elements like mercury, arsenic, chlorine, fluorine, phosphorus etc. exist, which affect the biotic life and pollute water by agricultural effluents. In the beginning, fertilizers were used lo the maximum extent but when their destructive effect was known, I lie developed countries started their balanced use. DDT insecticide being the most harmful, it’s used was banned.
In India also, ban was imposed on 30 September 1992, on most harmful insecticides. The main among them were andrine, touxafan, haftachlor, aldrine nitrofan, tetradiphone, pentachlorophenol, chloroden, pentachloro- niytobenzene (PCNB), hybromo-chloro-propane, methyl parathion and paraquait – diamethyl-sulphate.
During present times, some common chemical pesticides used m agriculture contain the following carbonic and non-carbonic elements:
1. Organochlorine insecticide – aldrine, dia aldrine, BHC (Benzene Hexachloride), DDT (Diachloro-diaphenoyl- trichloromethyl methane), heftachlore, hdane
2. Carbomate insecticide – Carbaril
3. Diathaio carbamet fungicide – capton, furbace, meneb, menkozeb, propeneb, thyrum, jineb, jeerum
4. Orgonophosphat insecticide – chlorophyrophos, diamythoate, fenaitrothion, melathion, foret
During the use of the above chemical insecticides, mercury, lead, arsenic and other poisonous elements spread. Disturbances are also caused in the ecological system by water pollution caused by agricultural effluents. Food chains are being disturbed. Hence, fertilizers and chemical insecticides should be used in agriculture, keeping in mind their overall effects.