Developing Regulatory Standards for a Group of Organic Acids Based on Read Across and Mode of Action Evaluations

Project Summary

Biochemical analysis demonstrates organic acids differ from pesticides, increasing BCSLs 50 to 500-fold.

Our client faced investigation and potential remediation requirements when five organic acids were detected in groundwater at a former manufacturing facility in Nevada.

The Nevada Department of Environmental Protection (NDEP) initially proposed risk-based target concentrations (Basic Comparison Levels, or BCLs) for these phosphate-containing organic acids. Their approach assumed these compounds shared the same toxic mechanism as organophosphate pesticides, which are acute neurotoxicants.

We conducted a comprehensive toxicological assessment that included:

• Evaluation of biochemical mechanisms of action
• Analysis of structure-activity relationships
• Review of available in vivo and in vitro toxicological data

Our analysis demonstrated that these organic acids differed significantly from organophosphate pesticides in both toxicity and potency. This scientific evidence resulted in BCLs that were 50 to 500 times higher than originally proposed values.

The state regulatory agency accepted our work, and these revised values remain in use today.