Ruining the world’s water supply



Agricultural run-offs containing fertilizers, animal wastes and pesticides are infecting rivers and water courses with blue-green algal blooms and toxic chemicals. While the problem is particularly evident in developing countries - Canada, Australia and the United States contain some of the world’s most polluted rivers, and poor agricultural practices are the root cause.

Almost one-fifth of the world’s population lacks consistent access to clean water says the United Nations Environment Program, and the problem is being made worse by the improper farming practices - particularly in developing countries where excessive use of fertilizers are needed to feed rapidly expanding populations.

Biologists say the main culprits from poor agriculture practices are phosphorous, ammonia and nitrates - the results of pesticide and fertilizer runoff and the animal waste from intensive and industrial-scale agriculture. Scientists note that livestock, such as pigs, cattle and chickens, generate prodigious quantities of fecal matter which usually end up in water ways.

Synthetic pesticides that are being used add dangerous toxins to watersheds while fertilizers and animal wastes propagate blooms of blue-green algae. Through metabolism and decay, algae uses up most of the oxygen in a body of water, literally suffocating other, less hardy species.

In India, one of the planet’s fastest developing economies, agricultural waste has contributed to the severe pollution of most of its rivers. Although a large portion of the pollution results from human sewage, agriculture along the Ganges River and its tributaries only adds to the escalating problem.

'In India, there is the pressure to achieve GDP (gross domestic product) growth and create jobs at any cost. In such an atmosphere, environment is perceived as an impediment to economic progress,' said Ramesh Ramaswamy, managing trustee of the Resource Optimisation Initiative - a non-profit research institution in Bangalore - in a lecture at Harvard University. 'What we need is an integrated approach,'

The environment movement in India is being perceived as elitist, said Ramaswamy, adding that environmental laws are ineffective, partly because they focus on pollution by big businesses without addressing either pollution by small-scale businesses or agricultural pollution. According to Ramaswamy, 'there is no system to monitor pesticide and fertiliser pollution.'

Ecologists also note that intensive deforestation adds to the problem, especially along riverbanks. Deforestation activities contribute to runoff, erosion and turbidity problems - the muddy water in turn makes it hard for aquatic organisms to survive - and municipal storm sewers and sanitary sewage have compounded everything. In developing countries particularly deforestation to provide agricultural land is causing such problems.

For example, the Northwest Province of Cameroon is 90% dependent on farming for survival. According to the UN, its lack of clean drinking water is exacerbated by agricultural deforestation, aquifer depletion, and soil erosion.

The Amazon River and its tributaries are experiencing a similar problem. Beneath the Amazon Rainforest, the soil layer is thin and loose and easily washed away by the region’s heavy rains. Rapid deforestation of the Amazon to make room for agricultural land is increasing the turbidity of the river and resulting in algal blooms.

This issue is not isolated to developing countries. North America, Europe and Australia are all facing river pollution from agricultural.

Australia, already facing one of its worst droughts in recent history has tainted the continent’s two longest rivers, the Murray and the Darling. Agriculture is the primary pollution source.

The 2,500 km long Murray River is laden with salt, agricultural chemicals and other pollutants - the residue of farm management practices that can no longer be sustained, Australia officials and researchers say. An official government report released in 2000 warned that if the river was not cleaned up, its water would be undrinkable within 20 years.

'Water quality is increasingly under threat from poorly managed riverine systems, increased salinity and other flow-on effects from land use,' said Australian Federal Environment Minister, Robert Hill. 'This is a great national challenge.'

Canada has a large number of river systems that are highly polluted in part due to agriculture. On the West coast, pollution in both Alberta and BC is affecting Chinook salmon populations, a commercial species. In Eastern Canada Quebec is home to 13 of the nation’s most polluted rivers each of which run through the heart of the province’s agricultural region.

According to Monique Boily, a biology professor and environmental toxicologist at the Université du Québec à Montréal, long-term pollution has made the water unfit for consumption.

'We are talking about an extremely stressed environment ... in the case of some of the tributaries, we use the term ‘river’ out of habit or convenience, in some cases it’s more like an open sewer,' said Boily of the Yamaska watershed, the most polluted river system in Canada.

What are the solutions?

Many agricultural experts are suggesting new farming techniques to help limit the amount of agricultural run-off entering river systems, such as the ‘no-till’ technique. According to research conducted by the Thomas Jefferson Institute, ‘no-till’ farming, a process that eliminates the churning of soil, reduces the movement of silt into watersheds by an estimated 95%. Because no-till doesn’t disturb the soil surface, phosphorous and nitrogen fertilizers, which reside within the top six inches of the soil, are not washed into streams and rivers.

The United States Department of Agriculture has developed two programs which help farmers minimize nutrient leeching and run-off; the Phosphorus Index and the Nitrate Leaching and Economic Analysis Package (NLEAP).

The Phosphorus Index provides field staffs, watershed planners, and land users with a tool to assess the various landforms and management practices for potential risk of phosphorus movement to water bodies.

NLEAP is a field-scale computer model developed to provide a rapid and efficient method of determining potential nitrate leaching associated with agricultural practices. It combines basic information concerning on-farm management practices, soils, and climate and then translates the results into projected nitrogen budgets and nitrate leaching below the root zone and to ground water supplies, and estimates the potential off site effects of leaching.

Environmentalists believe that tighter legislation regarding remediation, fertilizers use, water use and pesticide use is required.

In developed nations, legislation is developing slowly. Pesticide laws have improved significantly over the past few decades and no pesticides can be used in North America that pose a significant risk to human health or the environment.

Laws regarding nutrients, i.e. nitrogen and phosphorus, from fertilizer and livestock waste, are lacking. Most governments in developed nations have focused on removing phosphates from personal hygiene and cleaning products but have been slow to address agricultural waste.

Several plans are in development, such as Quebec’s 'green' agricultural plan which is to be released in the near future. Several state Departments of Agriculture in the US now require farms over a certain size to implement third party audited nutrient management plans in order to protect water quality.

Unfortunately, in developing nations such legislation is not likely and remediation of polluted rivers is far too expensive. Citizens of these countries do not have access to the most recent information on more sustainable farming practices.

The situation is developing nations is critical and according to UNEP it has reached crisis levels and requires a more immediate international response from developed nations. Without international support, the problem will persist, and access to potable water in these regions will continue to decline.

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