Passive biomonitoring for Per- and Polyfluoroalkyl substances using invasive clams, C. fluminea

Per-and polyfluoroalkyl substances (PFAS) are a class of toxic manufactured chemicals in commercial and consumer products. They are resistant to environmental degradation and mobile in soil, air, and water. This study used the introduced bivalve Corbicula fluminea as a passive biomonitor at sampling locations in a primary drinking water source in Virginia, USA. Many potential PFAS sources were identified in the region. Perfluorohexane sulfonate (PFHxS) and 6:2 fluorotelomer sulfonic acids (6:2 FTS) levels were highest downstream of an airport. The highest levels of short-chain carboxylic acids were in locations downstream of a wastewater treatment plant. Measured PFAS concentrations varied by location in C. fluminea, sediment, and surface water samples. Two compounds were detected across all three mediums. Calculated partitioning coefficients confirm bioaccumulation of PFAS in C. fluminea and sorption to sediment. C. fluminea bioaccumulated two PFAS not found in the other mediums. Perfluoroalkyl carboxylic acids and short-chain compounds dominated in clam tissue, which contrasts with findings of accumulation of longer-chain and perfluorosulfonic acids in fish. These findings suggest the potential for using bivalves to complement other organisms to better understand the bioaccumulation of PFAS and their fate and transport in a freshwater ecosystem. Environmental Implication In 2022, the EPA designated two specific per- and polyfluoroalkyl substances (PFAS) as hazardous. However, thousands more of these compounds are in our environment and are associated with various adverse health outcomes, such as cancer and endocrine disruption. Most exposure occurs through ingestion of contaminated food and drinking water. The site of this study includes one of two primary drinking water sources in Northern Virginia. This work offers a cost-effective and replicable method using invasive clams to detect and quantify PFAS. Identifying PFAS hot spots can inform stakeholders and policymakers how to prioritize remediation efforts to address environmental concerns.