Assessing Alternate Approaches to Estimating Uptake of Compounds by Plants and Animals in Ecological Risk Assessments

William R. Alsop, AMEC Earth & Environmental, 239 Littleton Road Suite 1B, Westford, MA 01886, Tel: 978-692-9090, Fax: 978-692-6633
John H. Samuelian, AMEC Earth & Environmental, 15 Franklin Street, Portland, ME 04101 , Tel: 207-879-4222, Fax: 207-879-4223
Robert Davis, US Army Corps of Engineers, 696 Virginia Road, Concord, MA 01742-2751, Tel: 978-318-8236, Fax: 978-318-8560

In the absence of empirical data, there are several approaches used to estimate uptake of metals, explosives, and propellants by plants and exposures to higher trophic level organisms.   The most commonly applied approach for metals used for Ecological Risk Assessments (ERAs) is to apply uptake factors reported by Baes et al. (1984), EPA’s Combustion Protocol (EPA, 1998a and 1999a), or those derived by Oak Ridge National Laboratory (Bechtel Jacobs, 1998).  For organic compounds (e.g., explosives and propellants), the typical approach would be to use the regression from Travis and Arms (1988) based on the octanol-water partition coefficient.  Alternate approaches are also available, such as those from EPA's Sludge Rule (EPA, 1992), EPA’s Cement Kiln Dust Risk Assessment (EPA 1998b) and Fertilizer Risk Assessment (EPA 1999b).  These alternate approaches often result in different predicted media concentrations, which are propagated to different predicted exposures to receptor organisms.   Unfortunately, many of these approaches do not take into account site-specific characteristics, such as soil type, soil particle distribution, organic carbon content, or complexing agents (such as iron, manganese, and phosphorous oxides) that can affect the bioavailability of the chemicals of concern.  These approaches could be used as part of a screening evaluation to determine the important contributors to estimated risks, but in many cases, the use of site-specific information provides the most defensible estimate of potential risk to ecological receptors.  This paper will compare the model results with site-specific data from the Massachusetts Military Reservation on the uptake of metals, explosives, and propellants by ecological receptors and provide recommendations for methodology, sampling, and assessment approaches.

Assessment of Exposure to Arsenic and Other Elements from Bangladesh's Drinking Water, Rice, and Soil

Richard Ortega and Guillaume Devès, Laboratoire de Chimie Nucléaire Analytique et Bioenvironnementale, CNRS UMR 5084, Université de Bordeaux 1, BP120 Le Haut Vigneau, 33175 Gradignan, France, Tel : (33) 557 12 09 07, Fax : (33) 557 12 09 00
Seth H. Frisbie, Better Life Laboratories, Inc., 293 George Rd, East Calais, VT 05650, Tel : 802-456-7054, Fax : 802-456-7054
Dorothea Alber, Hahn-Meitner-Institut Berlin, Glienicker Str. 100, D-14109 Berlin, Germany, Tel :  (49) 30 80 62 27 86, Fax : (49) 30 80 62 27 81
Donald M. Maynard, The Johnson Company, Inc., 100 State,
St., Montpelier, VT 05602, Tel : 802-229-4600 , Fax : 802-229-5876     
Bibudhendra Sarkar, Department of Structural Biology and Biochemistry, 555, University Avenue, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada, Tel : 416-813-5921, Fax : 416-813-5379

This is the first assessment of exposure to arsenic, barium, cesium, chromium, cobalt, iron, manganese, rubidium, selenium, and zinc from Bangladesh's drinking water, rice, and soil. The people of Bangladesh used to rely on surface water for drinking, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases.  To reduce the incidences of these diseases, 8,000,0000 to 12,000,000 tubewells were installed in Bangladesh since independence in 1971.  Today 97% of Bangladesh's 137,000,000 people drink tubewell water.  This recent transition from surface water to tubewell water has significantly reduced deaths from water-borne pathogens; however, tens of millions of Bangladeshis are drinking water with unsafe concentrations of arsenic or manganese. Approximately 49% of Bangladesh's area contains tubewell water with arsenic concentrations greater than the World Health Organization (WHO) 10 µg/L health-based drinking water guideline.  Similarly, approximately 50% of Bangladesh's area contains tubewell water with manganese concentrations greater than the WHO 500 µg/L health-based drinking water guideline. There is sufficient evidence from human epidemiological studies linking increased mortality from skin, liver, colon, kidney, bladder, and lung cancers to drinking arsenic-contaminated water.  In addition, manganese is a known mutagen. The accumulation of manganese may cause hepatic encephalopathy. The chronic ingestion of manganese in drinking water is associated with neurological damage. The 500 µg/L WHO drinking water guideline for manganese was calculated using human exposures in Japan and Greece, and studies of various laboratory animals where neurotoxic and other effects were observed. Our study suggests 55%, 45%, 0.3%, and 0.0004% of Bangladesh's exposure to arsenic is from drinking water, eating rice (their main staple), ingesting soil, and inhaling soil, respectively. This study also suggests 18%, 81%, 0.8%, and 0.001% of Bangladesh's exposure to manganese is from drinking water, eating rice, ingesting soil, and inhaling soil, respectively.

Risk Evaluation of Volatile Organic Chemical Contamination of Groundwater/Soils in Support of Property Transfer

Lee Ann Sinagoga, Tetra Tech NUS, Inc., Foster Plaza No. 7, 661 Andersen Drive, Pittsburgh, PA 15220-2745, Tel: 412-921-8887, Fax: 412-921-4040, Email: sinagogal@ttnus.com
Robert Jupin, Tetra Tech NUS, Inc., Foster Plaza No. 7, 661 Andersen Drive, Pittsburgh, PA 15220-2745, Tel: 412-921-8195, Fax: 412-921-4040, Email: jupinr@ttnus.com

Trichloroethene is among the most common volatile organic contaminants (VOCs) detected in environmental media at both publicly and privately owned sites undergoing environmental investigations.   It is a synthetic chemical historically used in the United States (U.S.) as a degreasing agent and extraction solvent.  A draft cancer slope factor recently published by the Environmental Protection Agency (EPA) indicates that it may be among the more potent of the carcinogens studied by the scientific community.  Unfortunately, VOC contamination in subsurface soils and groundwater has the potential to impact the indoor air quality of buildings overlying the contamination. However, many factors must be considered in the estimation of the potential for VOC migration and the existing EPA models used to evaluate this pathway are still under review. This paper presents a case study of a human health risk assessment conducted in support of a property transfer of a large, multi-acre Department of Defense (DoD) building overlying subsurface TCE contamination.  The case study presents the project objectives developed during the project planning process (i.e., the Data Quality Objective process) and an overview of the sampling and analytical protocol used to develop the exposure point concentrations for risk assessment (soil, groundwater, and soil gas samples were collected during the investigation).  Human health risk assessment protocols and results are provided. Recommendations are included, based on the results of the investigation and risk assessment, for the applicability of this type of investigation at similar sites.  Because numerous structures may be potentially impacted by subsurface VOC contamination, this case study will be of interest to regulatory agency and private/public sector groups involved in risk management and property transfer. 

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