Service Area

Exposure & Risk Assessment

Human health and ecological risk assessment have evolved as important decision-making tools for the management and development of site remediation strategies.  Gradient has long been recognized as one of the nation’s premier exposure assessment firms.  Our strengths lie in our equally balanced toxicology, exposure modeling, and quantitative analysis skills.  Gradient’s scientists use these diverse talents to assess potential risks to human health and the environment.

Our broad areas of expertise in human health and ecological risk assessment include bioavailability of metals; persistent and bioaccumulative toxicants, such as polychlorinated biphenyls (PCBs) and dioxins; ecotoxicology; site-specific exposure modeling; and probabilistic risk analysis.

Questions That Exposure Assessment Can Help Answer:

  • Should this product be redesigned?
  • Does this site require risk management measures to reduce exposures?
  • Is a product recall necessary?
  • How much does this site contribute to overall exposures?
  • Should this lawsuit be settled?
  • Would additional information yield a better decision?

Sample Projects

Pesticide Spray Drift Risk Assessment

Gradient assessed the health risks of pesticide applications to young children using site-specific pesticide air release and deposition data, supplemented with air dispersion and deposition modeling.  We estimated exposures from inhalation, dermal absorption of pesticides deposited as droplets onto surfaces, ingestion of residues via hand-to-mouth activity, and consumption of homegrown fruits/vegetables.

Risk Assessment for a Nuclear Power Plant Site Closure

Gradient prepared human health and ecological risk assessments for radionuclides, metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) in which we evaluated the cumulative chemical and radiation risks.  Our evaluation was used to support the power plant’s dismantling and environmental site closure requirements.

Coal Ash Risk Assessment

Gradient evaluated potential multi-pathway exposures to trace metals from a coal ash disposal site, as well as risks for residents living near the site.  We assessed potential exposures and health risks from beneficial uses of coal combustion products used in wallboard, concrete, and cement-building materials.

Lead Smelter Ecological Risk Assessment

Gradient performed a baseline ecological risk assessment for a former lead smelter site.  We identified field sampling plans for the collection of sediment, soil, surface water, and wildlife tissue, and also characterized risks based on site-specific bioavailability and toxicity to aquatic organisms, birds, mammals, amphibians, and other ecological receptors.

Our Team