John A. Bleiler, ENSR International, 2 Technology Park Drive, Westford, MA  01886, Tel:  978-3589-3000, Fax: 978-589-3100, Email: Jbleiler@ENSR.com
David Pillard, ENSR International, 4303 W. Laporte Avenue, Fort Collins, CO 80521-2154, Tel: 970-416-0916, Fax: 970-490-2963, Email: DPillard@ENSR.com
Mark S. Johnson, United States Army, Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, Aberdeen, MD, 21010, Tel: 410 436 5081, fax: 410 436 6710, Email: mark.s.johnson@us.army.mil
David J. Barclift, United States Navy, Engineering Field Activity Northeast, 10 Industrial Highway, Lester, PA  19113, Tel: 610-595-0567 x 183, Fax: 610-595-0555, Email: david.barclift@navy.mil
Jason A. Speicher, United States Navy, Engineering Field Activity Northeast, 10 Industrial Highway, Lester, PA  19113, Tel: 610-595-0567 x 188, Fax: 610-595-0555, Email: jason.speicher@navy.mil
Amy Hawkins, United States Navy, Naval Facilities Engineering Service Center, 1100 23rd Ave, Port Hueneme, CA 93043, Tel: (805) 982-4890, Fax:  805-982-4304, Email: amy.hawkins@navy.mil
Christine Archer, ENSR International, 2 Technology Park Drive, Westford, MA  01886, Tel:  978-3589-3000, Fax: 978-589-3100, Email: CArcher@ENSR.com

Amphibians are a front-line indicator of possible adverse impacts to wetland ecosystems; however, no standardized procedure exists to evaluate the potential toxicity of sediments and hydric soils to amphibians.  This project was conducted to develop a standardized approach for assessing potential risks to amphibians at Department of Defense facilities.  The first phase of work included a literature review, developing standardized laboratory testing techniques, validation of the toxicity testing using spiked sediments, developing amphibian screening values, and preparation of a guidance manual for assessing potential risks to amphibians at Navy facilities. The second phase of work involves refining the test protocol for use with frogs and salamanders, demonstrating and validating use of the amphibian risk assessment protocol at nationwide DoD sites, and achieving ASTM certification.  The guidance manual presents a standardized two-tiered risk assessment protocol for evaluating potential risks to amphibians. The Tier I Amphibian Ecological Risk Assessment (ERA) Protocol comprises a screening level ERA.  This approach uses readily available information to identify potential amphibian exposure pathways at a site and determine which exposure pathways are potentially complete.  Ultimately, the results of the Tier I protocol are used to determine whether or not additional amphibian ERA is warranted.  The Tier II Amphibian Ecological Risk Assessment Protocol comprises a refined ERA, and is conducted if recommended at the conclusion of the Tier I assessment. The Tier II protocol approach uses site-specific information to evaluate complete exposure pathways and amphibian ecological resources that are identified through the Tier I screening.  For both salamanders and frogs, the refinement, demonstration, and validation phase of work includes additional analysis in the laboratory and the field using two constituents commonly co-located and found at military sites and ranges (lead and copper) and a variety of bioavailability scenarios designed to account for site-specific geochemical and contaminant complexation effects.

The Environmental Impact of Conducting Environmental Work

Ben T. Foster, Blasland, Bouck & Lee, Inc., 3350 Buschwood Park Drive, Suite 100, Tampa, Florida 33618, Tel: 813-933-0697, Fax: 813-932-9514, Email: bfoster@bbl-inc.com

Performing environmental related work creates environmental impacts.  Assessment and remediation activities consume natural resources, produce waste products, and create certain exposure concerns.  Activities such as drilling, well installation, sampling, dewatering, excavation, treatment, and disposal require equipment, material, fuel, air, and water.  These resources are consumed by the environmental work leaving air emissions, wastewater discharges, and soil and material waste streams that then must be dealt with.  Assessment and remediation activities also result in exposing contaminants of concern to the environment. 

In many cases, subsurface soil and groundwater impacts do not represent either an immediate or practical long term exposure concern prior to the initiation of such work.  While it is true that the performance of almost any activity has an associated environmental impact, projects such as building a road, a bridge, or a school are not conducted under the onus of protecting the environment.   Prior to the consideration of non-time critical projects, a resource, risk, and remediation evaluation should be conducted.  This kind of evaluation would show that many environmental projects should either be limited or not performed. 

This discussion describes the means for evaluating the impact of conducting environmental work.  This includes the calculation of direct and indirect resource consumption, the calculation of waste streams, and the calculation of exposure.  The technical arguments provided by such an evaluation could assist with expediting and economizing overall environmental liabilities.

Development of Soils Cleanup Levels and Distribution Functions in the Mexican Framework

Ma. Inés J. Navarro González, Institute of Engineering, UNAM, Cd. Universitaria Circuito Escolar Edificio 1, 2o Piso Administración, 04510 Coyoacán, D.F. México, Tel: 525-623-3600, Fax: 525-616-2164, Email: ing@pumas.iingen.unam.mx

The results of probabilistic risk assessment to develop site specific cleanup levels are presented. Characterization of the exposure duration and of the potential Mexican population expose to hydrocarbon contaminated soils is one of the purposes of the study. Sensitive analysis was performed to an exposition model to direct occupational contact exposure to benzene in soil: variables in risk model which contribute most to the variation in estimates of risk conducted field studies. Field investigations focuses on an epidemiological study applied to 350 adults in an urban/rural Mexican community in order to develop empirical distribution functions to address site-specific conditions. Discussion of variability and uncertainties on the main exposure variables developed for Mexican context shows relevant differences with typical default values; arguments on the input variables with point estimates are also discussed. The iterative truncation method was used to identify the concentration at which the risk is acceptable and the maximum concentration that might be left in place. Final discussions about actual remediation goals used in Mexico and alternatives to address concern on uncertainties and variability in Mexican context are presented. This information can be used to guide Mexican research on risk assessment to prioritize resource allocations for additional data collection efforts (e.g., children characterization) and to focus discussions on remediation policy choices.

Development of Site-Specific, Ecological PRGs for PCBs and Mercury

Rebekah A. Young, Tetra Tech NUS, Inc., 661 Andersen Drive, Pittsburgh, PA 15220, Tel: 412-921-8167, Fax: 412-921-4040, Email: youngr@ttnus.com
Aaron Bernhardt, Tetra Tech NUS, Inc., 661 Andersen Drive, Pittsburgh, PA 15220, Tel: 412-921-8433, Fax: 412-921-4040, Email: bernhardta@ttnus.com
Walter Legg, Pine Bluff Chemical Agent Disposal Facility (PBCDF) US Army Chemical Materials Agency, 57-120 Webster Road, Pine Bluff, AR 71602, Tel: 870-540-2025, Email: LeggW@pbcdf.com

Ecological PRGs for sediment were developed using site-specific bioaccumulation factors for PCBs and mercury at the former Naval Surface Warfare Center (NSWC) White Oak, Silver Spring, Maryland.  The ecological PRGs were developed for remedial efforts associated with a perennial stream that supports a benthic community and a small fish population.  Post removal sediment sampling of West Farm Branch after a removal action at an adjacent site indicated high levels of mercury, silver, and PCBs in the sediment at concentrations that exceeded previously developed base-wide risk-based levels.  The base-wide levels were developed based on data collected from streams other than Westfarm Branch at the base and so a study was initiated to develop sediment PRGs from composite sediment and fish samples collected from the creek.  Black-nose dace were selected as the preferred target species, based on their abundance in previous collection records from the area and their relatively small home range.  PRGs developed for the protection of piscivorous wildlife were calculated as the average allowable sediment contaminant concentration over the entire length of Westfarm Branch on the White Oak property using the belted kingfisher and mink as surrogate receptors.  PRGs from fish were calculated using tissue residue data from the literature to develop 5th and 50th percentile LOAEL concentrations.  A range of PRGs were calculated to be used in risk management decision making. 

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