ENVIRONMENTAL EFFECTS OF USING CHEMICALS IN AGRICULTURE PART -2

ENVIRONMENTAL IMPACTS OF PESTICIDES

The major problem with the use of pesticides is that so little actually reaches the target pests. The estimate is that less than 5% of the pesticides that are applied reach the target pest. Rest of the 95% of pesticide that is applied pollutes the environment. This becomes a major problem due to the following properties exhibited by most of the pesticides.

1) Non-biodegradability:-Pesticides are not degraded into other simple compounds instead they persist in their original form for longer period of time.

2) Bio-accumulation & magnification: They enter the bodies of human beings and other non-target species through food chain. As they climb up the food chain there amount in the body of species increases dramatically (magnify). Human beings being in the top of the food chain even small amount of pesticide used will result in accumulation of fatal amount in human beings. For example even though negligible concentration of it is applied to a pond as it reaches human beings through fish ,water etc its concentration may become very high it will be fatal for their health.

EFFECTS ON SOIL: Pesticides enter the soil via spray drift during foliage treatment, wash-off from treated foliage, release from granulates or from treated seeds in soil. Some pesticides such as soil fumigants and nematocides are applied directly into soil to control pests and plant diseases presented in soil. Many pesticides are persistent soil contaminants, whose impact may endure for decades and adversely affect soil conservation. The use of pesticides decreases the general biodiversity in the soil by killing the microorganism that increases soil fertility. Some of the pesticides destroy nitrogenous bacteria this will decrease the nitrate content of soil. They also adversely affect the water retention capacity of soil which is necessary for plants to grow.

EFFECTS ON Air: As I mentioned above most of the pesticides applied does not reach their targets. They drift in the air to nearby areas potentially contaminating the environment in those places. This can have horrible consequences especially when they are aerially sprayed For instance when the chemical Endosulphan was applied using helicopter to cashew nut fields in Kerala and Karnataka it drifted to nearby villages and caused severe health problems to those villagers. Pesticides that are sprayed on to fields and used to fumigate soil can give off chemicals called volatile organic compounds, which can react with other chemicals and form a pollutant called tropospheric ozone. Pesticide use accounts for about 6 percent of total tropospheric ozone levels.

EFFECTS ON WATER: There are four major routes through which pesticides reach the water: it may drift outside of the intended area when it is sprayed, it may percolate, or leach, through the soil, it may be carried to the water as runoff, or it may be spilled, for example accidentally or through neglect. They may also be carried to water by eroding soil. After reaching the water sources like ponds they enter into our food chain & due to their bio-magnification and other factors it creates severe problems for human beings and other species. Ground water gets severely polluted to the percolation of pesticides. It causes severe health problems to the people who use that source.

EFFECT OF PESTICIDES ON BIOLOGICAL SPECIES

Soil microorganisms play a key role in soil. They are essential for maintenance of soil structure, transformation and mineralization of organic matter, making nutrients available for plants. The application of pesticides (especially long-term) can cause significant irreversible changes in their population. Inhibition of species, which provide key process, can have a significant impact on function of whole terrestrial ecosystem. Pesticides kill usefull organisms like earthworms, nitrogenous bacteria which will have adverse effects not only on fertility of soil also on the entire eco-system of that place. They also kill insects which are important for pollination of plants. It will result in the loss of bio-diversity and also agricultural production.

Aquatic life: A major environmental impact has been the widespread mortality of fish and marine invertebrates due to the contamination of aquatic systems by pesticides. This has resulted from the agricultural contamination of waterways through fallout, drainage, or runoff erosion, and from the discharge of industrial effluents containing pesticides into waterways. Additionally, many of the organisms that provide food for fish are extremely susceptible to pesticides, so the indirect effects of pesticides on the fish food supply may have an even greater effect on fish populations. Some pesticides, such as pyrethroid insecticides, are extremely toxic to most aquatic organisms.

Animals: Animals may be poisoned by pesticide residues that remain on food after spraying. An application of pesticides in an area can eliminate food sources that certain types of animals need, causing the animals to relocate, change their diet, or starve. Poisoning from pesticides make its way up the food chain; for example, birds can be harmed when they eat insects and worms that have consumed pesticides.

Birds: There is evidence that birds are being harmed by pesticide use. Types of fungicides used in farming are only slightly toxic to birds and mammals, but may kill off earthworms, which can in turn reduce populations of the birds and mammals that feed on them. Another way they are affects is that some pesticides come in granular form, and birds and other wildlife may eat the granules, mistaking them for grains of food. A few granules of a pesticide are enough to kill a small bird. Pesticides reach birds through their food like insects or fish. If they are accumulated to a certain degree they will cause disability in the new born birds and other severe effects on their body.

Totally they affect every part of our earth. They damage every part of our eco system

EFFECTS ON HUMAN BEINGS

Health effects: Human beings are continuously being exposed to pesticides from all possible ways. Eating food grown using pesticides, by drinking water that is contaminated by pesticides, through air that contains drifting pesticide particles. Many people mostly farmers’ get direct exposure while applying pesticides to crops.

These pesticides accumulate in the body causes lot of health problems to people. Many of the pesticides are carcinogenic i.e. they cause cancer. It is observed that exposure of the developing child to even small levels of common everyday chemicals can result in learning or behaviour problems evident throughout life. Malathion is a mosquito control pesticide which has been shown to have serious health effects upon humans. Observed effects include weakening of the immune system (thereby resulting in increased colds, flu and infections), birth defects, and genetic damage, accelerated aging of certain body organs, and increased neurological damage to the elderly and serious harm to wildlife. Many of the pesticides are reported to cause disruptions in metabolic activities of cell like oxidation which causes severe health problems.

Disabled children are born due to the effect of pesticide which has been passed on to the womb through the mother’s body. Even the mother’s milk is found to have pesticide content in it.

It is extremely clear that these pesticides are extremely harmful not only to human beings but to the entire eco -system. So i think one should stop using the pesticides and find other alternatives.