Application of a Framework for Grouping and Mixtures Toxicity Assessment of PFAS: A Closer Examination of Dose Additivity Approaches

TRRP Training: 2022 Program

presented by: GSI Environmetal Inc.

Texas Risk Reduction Program regulations (TRRP; 30 TAC 350) establish consistent risk-based protocols for assessment and response to soil, groundwater, or surface water impacts associated with environmental releases of regulated wastes or substances.

Presented by GSI Environmental Inc., this popular and informative training series is a must for professionals who need a working understanding of TRRP and those needing to stay up-to-date with the latest TCEQ TRRP guidance and policies.

TRRP Training Course (2 Days): Provides an overview of the TRRP framework and step-by-step training on property assessment and response action procedures established under the TRRP rule

Attendees will become acquainted with rules, key guidance and policies covering affected property assessments, protective concentration levels, and response actions. The course material presents strategies for efficient project management in compliance with TRRP and explains the various report forms adopted by TCEQ.

Dates and Location

Dates

June 14th and 15th, 2022

Location

Crowne Plaza River Oaks 2712 SW Freeway Houston, Texas 77098 713.523.8448 http://www.crowneplaza.com/

Price and Registration

Early-Bird Price

(Paid by May 1, 2022)
$XXX

Standard Price

(Paid after May 1, 2022)
$XXX

TAEP Membership Price

$XXX

Government Price

$XXX

Lodging and meals are not
included in course cost

Authors: Philip E. Goodrum, Janet K. Anderson, Anthony L. Luz, Graham K Ansell

Published: July 2020 in Toxicological Sciences.

Abstract

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Environmental occurrence and biomonitoring data for per- and polyfluoroalkyl substances (PFAS) demonstrate that humans are exposed to mixtures of PFAS. This paper presents a new and systematic analysis of available PFAS toxicity study data using a tiered mixtures risk assessment framework consistent with U.S. and international mixtures guidance. The lines of evidence presented herein include a critique of whole mixture toxicity studies and analysis of dose-response models based on data from subchronic oral toxicity studies in rats. Based on available data to-date, concentration addition and relative potency factor methods are found to be inappropriate due to differences among sensitive effects and target organ potencies and noncongruent dose-response curves for the same effect endpoints from studies using the same species and protocols. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) lack a single mode of action or molecular initiating event and our evaluation herein shows they also have noncongruent dose-response curves. Dose-response curves for long chain perfluoroalkyl sulfonic acids (PFSAs) also significantly differ in shapes of the curves from short chain PFSAs and perfluoroalkyl carboxylic acids (PFCAs) evaluated, and additional differences are apparent when curves are evaluated based on internal or administered dose. Following well-established guidance, the hazard index (HI) method applied to PFCAs and PFSAs grouped separately is the most appropriate approach for conducting a screening level risk assessment for non-polymeric PFAS mixtures, given the current state-of-the science. A clear presentation of assumptions, uncertainties, and data gaps is needed before dose additivity methods, including HI, are used to support risk management decisions. Adverse outcome pathway(s) and mode(s) of action information for PFOA and PFOS and for other non-polymer PFAS are key data gaps precluding more robust mixtures methods. These findings can guide the prioritization of future studies on single chemical and whole mixture toxicity studies.