Botanical plants could rid soil of heavy metals
A new technology that is now emerging holds promise of revolutionizing the remediation of soils contaminated with heavy metals. Called phytoremediation, it would use green plants to remove the metals. Plants take up the metals in their roots and translocate them to their shoots, which are harvested, burned in a kiln, and the metals recovered and recycled. The challenge is finding or engineering plants that can absorb, translocate, and tolerate heavy metals while producing enough foliage to make the process efficient. All plants take up small amounts of metals, he notes. What he looks for are weird plants that can accumulate them. Such plants exist, he says, giving credence to the feasibility of phytoremediation. Naturally occurring plants with spectacular metal uptake have been found growing on ore outcroppings, he explains. Cunningham scouts waste repositories and mining and industrial sites for metal-accumulating plant species. So far, he has identified two common weeds - hemp dogbane and ragweed - as candidates for remediating lead-contaminated soils. Both plants accumulate lead, he says, but their abilities vary across soils because lead exists in several forms in soil, and not all of its forms are easily absorbed. He finds that lowering the pH and the phosphate and sulfate content of the soil enhances uptake of the metal. The downside is these changes can impair the plant's nutritional environment. So, the chemistry of the soil must be carefully manipulated to boost metal uptake without losing plant biomass, he emphasizes. Cunningham's scheme is being field-tested at Chambers Works, a Due Pont facility in New Jersey. If ragweed proves to be the species of choice for remediating weapons sites and other lead-contaminated sites, he says allergy sufferers needn't worry. Only mutants of the weed that don't pollinate will be grown.
- OSTI ID:
- 6388857
- Journal Information:
- Chemical and Engineering News; (United States), Vol. 71:17; ISSN 0009-2347
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
LEAD
BIODEGRADATION
MATERIALS RECOVERY
PLANTS
SENSITIVITY
SOILS
DECONTAMINATION
GENETIC ENGINEERING
LAND POLLUTION
RECYCLING
REMEDIAL ACTION
BIOTECHNOLOGY
CHEMICAL REACTIONS
CLEANING
DECOMPOSITION
ELEMENTS
MANAGEMENT
METALS
POLLUTION
PROCESSING
WASTE MANAGEMENT
WASTE PROCESSING
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology
320305 - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Industrial Waste Management