Gradient

Risk Sciences

Perfluorinated Compounds

Overview
Example Projects
Experts

Overview

PFC-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 PFC-related matters.

PFOA

Example Projects

Comments on US EPA and NTP Health Effects Evaluations for PFOA and PFOS

Full Description

Gradient submitted comprehensive written comments in response to the US EPA draft Health Effects Documents for Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA), and NTP's draft systematic review of immunotoxicity associated with PFOA and PFOS. We analyzed the scientific validity of the approaches used by US EPA in developing the oral reference doses (RfDs) and by NTP in determining the immunotoxicological hazards for both chemicals. We provided alternate methods for development of RfDs and hazard assessments that considered mode-of-action understandings and incorporated findings from human biomonitoring data. The comments were submitted to US EPA and to NTP during the comment periods allowed for public and stakeholder input.

Remedial Strategy Reevaluation Due to Potential Presence of PFCs

Full Description

At several Superfund and State lead Sites where PFC-containing products may have been used historically (e.g., in fire fighting, chromium plating or other operations), Gradient has developed remedial strategies. Key issues in these evaluations have included generation of reliable analytical data, development of risk-based screening criteria, and risk assessments accounting for site-specific fate and transport considerations.

Risk Assessment of PFOA and PFOS via Potential Drinking Water Exposures

Full Description

Gradient submitted comments to a state agency regarding the toxicological significance of exposure to PFOA and PFOS via drinking water. Our comments included an evaluation of the human health and animal toxicity data, a discussion of the basis of the regulatory criteria, and a risk assessment.

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

David G. Dodge Read Bio

Laura E. Kerper Read Bio

Heather N. Lynch Read Bio

Manu Sharma Read Bio

Tim Verslycke Read Bio

A. Dallas Wait Read Bio