1. Surficial cap water quality assessment
Supplementary PDMS/SPME sampling
Surficial cap water quality assessment

2. Methods x Polydimethylsiloxane (PDMS) Thin coating on glass fibers
PDMS 30 µm layer on 1 mm core
Inserted for one week
and sampled at 3 depths

3. Detection limits/COV%
Compound
MDL (µg/L) direct injection
MDL (µg/L)
by SPME
COV%
Low Conc.
Separate study
Naphthalene
0.07
0.0105
88.8%
Fluorene
0.81
0.0249
5.6%
Acenaphthene
0.32
0.0161
14.1%
Phenanthrene
0.23
0.0033
1.3%
Anthracene
0.22
0.0034
18.1%
Fluoranthene
0.21
0.0009
9.9%
Pyrene
8.1%
Chrysene
8.342E-05
19.1%
Benzo (a) anthracene
0.03
2.921E-05
3.9%
Benzo (b) fluoranthene
0.04
4.817E-05
11.6%
Benzo (k) fluoranthene
0.01
5.456E-06
8.0%
Benzo (a) pyrene
0.02
1.515E-05
5.8%
Dibenz (a,h) anthracene
5.552E-06
5.5%
Benzo (ghi) + Indeno
0.05
1.018E-05
7.0%

4. PDMS/SPME Detections Classifications Dataset Counts
Dataset Percentages
Non Detects (U)
591
49%
Detections under PQL (J)
258
22%
Detection below Max Blank (B) 72 6%
Detections above Blank
279
23%
Total Possible Detects
1200
100%

5. Parity Plot – PDMS/SPME and conventional sampling

6. 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 – µg/L (0.018µg/L)
Benzo(a)anthracene µg/L (0.018 µg/L)
Benzo(b)fluoranthene – µg/L (0.018 µg/L)

7. Compound Profile – Site 9

8. Example variation across site

9. 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