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Supplementary PDMS/SPME sampling. Surficial cap water quality assessment. x. Methods. Polydimethylsiloxane (PDMS) Thin coating on glass fibers. PDMS 30 µm layer on 1 mm core. Inserted for one week and sampled at 3 depths. Detection limits/COV%. PDMS/SPME Detections.
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Supplementary PDMS/SPME sampling Surficial cap water quality assessment
x Methods • Polydimethylsiloxane (PDMS) • Thincoating on glass fibers PDMS 30 µm layer on 1 mm core Inserted for one week and sampled at 3 depths
PDMS/SPME overall results • Exceedances of surface water criteria • No near-surface samples exceed surface water criteria (interarmoring layer or upper sand cap layer) • 12 inches into subarmoring layer exceedances of surface water criteria at site 9 (shoreline just east of railroad bridge) • cPAH – 0.3 µg/L (0.031 µg/L SW criteria) • Chrysene – 0.076 µg/L (0.018µg/L) • Benzo(a)anthracene -0.17 µg/L (0.018 µg/L) • Benzo(b)fluoranthene – 0.035 µg/L (0.018 µg/L)
Conclusions No observed exceedances of surface water criteria in interarmoring or upper subarmoring layer Some exceedances of surface water criteria in deep subarmoring layer at one location No evidence of NAPL migration or significant dissolved PAH migration PDMS/SPME a useful tool for identifying interstitial concentrations and potential migration