Comparison of chemical contaminant measurements using CLAM, POCIS, and silicone band samplers in estuarine mesocosms

Discrete water samples represent a snapshot of conditions at a particular moment in time and may not represent a true chemical exposure caused by changes in chemical input, tide, flow, and precipitation. Sampling technologies have been engineered to better estimate time‐weighted concentrations. In this study, we consider the utility of three integrative sampling platforms: polar organic chemical integrative sampler (POCIS), silicone bands (SBs), and continuous, low‐level aquatic monitoring (CLAM). This experiment used simulated southeastern salt marsh mesocosm systems to evaluate the response of passive (POCIS, SBs) and active sampling (CLAM) devices along with discrete sampling methodologies. Three systems were assigned to each passive sampler technology. Initially, all tanks were dosed at nominal (low) bifenthrin, pyrene, and triclosan concentrations of 0.02, 2.2, and 100 µg/L, respectively. After 28 days, the same treatment systems were dosed a second time (high) with bifenthrin, pyrene, and triclosan at 0.08, 8.8, and 200 µg/L, respectively. For passive samplers, estimated water concentrations were calculated using published or laboratory‐derived sampling rate constants. Chemical residues measured from SBs resulted in high/low ratios of approximately 2x, approximately 3x, and 1x for bifenthrin, pyrene, and triclosan. A similar pattern was calculated using data from POCIS samples (~4x, ~3x, ~1x). Results from this study will help users of CLAM, POCIS, and SB data to better evaluate water concentrations from sampling events that are integrated across time. Integr Environ Assess Manag 2024;20:1384–1395. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points Integrative passive samplers can be an important tool in coastal chemical pollutant monitoring programs, but salt content in marine and estuarine systems can pose a challenge when estimating time‐weighted average concentrations. Remote sampling systems that track the total volume extracted, such as the continuous low‐level aquatic monitoring (CLAM) unit, may be appropriate for monitoring in remote areas and generating integrated chemical concentrations. Passive sampler devices require sampling rate constants (Rs and KPW) that are sensitive to environmental factors such as salinity. There is a general lack of reported constants measured under saline conditions.