Passive sampling methods for contaminated sediments: Practical guidance for selection, calibration, and implementation

Abstract

This article provides practical guidance on the use of passive sampling methods (PSMs) that target the freely dissolved concentration (Cfree) for improved exposure assessment of hydrophobic organic chemicals in sediments. Primary considerations for selecting a PSM for a specific application include clear delineation of measurement goals for Cfree, whether laboratory-based “ex situ” and/or field-based “in situ” application is desired, and ultimately which PSM is best-suited to fulfill the measurement objectives. Guidelines for proper calibration and validation of PSMs, including use of provisional values for polymer–water partition coefficients, determination of equilibrium status, and confirmation of nondepletive measurement conditions are defined. A hypothetical example is described to illustrate how the measurement of Cfree afforded by PSMs reduces uncertainty in assessing narcotic toxicity for sediments contaminated with polycyclic aromatic hydrocarbons. The article concludes with a discussion of future research that will improve the quality and robustness of Cfree measurements using PSMs, providing a sound scientific basis to support risk assessment and contaminated sediment management decisions. Integr Environ Assess Manag 2014;10:210–223. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC.

A passive sampler based on solid phase microextraction (SPME) for sediment-associated organic pollutants: Comparing freely-dissolved concentration with bioaccumulation

“…Likewise, if attainment of equilibrium by the passive sampler is slower than for the organism, a slope of less than one would result (You et al, 2011;Thomas et al, 2014). Clearly, achievement of equilibrium (or nearly so) in both compartments simplifies the interpretation of log-linear relationships, and thus maximizes their utility to predict bioaccumulation across scenarios (Ghosh et al, 2014). This is demonstrated in the spiked sediment lab exposures in the present study (Figs.…”

“…4). Performance reference compounds (PRCs) pre-loaded into passive samplers prior to exposure have been proposed as a remedy to correct for non-equilibrium, however, this practice adds complexity and cost (Ghosh et al, 2014). Depletion of freely dissolved HOCs by a passive sampler with excess sorptive mass relative to sediment TOC can also alter the kinetics of exchange resulting in an underestimation of C free .…”

“…Debate over the utility and interpretation of PSM data generated in situ vs. ex situ rages; however, there is little doubt that successful deployment in situ provides highly relevant data (Ghosh et al, 2014). In situ PSMs based on dialysis have been used for geochemical research (Doig and Liber, 2004); however, this multi-barrier concept suffers from a lack of HOC-compatible membranes and an inherent difficulty in modeling non-steady conditions (Grigg et al, 1999).…”

Solid Phase Microextraction (SPME) Fibers: in situ Measurements of Endocrine Disrupting Chemicals in Seawater

“…13 It is traditionally used for organic micropollutants determination in aqueous phase, but it can also be applied for porewater concentrations if equilibrium time is taken into account. 14,15 Non depletive SPME studies are also described, where the partitioning equilibrium is not disturbed and the adsorption can mimic organism uptake. 16 Sensibility of SPME sampler is directly related with the compound K ow (octanol-water partition coefficient) and increases with sorbent volume (V f ), 17 and is mainly applied to evaluate the uptake of hydrophobic organic compounds (HOCs) as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), but also contaminants of emerging concern as polybrominated diphenyl ethers (PBDEs).…”

Modeling Compound Loss from Polydimethylsiloxane Passive Samplers

“…Even with the documented benefits of passive sampling [2][3][4][5][6][7][8][9][10], it has seen limited acceptance by regulatory agencies for sediment management decisions in part due to the lack of robust quality assurance and quality control (QA/QC) measures [8,9,11]. In order to achieve quantitative measurements of porewater concentration, the passive sampler must achieve a known degree of equilibration during the absorption phase and losses between uptake and extraction into a solvent must be negligible.…”