Exposure & Risk Assessment

Example Projects


Both 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 risk 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 PCBs and dioxins, ecotoxicology, site-specific exposure modeling; and probabilistic risk analysis.

Example publications:

Seeley, M; Wells, CS; Wannamaker, EJ; Mattuck, RL; Ren, S; Beck, BD. 2013. "Determining soil remedial action criteria for acute effects: The challenge of copper." Regul. Toxicol. Pharmacol. 65:47-59.

 hands in water gradient exposure model

Example Projects

Pesticide Spray Drift Risk Assessment

Full Description

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

Full Description

Gradient prepared human health and ecological risk assessments for radionuclides, metals, PAHs, and 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

Full Description

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

Full Description

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.


Barbara D. Beck Read Bio

Teresa S. Bowers Read Bio

Grace I. Greenberg Read Bio

Mary L. Hixon Read Bio

Laura E. Kerper Read Bio

Julie C. Lemay Read Bio

Christopher M. Long Read Bio

Rosemary Mattuck Read Bio

Margaret C. Pollock Read Bio

Robyn L. Prueitt Read Bio

Sara Pacheco Shubin Read Bio

Peter A. Valberg Read Bio

Tim Verslycke Read Bio