Environmental Sciences and Engineering

Monitoring the impact of hazardous operations on the environment continues to be a major thrust at SwRI. Scientists and engineers assist industrial and government organizations in developing and applying methods to detect, identify, and measure the concentration of trace-level pollutants such as metals, chemical agents, rocket fuel degradation products, radioisotopes, explosives, pesticides, dioxins, and endocrine disruptors. The Institute works with regulatory agencies to validate human exposure monitoring methods and sends field teams to document the efficiency of hazardous waste destruction processes.

Field personnel set up a light trap to capture flying insects as part of the total invertebrate sample to be analyzed by Institute staff. These samples, along with soil, water, small mammals, and vegetation, are analyzed quarterly for possible contamination surrounding the U.S. Army's Umatilla Chemical Agent Disposal Facility, Oregon, which will soon begin operations to destroy chemical munitions.

The Institute is conducting quarterly monitoring of the Umatilla Chemical Agent Disposal Facility, under construction in eastern Oregon. Background levels of selected compounds are being measured in soil, water, vegetation, invertebrates, and small mammals surrounding the site and up to 50 miles beyond the facility. Scientists will perform comprehensive environmental monitoring during the facility's operational period and for some time after the agent stockpile has been destroyed. SwRI is in its second year of this eight-year Comprehensive Monitoring Program.

SwRI supports the demilitarization of chemical warfare agents by ensuring that the analytical methods used to measure these compounds in the environment perform to standards set by the Department of Health and Human Services. The studies are being conducted in SwRI's 3,800-square-foot Chemical Surety Laboratory, which is designed to handle hazardous compounds. Using criteria determined by the National Institute of Occupational Safety and Health, these studies will validate the performance of the analytical methods. The Institute currently generates performance data under various temperature and humidity conditions.

Because of opposition to chemical agent incineration by some groups and communities, Congress has directed the U.S. Army to evaluate alternative technologies for the destruction of these stockpiles. Two new technology programs have been established: Alternative Technologies and Approaches for destroying bulk agents, and Assembled Chemical Weapons Assessment for demilitarization of chemical munitions. The Institute provides technical assistance to the Army and others for several destruction technologies, including chemical hydrolysis, supercritical water oxidation, electrochemical oxidation, and a proprietary solution from Teledyne-Commodore LCC, Solvated Electron Technology^TM.

Public health concerns about the agricultural and domestic use of pesticides have led to increased research on such exposures. Because young children spend considerable time on the floor and engage in frequent mouthing activities, they may pick up pesticide residues from floors and carpets, resulting in exposures from oral ingestion and dermal absorption. In a series of studies for the U.S. Environmental Protection Agency (EPA), the Institute compared the transfer of dry pesticide residues from treated floors and turf grass to the palm of a volunteer's hand, both when dry and after moistening with human saliva. It was found that a child's hand, moistened with saliva from mouthing or sucking, picks up two to five times more pesticide than it would if it were dry. A similar increase existed for pesticide residues picked up from grass. In addition, pesticide transfers were two to 10 times greater from vinyl flooring than from carpet. These data will assist health professionals in examining different pathways to pesticide exposure.

SwRI staff use an atmospheric generator (at right) to validate monitoring methods and test instrumentation for the detection of chemical agents. The generator simulates wide ranges of environmental conditions of temperature and humidity, including those encountered at chemical demilitarization sites.

Increased concerns about pesticide exposure have driven demands for improved monitoring procedures and analytical methods. In a series of studies for the EPA, SwRI scientists have enhanced techniques that increase the operational flexibility and cost efficiency of field studies. The Institute evaluated the storage stability of 31 pesticides and two herbicides for the Agricultural Health Study exposure pilot. In another study, the Institute evaluated the analytical procedures developed for multi-residue monitoring of organochlorine and organophosphorus pesticides to see if they would be valid for seven synthetic pyrethroids, a safer pesticide for indoor use. The studies included experiments to determine how pesticide residues could be extracted and analyzed from air sampling, hand wipes, and house dust. Based on these studies, SwRI staff determined that current multi-residue methods can be used to determine exposure to pyrethroids.

As part of a study on non-Hodgkin's lymphoma, the Institute is working with the National Cancer Institute to determine the concentrations of 17 insecticides, seven herbicides, seven polycyclic aromatic hydrocarbons (PAHs), and five polychlorinated biphenyls (PCBs) in carpet dust. Scientists analyzed samples from the winter and spring seasons in the Detroit area, the state of Iowa, Los Angeles County, and the Seattle area. Ten insecticides were detected in more than 50 percent of the samples. Most of the detected insecticides are currently in use, but some, like dichlorodiphenyltrichloroethane (DDT), have been banned for many years. The study found the highest levels of insecticides currently used in and around homes in the Los Angeles County area. Agricultural herbicides were found in relatively few homes. However, more than one-third of the samples collected in Iowa contained a herbicide used predominantly on corn. Benzo(a)pyrene and six other PAH analytes were detected in almost all the homes. The analysis found PAHs and PCBs detected more frequently and at higher concentrations in Detroit than at the other sites.

Institute scientists have developed a method of sampling a fraction of the pesticide residues found on an applicator's hands. The method minimizes intrusion upon other elements related to human exposure such as the ability of pesticides to be absorbed through the skin and subsequently detected in biomarker measurements.

SwRI engineers assisted an international specialty chemical company, Velsicol Chemical Corporation, in examining the processing method and properties of one of their long-standing products used to make a variety of useful chemicals. The firm recreated one of its 50-year-old process streams that ultimately leaves behind a waste by-product that must be in a form acceptable for disposal. By simulating and distilling the stream at different compositions, several possible waste stream compositions were created. These samples indicated how much of the valuable product could be removed before the waste stream became too thick to be pumped.

Using an SwRI-designed continuous flow laboratory reactor that simulates the hydrogenation process, SwRI staff recreated a complex step of a liquefaction process in a pilot plant experiment for the U.S. Department of Energy (DOE). Working with liquids produced by another DOE contractor from Eastern bituminous and Western subbituminous coals, SwRI simulated process improvements with the bituminous coal liquid that the contractor had only been able to apply to the subbituminous liquid. Although both of the starting liquids made good test fuels, the effect of the upgraded process had been questioned. By simulating the process on a microscale, SwRI engineers found a cost-effective solution to the problem of having to repeat the process.

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