Polyethylene Devices:  Passive Samplers for Measuring Dissolved Hydrophobic Organic Compounds in Aquatic Environments

Abstract

We demonstrate the use of polyethylene devices (PEDs) for assessing hydrophobic organic compounds (HOCs) in aquatic environments. Like semipermeable membrane devices (SPMDs) and solid-phase microextraction (SPME), PEDs passively accumulate HOCs in proportion to their freely dissolved concentrations. Polyethylene-water partition constants (K(PEW)S) were measured in the laboratory for eight polycyclic aromatic hydrocarbons (PAHs), five polychlorinated biphenyls (PCBs), and one polychlorinated dibenzop-dioxin (PCDD), and these were found to correlate with octanol-water partition constants (K(OW)s; log K(PEW) = 1.13 log K(OW) - 0.86, R2 = 0.89). Temperature and salinity dependencies of K(PEW) values for the HOCs tested were well predicted with excess enthalpies of solution in water and Setschenow constants, respectively. We also showed that standards, impregnated in the PED before deployment, can be used to correct for incomplete equilibrations. Using PEDs, we measured phenanthrene and pyrene at ng/L concentrations and 2,2',5,5'-tetrachlorobiphenyl at pg/L concentrations in Boston Harbor seawater, consistent with our findings using traditional procedures. PEDs are cheap and robust samplers, competent to accomplish in situ, time-averaged passive sampling with fast equilibration times (approximately days) and simplified laboratory analyses.

Distribution, diffusive fluxes, and toxicity of heavy metals and PAHs in pore water profiles from the northern bays of Taihu Lake

“…A water quality index (interstitial water toxicity criteria unit, IWCTU) was applied to examine the toxicity of heavy metals in pore water (Adams et al 2007):…”

Passive sampling techniques for sensing freely dissolved hydrophobic organic chemicals in sediment porewater

“…Adams et al [24] found that the partition coefficients of phenanthrene and pyrene between LDPE and freshwater were approximately 94% of those obtained with 0.1 M NaCl solution instead of freshwater, but the deviation could be corrected with the Setschenow constant [25]. Generally, the aqueous solubility of HOCs would decrease with increasing dissolved salt content, similar to the salting-out effects in liquidliquid extraction.…”

Passive samplers of hydrophobic organic chemicals reach equilibrium faster in the laboratory than in the field

“…The reason for the shorter equilibration times can be qualitatively understood by considering that equilibrium attainment in a closed system is promoted by depletion of the water as well as by accumulation by the sampler. Phrased differently, in small water volumes a smaller amount of HOC needs to be transferred to the sampler before equilibrium is reached, resulting in a faster equilibrium attainment at a lower concentration level (Adams et al, 2007).…”