The use of lipid-containing semipermeable membrane
devices (SPMDs) is becoming commonplace, but very little
sampling rate data are available for the estimation of
ambient contaminant concentrations from analyte levels
in exposed SPMDs. We determined the aqueous sampling
rates (R
ss; expressed as effective volumes of water
extracted daily) of the standard (commercially available
design) 1-g triolein SPMD for 15 of the priority pollutant (PP)
polycyclic aromatic hydrocarbons (PAHs) at multiple
temperatures and concentrations. Under the experimental
conditions of this study, recovery-corrected R
s values
for PP PAHs ranged from ≈1.0 to 8.0 L/d. These values
would be expected to be influenced by significant changes
(relative to this study) in water temperature, degree of
biofouling, and current velocity-turbulence. Included in this
paper is a discussion of the effects of temperature and
octanol−water partition coefficient (K
ow); the impacts of
biofouling and hydrodynamics are reported separately. Overall,
SPMDs responded proportionally to aqueous PAH
concentrations; i.e., SPMD R
s values and SPMD-water
concentration factors were independent of aqueous
concentrations. Temperature effects (10, 18, and 26 °C)
on R
s values appeared to be complex but were relatively
small.
The triolein-filled semipermeable membrane device (SPMD) is a simple and effective method of assessing the presence of waterborne hydrophobic chemicals. Uptake rate constants for individual chemicals are needed to accurately relate the amounts of chemicals accumulated by the SPMD to dissolved water concentrations. Brown trout and SPMDs were exposed to PCB-contaminated groundwater in a spring for 28 days to calculate and compare uptake rates of specific PCB congeners by the two matrixes. Total PCB congener concentrations in water samples from the spring were assessed and corrected for estimated total organic carbon (TOC) sorption to estimate total dissolved concentrations. Whole and dissolved concentrations averaged 4.9 and 3.7 µg/L, respectively, during the exposure. Total concentrations of PCBs in fish rose from 0.06 to 118.3 µg/g during the 28-day exposure, while concentrations in the SPMD rose from 0.03 to 203.4 µg/ g. Uptake rate constants (k 1 ) estimated for SPMDs and brown trout were very similar, with k 1 values for SPMDs ranging from one to two times those of the fish. The pattern of congener uptake by the fish and SPMDs was also similar. The rates of uptake generally increased or decreased with increasing K OW , depending on the assumption of presence or absence of TOC.
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