Client Comments

Human Health Risk Assessment Client:
"You did an excellent job of pulling all this together. I appreciate all of the hard work you put in on this document. [Once this has been approved by the agency] I feel we will have passed one of the most important milestones for this project. [Your work] has allowed us to develop a very positive relationship with [the lead regulator]."

U.S. Environmental Protection Agency Regional Risk Assessor in regard to human health risk assessment:
"Because of [her] knowledge, expertise, and team-oriented attitude, Dr. Heath has been wonderful to work with. [She is a] well versed professional in the risk assessment process. [She is] prepared for every meeting, make[s] recommendations on improving the risk assessment or resolving complex issues, and deliver[s] a high quality product on schedule. [Her] strong academic background and understanding of current toxicological issues and research make [her] and invaluable asset when applying new approaches to a site, chemical or mathematical model. [She is] also skilled at communicating the results of highly technical material to a lay person and working towards resolution in a stakeholder group that has strong and diverse opinions."



pipeline, refinery at night, open pit mining

Human Health Risk Assessment, Sample Projects

Active Gas Plant Risk Assessment: As the Risk Assessment Task manager for an active gas plant in a state voluntary remediation program, engaged in a multi-year collaborative process with the state agency involving a series of technical meetings and conference calls. Wrote the human health Risk Assessment Work Plan; the draft Risk Assessment Work Plan was accepted by the agency with no comments requiring revisions. Managed the updated ecological exclusion assessment, which evaluated whether plants, invertebrates, fish and wildlife were likely to be affected. This document was accepted by the agency. Identified risk-based needs for further soil sampling and assisted in preparation and negotiation of the sampling plan. Contributed to refinement of the analyte list (and detection limits) for ongoing groundwater sampling. Managed the Human Health Risk Assessment, including writing the 3-volume document. Several unique agreements were implemented, including a process to meaningfully combine older and newer soil data and area-weight the results. When the agency’s project manager resigned near the end of this multi-year process, helped bring the agency’s new team up to date on historical agreements and the agreed-upon risk assessment process.

Pipeline Mercury Meters: For a client with dozens of very small mercury releases from mercury meters along a pipeline in CO, TX, WY, and OK, (1) helped to determine which program in each state would be most appropriate, (2) evaluated default as well as higher defensible soil cleanup goals, and (3) developed materials in support of the selected target cleanup level for each state. Direct human contact with soil and protection of groundwater were considered; in several cases, the pH-dependent Kd and toxicity of various forms of mercury were key concepts.

Active Refinery: For an active refinery (RCRA) site in Colorado, teamed with a small engineering firm to jointly develop a groundwater sampling work plan to implement the pre-existing human health risk assessment work plan, including meetings with state and federal regulators and with the adjacent refinery. The site had a history of discharge of NAPL to surface water. Refined the pre-existing risk assessment work plan, and managed preparation of the risk assessment, including writing all text.

Active Hard Rock Mine: Worked on this site over the course of roughly a decade. Conducted toxicology aspects of a task related to NPL listing; a voluntary program was negotiated. Attended meetings with many parties (EPA and their contractors, mine and multiple contractors, USGS, USFWS, state environmental and mine permitting agencies) monthly to quarterly for several years, preparing live notes and action items that were simultaneously projected (and corrected by meeting participants); these were the primary form of documentation of the meetings and related commitments by the parties. Commented on agency work products related to risk assessment, including an ATSDR Public Health Assessment. Evaluated the safety of livestock (cattle, sheep and horses) grazing (forage and soil ingestion) and drinking water on privately owned off-site property potentially affected by mine-related metals. Peer reviewed the evaluation of risk to humans from exposure to environmental media and ingestion of beef. Over the course of several months and multiple meetings among many parties, negotiated a detailed conceptual site model, including receptors, exposure media, fate and transport, and post-closure exposures. Coordinated responses to 100 pages of comments on a 3-volume deliverable. Participated in development of DQOs to guide sampling for human health risk assessment needs. Managed the preparation of a mine closure report on wildlife for this large open pit and underground (block cave) site in Southwestern U.S. Task manager for two wildlife evaluations and the work plan for a plant uptake study at this active mine. Assembled comments from several experts on EPA’s draft ecological toxicity reference values (TRVs) for surface water, sediment, surface soil. Prepared comments on EPA Human Health Risk Assessment Work Plan and on the Human Health Risk Assessment, including incorporation of comments by other mine contractors as well as in-depth review of specific toxicological issues and comments on appropriate use of extensive site data in the documents.

Former Smelter Superfund Site: As lead human health risk assessor for a Superfund site in the southwestern U.S. consisting of a number of large and small former smelters, developed a cost-effective phased approach allowing the majority of the risk work for residential, recreational, and industrial areas to be completed prior to the conclusion of the RI, thus helping to guide completion of the RI.

Large, Federal RCRA Facility: Participated on this project over the course of several years. Managed a team to adapt and implement an EPA model for volatilization from the subsurface to trench air so that it would be more representative for a much larger “air box,” in this case, a gulch with seeps and a stream. Developed comments on the state’s proposed indoor air (vapor intrusion) guidance. Participated in development of site-wide strategy related to vapor intrusion from subsurface to indoor air, including evaluation of indoor air at a school. Contributed to and finalized the human health risk assessment workplan, designed to reduce the number of potential chemicals of concern, to minimize sampling, and to yield cost-effective remedial actions. Lead expert in responding to agency comments on the human health risk assessment work plan. Peer reviewed the human health risk assessment for areas being considered for redevelopment as a transportation corridor. Conducted the human health risk assessments for several sites in some cases managing other subcontractors.

Redevelopment of Landfills: When a city accepted transfer of three former landfills at a former military base, managed the human health and ecological screening-level risk assessments. Negotiated the risk assessment approach with the state agency based on then-current guidance and comments from several agencies on a previous document.

Re-permitting of Nuclear Power Plant: Reviewed available data and prepared for expert evaluation related to claims of human health and dairy animal impacts associated with alleged releases from past operations.