Focused/Goal-Oriented Risk Assessment


Massachusetts Contingency Plan Characterization of Human Health Risk. Over the last 15 years, Dr. Smith has performed more than 100 separate risk characterizations of petroleum release sites in Massachusetts, including Massachusetts Contingency Plan (MCP) Method 1, 2, and 3 risk characterizations in support of Phase I, II, III, IV, and V document submissions and Response Action Outcome (RAO) Statements.

PAH Source Determination The source of polycyclic aromatic hydrocarbon (PAH) compounds in environmental media determines whether such compounds are subject to the provisions of the Massachusetts Contingency Plan (MCP).  The release and/or threat of release of oil and/or hazardous material related to coal, coal ash, or wood ash, but not wood ash resulting from the combustion of lumber or wood products, is exempt from notification under the MCP, and consequently may be excluded from evaluation in risk assessment.  Dr. Smith uses a quantitative analytical tool, methyl aromatic ratio analysis (MARA) as the cornerstone of his approach to determining whether soil PAH compounds derive from a petrogenic (i.e., petroleum) or pyrogenic (i.e., coal or coal ash) source.  In many cases, existing Gas Chromatograph/Mass Spectrum (GC/MS) data can be used in MARA.

Characterization of Human Health Risk Under the TSCA PCB Mega Rule. Dr. Smith performed one of the first risk assessments of PCB-impacted soils under the PCB Mega Rule.  The risk characterization was performed for the Arsynco, Inc. in Carlstadt, New Jersey, in order to comply with the requirements of the amended Toxic Substances Control Act (TSCA), 40 Code of Federal Regulations (CFR) 761– Disposal of Polychlorinated Biphenyls (PCBs).  The proposed remedial plan included excavation and offsite disposal of all material with PCB concentrations ≥500 ppm and the consolidation, capping, and containment (including berms for flood control) of remaining material with concentrations of PCBs ≥50 ppm.  Dr. Smith conducted the “baseline” risk assessment required by U.S. EPA and also evaluated risks associated with an “alternative remedy” involving only the removal of material with PCB concentrations ≥500 ppm while leaving all remaining PCB contaminated materials in place (i.e. - no consolidation, capping or containment).  Dr. Smith demonstrated that there is no significant health risk to potential human receptors under the U.S. EPA baseline remedy condition and no significant health risk associated with the less conservative alternative remedy condition.

Characterization of Human Health Risk at a Charter School. A private charter school was constructed within a former manufacturing facility contaminated by petroleum products, metals, bird excrement, and polychlorinated biphenyl (PCB) compounds.  After construction, the City refused to provide a Certificate of Occupancy (C of O) to the owner of the school without assurance children, teachers, and maintenance personnel would be without significant health risk.  The issues of concern included PCB compounds detected in air within a storage area adjacent to the school, PCB and petroleum compounds in offsite soils, pigeon droppings from roosts near the school, and mold.  The Licensed Site Professional (L.S.P.) of record engaged Dr. Smith to address human health risks at the school, including identification of additional data necessary for risk characterization, air sampling requirements, and correct identification of PCBs in soil and air.  The risk characterization demonstrated that materials at the school posed 'No significant Risk' to students, teachers, and maintenance workers. Dr. Smith presented credible evidence regarding the health risk posed by site-related compounds in a civil court hearing.  The court found Dr. Smith’s testimony to be credible and reliable.

Evaluation of Cyanide Availability and Mobility in Groundwater Pennsylvania Department of Environmental Protection (PADEP) identified groundwater at a former industrial site as exceeding allowable cyanide concentrations.  The presence of cyanide in groundwater at the site is associated with the historical use of soluble potassium cyanide in metal plating operations, which ceased more than 45 years ago.  Dr. Smith used multiple year quarterly ground water monitoring results and existing ground water analytical data obtained from selected wells using a unique pump and sampling protocol to derive an estimate of the free (i.e., dissolved) cyanide concentration in groundwater of less than 10 percent the total cyanide concentration measured in groundwater.  Dr. Smith demonstrated groundwater cyanide concentrations were in compliance and did not require further monitoring or remediation.

Risk Characterization of PCBs at a Former Industrial Site Pending sale of a former industrial site located in Massachusetts, the sellers due diligence site investigation identified several areas of environmental concern, which included the discovery of soils contaminated with fuel oil, polycyclic aromatic hydrocarbon (PAH), volatile organic compound (VOC), and polychlorinated biphenyl (PCB) compounds.  Dr. Smith conducted a Massachusetts Contingency Plan (MCP) Method-3 risk characterization of the site for the purpose of minimizing the removal of PCB contaminated soils while obtaining a condition of no significant risk of harm to human health.  The property subsequently sold at fair market value.

Modified Baseline Risk Characterization.  A developer, negotiating purchase and development of a former wood treatment /manufactured gas plant facility in Massachusetts, was concerned that the cost of site remediation would make the venture unprofitable.  Dr. Smith used a narrowly focused Massachusetts Contingency Plan (MCP) Method 3 “modified” baseline risk characterization to provide the developer with site-specific information concerning the potential cost of site remediation and development.  Dr. Smith focused the risk characterization to evaluate only exposure of construction workers to on site inorganic and organic contaminants in soil, surface water, and air.  As a result, the developer modified plans for site development to minimize potential health risks posed by contaminants.  Following site development, the “modified” baseline risk characterization was submitted to regulatory authorities to demonstrate a finding of “no significant risk of harm to health, safety, public welfare, and the environment.” No further remediation was required under the MCP.

Dose Reconstruction, Remedial Design, Derive Indoor Air Level A gas utility employee accidentally released elemental mercury into a residential home in Rhode Island during routine replacement of a gas regulator.  The release went unnoticed for nearly a year before discovery by the occupant’s son, who collected it and subsequently spread it throughout the home.  A Prior attempt to remediate the residence by an unqualified contractor led to further widespread contamination of the dwelling.  In anticipation of litigation, attorneys engaged Dr. Smith as an expert witness.  Dr. Smith reconstructed resident exposure to mercury vapor in indoor air and evaluated the potential for adverse health effects in exposed residents.  Although the residence would typically have been demolished and the hazardous waste appropriately disposed of at little cost, the gas utility was concerned that these actions would unduly alarm its customers and the public. Dr. Smith identified an appropriate, low profile cleanup strategy to obtain an appropriate health protective level of mercury in indoor air.  Dr. Smith evaluated remediation of the residence with respect to a site-specific health risk-based allowable mercury concentration in indoor air.  Through these actions, Dr. Smith obtained a letter from the Rhode Island Department of Health declaring the residence safe for immediate occupancy.

Support of a No Action Alternative.  Potable ground water at a former electronics manufacturing plant in Connecticut contained chlorinated volatile organic compound (cVOC). Analytical differentiation of degradation products identified an anaerobic transport pathway augmented with organic compounds (sewer line).  This information allowed for a more focused evaluation of environmental transport of cVOC contaminants.  Dr. Smith alerted the client to problems with existing analytical cVOC data collected using an inappropriate sampling method and the use of a technical infeasibility argument for limiting further groundwater treatment at the site.  Dr. Smith supported a no action alternative with the development of a Public Health and Environmental Risk Evaluation (PHERE) demonstrating that there are no human receptors impacted by groundwater contaminates. 

Product Evaluation; Human Health RiskThe state of Pennsylvania expressed concern that concentrations of polychlorinated dibenzo-p-dioxins (dioxins or PCDDs) and dibenzofurans (furans or PCDFs) in composted pulp and paper mill sludge might pose a human health risk when used as either a soil amendment or as a retail mulch.  Dr. Smith assisted in a conservative assessment of human health risk posed by these compounds. The risk assessment included evaluation of residential exposure through incidental ingestion of amended soil and vegetables grown in amended soil, as well as potential occupational exposure from direct contact with both sludge and mulch.  The evaluation found no increase in carcinogenic or non-carcinogenic risk to human health from the use of these products.

Preliminary Characterization of Inhalation Air Risk. At a former frop forge site in Massachusetts, Dr. Smith assessed the potential health risk to residents at a nearby apartment building.  Air contaminants of potential health concern included several polycyclic aromatic hydrocarbon (PAH) compounds, benzene, and chlorinated and non-chlorinated volatile organic compounds (cVOC and VOC, respectively).  The result identified additional sampling and risk assessment alternatives under the Massachusetts Contingency Plan (MCP) to reduce potential receptor health risks.

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