Prof. Ellen Wohl, Colorado State University, United States

Transcription

1 Prof. Ellen Wohl, Colorado State University, United States The Ganges, or as it known in India, the Ganga, is a river of stories. Scholars have collected many tales about this river that springs from a dozen sources on the roof of the world. Each of the stories shares the theme that Ganga, daughter of the Himalaya, is persuaded to shed her purifying waters on the sinful Earth and thus bring salvation to humanity. The Ganga, Varanasi, India The Ganga is the great collector of Himalayan snows. The many sources of the Ganga flow south and east from melting glaciers in these highlands, collecting into the great trunk stream that flows due east before bending slightly southward into the Bay of Bengal. Little water comes from the dry lowlands across the western and southern portions of the Ganga drainage basin. As the rivers of the Ganga basin leave the steep topography of the Himalaya and enter the hill country to the south, they flow through the first of many cities spread along their courses. Cities such as Kathmandu, Nepal, along the tributary Bishnumati River, release a variety of contaminants into the rivers, and water quality deteriorates rapidly downstream. Organic pollution comes from the tens of thousands of bodies cremated on the Ganga itself, as well as human and animal wastes. More dangerous and persistent chemical contaminants released by the hundreds of factories along the Ganga and its tributaries include mercury, highly toxic heavy metals such as lead and copper, and various synthetic chemicals. Crop lands leak pesticides and excess fertilizers into the rivers 1. A 2001 study of contaminants in tissue from humans, domestic animals, and wildlife Global Water Forum 1

2 throughout India found that compounds such as PCBs are ubiquitous 2. These compounds persist in the environment and accumulate in the tissues of living creatures, reaching higher concentrations than those ingested by the organism. Many of the compounds disrupt reproduction and development, as well as being carcinogens. Foreign visitors to India have long commented on the filth of the Ganga. Indians historically believed that the river was physically as well as spiritually pure and thus had no trouble bathing in and drinking water in which partially cremated corpses floated downstream. Nonetheless, 80 percent of the health problems in contemporary India come from waterborne diseases. No one in India spoke of the Ganga as polluted until the late 1970s, by which time large stretches of the river over 600 kilometers were effectively ecologically dead. National attitudes have now changed dramatically, and grassroots environmental concern about water pollution, as well as government attempts to control pollution, are growing. The government launched the Ganga Action Plan (GAP) in GAP includes interception and diversion of sewage, construction of sewage treatment plants, and development of water quality standards and protective legislation. Some aspects of water quality dissolved oxygen levels, phosphate and nitrate concentrations have improved locally as a result of GAP, but other contaminants such as pesticides in agricultural runoff remain largely unchanged because they are not treated in wastewater plants. A 1994 study found that residues of the insecticide aldrin, for example, commonly exceeded the World Health Organization s guidelines for drinking water 3. As in much of the world, water quality standards in India are only as good as their enforcement, which has Temple by the Ganga, Varanasi, India Global Water Forum 2

3 been uneven. Clean water is now a limiting resource across the Ganga drainage, despite the relatively wet climate of much of the region. River pollution is in many ways difficult for people to grapple with. An activist cannot literally embrace a portion of a river the way that people protesting excessive tree cutting in India can hug a tree. Because a river integrates an entire drainage basin, the contaminants present at any point along the river represent everything entering the main channel upstream, as well as tributaries, surface runoff, and subsurface flow. Unless the contaminants produce a highly visible result such as a massive fish kill below an industrial point source, the effects of water pollution are usually subtle and slow-acting. Men in boat, Ganga, India Other challenges to river ecological health are present across the Ganga drainage. Headwater glaciers that supply the majority of flow within the river network are retreating rapidly as a result of warming climate, threatening the dependable supply of water on which the ten percent of global population living in the Ganga, Brahmaputra, and Indus River basins rely. Water engineering in the form of large hydroelectric dams in the Himalaya, and numerous diversions and water-storage dams in the middle and lower portions of the Ganga drainage, has caused massive side effects ranging from dislocation of human communities, through loss of resources such as fishery stocks, and increased hazards from flooding, to saltwater incursions and erosion of the Ganga delta. Excessive groundwater pumping for irrigated agriculture has caused surface subsidence and Global Water Forum 3

4 reduced stream flows. Efforts to improve the water quality of the Ganga must consider this complicated context. The good news is that rivers are resilient and, in places where water quality has improved, at least some of the components of a healthy river ecosystem have returned. Several basic steps are necessary to improve water quality in the Ganga. First and foremost, people must be aware of the problem and sufficiently concerned to put forth the very real effort needed to reverse declines in water quality. Second, setting and enforcing legal standards for water quality that incorporate not only organic contaminants, but also synthetic chemicals, is critical. Such standards rely on systematic knowledge of existing water quality conditions and the political will to create and enforce regulations, and neither the resources for systematic water-quality monitoring nor the enforcement of regulations are likely to occur without public support. Third, patterns of resource use must be altered in ways that facilitate improvement of water quality. Examples include expanded construction of residential sewage systems and municipal wastewater treatment plants; treatment of industrial effluents; and restoration of wetlands and riparian vegetation that can trap and retain the silt and clay particles to which excess nutrients and other contaminants are commonly physically attached. Even the sacred Ganga cannot withstand the onslaught of contemporary resource use and remain eternally pure. The recognition that people can, and must, make a difference in the quality of the region where they live has the potential not only to save the rivers of the Ganga drainage, but to empower the people living along the banks of these rivers and relying on river water for life itself. References: 1. Wohl, E. (2011), A World of Rivers: Environmental Change on Ten of the World s Great Rivers, University of Chicago Press, Chicago. Global Water Forum 4

5 2. Kumar, K.S., K. Kannan, O.N. Paramasivan, V.P.S. Sundaram, J. Nakanishi, and S. Makunasa (2001), Polychlorinated dibenzo-p-dioxins, dibenzofurans, and polychlorinated biphenyls in human tissues, meat, fish, and wildlife samples from India. Environmental Science and Technology, v. 35, p Agnihotri, N.P., V.T. Gajbhiye, M. Kumar, and S.P. Mohapatra (1994), Organochlorine insecticide residues in Ganges River water near Farrukhabad, India. Environmental Monitoring and Assessment, v. 30, p Professor Ellen Wohl is a geologist at Colorado State University. She studies river form and process, including how human activities alter rivers. She has worked on rivers around the world for more than 20 years, and written several books about human effects on rivers, including Virtual Rivers (Yale University Press, 2001), Disconnected Rivers (Yale University Press, 2004), and Of Rock and Rivers (University of California Press, 2009). This article is adapted from the book A World of Rivers: Environmental Change on Ten of the World s Great Rivers (University of Chicago Press, 2011), which explores human-induced environmental changes on the Ganges and other major rivers in more detail. The views expressed in this article belong to the individual authors and do not represent the views of the Global Water Forum, the UNESCO Chair in Water Economics and Transboundary Water Governance, UNESCO, the Australian National University, or any of the institutions to which the authors are associated. Please see the Global Water Forum terms and conditions here. Global Water Forum 5