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Maryann Welsch

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Maryann Welsch
Consultant

Maryann Welsch

Consultant (207) 800-3808 Portland, ME mwelsch@integral-corp.com

Ms. Maryann Welsch has more than 20 years of experience in ecological risk assessment, natural resource damage assessment (NRDA), biological sampling and site investigations, and estuarine, stream, and wetland assessment and restoration. She has conducted aquatic and terrestrial ecological risk assessments addressing complex site characteristics including multiple stressors and exposure pathways and the development of trophic transfer modeling evaluations for bioaccumulative constituents such as mercury, PCBs, and per- and polyfluoroalkyl substances (PFAS). Ms. Welsch has advised clients on determining the potential for natural resource injuries related to ecological exposures in surface water, sediment, soil, and groundwater and has provided recommendations for restoration in support of NRDAs. Ms. Welsch also has experience in abiotic and biotic sampling methodologies and has designed sampling programs for a variety of settings and performed statistical evaluations to support data analysis including the determination of background thresholds. She has managed and provided technical and strategic support on numerous site investigations in New England, the Mid-Atlantic region, the Great Lakes region, the Southeast, and the Pacific Northwest.

Beneficial Use of Contaminated Sediments: Focused Review of Treatment Technologies

Poster

January 30 2025

Ecological Risk Assessment

RI/FS and Ecological Risk Assessment, Lower Anacostia River, Washington, DC Conducted a baseline ecological risk assessment for aquatic receptors associated with river sediments adjacent to a former electric power facility. Evaluated potential risks to benthic invertebrates using multiple lines of evidence including sediment bioassays, a macroinvertebrate community survey, sediment and porewater chemistry (particularly PCBs), and metals. Also evaluated PAH bioavailability in sediment and porewater using the equilibrium partitioning approach. Potential risks to fish and wildlife were evaluated based on fish tissue residue concentrations in comparison to risk-based tissue concentrations and trophic transfer modeling. Performed statistical analyses for the comparison of site-related risks relative to urban background reference conditions. Incorporated site-specific data as well as data from outside sources in the evaluation to determine spatial trends of the potential impacts and to help define remedial activities.
RI/FS and Ecological Risk Assessment, Minneapolis, Minnesota Supported a baseline ecological risk assessment for aquatic receptors in a flood control system in the Tri-Lakes area. Developed site-specific bioaccumulation models of PFAS compounds for an aquatic trophic transfer model in support of an ecological risk assessment. Conducted trophic transfer modeling for herbivorous mammals and birds based on site-specific plant tissue concentrations.
RI/FS and Ecological Risk Assessment, Lower Anacostia River, Washington, DC Supported a baseline ecological risk assessment for aquatic receptors associated with river sediments adjacent to a manufactured gas plant. Evaluated risks to benthic invertebrates using multiple lines of evidence including sediment bioassays, a macroinvertebrate community survey, and sediment chemistry. Also evaluated PAH bioavailability in sediment and porewater using the equilibrium partitioning approach. Performed statistical analyses including the calculation of reference envelope thresholds to support the sediment quality triad presented in the baseline ecological risk assessment risk characterization. Developed and implemented a strategy for determining background conditions for river surficial and subsurficial sediment to support the remedial investigation and inform subsequent remedial actions.
Ecological Evaluation, Raritan River, New Jersey Performed ecological risk assessments following New Jersey Department of Environmental Protection guidelines for aquatic receptors associated with river sediments adjacent to two generating stations on the Raritan River. Lines of evidence evaluated included benchmark screening and wildlife dietary exposure modeling. Developed sampling programs and evaluated regional background sediment conditions to support the investigations.
Remedial Investigation and Ecological Risk Assessment, Newport, Rhode Island Supported a baseline ecological risk assessment for aquatic and terrestrial receptors associated with soils and sediments at or adjacent to a military facility. Lines of evidence evaluated included sediment invertebrate toxicity testing and invertebrate community surveys, benchmark screening, wildlife dietary exposure modeling, and comparisons to background conditions.
Remedial Investigation and Ecological Risk Assessment, Washington, DC Conducted a screening-level ecological risk assessment of groundwater discharging from a military facility to the surface waters of the Potomac River. Lines of evidence evaluated included groundwater and surface water benchmark screening, background comparisons, and site-specific groundwater dilution factors.
Remedial Investigation and Ecological Risk Assessment, Stump Neck, Maryland Conducted a screening-level ecological risk assessment of surface soil and groundwater at or adjacent to a military facility. Lines of evidence evaluated included benchmark screening, dietary dose modeling for wildlife exposures, and comparisons with background.
Ecological Risk Assessment, Mount Vernon, Indiana Performed an ecological risk assessment of modeled air deposition concentrations in soils, sediments, and surface water for permit compliance. Lines of evidence evaluated included benchmark screening and aquatic and terrestrial dietary dose modeling for wildlife exposures based on current and future concentrations expected from emissions.
Ecological Evaluation, Linden, New Jersey Performed an ecological risk assessment following New Jersey Department of Environmental Protection guidelines for aquatic receptors associated with wetland and river sediments at a petrochemical storage and distribution facility. Lines of evidence evaluated included benchmark screening and wildlife dietary exposure modeling. Developed sampling programs for the collection of site and background samples and evaluated regional background sediment conditions to support the investigations.
Ecological Risk Assessment, Wilmington, Massachusetts Conducted a baseline ecological risk assessment of soil, groundwater, sediment, and surface waters at an industrial facility following Massachusetts Contingency Plan risk assessment guidance in support of a Permanent Solution Statement. Lines of evidence evaluated included benchmark screening, dietary dose modeling for wildlife exposures, and comparisons with background. This evaluation was subsequently updated as part of the temporary solutions status five-year review.
Remedial Investigation and Ecological Risk Assessment, North Kingstown, Rhode Island Conducted a screening-level ecological risk assessment of surface soil, surface water, and sediment located at or adjacent to a waste disposal facility. Lines of evidence evaluated included benchmark screening, dietary dose modeling for wildlife exposures, and comparisons with background. Developed sampling programs for further evaluation to refine the ecological risk assessment.
RI/FS and Ecological Risk Assessment, Brunswick, Maine Supported a baseline ecological risk assessment for aquatic receptors associated with surface water and sediments in a drainage system at or adjacent to a former military facility. Lines of evidence evaluated included benchmark screening, wildlife dietary exposure modeling, and comparisons to background conditions. Coordinated and assisted with the collection of abiotic and biotic sediment and surface water samples for chemical and physical analyses to inform the RI/FS.
Ecological Risk Assessment, Framingham, Massachusetts Conducted a baseline ecological risk assessment of groundwater, soils, surface water and sediments adjacent to a historic landfill following Massachusetts Contingency Plan risk assessment guidance to support a comprehensive site assessment and imminent hazard evaluation. Lines of evidence evaluated included benchmark screening, dietary dose modeling for wildlife exposures, and comparisons with background.
RI/FS and Ecological Risk Assessment, Belle Mead, New Jersey Performed an ecological risk assessment of soils and hydric soils at an industrial facility. Developed risk-based remedial goals to inform the remedial design.
Ecological Risk Assessment, Salem, Massachusetts Conducted a baseline ecological risk assessment of soil and groundwater at an industrial facility following Massachusetts Contingency Plan risk assessment guidance in support of a Permanent Solution Statement. Lines of evidence evaluated included benchmark screening and comparisons with background.
Remedial Investigation and Ecological Risk Assessment, Cutler, Maine Supported a baseline ecological risk assessment for aquatic and terrestrial receptors associated with soil, surface water, and sediment at or adjacent to a military facility. Lines of evidence evaluated included benchmark screening, wildlife dietary exposure modeling, and comparisons to background conditions.
Ecological Risk Assessment, Farmington, New Mexico Supported an ecological risk assessment of modeled air deposition concentrations in soil, sediment, and surface water for an environmental impact statement. Lines of evidence evaluated included benchmark screening and aquatic and terrestrial dietary dose modeling for wildlife exposures based on current and future concentrations expected from emissions.
Remedial Investigation and Ecological Risk Assessment, Lake Macatawa, Michigan Conducted an ecological risk assessment of sediment and surface adjacent to an industrial facility based on exposure to inorganic and organic constituents (primarily barium and PCBs). Lines of evidence included sediment invertebrate toxicity tests, sediment benchmark screening, dietary exposure modeling for wildlife, and comparisons to background conditions.
Remedial Investigation and Ecological Risk Assessment, Rocky Hill, Connecticut Supported screening-level and baseline ecological risk assessments for the evaluation of potential risks of metals in sediment to aquatic organisms. Lines of evidence included benchmark screening, sediment invertebrate toxicity tests, and modeled dietary exposure for wildlife.
Ecological Risk Assessment for RCRA Facility Investigation, Fort Belvoir, Virginia Conducted screening-level ecological risk assessments for benthic invertebrates, soil invertebrates, plants, and wildlife to identify the potential for risks associated with potential exposures to onsite and offsite soil, hydric soil, surface water, and sediment. Provided support for making decisions on further investigations and remedial actions.
RI/FS and Ecological Risk Assessment, Newark, New Jersey Supported an ecological risk assessment of sediment and surface water conducted on the Lower Passaic River. Developed and implemented field sampling programs for collection of empirical data including fish and benthic invertebrate tissue to support the evaluation of potential risks to invertebrates, fish, birds, and mammals. Performed statistical analyses of fish tissue body burdens to develop background threshold values for use in risk assessment and feasibility study.
Remedial Investigation and Ecological Risk Assessment, Portland, Oregon Supported an ecological risk assessment of sediment and surface water conducted on the Lower Willamette River. Supported the development and implementation of field sampling programs for the collection of abiotic and biotic samples.
Remedial Investigation and Ecological Risk Assessment, Seattle, Washington Supported an ecological risk assessment of sediment on the Lower Duwamish Waterway. Developed and implemented field sampling programs for the collection of abiotic and biotic media including fish, benthic invertebrates, and clam tissue for chemical and biological analyses. Supported the evaluation of potential risks to aquatic organisms.

Natural Resource Damage Assessment

NRDA, Mid-Atlantic United States Conducted an evaluation of potential natural resource injuries to ecological resources based on soil, groundwater, surface water, and sediments associated with historical industrial waste disposal. Applied the habitat equivalency analysis (HEA) model to evaluate potential injuries. Assisted client with agency negotiations and litigation support.
NRDA, Lower Anacostia River, Washington, DC Conducted an evaluation of potential natural resource injuries to ecological resources based on surface water and sediments at an industrial facility. Applied the HEA model to evaluate potential injuries and compensatory restoration actions such as the creation of mussel habitat. Coordinated the development of a restoration project associated with the remedial design. Assisted client with agency negotiations and additional technical and strategic approaches.
NRDA, Mid-Atlantic United States Supported an evaluation of potential natural resource injuries to ecological resources based on sediments in a large river. Evaluated the potential for future risks to wildlife based on various restoration project concepts. Assisted with client support in terms of technical and strategic approaches for the design of restoration projects.
NRDA, Mid-Atlantic United States Conducted an evaluation of potential natural resource injuries to ecological resources based on soil, surface water, and sediment at a historical industrial facility. Applied the HEA model to evaluate potential injuries. Assisted with agency negotiations and additional technical and strategic approaches.
NRDA, Washington, DC Evaluated potential injuries related to a mineral oil spill in a tributary to the Anacostia River. Designed a sampling program for the collection of site-specific biological community data (aquatic invertebrates and fish). Potential injuries were evaluated based on the comparison of aquatic community parameters relative to urban background, forensic analysis, and fate and transport analysis of PAHs related to the spill.
NRDA, Arlington, Virginia Conducted an evaluation of potential natural resource damages associated with a small mineral oil spill to the Potomac River based on the forensic analyses of PAHs, fate and transport analysis, and biological data such as macroinvertebrate surveys and wildlife mortalities. Used the HEA model to inform technical and strategic approaches based on the comparison of potential injuries, subsequent remediation, and possible restoration scenarios.
NRDA, Mid-Atlantic United States Evaluated potential restoration projects for the compensation of natural resource damage liabilities on a large urban river. Applied the HEA model for the comparison of restoration of different resources and among proposed projects. Assisted with the development of technical and strategic approaches for negotiations with the trustees.
NRDA, Tacoma, Washington Developed a stream and wetland restoration project on a tributary of Hylebos Waterway in Commencement Bay to compensate for natural resource injuries to fish (juvenile salmonids) and aquatic birds. Applied the HEA model to the range of restoration credits. Assisted client with negotiations with the trustee group. Procured necessary permits and developed the postconstruction monitoring program for compliance with permit requirements and the consent decree. Also conducted required site assessments to satisfy permitting requirements including wetland delineation, stream channel, and habitat assessments.

Statistical Analysis

Evaluation of Long-Term Monitoring Data, New Bedford, Massachusetts Performed a review of 28 years of long-term monitoring data collected in New Bedford Harbor to evaluate spatial and temporal trends in sediment PCB chemical concentrations and benthic infaunal community metrics. Explored the potential for relationships between sediment chemistry and benthic community. Determined methodologies for evaluating the effectiveness of sediment remediation over the long term.

Litigation Support

Expert Witness Reports, Western United States Primary author of two expert reports on PCB contamination related to specific upland sources. Evaluated historical land uses, abiotic data, and transport mechanisms of contaminants from upland facilities downgradient to river sediments.

Contaminated Sediments

RI/FS and Ecological Risk Assessment, Lower Anacostia River, Washington, DC Conducted a baseline ecological risk assessment for aquatic receptors associated with river sediments adjacent to a former electric power facility. Evaluated potential risks to benthic invertebrates using multiple lines of evidence including sediment bioassays, a macroinvertebrate community survey, sediment and porewater chemistry (particularly PCBs), and metals. Also evaluated PAH bioavailability in sediment and porewater using the equilibrium partitioning approach. Potential risks to fish and wildlife were evaluated based on fish tissue residue concentrations in comparison to risk-based tissue concentrations and trophic transfer modeling. Performed statistical analyses for the comparison of site-related risks relative to urban background reference conditions. Incorporated site-specific data as well as data from outside sources in the evaluation to determine spatial trends of the potential impacts and to help define remedial activities.
RI/FS and Ecological Risk Assessment, Lower Anacostia River, Washington, DC Supported a baseline ecological risk assessment for aquatic receptors associated with river sediments adjacent to a manufactured gas plant. Evaluated risks to benthic invertebrates using multiple lines of evidence including sediment bioassays, a macroinvertebrate community survey, and sediment chemistry. Also evaluated PAH bioavailability in sediment and porewater using the equilibrium partitioning approach. Performed statistical analyses including the calculation of reference envelope thresholds to support the sediment quality triad presented in the baseline ecological risk assessment risk characterization. Developed and implemented a strategy for determining background conditions for river surficial and subsurficial sediment to support the remedial investigation and inform subsequent remedial actions.
Ecological Evaluation, Raritan River, New Jersey Performed ecological risk assessments following New Jersey Department of Environmental Protection guidelines for aquatic receptors associated with river sediments adjacent to two generating stations on the Raritan River. Lines of evidence evaluated included benchmark screening and wildlife dietary exposure modeling. Developed sampling programs and evaluated regional background sediment conditions to support the investigations.
Ecological Evaluation, Linden, New Jersey Performed an ecological risk assessment following New Jersey Department of Environmental Protection guidelines for aquatic receptors associated with wetland and river sediments at a petrochemical storage and distribution facility. Lines of evidence evaluated included benchmark screening and wildlife dietary exposure modeling. Developed sampling programs for the collection of site and background samples and evaluated regional background sediment conditions to support the investigations.
RI/FS and Ecological Risk Assessment, Brunswick, Maine Supported a baseline ecological risk assessment for aquatic receptors associated with surface water and sediments in a drainage system at or adjacent to a former military facility. Lines of evidence evaluated included benchmark screening, wildlife dietary exposure modeling, and comparisons to background conditions. Coordinated and assisted with the collection of abiotic and biotic sediment and surface water samples for chemical and physical analyses to inform the RI/FS.
RI/FS and Ecological Risk Assessment, Belle Mead, New Jersey Performed an ecological risk assessment of soils and hydric soils at an industrial facility. Developed risk-based remedial goals to inform the remedial design.
Remedial Investigation and Ecological Risk Assessment, Lake Macatawa, Michigan Conducted an ecological risk assessment of sediment and surface adjacent to an industrial facility based on exposure to inorganic and organic constituents (primarily barium and PCBs). Lines of evidence included sediment invertebrate toxicity tests, sediment benchmark screening, dietary exposure modeling for wildlife, and comparisons to background conditions.
Remedial Investigation and Ecological Risk Assessment, Rocky Hill, Connecticut Supported screening-level and baseline ecological risk assessments for the evaluation of potential risks of metals in sediment to aquatic organisms. Lines of evidence included benchmark screening, sediment invertebrate toxicity tests, and modeled dietary exposure for wildlife.
RI/FS and Ecological Risk Assessment, Newark, New Jersey Supported an ecological risk assessment of sediment and surface water conducted on the Lower Passaic River. Developed and implemented field sampling programs for collection of empirical data including fish and benthic invertebrate tissue to support the evaluation of potential risks to invertebrates, fish, birds, and mammals. Performed statistical analyses of fish tissue body burdens to develop background threshold values for use in risk assessment and feasibility study.
Remedial Investigation and Ecological Risk Assessment, Portland, Oregon Supported an ecological risk assessment of sediment and surface water conducted on the Lower Willamette River. Supported the development and implementation of field sampling programs for the collection of abiotic and biotic samples.
Remedial Investigation and Ecological Risk Assessment, Seattle, Washington Supported an ecological risk assessment of sediment on the Lower Duwamish Waterway. Developed and implemented field sampling programs for the collection of abiotic and biotic media including fish, benthic invertebrates, and clam tissue for chemical and biological analyses. Supported the evaluation of potential risks to aquatic organisms.
NRDA, Lower Anacostia River, Washington, DC Conducted an evaluation of potential natural resource injuries to ecological resources based on surface water and sediments at an industrial facility. Applied the HEA model to evaluate potential injuries and compensatory restoration actions such as the creation of mussel habitat. Coordinated the development of a restoration project associated with the remedial design. Assisted client with agency negotiations and additional technical and strategic approaches.
NRDA, Arlington, Virginia Conducted an evaluation of potential natural resource damages associated with a small mineral oil spill to the Potomac River based on the forensic analyses of PAHs, fate and transport analysis, and biological data such as macroinvertebrate surveys and wildlife mortalities. Used the HEA model to inform technical and strategic approaches based on the comparison of potential injuries, subsequent remediation, and possible restoration scenarios.
Evaluation of Long-Term Monitoring Data, New Bedford, Massachusetts Performed a review of 28 years of long-term monitoring data collected in New Bedford Harbor to evaluate spatial and temporal trends in sediment PCB chemical concentrations and benthic infaunal community metrics. Explored the potential for relationships between sediment chemistry and benthic community. Determined methodologies for evaluating the effectiveness of sediment remediation over the long term.
Expert Witness Reports, Western United States Primary author of two expert reports on PCB contamination related to specific upland sources. Evaluated historical land uses, abiotic data, and transport mechanisms of contaminants from upland facilities downgradient to river sediments.

Ecological Restoration

NRDA, Lower Anacostia River, Washington, DC Conducted an evaluation of potential natural resource injuries to ecological resources based on surface water and sediments at an industrial facility. Applied the HEA model to evaluate potential injuries and compensatory restoration actions such as the creation of mussel habitat. Coordinated the development of a restoration project associated with the remedial design. Assisted client with agency negotiations and additional technical and strategic approaches.
NRDA, Mid-Atlantic United States Supported an evaluation of potential natural resource injuries to ecological resources based on sediments in a large river. Evaluated the potential for future risks to wildlife based on various restoration project concepts. Assisted with client support in terms of technical and strategic approaches for the design of restoration projects.
NRDA, Mid-Atlantic United States Evaluated potential restoration projects for the compensation of natural resource damage liabilities on a large urban river. Applied the HEA model for the comparison of restoration of different resources and among proposed projects. Assisted with the development of technical and strategic approaches for negotiations with the trustees.
NRDA, Tacoma, Washington Developed a stream and wetland restoration project on a tributary of Hylebos Waterway in Commencement Bay to compensate for natural resource injuries to fish (juvenile salmonids) and aquatic birds. Applied the HEA model to the range of restoration credits. Assisted client with negotiations with the trustee group. Procured necessary permits and developed the postconstruction monitoring program for compliance with permit requirements and the consent decree. Also conducted required site assessments to satisfy permitting requirements including wetland delineation, stream channel, and habitat assessments.

PFAS

RI/FS and Ecological Risk Assessment, Minneapolis, Minnesota Supported a baseline ecological risk assessment for aquatic receptors in a flood control system in the Tri-Lakes area. Developed site-specific bioaccumulation models of PFAS compounds for an aquatic trophic transfer model in support of an ecological risk assessment. Conducted trophic transfer modeling for herbivorous mammals and birds based on site-specific plant tissue concentrations.

Henning, M., M. Welsch, and X. Santiago. 2023. Expert Analysis: Enviro justice can help cos. with regulators, communities. Law360, New York, NY. March 9. https://www.law360.com/articles/1583250/enviro-justice-can-help-cos-with-regulators-communities.

Henning, M., and M. Welsch. 2023. Opportunities for meaningful environmental justice actions by the regulated sector. JDSupra. July 12. https://www.jdsupra.com/legalnews/opportunities-for-meaningful-9693652.

Yavitt, J., J. Burtis, K.A. Smemo, and M. Welsch. 2018. Plot-scale spatial variability of methane, respiration, and net nitrogen mineralization in muck-soil wetlands across a land-use gradient. Geoderma 315:11–19.

Welsch, M., and J.B. Yavitt. 2007. Microbial CO2 production, CH4 dynamics and nitrogen in a wetland soil (New York State, USA) associated with three plant species (Typha, Lythrum, Phalaris). Eur. J. Soil Sci. 58:1493–1505.

Welsch, M., and J.B. Yavitt. 2003. Early stages of decay of Lythrum salicaria and Typha latifolia in a standing-dead position. Aquat. Bot. 75:45–57.

Welsch, M., C. Archer, H. Loso, C. Puopolo, H. Patterson, H. Temme, and A. Gorski. 2021. Developing site-specific uptake factor relationships for a PFAS investigation and risk assessment at a flood control system in Minnesota. 42nd Annual Meeting of SETAC North America, Ecological Risk Assessment for Contaminants of Emerging Concern. November.

Archer, C., H. Loso, H. Patterson, C. Puopolo, M. Welsch, H. Temme, and A. Gorski. 2021. PFAS investigation and risk assessment at a flood control system in Minnesota. 42nd Annual Meeting of SETAC North America, Ecological Risk Assessment for Contaminants of Emerging Concern. November.

Welsch, M., B. Ruffle, H. Jones, J. Bleiler, R. Damera, and F. Mahvi. 2015. Evaluating risks to benthic invertebrates and fish at an urban waterfront site on the Lower Anacostia River. North Atlantic Chapter of SETAC Meeting.

Hurley, K., L. Saban, and M. Welsch. 2009. Practical considerations of implementing a natural resources damage assessment restoration project. National Conference on Ecosystem Restoration, Los Angeles, CA.

Welsch, M. 2007. Ecological factors to consider when selecting a mitigation site. Law Seminars International Workshop on Mitigation and Conservation Banking. Seattle, WA.

Welsch, M., T. Deshler, S. Pierce, and S. Reiersgaard. 2004. Monitoring changes in wetland habitat functions following the introduction of wastewater effluent from cheese manufacturing. SETAC 25th Annual Meeting, Portland, OR.

Johns, D.M., L. Saban, M. Welsch, M. Luxon, D. Pelletier, and C. Jackson. 2004. Use of habitat suitability index models to scale site-specific injury for multiple resources. SETAC 25th Annual Meeting, Portland, OR.

Johns, D.M., L. Saban, M. Luxon, and M. Welsch. 2003. Establishing habitat valuations for HEA. SETAC 24th Annual Meeting, Austin, TX.

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