Special treatment: disposing of CCA-treated wood.
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Biomedical subjects
Publications and source records attributed to W C Holton.
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Farmers strive to increase the yield of their fields by adding nutrients and water to the land, and using pesticides to control insects and disease. In addition to bountiful harvests, the results of their endeavors may include elevated amounts of fertilizers in surface waters and aquifers and potential risk to themselves and their neighbors from exposure to pesticides. Precision agriculture is the use of modern information technologies such as geographic information systems, the global positioning system, and remote sensing from the air to reduce the environmental effects of these chemicals while enhancing the productivity of farming. By combining crop yield maps with soil survey maps and remote sensing output, farmers can identify areas that need more or less fertilizer, water, or pesticide.
Individual countries acting alone cannot solve environmental problems that span national borders. The Global Environment Facility (GEF) was created in 1991 to serve as a mechanism for international cooperation in the funding of grants to address concerns in four areas of the global environment: biological diversity, climate change, international waters, and ozone layer depletion. To date, more than 500 projects have been funded with over $2 billion of GEF funds and another $5 billion leveraged from public and private sources, including $2 billion in matching funds from developing countries.
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Monsanto's "Lasagna" process uses layers of treatment zones spaced between buried electrodes to remove trichloroethylene (TCE) from contaminated soil and groundwater. TCE is used primarily as a metal degreaser as well as in products such as dyes, printing ink, and paint. TCE can eventually make its way into the environment and is prevalent in the water and soil of industrialized nations. Although TCE breaks down in a few days when released into the atmosphere, it degrades much more slowly in soil, taking months or years. Moreover, it is often broken down by microbes into toxic substances such as vinylidene chloride (a suspected human carcinogen) and vinyl chloride (a known human carcinogen). The Lasagna process is based on the principle of electro-osmosis, in which an electric current draws water from low--permeability soils such as clays, silts, and fine sands. To remove TCE from contaminated soils, Monsanto scientists added layers of filtering media, which attack the contaminant as it is pulled from electrode to electrode. The technology has been tested at the Paducah Gaseous Diffusion Plant in western Kentucky, where it removed over 98% of TCE from contaminated soil.
Trichloroethylene (TCE) is a common industrial solvent that poses a particular pollution problem in groundwater; while TCE disappears from surface water within a few weeks, groundwater contamination can take months or years to degrade. Humans have not conclusively been shown to develop cancer in response to TCE exposure, but rats and mice exposed to TCE have an increased incidence of liver and lung cancers.
Mercury pollution is a persistent and increasing problem in the environment. Along with some natural sources of the metal, major man-made sources of mercury pollution include incinerators, fossil fuel plants, and municipal sewage systems. The EPA estimated that in 1989, approximately 643,000 kg of mercury was discarded as municipal solid waste, with 84% of it landfilled.