New diseases are emerging with changes in the environment, some old diseases are also staging a comeback
-- (Credit: Pradip Saha /CSE)What does environmental deterioration lead to? It leads to changes in the planet's life support systems. When these systems become weak, their ability to support life deteriorates. Consequently, the health of individuals living in that ecosphere is bound to be affected. Some species profit by these changes and others lose out in the struggle for survival. As a result, scientists have observed disturbing phenomena an increase in disease burden, genetic changes, new diseases, declining immunity, and a sharp decline in sperm count.

The health impacts of environmental degradation are varied:

Genetic, hormonal changes brought about by toxins

Harmful effects of toxins on the immune system and nervous system.

Cardiac, respiratory and other disorders due to indoor and ambient air pollution.

Rise in vector-borne diseases

P K Seth, director of Industrial Toxicology Research Centre (ITRC), Lucknow, notes that health-impact studies of pesticides in India indicate neurological, reproductive and immunological abnormalities. Seth stresses the need to monitor pesticides residues in water, human milk and tissues, meat and agricultural products. Findings of H N Saiyed, director, National Institute of Occupational Health, (NIOH), Ahmedabad, buttress the case against pesticides. Saiyed says that workers exposed to pesticides have revealed high levels of pesticide residue in the blood, immunological abnormalities, changes in their electro-cardiograms and altered enzyme activities.

Heavy metal pollution also has a serious health impact. Sahu notes that heavy metal accumulation in vital organs like the kidneys and liver have shown a distinct increase. Chemicals that cannot be digested or rejected reach the liver and kidney through the blood stream and often get accumulated.

Devika Nag, head of the department of neurology, King George's Medical College, Lucknow, notes that metals, along with pesticides, have been identified as a cause of neurological illnesses in humans. Exposure beyond a limit to organochlorines, such as DDT, and even mercury and manganese can lead to abnormal behaviour and nervous disorders. Nag noted that children are especially vulnerable, as their central nervous system is not protected from toxins that do not normally affect adults.

Sangamitra D Gadekar of Anumukti, Surat, quoted the results ofa 1991 study of five villages within 10 km from the Rajasthan Atomic Power Station (RAPS) at Rawatbhata near Kota. Gadekar's team observed an extraordinary rise in congenital and chronic diseases in the area since the plant came up in 1972. Significanly, there was a sharp increase in congenital deformities in people who were born after the plant came up. The team found that tumours were seven times more prevalent in villages near the plant, when compared with the control villages over 50 km away.

Pesticides and industrial waste contaminate water resources. Geological factors contribute to the problem. The problem is aggravated further by environmental degradation. For instance, the ground water in eight out of 16 districts of West Bengal contains arsenic, leading to the worst cases of arsenic contamination in the world. According to the state government, about 4.5 million people are exposed to the problem. Medical records show that apart from the known effects of arsenic poisoning such as skin abnormalities, lesions, thickening of the palms and soles, and liver problems, 44 per cent of the patients also had cough and breathing difficulty. About 200,000 people are suffering from arsenic related diseases (See box: Pumping poison).

Lead can also be an airborne threat. Though lead inhaled by human beings is ten times less than that which is ingested, absorption through inhalation is greater. Almost 90 per cent of the lead gets deposited in bones and 10 per cent in soft tissues, affecting intelligence and behaviour. Studies by Veena Kalra of AIIMS, showed unacceptably high blood lead levels in school children in Delhi. Of the 180 children studied, 64 per cent showed elevated blood lead levels. High quantity of lead intake can cause acute brain damage and can also lead to death. It can also affect the heart function as well as the kidneys.

Volatile organic compounds (voc) and ozone are also not far behind as environmental villains, "voc and ozone have a great role to play on health, both from the physiological and the psychological aspects," says C K Varshney of lawaharlal Nehru University (JNU). According to him VOC levels in JNU a comparatively clean, green area in Delhi is 19.96 per cent higher than the accepted level (HOum/m3), and is 4.2 times higher in the busy street, Vikas Marg. Ground-level ozone concentration is increasing continuously and consistently. Ozone can create respiratory problems and can increase the chances of cardiac arrest by more than 40 per cent, notes Varshney.

"The kitchen kills more than the sword." Kirk R Smith, professor of environmental health sciences at the University of California, USA, invokes this Latin proverb, to describe indoor air pollution. Smith claims that foul indoor air has been responsible for a morbidity and mortality rate far higher than that caused by all the wars of this century put together. Poor sanitation, burning of dirty solid fuels such as biomass and coal for cooking and heating in poorly ventilated conditions are responsible for indoor air pollution. Whereas air in such cities as Delhi, Xian in China and Mexico City contains a daily average of 500 micrograms per cubic meter of total suspended particulates, smoky rural houses in Nepal, India and Papua New Guinea have peak levels of 10,000 or more, suggests Smith (See graph: Unhealthy cooking).

Recent estimates of the premature deaths in India from indoor air pollution exposures range from 500,000 to two million per year, he notes. Indoor air pollution contributes to acute respiratory infections in young children , chronic lung diseases and cancer in adults, and adverse pregnancy outcomes (such as still births) for women exposed during pregnancy. Acute Respiratory Infections (ARI) principally pneumonia are the chief killers of young children. ARI accounts for 13 per cent of illness in India, and 80 per cent of ARI is due to indoor air pollution.

Statistics show that there is one premature death for every 200 open biomass stoves per year. Lung disorders have a high correlation to fuel type and the environment. Studies have shown that up to half of adult women (few of whom smoke) suffer from chronic lung and heart diseases. Non-smoking women exposed to indoor coal smoke have a risk of lung cancer similar to that of men who smoke lightly says Smith. It has also been established that cooks receive a larger total dose of pollutants than residents of the dirtiest urban environment.

To avoid the harmful effects of indoor air pollution, people should be ^ encouraged to move up the energy ladder, notes Jamuna Rarnakrishna, Head, Humanist Institute for Cooperation with Developing Countries (mvos), Bangalore. Energy sources of the well-to-do, such as cooking gas, pollute less. She complains that India's numerous stove programmes have failed miserably. She also notes that the potential of chimneys has not been explored and exploited so far.

Each region needs a different kind of stove based on regional patterns of climate, ventilation, house types , fuel availability, diet, cooking practices and the function of the stove. Says Madhu Sarin, an architect working on design aspects of the stove: "Designing a nuclear reactor is easier than designing a chullah."

If the bitter battle between humans and pathogens is fought on a badland, humans stand to lose. "The occurrence of major vector-borne disease is closely related to a naturally existing environmental condition to human activities and to urbanisation," says Ramalinga swami. Malaria is a perfect example of a human-made epidemic. Sharma of MRC notes that when highways are built, trenches are dug, canals lead to water-logging and construction sites leave puddles. All these activities contribute to the proliferation of mosquitoes.

T Jacob John, professor of Indian Council of Medical Research (ICMR) and professor of eminence at Christian Medical College, Vellore, notes that apart from malaria, kalaazar, Japanese encephalitis, dengue and lymphatic filariasis, vector-borne diseases such Kyasanur forest diseases, sandfly fever, Indian tick and plague are found in India. "Due to the abundance of vectors, we are now vulnerable to the reintroduction of chikungunya and importation of yellow fever," says John (See box: The riceroot vectors).

One of the most serious hidden disease threats is that of plague. The reason behind the threat is the changing vector ecology, effected by human activity, says Ishwar Prakash, a leading rodent expert with Zoological Survey of India (ZSI). Plague spreads through rodents and rat fleas. "As a consequence of increasing irrigated agriculture, not only is the population of several rodent species increasing, but their reproductive rate has significantly enhanced," Prakash points out. Ever since the Green Revolution, irrigated cultivation is increasing, and new areas are being brought under cultivation, even in the Rajasthan desert. In recently transformed irrigated agriculture lands, the changing ecology of rodents has been well studied in Punjab, Haryana, the Aravalli mountain range and Rajasthan desert, claims Prakash. He notes that ecological changes promote intermingling of several domestic and wild species.

This intermingling is a dangerous trend, Indian gerbil (Tetera indica),s the reservoir of the plague bacillus. The house rat (Rattus rattits) is highly susceptible to plague bacillus. Several other species found in India, including the bandicoot (Bandicota bengalensis) and desert gerbil have been found seropositive to the plague bacillus.

Pondicherry. About half the filaria cases in the world are distributed in the south east Asia region (of World Health Organisation classification, which includes India.) The Culex quinquefasciatus is ubiquitous in India. "Environmental sanitation and targeted vector control are the ways to prevent filariasis, Das notes.

Kalaazar (Visceral Seishtnaniasis) has been a bane in the humid eastern parts of India, mainly Bihar. But of late, new outbreaks have been reported in irrigated tracts of Gujarat and the sub-Himalayan belt of Jammu and Kashmir, Himachal Pradesh and Uttar Pradesh. This is due to environmental changes brought about by irrigation projects and deforestation since the green revolution years, experts note. The disease vector sandfly thrives under humid conditions. "Changing vector ecology of kalaazar is one of the least investigated topics," says N L Kalra of Malaria Research Centre (MKC), an expert on the disease (See graph: Vector control).

Changes in environment not only shoot pollution and vector populations up, but also depletes natural resources, throwing life-supporting systems in disarray. In turn, people become more susceptible to illnesses. )ashodhara Dasgupta of the NGO Sahayog, Almora, points out that the rural women of Uttarakhand, the Himalyan belt of Uttar Pradesh, spend all their waking hours deal Prakash points out that the recent resurgence of plague, after almost 25 years, at Mamla (Beed, Maharashtra) and Surat ; (Gujarat), occurred mainly due to disturbance in the ecology due to natural calamities. The Latur earthquake changed the g vector ecology at Manila while the floods disrupted it in Surat. The new foci may be sites of human induced ecological upheavals, such as small pockets along the Indira Gandhi canal, he notes.

Filariasis and kala azar can be classified as diseases of bad environment. "Filariasis is spreading all over the country," says P K Das, director of the Vector Control Research Centre, ing with soil, water and forests. They lead a tough life, trekking many kilometres for water and firewood. Dasgupta's 1996-97 study on 1,000 women in 10 locations in Uttarakhand showed about 30 per cent of the women had spontaneous abortions. Elsewhere in the country, deforestation has caused a shortage of forest produce, breakdown of existing community systems and poverty. Says Narendra Gupta of Prayas, a Jaipur based NGO: "This has resulted in elimination of trees, increased water shortage, increased crowding and dust, and an increase in the virulence of vectors and rodents. Coupled with this is the decreased availability of nutritious food."

Afforestation measures have brought relief to rural communities in many places. But introducing alien species may have its own problems. Prosopis juliflora, a favourite amongst horticulturists, has spread in wastelands of India reducing the fuel-wood crisis in many areas. But its pollen has led to a number of allergenic reactions, points out A B Singh of the Centre for Biochemical Technology, New Delhi.

The desire to be clean and modern creates further problems. Most conventional sanitation technologies are based either on removal of human excreta through a network of underground pipes or on-site storage in deep pits. In both cases there arc disposal problems. Says Uno Winblad, a Swedish consultant, "The sewage system is causing a major ecological problem. Not only does it lead to contamination of our lakes and rivers, but it also leads to a lot of wastage of water."

There is a need for a third option. Dry compost latrines which disintegrate the waste are the solution, he says. For this purpose is required a latrine where faeces and urine do not come into contact with each other.
Down To Earth