# _Pollution from Agricultural Chemicals_

The indiscriminate use of agricultural chemicals, such as fertilizers and pesticides, has contaminated ground- and surface water. Excess nutrient loading as a result of fertilizer run-off can lead to uncontrolled algae growth. Pesticide run-off has caused an increase in the numbers of dead fish (especially on the banks of the Kabul River in certain seasons). Pesticide residues are of particular concern because they are assimilated into the environment at a slow rate, and accumulate in fish and animal tissue. Increased intensities of nitrates in groundwater wells are converted into more toxic nitrites in the stomachs of adults and infants, and are known to cause blood disorders in infants. Other risks from agricultural chemicals include contamination of shallow wells used for drinking water in villages and cities, and pesticide residues on grain and vegetables products in markets.

Agricultural chemical use in Pakistan's irrigated agriculture has expanded rapidly over the past twenty years. The most serious agricultural chemical problem stem from the rapid increase in pesticide use, from less than 1,000 tons in 1980 to more than 20,000 tons in 1993. The most commonly used pesticide is insecticide, most of which is applied to the cotton crop. Pesticide use was initially stimulated by subsidies, discontinued in 1985, and by a major government and private sector campaign to induce small cotton farmers to use pesticides in the wake of the pest epidemic of 1983.

The widespread use of often dangerous pesticides on the cotton crop is associated with several potential health hazards, including contamination of workers who apply it (three quarters of producers use a back-pack sprayer and no protective clothing), harvesters (all of whom are women), soil and groundwater used for drinking, and consumers of agricultural products. Very few data are available to document the extent of these various health hazards. Jabbara and Mallick (1994) summarized evidence from blood tests that shows that as many of one third of cotton workers in Pakistan have been exposed to dangerous levels of pesticides. Other studies have noted unacceptable levels of pesticide residues on at least 20 percent of samples of vegetables in urban markets.

The exclusive reliance on pesticides to reduce pest losses is unsustainable as pest populations change and some pests develop resistance to commonly used pesticides. Resistance to pesticides has caused the cotton crisis of the past two years, in which losses from curl-leaf virus have sharply reduced the cotton harvest and even threatened supplies to the domestic textile industry. Shortrun success in increasing cotton production over the past decade has come at the price of long-run sustainability.

Integrated pest management (1PM) is widely advocated as a means of reducing pesticide use and developing more sustainable production systems through the employment of a range of practices to combat pest populations. Despite the magnitude of the environmental and health problems associated with high levels of pesticide use on some crops, Pakistan has been a latecomer to the practice of IPM, and has been reactive rather than proactive. IPM is a knowledge-intensive practice that requires good extension service and is facilitated by literate farmers. Both are deficient in Pakistan and unless major emphasis is placed on promoting IPM it will be decades before pesticide use is reduced significantly.

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