Agricultural pollutants affect drinking water quality nationwide
Economic losses caused by nutrient pollution of U.S. freshwaters are felt by people all around the country, according to the policy analysis by the Kansas State University team of scientists led by Walter Dodds.
Repeated application of nitrogen and phosphorus fertilizers, intensive tillage of soil, discharge of manure from animal farms, and lack of conservation vegetative buffers between plowed croplands and waterways result in a significant nutrient runoff from fields into rivers, streams and lakes that negatively impacts water quality nationwide as well as creates dead zones in coastal areas.
How severe is the problem of freshwater contamination with phosphorus and nitrogen? With the exception of certain forested areas, 90% of rivers and lakes across the U.S. contain levels of these nutrients much higher than what is normal for these freshwater ecosystems, scientists report. And just as excess food intake is harmful for human health, high levels of nitrogen and phosphorus in freshwater affect environmental health, leading to excessive growth of algae, algal toxins in water, fish kills, and foul look, taste, and smell of water.
These are ecological consequences - and economic harms follow closely, with negative impact on drinking water quality; livestock and human health; swimming, angling and other forms of water recreation; commercial fisheries and aquaculture; stream biodiversity; as well as diminished values of waterfront property that fall progressively with decreasing water clarity.
The present analysis sets the stage for economic valuation of social costs associated with nutrient pollution of freshwaters. As the authors acknowledge, the true costs are likely to be much higher than they can currently estimate. For example, how can we put a monetary value on clean drinking water? The authors correctly point out that when the quality of tap water declines, people turn to bottled water. As reviewed in the EWG's Bottled Water Quality Investigation, in 2008 bottled water sales approached twelve billions of dollars.
In contrast to the large amount of money spent on bottled water, a relatively non-essential commodity, an amount two and a half times smaller is allocated annually for all conservation programs that work towards improving water and air quality, decreasing soil erosion and sedimentation, and preserving availability of water for drinking and irrigation - essential programs that mitigate agricultural pollution of freshwaters.
Are we spending our money in the right place? Investing in conservation programs and decreasing nutrient pollution of rivers and streams would go a long way towards protecting tap water quality. In the opinion of water quality and environmental economics experts, as reported by Rhitu Chatterjee in January issue of Environmental Science and Technology, "it is cheaper to prevent pollution than to clean it up." Otherwise, the costs of pollution now inflicted on the environment, "will still have to be paid by our children and our children's children." All Americans, present and future, deserve access to safe, healthy drinking water. Protecting freshwaters from nutrient pollution is the key step in ensuring that this public health goal would be met.
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