Gradient

Perfluorinated Compounds

Overview
Example Projects
Experts

Overview

PFAS-related scientific topics include potential for accumulation in humans and ecosystems, fate and transport in the environment, potential toxicity and risk assessment, and remedial decision-making. Gradient's health scientists and engineers have applied their specialized skills in these areas to address PFAS-related matters.

PFOA

Example Projects

PFAS Fate and Transport Assessment at a Municipal Solid Waste Landfill

Full Description

To support an administrative hearing regarding a landfill expansion permit, Gradient evaluated potential impacts to groundwater and surface water quality near the landfill. We compared chemical concentrations in landfill leachate, groundwater monitoring wells, and nearby surface water with regulatory benchmarks. We used multiple lines of evidence, including an evaluation of the effectiveness of the landfill liner system and temporal evolution of PFAS concentrations in leachate, to estimate the scale of potential surface water impacts if the landfill was expanded.

PFAS Fate and Transport Evaluation

Full Description

Gradient conducted site research and evaluated the extent of perfluorinated alkyl substances (PFAS) at multiple locations throughout the US. Our evaluation included a review of potential PFAS transport from industrial facilities, landfills, and fire training areas to soil, groundwater, surface water, and sediment. Gradient also compiled information on remediation activities and water treatment systems.

PFAS Analytical Chemistry

Full Description

Gradient wrote a white paper on the history of analytical method development for the analysis of per- and polyfluoroalky substances (PFAS) in environmental and biological matrices. The goal was to define the data quality standards relevant for different analytical methods, matrices and time periods.

Evaluation of Dietary Intake of Perfluorooctane Sulfonate (PFOS) and Implications for Drinking Water Limits

Full Description

In the context of setting drinking water limits, Gradient evaluated the scientific support for the commonly-used default assumption of 10 to 20% of exposure being attributable to drinking water (referred to as relative source contribution or RSC). We assessed the relative intakes of PFOS from various sources and evaluated the implications of alternative RSC values on PFOS drinking water guidelines. The analysis was presented at a toxicology conference.

Experts

Barbara D. Beck Read Bio

Ali Boroumand Read Bio

Samuel A. Flewelling Read Bio

Laura E. Kerper Read Bio

Ari S. Lewis Read Bio

Manu Sharma Read Bio

Caroline B. Tuit Read Bio

Tim Verslycke Read Bio

A. Dallas Wait Read Bio