Decrease in Metals Contamination Seen Over the Past 30 Years

Jun 15, 2006

The U.S. report card on metals contamination in sediment is showing marked improvement. A new study has analysed the past three decades of environmental legislation and regulation, changing demographics and land-use practices on concentrations of metals, finding positive results. The study is published in the latest issue of Environmental Toxicology and Chemistry.

Researchers assessed metals accumulation in the sediment of 35 reservoirs and lakes across the United States. Sediments provide a long-term record of metal inputs because they act as a repository for metals released into aquatic systems.
Sediment contamination by metals has been a widespread problem, especially in urban areas. In the past 30 years, the American population has increased by 42%, urban land has increased by 90%, and the number of vehicle miles driven has increased by 150%.

Despite the numbers, efforts to control metals contamination are working, researchers found. Decreasing trends outnumbered increasing trends of metals contamination for all seven metals analysed: cadmium, chromium, copper, lead, mercury, nickel, and zinc. The greatest improvements were seen in urban areas.
Because of its removal from gasoline, not unexpectedly, lead showed the greatest drop, with decreases in 83% of the lakes sampled. Overall, lead had a median decrease of 46%, with chromium coming in next, with a median decrease of 34%. Increasing trends, however, outnumber decreasing trends in zinc in urban watersheds. Previous studies have attributed this in part to increased vehicle traffic, particularly urban runoff from tires.

The findings of this study indicate that actions such as those taken in environmental regulation and technology have helped to curb the effects of a growing population on metals contamination of US water bodies. It is likely, researchers say, that other countries that have taken similar actions are also seeing positive trends.

Source: Alliance Communications Group

Explore further: Managing land into the future

add to favorites email to friend print save as pdf

Related Stories

Rodent populations proliferate in some parts of Texas

Mar 19, 2014

While the presence of rats and mice is nothing new in homes, sheds, barns and other structures, some areas of Texas are experiencing greatly increased rodent activity, leading residents to ask for advice ...

Japan's Panasonic to give China expats 'pollution pay'

Mar 13, 2014

Japanese electronics giant Panasonic said Thursday it would give employees sent to China a wage premium to compensate for the country's hazardous air pollution, in a possible first for an international company.

Health of honey bees adversely impacted by selenium

Oct 03, 2013

Traditionally, honey bee research has focused on environmental stressors such as pesticides, pathogens and diseases. Now a research team led by entomologists at the University of California, Riverside has ...

Recommended for you

Big changes in the Sargasso Sea

3 hours ago

Over one thousand miles wide and three thousand miles long, the Sargasso Sea occupies almost two thirds of the North Atlantic Ocean. Within the sea, circling ocean currents accumulate mats of Sargassum seawee ...

Water-quality trading can reduce river pollution

3 hours ago

Allowing polluters to buy, sell or trade water-quality credits could significantly reduce pollution in river basins and estuaries faster and at lower cost than requiring the facilities to meet compliance costs on their own, ...

Managing land into the future

7 hours ago

Food production is the backbone of New Zealand's economy—and a computer modelling programme designed by a Victoria University of Wellington academic is helping ensure that farming practices here and overseas ...

Is TV coverage of climate change too focused on disaster?

7 hours ago

TV news bulletins also gave much less air time to other potential focuses – the uncertainty surrounding climate change, the opportunities it presents and the explicit risks it presents, says the study published ...

User comments : 0