Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Composted biosolids bind lead in soil, reducing danger of poisoning

03.03.2003


Adding composted biosolids rich with iron, manganese and organic matter to a lead-contaminated home garden in Baltimore appears to have bound the lead so it is less likely to be absorbed by the bodies of children who dirty their hands playing outside or are tempted to taste those delicious mud pies they "baked" in the backyard.



The garden soil in the study is similar to potentially hundreds of thousands of yards contaminated with lead in Baltimore and other inner cities, according to Sally L. Brown, University of Washington research assistant professor of forest resources and lead author of an article in the current issue of the Journal of Environmental Quality.

Even yards that were never near smelter operations can have contaminated soils because of lead-based paints from older buildings and auto exhaust from leaded gasoline. The Centers for Disease Control and Prevention says that 50 percent of inner-city children in the United States have lead levels in their blood high enough to cause irreversible damage to their health.


Children swallow particles of lead if they are still at the age when they’ll put anything – including dirt – into their mouths or if they pick up particles on their hands and clothes and then go inside to eat a snack.

The bioavailability – that is the amount of lead available to enter the bloodstream – was lowered 20 percent to 38 percent after mixing composted biosolids with the contaminated garden soil, according to Brown and her co-authors, Rufus Chaney, Judith Hallfrisch and Qi Xue of the U.S. Department of Agriculture, Agricultural Research Service, Maryland. The best mixture for reducing bioavailability was one made from Baltimore biosolids that contained more iron and manganese than the others tested.

Biosolids are the organic residuals produced during wastewater treatment. Once composted, biosolids look like other commercially available composts and are approved for use by the U.S. Environmental Protection Agency as a soil amendment by home gardeners, farmers and others.

Using composted biosolids to remediate soils would be far less costly than other alternatives, Brown says. While soil contaminated with lead might be removed and replaced if it was at a Superfund site, that is just not possible within cities.

"We’re not going to be able to ’remove’ Baltimore," Brown says.

Co-author Chaney, a metals specialist, says, "Ever since we found the extensive urban-soil lead problems in the mid ’80s, we’ve been seeking a lower-cost option to soil removal. This appears to be the answer."

In the study, funded by the non-profit Water Environment Research Federation headquartered in Virginia, the scientists tested seven different biosolids and composted biosolid treatments, adding 3 inches of each to different areas of the garden, then thoroughly mixing the soils weekly for 30 days. Soil samples and laboratory rats exposed to the soils were tested for changes in lead levels. Since then, findings from a pilot program adding composts to other home gardens in Baltimore and East St. Louis, Ill., appear to confirm the findings.

Brown says researchers still need to find out how long the effects last and if similar results can be obtained using compost that doesn’t come from biosolids.

They’d also like to investigate exactly why composted biosolids change the nature of lead so it’s not so readily absorbed by the body. Brown and her co-authors hypothesize that this happens because biosolids are generally more than 50 percent organic matter, often contain high concentrations of iron, as well as high levels of phosphorous and manganese. Studied singly by other groups of scientists, each of these soil conditions was shown to reduce lead availability in soils, according to studies published in 1999 and 2000. Brown and her co-authors studied all three components at once and monitored effects on living organisms as well as changes in soils.

Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Agricultural and Forestry Science:

nachricht Robotic weeders: to a farm near you?
10.01.2018 | American Society of Agronomy

nachricht Alfalfa loss? Annual ryegrass is a win
03.01.2018 | American Society of Agronomy

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

White graphene makes ceramics multifunctional

16.01.2018 | Materials Sciences

Breaking bad metals with neutrons

16.01.2018 | Materials Sciences

ISFH-CalTeC is “designated test centre” for the confirmation of solar cell world records

16.01.2018 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>