Pesticides — health and environmental hazards

November 13, 2006

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EXCESSIVE use and misuse of pesticides are hazardous to human health and poisons thousands of farm workers. These poisons become hazardous to environment if transportation, storage and disposal rules are not followed. Those affected by it are animals, birds, fish, non-target plants, beneficial insects/animals, people, soil, water resources, air, etc.

The intensive use of pesticides started with the introduction of the Green Revolution Technologies in early 60s to safeguard agriculture produce from the ravage of insect and pest attacks. Prior to this, farmers used to control pests through farming practices and mechanical and biological means.

The high yielding varieties of wheat and rice were cultivated widely in the country but these proved susceptible to various insects/pests. Pesticides thus became the pest control solution in Pakistan.

To get potential yields of crops, a large amount of pesticides are used to control insect pests. For example on an average, 63 per cent pesticides are used in controlling cotton pests, and 19 per cent on rice, sugarcane and fruits and vegetables. This high dependence has disturbed the agro-ecosystems by increasing health hazards and polluting the environment.

Nearly 50 per cent of these are either extremely hazardous or highly hazardous. The residues cause dermal and nervous systems toxicity, adverse immune functions, peripheral, neuropathies and allergic sensitization reactions particularly to skin.

Water containing pesticides when used for drinking purposes can lead to harmful effects ranging from mild headaches and skin cancer to cancer of internal organs and even death.

Accidental poisoning in homes from inappropriate storage of pesticides poisoning is due to the use of empty containers for storing water etc. Adverse health effects depend upon the degree of toxicity, amount of water intake each day and the individual health.

Indiscriminate use of insecticides is a major problem in developing countries and this seems to be responsible for poisoning small farm animals, human beings and farm ecosystems. Major threat to agriculture comes from the pests. Poor planning, faulty management and ineffective control strategies add to the huge crop losses each year.

Pesticides are used to protect foodstuff, house pests, livestock and food grain. The development of resistance in insect pests against pesticides poses a severe threat to oilseed crops, cereals, cotton, fruits and vegetables.

The financial and material loss to crops by insects, mites, nematodes, rodents, fungi, bacteria and virus, and from the competition with weeds is estimated from 40 to 60 per cent annually.

When pesticides are applied to different crops, their residue is left in the crop products. This residue enters into the system and brings fatal results. A number of complicated diseases have appeared which are also attributed due to the toxic effects of pesticides.

Despite the drawbacks insecticides appear to be our best protection against the pests. We need to use them often to boost food production. And there is no doubt about it that insecticides are the most powerful tools in our fight against pest menaces.

Nevertheless, the potent poisons need to be used only when necessary and require careful handling. It is essential to encourage the development and marketing of target-oriented pesticides to avoid damage to our environment.

In Pakistan, among various crops, cotton is recognized as a sink of agro-chemical. Since 1980, there is almost a linear increase in the use of pesticides in the country. At present, about 86 companies are registered with Minfal. During 1999, the pesticide consumption was 30,212 metric tons. Heavy amount is used on cotton during four months from June to October, and about 10 per cent on vegetables and other crops.

Moreover, cotton is an important cash crop of Pakistan which contributes to 60 per cent of export earnings. The Southern Punjab and the Northern Sindh are major cotton growing areas. This crop suffers about 20-40 per cent losses from insect pests and diseases for the control of which more than 76 per cent of pesticides are used.

Cotton, picking which is traditionally done by women is pesticide-intensive and these workers get exposed to toxic chemicals. The majority of female pickers are not aware of these hazards and do not take precautionary measures.

Studies show that more than two million women get sick annually from the exposure to pesticides. They are involved in a number of on-farm activities for example; weeding, hoeing, grass cutting, picking, cotton-sticks collection, besides the separation of seeds from fibre in ginning factories. They also help men in mixing and preparing pesticides solution.

According to reports a farmer dies every hour from pesticide poisoning in developing countries. Each year more than 10,000 die and another 400,000 get sick by pesticide poisoning. The profit margin of growers has eroded and the lack of proper education among farmers about the use of insecticides and their residue has generated tremendous health problems, as treated vegetables can make their way into the market next day.

The following points may help in controlling the problems: i) Companies manufacturing the pesticides must be directed to employ trained manpower who must keep a watch on pesticides during field application; ii) Pesticides detoxification medicines must be provided in rural dispensaries to tackle emergencies immediately and properly; iii) The sprayed area should be demarcated and there must be a continuous watch to avoid any emergencies. iv) The Government Act should be strictly obeyed; v) Agencies should be only given to qualified persons with the technical know-how of the pesticides; vi) The distributors should supply pesticides only to farmers with prescription from the qualified agriculture officer; vii) Courses/seminars may be arranged to create awareness among the farmers. viii) Dangerous aspects of pesticides and precautions must be broadcast on radio/television; ix) Farmers need to be educated to make them aware of long-term risks associated with persistent poisons. Farmers need to plan and direct their pest control operations in consultation with the people who can offer expert advice with regard to pest problems; x) The habit of over-eating or over-feeding must be avoided. xi) Eating, drinking or smoking with pesticides contaminated hands should be avoided. After spraying, the hands should be washed with sufficient water.

The pesticide may touch its toxic level in the body. Select pesticides of low toxicity which are not harmful to aquatic organisms (e.g., fish); avoid spraying near or over water; pesticides should be stored and transported as per the FAO guidelines and instructions.