Fraser River Estuary fish habitat: Contaminant concentrations, profiles and risks in water and sediment

<jats:p>Water is essential for life, and steps are needed to understand, protect and restore its health in fish habitat throughout British Columbia. The Raincoast Healthy Waters program was launched in 2023 to establish community-oriented water pollution monitoring in select BC watersheds. In this study, we conducted a risk-based assessment of a suite of contaminants of concern in the Fraser River Estuary, an important feeding, rearing and migratory habitat for Pacific salmon. Our team determined basic water properties (temperature, conductivity, pH, dissolved oxygen and turbidity) in situ at sampling sites on March 19, 2025. Water and intertidal sediment samples were then collected from 10 sites within the Fraser River Estuary, including five sites in the North Arm of the river, four sites in the South Arm of the river, and one site upstream in the Fraser River main stem. Two water samples (NA-OS and SA-TS) were submitted to both ALS and SGS-Axys for a comprehensive contaminant analysis including: coliform, nutrients (6), physical parameters, metals (37), pesticides (62), polycyclic aromatic hydrocarbons (PAHs; 76), pharmaceuticals and personal care products (PPCPs; 141), polychlorinated biphenyls (PCBs; 209), alkylphenol ethoxylates (APEs; 4), bisphenols (BPs; 6), per- and poly-fluoroalkyl substances (PFAS; 40), and sucralose. Analysis of 6PPD-quinone is pending. The remaining eight water samples were submitted to ALS Environmental for determination of coliform, nutrients (6), physical parameters, and metals (37). Sediment samples from all 10 sites were submitted to SGS Axys for comprehensive contaminant analyses: polycyclic aromatic hydrocarbons (PAHs; 76), polychlorinated biphenyls (PCBs; 209), polybrominated diphenyl ethers (PBDEs; 209), dioxins and furans (DFs; 19), alkylphenol ethoxylates (APEs; 4), bisphenols (BPs; 6), and per- and poly-fluoroalkyl substances (PFAS; 40).</jats:p>