Southwest Research Institute 1995 Annual Report

Institute capabilities for monitoring and analyzing hazardous substances are among the nation's best in terms of staff, equipment, and timeliness and accuracy of results. The Institute assists in the clean-up of military facilities, U.S. Environmental Protection Agency (EPA) Superfund sites, and Department of Energy installations contaminated with low- level radioactive wastes. Air and water quality studies and environmental impact assessments are performed for national and international clients, especially in Mexico, where the requirement for such services is rising. In support of its environmental monitoring and analysis services, SwRI maintains a strong quality assurance and data validation program in accordance with all requisite federal and state agency regulations.

A comprehensive environmental audit, including 10 months of field studies, was completed for one of the world's largest steel mills in Monclova, Coahuila, Mexico. To determine the plant's potential impact on the environment and surrounding community, SwRI scientists assessed chemical releases from all plant processes. The assessment results were used to implement sampling strategies for the plant's wastewater and air discharges, as well as programs to monitor the ambient air and trace metals in the soil around the plant. Sampling results were compared to historical data to reveal areas of successful emissions reduction efforts and areas requiring further attention.

In support of an epidemiologic study investigating environmental risk factors for childhood leukemia, the Institute analyzed carpet dust samples from 550 homes in a nine-state Great Lakes region for 28 pesticides, 10 polyaromatic hydrocarbons (PAH), and cotinine (a tobacco smoke marker), to assess the exposure of children in the homes to these compounds. Maximum concentrations above 100 ppm were found for recently applied insecticides, benzo(a)pyrene and other mutagenic PAHs, and two banned insecticides — dieldrin and DDT, the latter detected in about 25 percent of the carpets even though its use was discontinued in the U.S. more than 20 years ago. Results are now being analyzed by the University of Southern California, which is conducting the epidemiological study through a grant from the National Cancer Institute (NCI).

For the exposure assessment pilot phase of the Agricultural Health Study sponsored by the NCI and the EPA, the Institute analyzed 302 environmental samples from six family farms in Iowa and North Carolina for 33 pesticides. Findings showed that, after a farmer applied a herbicide, its levels rose quickly inside his home and on the hands of his family members. However, dermal and respiratory exposures of the farmer during application were two to three orders of magnitude higher than his family's exposure in the home on the following day. Residues of the two most widely used herbicides, metolachlor and atrazine, on farmers' hands correlated strongly with levels on family members' hands, on indoor surfaces, and in the indoor air and carpet dust.

Because of the potentially adverse health effects to humans from environmental pollutants such as dioxins, extremely low detection limits in environmental samples are required to protect the general public. Institute scientists employ high-resolution gas chromatographs/high-resolution mass spectrometers (HRGC/HRMS) to detect extremely small amounts of organic compounds — as little as 5 femtograms (5x10-15 grams) of dioxin, for example — in samples such as soil, sediment, water, air, stack emissions, chemical waste, and biological tissues. For the Texas Natural Resources Conservation Commission (TNRCC), SwRI recently collected 176 surface soil samples in six Texas cities and analyzed the samples for dioxins and furans using HRGC/HRMS. The work was performed in response to a state legislative directive to the TNRCC to annually monitor dioxin and furan contamination levels in neighborhoods near municipal solid waste incinerators or cement kilns.

Proposed Clean Air Act regulations would impose stringent pollution control requirements on medical waste incinerators and significantly increase equipment and/or operating costs for health care facilities. Recently, the Institute designed two efficacy testing protocols for an alternative treatment system that disinfects infectious medical waste with chlorine dioxide. The system's ability to kill six different microorganism species was assessed, with kill requirements as high as 99.9999 percent, as required by state and EPA standards.

The Institute performs routine analyses and method development analyses in the area of radiochemistry. One such program for the Argonne National Laboratory consisted of validating a fast, simple method of testing for the fission products strontium 89 and 90 in water samples. For a Brooks Air Force Base spatial skills study, Institute scientists designed a method of measuring testosterone in saliva, instead of blood, using a radioimmune assay that incorporates iodine-125. The Institute has also developed a procedure using electrolysis to isolate tritium from water. Tritium measurement provides information regarding the age of groundwater, which is useful in the planning of municipal water supplies.

The U.S. Army, with the assistance of the National Research Council, has completed a congressionally mandated project to examine alternatives to incineration for the destruction of chemical weapon stockpiles. As part of this program, the Army funded studies of chemical neutralization, as well as neutralization followed by biodegradation, for disposal of a nerve agent called VX. The Institute is participating in laboratory-scale evaluations of candidate biological systems to ascertain their treatment capabilities and is developing analytical methods to validate biodegradation of the organic constituents of the nerve agent. The Army will use the results to decide whether to pursue a pilot-scale demonstration of the technology.

The Institute analyzed organic compounds in the ambient air at eight proposed chemical warfare agent demilitarization sites in the United States. A major objective of the program was to identify substances such as agricultural pesticides and herbicides as well as industrial by-products that could interfere with chemical warfare agent detection instruments. Institute engineers designed and fabricated a system to collect samples 24 hours a day for one week at the eight sites. Sample analyses indicated that pesticide application in nearby fields did not interfere with chemical agent detection. However, degradation products from pesticides, which are more volatile and migrate further from the point of use than pesticides themselves, may pose a threat to monitoring device reliability. To assist the U.S. Army, SwRI will compile a library of interfering agents for use by laboratories interpreting monitoring results at each site.

In the fourth year of a five-year contract, the Institute continues to provide environmental monitoring in support of the Army's first full-scale plant for the destruction of chemical warfare agents. The Johnston Atoll Chemical Agent Demilitarization System (JACADS) is the only operational plant for destruction of the U.S. chemical weapon stockpile. During the past year, the JACADS staff supported successful destruction of rockets stored on the island, and munition destruction of nerve agent-filled bombs is continuing. Lessons learned at JACADS are being incorporated into monitoring schemes and program plans for similar weapon demilitarization programs in the continental United States.

Since 1989, the Institute has performed a daily pesticide monitoring program for a San Antonio-based grocery chain. The program serves to screen pesticides in produce for any violation of EPA or Food and Drug Administration tolerance levels, and to develop a database of growers and suppliers for the client that includes findings regarding frequency and levels of pesticide residues.

The measurement and identification of metals, especially at ultratrace levels, is an area of increased concern to clients in the electronics industry as well as the U.S. Department of Energy. Low-level analyses are achieved for metals and radionuclides using an inductively coupled plasma/mass spectrometer. This instrument can also be operated with an ion chromatograph to provide low-level analyses of ionic compounds such as polyphosphates.

Under subcontracts from the University of Dayton Research Institute and Lawrence Associates, Inc., SwRI has built a full-scale prototype non-ozone depleting cleaning system for the U.S. Air Force Wright Laboratory. Tests with aerospace parts supplied from the Air Force, NASA, and industry are under way to prove the viability of the system. A patent has been issued to SwRI for the new technology, which circumvents the use of ozone-depleting compounds by using carbon dioxide as the cleaning solvent and incorporating a thermoelectric cooler as the refrigeration system. Aerospace applications being evaluated include cleaning of gyroscopes, heat pipes, components for oxygen service, jet engine impellers, satellite components, and ball bearings

Copyright© 1995 by Southwest Research Institute. All rights reserved under U.S. Copyright Law and International Conventions. No part of this publication may be reproduced in any form or by any means, electronic or mechanical, including photocopying, without permission in writing from the publisher. All inquiries should be addressed to Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510.

Environmental Sciences and Engineering