Killers at large
Vultures are dying in India. And Down To Earth, India's leading science and environment fortnightly, reports high levels of pesticides in the carrion of buffaloes, the main food source of the vultures, in its latest issue (dated January 15, 1999; Vol 7, No 16). Bharatpur's Keoladeo National Park, in particular, has had massive losses in its vulture population, the Bombay Natural History Society (BNHS) has noted. From 2,000 noticed in 1995, the vulture population has been reduced to just four in a span of just three years. Scientists and ornithologists such as Dr Asad R Rahmani, director, BNHS, believe this decline is a nation-wide trend with many Indian states reporting losses in populations of vultures and other birds of prey.

Disturbed by this information, the Delhi-based NGO Centre for Science and Environment (CSE), has collected and analysed samples taken from dead cattle from Bharatpur, Rajasthan, Uttar Pradesh and from areas around Delhi. The analysis was completed at Indian Institute of Technology, Kanpur. The study revealed high levels of pesticides such as dichlorodiphenyl trichloroethane (DDT), hexachloro cyclohexane (HCH) and dieldrin. The maximum level of DDT in samples from Delhi was 0.632 parts per million (ppm). Maximum levels of HCH were found to be even higher -- at 0.839ppm in buffalo carcass and 1.071ppm in pig carcass. Among the various forms of HCH, the most toxic forms, alpha-HCH and beta-HCH, were found to be higher than the other forms.

Though studies on impacts of pesticides on birds are almost non-existent in India, research conducted in West has revealed that these chemicals disrupt reproductive, developmental and hormonal functions severely in birds, leading to thinner egg shells and erratic mating patterns.

The US was the first to face the pesticide threat. In the early 1950s, US farmers used pesticides extensively to eliminate agricultural pests. By the mid 1950s, the country witnessed thousands of bird deaths. Then, in 1963, Rachel Carson published her landmark book, Silent Spring, detailing the fatal impacts of pesticides on birds and wildlife.

"This is a matter of serious concern," says Anil Agarwal, editor of Down To Earth, "because humans are also dependent on these animals for dairy and meat products." Like humans, the vultures, too, are on the top of the food chain. And if, through progressive accumulation, pesticides have reached and affected these birds, they could affect humans too.

Already, several studies, including one conducted by the Indian Council of Medical Research in 1993, have found alarmingly high levels of DDT, HCH and other extremely toxic pesticides in vegetables, fruits and milk in Delhi and other states such as Maharashtra, Punjab, Andhra Pradesh, Uttar Pradesh. The average daily diet of an Indian today contains 0.27mg of DDT. No one, not even infants, are safe: 25 Delhi women have tested positive for pesticides such as DDT, BHC, dieldrin and aldrin in their breast milk and maternal serum.

Similarly, high levels of these pesticides have been found in the blood of Indians. It is only a matter of time before their effects in humans become perceptible, and the recent vulture deaths should be heeded as a warning of serious human health problems.

DDT, dieldrin, aldrin and HCH are organochlorine pesticides whose extreme toxicity has been scientifically established in the West. Worse, many of these chemicals affect reproductive, developmental, hormonal and immunological functions. They often mimic and/or interfere with male and female hormones, thus modifying development and reproduction. Further, being what scientists call Persistent Organic Pollutants or POPs, they do not disintegrate and remain active in the environment for hundreds of years. The implications can be frightening: pesticides sprayed half a century ago are still active in the food chain and will remain so for many years to come. And though DDT and several other persistent organochlorine pesticides have been banned in the West, they still pose a serious threat in the developing world, where their use goes on, unabated. India, for instance, insists on using DDT in its health programmes. Between 1995 and 1996, for instance, some 9,000 tonnes of DDT were supplied to the state governments by the National Malaria Eradication Programme.

India's apathetic administration is yet to wake up to the pesticide threat. Birds have been known to indicate the state of the environment. And going by the vultures, India's environment is far from healthy. India lacks proper pesticide management plans. Worse still, pesticide production has shown a marked increase in recent years. "Unless action is taken now, most of these chemicals will not only wipe out agricultural pests, but many birds, animals and humans as well," says Agarwal.