Removal of mercury from soil with earthworms
- Monmouth Coll., West Long Branch, NJ (United States)
Earthworms can live in soils containing high quantities of mercury, lead, and zinc. The worms (Lumbricus terrestris) concentrate these heavy metals in their tissues. The use of these worms to reduce the quantities of mercury and other heavy metals in soils may be practical. In July, 1993, a preliminary study was made using earthworms and soils with differing amounts of mercury, The quantities were 0.0 grams, 0.5 grams, and 1.0 grams of mercury as mercuric chloride. Earthworms were placed into these soils for two or more weeks, then harvested. The worms were rinsed with deionized water, then dissolved in nitric acid. Each sample was prepared for analysis with the addition of HNO{sub 3}, H{sub 2}SO{sub 4}, potassium permanganate, and hydrozylamine hydrochloride. A Jerome Instrument gold foil analyzer was used to determine levels of mercury after volatilizing the sample with stannous chloride. Worms exposed to contaminated soils remove 50 to 1,400 times as much mercury as do worms in control soils. In a hypothetical case, a site contaminated with one pound of mercury, 1,000 to 45,000 worms would be required to reduce mercury levels to background levels in the soil (about 250 ppb). After harvesting worms in contaminated soil they could be dried (90% of their weight is water), and the mercury regained by chemical processes. Soil conducive to earthworm survival is required. This includes a well aerated loamy soil, proper pH (7.0), and periodic watering and feeding. There are several methods of harvesting worms, including flooding and electricity. Large numbers of worms can be obtained from commercial growers.
- OSTI ID:
- 37470
- Report Number(s):
- CONF-9410273-; TRN: IM9519%%394
- Resource Relation:
- Conference: 15. annual meeting of the Society of Environmental Toxicology and Chemistry (SETAC), Denver, CO (United States), 30 Oct - 3 Nov 1994; Other Information: PBD: 1994; Related Information: Is Part Of Society of Environmental Toxicology and Chemistry 15th annual meeting: Abstract book. Ecological risk: Science, policy, law, and perception; PB: 286 p.
- Country of Publication:
- United States
- Language:
- English
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