Project Experience
Ecological Risk Assessments
Screening Level Risk Assessments at an Abandoned Mine Site. Dr. Pascoe performed screening level ecological and human health risk assessments for an abandoned mine site in the Cascade Mountains, central Oregon. Hard rock mine wastes containing elevated concentrations of lead and zinc, among other metals, had been piled in tributaries to a trout stream and used as road bed material. Dr. Pascoe directed sampling of onsite soils, and surface water and sediment of a tributary running through the site and a receiving water trout creek. Dr. Pascoe collected stream sediment macroinvertebrates for enumeration, and evaluated results using the ODEQ rapid macroinvertebrate procedure. Ecological risks were screened using Oregon Department of Environmental Quality criteria for soil, surface water, and sediment. Human health risks were screened using USEPA screening criteria and cancer and noncancer risks were calculated for adult and child recreational uses of the area. Human health risks were found to be below regulatory thresholds of concern. Elevated concentrations of zinc and lead in stream sediment and depressed macroinvertebrate community indices suggested localized impacts on stream communities immediately downstream of the confluence with tributaries and road run-off.
Fort Clatsop-Lewis River Sampling. Dr. Pascoe directed a focused sampling effort for property near the Fort Clatsop National Park, Oregon, for use in screening for potential ecological risks. A Phase 1 study had found an underground storage tank adjacent to the Lewis River and elevated metals from historical use as a rail yard. Data were collected on petroleum chemicals and metals in soils, groundwater, and surface water of the river, and an ecological check list and exposure analysis were completed following Oregon Department of Environmental Quality screening level I guidelines. Sampling and ecological screening were performed with a focus on the potential for PAHs and other petroleum hydrocarbons in groundwater to impact the aquatic environment of the Lewis River.
Upper Columbia River Data Needs Analysis and Risk Assessment Work Plan. Co-authored a data needs and collection and risk assessment work plan for an Upper Columbia River investigation, for a local tribe. Potential ecological risks include aquatic and terrestrial habitats, with exposures due to both upstream smelter wastewater discharges to the river and stack releases to air.
Ecological Risk Assessment for the Milltown Reservoir/Clark Fork River Sediments Site. Project manager and primary author of a site-specific ecological risk assessment for the Milltown Reservoir Sediments Site, a metals-contaminated wetland in Montana. Coordinated work plans and field sampling and assessment efforts of USEPA, U.S. Fish and Wildlife Service, university researchers, and state and county agency technical personnel. Risk severity ranking supported natural attenuation as the final selected remedial alternative. The first comprehensive fresh water ecological risk assessment in the Superfund program. Collaborative publication efforts with USEPA helped inform guidance on field methodology for ecological risk assessments.
Food Web Analysis for Mining Waste Metals. Manager and technical oversight of a food chain analysis of metals contaminants in a montane wetland at Milltown Reservoir, MT. Receptors of concern consisted of eagles, osprey, deer, muskrat, beaver, and various waterfowl species. Database included tissue residues of aquatic and terrestrial plants and terrestrial small mammals. Results were integrated with habitat and wildlife surveys to support natural attenuation of the metals risks.
Risk Screening at Abandoned Mine Sites. Performed screening-level evaluations of risks associated with terrestrial and aquatic wildlife exposures to metals at abandoned mine sites for the USFS.
Risk-Based Corrective Action Approach for the Naval Arctic Research Laboratory. Technical assistance in developing a white paper on performing a Risk-Based Corrective Action (RBCA) approach to assessing risks to human health and ecological receptors from total petroleum hydrocarbon (TPH) contamination at the Naval Arctic Research Laboratory, Pt. Barrow, AK. Reviewed impacts of TPH and petroleum products on arctic mammalian health and ecology.
Risk Assessment for the Naval Arctic Research Laboratory. Manager and primary author of the final ecological and human health risk assessments, proposed plans, and feasibility studies for two sites at the Naval Arctic Research Laboratory, Barrow, AK. Risks were also calculated for Total Petroleum Hydrocarbon measurements, based on the fractionation and surrogate toxicity approach. Risk-based cleanup levels were developed for human health and ecological receptor exposures to PAHs, metals, chlorinated solvents, and TPH in soil, groundwater, and freshwater and estuarine sediments. Remedial alternatives were developed to achieve the risk-based cleanup levels in an arctic environment. Presentations of the results of the risk assessments and proposed plans for the sites were presented to regulatory agencies and local citizens groups, including native Alaskan corporations. Managed and authored the management plans and proposed plans for remedial feasibility and design; manager and technical reviewer of Records of Decision.
Risk Assessment for OU 8 of the Bangor Subbase. Technical oversight and revisions to the human health and ecological risk assessments for exposures to groundwater and irrigation water at a naval site contaminated with chlorinated solvents and benzene. U.S. Navy, Engineering Field Activity, NW.
Surface Water and Sediment Quality Risk Assessments
Technical Reviews for the Lower Duwamish Waterway RI/FS. Dr. Pascoe currently provides technical support in risk assessment to Seattle City Light on the Lower Duwamish Waterway Remedial Investigation/Feasibility Study (RI/FS). As the downstream end of the Duwamish River, the Lower Duwamish Waterway is a tidal-influenced brackish waterway that flows through a highly industrialized area of Seattle. The waterway terminates in the East and West Waterways, saline waterways on either side of Harbor Island at the hydrologic connection to Elliott Bay. As part of the Lower Duwamish Waterway Group (LDWG), the City of Seattle shares responsibility for the RI/FS, including human health and ecological risk assessments. The RI and risk assessments have been performed as a two-phased approach, supported by multiple phases of field and analytical tasks, including sediment chemical and toxicity investigations, biota sampling and habitat/species surveys, public access surveys, groundwater and seep analyses, and analyses of seafood consumption data.
Dr. Pascoe has provided reviews of interim and final planning documents during the work plan and sampling plan stages of various tasks of both phases of the project, reviews of study results documents, and reviews of various phases of the risk assessments. Risk assessments have focused on exposures to PCBs, arsenic, PAHs, dioxins/furans, and various metals and organic chemicals in intertidal and subtidal sediment, groundwater adjacent to the waterway, and seep water. He has attended regular weekly meetings with LDWG on behalf of the City, including meetings on technical scope negotiation with EPA and Ecology regulators and technical staff on various aspects of data collection and parameter selection for the risk assessments, and has made numerous presentations to City managers on technical and strategy issues regarding the risk assessments and their link to site cleanup, public health and perception, and contaminant sources. He continues to provide technical support to the City, with a focus on human health risk assessment and identification of appropriate exposure scenarios for selection of risk-based cleanup levels in sediment, through his role as a subcontractor.Jackson Park Housing Complex/Naval Hospital RI/FS. Project manager on a focused RI/FS for the marine operable unit of the Jackson Park Housing Complex/Naval Hospital site on Puget Sound. The RI/FS followed regulatory guidance of both Superfund and the Washington Department of Ecology Model Toxics Control Act (MTCA). Designed remedial action objectives for sediments contaminated with mercury and ordnance compounds that focused on mitigating sediment toxicity to benthic organisms and impacts to benthic ecology. Remedial alternatives for various site units of the bay were developed using a combination of natural attenuation, thin layer covers, and full capping. A Treatability Study included field studies on sedimentology to calculate deposition rates, sediment transport using the Sediment Trends Analysis to identify offsite sources of contaminated sediment input, and additional site characterization and sediment bioassays to account for ammonia and sulfide impacts. Managed and authored the feasibility study and proposed plan; developed cleanup levels for no further action. Linked the risk assessment and sediment transport study results to offsite source identification. Modeled natural attenuation to meet cleanup levels with offsite source controls.
Jackson Park Housing Complex/Naval Hospital Management Plans. Manager and primary author of the Proposed Plan and draft Record of Decision for sediments of a marine operable unit contaminated with mercury and ordnance compounds in Puget Sound. The proposed plan was for no further action by the Navy at the site, based on the findings that the majority of biological impacts to the site sediments were from uncontrolled off-site sources.
Site-Specific Mercury Bioaccumulation. Managed field and laboratory studies and developed a siteñspecific bioaccumulation factor for mercury in various fish in a southeast coastal plains wetland. The factor was used to assess risks from consumption of local fish impacted by mercury emissions from a cement plant.
Dioxin Exposures at a Pulp and Paper Mill. Provided technical assistance in planning field sampling and chemical analyses; interpretation of results, for dioxins in various environmental media around the pulp and paper mill at Sitka AK.
Southwest Harbor Project, Port of Seattle. Manager and senior author of a regional risk assessment for PCBs and metals in soil and groundwater, across four remediation areas (i.e., sites) consisting of multiple industrial sites. Co-developed risk-based hydrogeologic model to identify groundwater and subsurface soil remedial goals protective of offsite surface water receptors. Model incorporated site-specific measurements of attenuation and dilution of metals, PCBs, and PAHs during ground-water transport; and partitioning of chemicals between soils and infiltrating water.
Review of Oregon DEQ Work Plan and Management Plan for Contaminated Sediments. Provided technical review of numerous versions of a work plan and management plan for performing a Remedial Investigation and Risk Assessment of contaminated sediments of the Willamette River. The plans were reviewed on behalf of the Port of Portland prior to listing the site under Superfund.
White Paper on Marine Studies. Task manager on a white paper to review and evaluate existing data on marine sediment studies at the Jackson Park Housing Complex Marine Sediments Site. Critiqued bioassay and chemistry results for site and reference area sediments. Recommendations were made for further studies to finalize the RI and proceed with the FS planning.
Keyport Post-ROD Monitoring Program. Project manager of a post-record of decision (ROD) five-year monitoring program for one of two operable units at the Naval Undersea Warfare Division-Keyport site on Puget Sound. Coordinated field and laboratory activities for four remedial areas of the site, and negotiated with state regulators on interpretation of data on volatile and semivolatile compounds, pesticides, and metals in ground water, seeps, intertidal sediments, offshore sediments, and clam tissues.
City of Charleston Sediment Impacts. Evaluated remedial options to contain contaminated sediments during construction of an aquarium at an estuarine National Park Service site.
Sediment Monitoring Program Toxicity Evaluations. Evaluated sediment toxicity results for the Puget Sound Sediment Monitoring Program of the Washington Department of Ecology. Performed quantitative comparisons with reference area sediments, and covariance analyses with benthic assemblages and sediment chemistry.
Clean Water Act Section 301(h) Permit Application Reviews. Performed technical evaluations of applications to alter National Pollution Discharge Elimination System (NPDES) permits under the Clean Water Act Section 301(h); focused on toxicity tests, bioaccumulation of organic compounds, and fish histopathology.
Los Angeles County CWA 301(h) Permit Review. Managed an assessment of ecological risks due to DDT, PCBs and heavy metal contamination in sediments and biota of a Southern California marine ecosystem as part of a review of a Clean Water Act 301(h) permit application. Evaluated effects of major environmental processes on DDT dynamics in marine sediments and tissues of demersal fish. Generated an empirical model of DDT bioaccumulation in demersal fish from contaminated sediments.
Pesticides of Concern in Puget Sound. Managed an evaluation of the potential for over 120 modern pesticides to pollute Puget Sound waters, sediments, and biota. Conducted usage surveys and environmental fate and toxicity data analyses. A level-of-concern approach was used to prioritize pesticides in a sampling strategy program for U.S. EPA Region 10.
Risk-Based Sediment Storage Management Tool. Managed and designed an approach for generating risk-based chemical concentrations for managing storage of marine sediments during dewatering at the Port of Oakland. Exposures of concern were inhalation and contact with contaminated sediments by workers at the marine terminal.
Reviews of Marine Toxicity Bioassays. Reviewed results of acute and chronic marine toxicity studies of effluent discharges from a number of municipal waste water treatment plants, for U.S. EPA.
Human Health Risk Assessments
Risks from PCB Releases at Sunken Vessels. Reviewed and revised the human health risk assessment for fishing exposures to PCB releases from the sinking of a US Naval vessel for the creation of an artificial reef off the coast of Florida.
Risks from Shellfish Collection and Consumption at a Creosote-Contaminated Bay. Assessed human health risks associated with consumption of shellfish and exposure to sediment during shellfish harvesting from a Puget Sound bay containing creosote-impregnated pilings and PAH releases, for a local tribe.
Field Testing of Modeled Mercury in Fish from an Arctic Lagoon Managed a project to collect field data on petroleum hydrocarbons in surface water, sediment, and fish tissue collected from an estuarine lagoon near the Naval Arctic Research Laboratory, Barrow, AK. The measured tissue concentrations were used to calculate health risks in place of estimated concentrations that were modeled from logKow values. An extraction methodology was developed with the laboratory to separate petroleum hydrocarbons from naturally occurring fish lipids, and received approval from the regulatory agency prior to field plan implementation.
Risk Screening at Abandoned Mine Sites. Performed screening-level evaluations of risks associated with recreational exposures, including dermal contact and consumption of fish, to metals at abandoned mine sites for the USFS.
Human Health Assessment for Milltown Reservoir. Project manager of a multitask human health risk assessment of a metals-contaminated recreational and residential site in Montana for the U.S. EPA Superfund program. This wetlands and riverine system in Western Montana was contaminated with mining waste metals. Coordinated workplans and field efforts of federal and state agencies, university researchers, and local regulatory personnel. Exposures included yard soils, air, drinking water, surface waters, sediments, fish, and wild edible plants. Performed an in-depth review of arsenic carcinogenicity. Assisted with public communication of risk results, presentations to citizens group.
Human Exposure Survey for Milltown, Montana. Manager of a survey of exposure pathways to residents of a small western town at a metals-contaminated wetland site for U.S. EPA. Survey questionnaire focused on types and magnitude of incremental exposures, including ingestion of home-grown produce, game animals, birds, and plants from the local wetland; ingestion of well and surface water; and direct contact with sediments in recreational areas of the wetland.
Reviews of Risk Assessments under TES contracts. Technical reviews of human health and ecological risk assessments at CERCLA and RCRA sites for U.S. EPA Regions 8, 9, and 10. Sites included Rocky Flats, Letterkenny Army Depot, McClellan Air Force Base, the 1990 Bay Road Site, BKK Landfill, Army Defense Depot-Tracy, Teledyne-Wah Chang ore processing facility, Monsanto and Kerr-McGee ore processing facilities, and the Wykoff Wood Treatment facility.
Human Health Risk Assessment for the W.R. Grace Site. Performed the human health risk assessment for the Radioactive Waste Disposal Area of the Curtis Bay facility. Evaluated risks for exposures of construction workers, industrial workers, and visitors to organic chemicals and metals in soils and air. Coordinated exposure scenario development with radiological team.
Ruston Way Site Risk Assessment. Manager and senior author of a human health and ecological risk assessment of an abandoned industrial property to determine soil cleanup levels for PCBs and metals, located along the shoreline of Commencement Bay, WA, for the Washington National Guard.
Risk Assessment for the Big West Oil Refinery. Manager of an assessment of human health risks to residents near an abandoned petroleum refinery in Montana, for the Montana Department of Health and Environmental Sciences. Concerns focused on PAHs and lead in soils, air, and sludge ponds.
Landfill Community Health Investigation. Project manager of a health investigation of a landfill receiving pulp and paper mill wastes, in southwest Washington. Provided a review of a community health survey, and assistance on toxicological issues to the county health department and the primary waste generator.
Hazardous Waste Landfill Risk Assessment. Managed a quantitative health risk assessment at a hazardous waste landfill in California. Over 75 chemicals, including volatile and semivolatile organics, metals, and pesticides, were evaluated in three exposure media; performed ground water and air transport modeling.
Air Studies/MultiPathway Risk Assessments
Multipathway Risk Assessments for Cement Plants Burning Hazardous Waste. Project manager of multipathway risk assessments at two cement plants in the southern US in support of RCRA Part B permits to burn hazardous waste, for Holcim (US) Inc. Site-specific protocols, air dispersion modeling, acute health risks, ecological risk assessment for water and sediment, mercury bioaccumulation factors, and back-calculated emission rate goals were generated as part of the assessments.
Derivation of a Mercury Bioaccumulation Factor. Managed the collection of field data on mercury and methylmercury in surface water and sediments of a freshwater swamp in southeastern US for the derivation of a bioaccumulation factor (BAF) for methylmercury. The site-specific BAF was accepted by EPA to substitute for the national value in the Mercury Report to Congress, for use in a multipathway risk assessment.
Dioxin Emission Controls at Cement Plant Burning Hazardous Waste. Provided technical assistance in developing alternative approaches to controlling dioxin emissions from a cement kiln. Evaluated engineering and chemical processes for dioxin emissions and risk reductions.
Air Dispersion Modeling and Risk Assessments for Cement Plants in Region 7. Project manager and technical direction of air dispersion modeling and multipathway risk assessments in support of a RCRA Part B permits for two cement plants burning hazardous waste in US EPA Region 7.
Memorandum of Understanding, Cement Industry and USEPA. Developed an MOU between the cement industry operating under RCRA Part B interim permits and US EPA Region 7 on technical issues around assessing risks from burning hazardous waste, including interpretation of guidance on receptor identification, bioconcentration factors for PAHs and mercury, and fish consumption rates.
Mercury Biomonitoring at a Cement Plant Burning Hazardous Waste. Manager and technical oversight in the sampling plan design, field sampling effort, and compilation of results of an evaluation of mercury contamination of sediments and biota of fresh water ponds in northern Mississippi.
Multipathway Risk Assessments for Cement Plants Burning Hazardous Waste. Technical direction and oversight on nine screening-level multipathway risk assessments for human health and ecological receptors related to combustion emissions from cement plants.
Corporate Risk Assessment Policy Support. Provided technical consultation in risk assessment to support policy decisions for a national cement manufacturer with combustion facilities burning hazardous waste.
Review of Health Impacts from Asphalt Hot Mix Plants. Reviewed the human health and water resource impacts of asphalt hot mix plants in preparation for a county board hearing for a citizen's group in Washington.
Environmental Health Impact Study of a Municipal Solid Waste Combustor. Program manager of a five year study of multipathway health risks from a state-of-the-art waste-to-energy facility for the Spokane (WA) Solid Waste Disposal Project. The study included a predictive pre-operational risk assessment based on modeling of emissions and air dispersion and two post-startup assessments based on stack emission measurements and soil and air sampling.
Valdez Air Study Review. Provided technical review of the Valdez Air Health Study for the Regional Citizens' Advisory Council (RCAC), Valdez, AK, funded under the Oil Spill Prevention Act. Review focused on the technical approach and methodology for assessing risks to the residents of Valdez from exposures to benzene released from crude petroleum transfer at the Alyeska Pipeline Terminal.
All Fired Up Publication. Performed a comprehensive review of health effects from use of hazardous waste as supplemental fuel in cement kilns. Review covered chemical toxicity, epidemiology studies, risk assessments of current and abandoned facilities, and a comparison of emissions data with and without hazardous waste supplementation. Environmental Toxicology International, Seattle, WA.
Risk Assessment for a Pesticide Formulation Facility. Assisted on the preliminary human health risk assessment for the FMC Fresno, CA, Pesticide Formulation Facility. Performed toxicity reviews and air dispersion modeling.
Toxicology/Regulatory Studies
Technical Reviews of ATSDR and USEPA Toxicology and Risk Assessment Guidelines. Performed reviews of risk assessment methods and guidelines for the USEPA hazardous waste identification rule. Continually performs reviews of draft toxicity profiles and chemical risk assessments on behalf of the Agency for Toxic Substances and Disease Registry and the USEPA.
Consumer Products Materials Certification. Performed evaluations of the toxicities of ingredients in art materials and consumer products under the Labeling of Hazardous Art Materials Act.
Environmental Health Reviews of Biodegradable Plastic Ingredients. Managed a comprehensive review of the environmental impacts of select ingredients in a biodegradable plastic, covering environmental fate and transport, toxicity to humans and wildlife, and potential for degradation in the environment, with descriptions of current waste treatment options. Report written for technically trained readers and laypersons.
Review of Arsenic Carcinogenicity. Authored a comprehensive review of the skin cancer of arsenic for U.S. EPA, with a focus on the potential for a threshold based on mechanisms of carcinogenicity and metabolism.
Toxicity Review of an Ordnance Chemical. Reviewed the toxicology and potential health risks of a U.S. Army chemical (diisopropyl-methyl-phosphonate, DIMP), for the State of Colorado. Evaluated exposure studies in animals for appropriateness for predicting human health effects and for determining dose-response relationships. Derived a reference dose and drinking water guidelines.
Consultation on Regulatory Issues. Provided consultation to U.S. EPA Office of Research and Development, the State of Washington, and citizens' groups on technical and regulatory issues regarding municipal wastes, air toxics, pesticide exposures, impacts of municipal solid waste management options, and design of solid waste compost guidelines.
Solid Waste Management Plan. Assistance to the State of Delaware in generating a solid waste management plan. Reviewed facility siting criteria and environmental and health issues on incineration and landfilling options.
Technical Support of Litigation
Litigation Support for Mill Discharges. Provided technical support on potential risks to the marine environment from paper mill discharges of dioxins and metals. Assistance on preparation of sampling program for soils, surface water and sediments of lakes and marine waters, and evaluation of program results.
Broderick Site Expert Witness. Served as expert witness in risk assessment to the Department of Justice for a Superfund hazardous waste site contaminated with PAHs, dioxins, metals, and chlorinated solvents from wood treatment activities.
Review of Deep Well Injection Practices and Regulations. Reviewed a permit application for a deep well injection system at a hazardous waste landfill, for the Department of Justice. The review focused on compliance of the permit application with the USEPA Underground Injection Control program under the Safe Water Drinking Act and RCRA, and on concerns within the scientific community and regulators over deep well injection options.
Litigation Support in Dioxin Risks. Reviewed the U.S. EPA and U.S. FWS assessments of dioxin risks to bald eagles in the Columbia River Basin, for a pulp and paper plant.
Smelter Slag Impacts on Aquatic Biota. Provided testimony on the potential for heavy metals in slag to leach to estuarine and marine waters, and for metals in soils runoff to adversely affect marine biota. Issues focused on the factors that govern the bioavailability of metals to aquatic biota, their potential impacts, and the regulatory history of ambient water quality criteria for metals, and the scientific understanding in the history of water quality regulations and the aquatic toxicity of metals found in smelter slag.