Contaminant Risk Factors - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 361

TABLE 10.10
CRF SOIL Values for Select PAHs
PAH Compound

Soil Type CRF SOIL

Naphthalene Clay 11.8

Silty clay 1.24

Sand silty clay 1.06

Sand 0.37

Chrysene Clay 2,407.00

Silty clay 240.00

Sand silty clay 204.00

Sand 61.00

Benzo[b]fluoranthrene Clay 146.00

Silty clay 14.60

Sand silty clay 12.40

Sand 3.70

Benzo[k]fluoranthrene Clay 126.00

Silty clay 12.60

Sand silty clay 10.70

Sand 3.21

Phenanthrene Clay 70.00

Silty clay 7.00

Sand silty clay 5.90

Sand 1.80

Benzo[g,h,i] perylene Clay 1,080.00

Silty clay 108.00

Sand silty clay 91.00

Sand 27.50

Benzo(a)pyrene Clay 797.30

Silty clay 79.70

Sand silty clay 67.50

Sand 20.20

Mean PAH CRF SOIL Clay 662.58

Silty clay 66.16

Sand silty clay 55.23

Sand 16.82

Source: Kaufman, M.M. et al., Environ. Geol ., 56,

1009, 2009.

highest likelihood of contaminating groundwater, whereas the low mean ratios of PCBs,
mercury, and chlordane position them as posing the greatest contamination threat to soil.
This conclusion is supported by the average extents of contamination shown in column 6,
which were measured using analytical data from hundreds of sites (Kaufman et al. 2005,
Rogers et al. 2007a; Kaufman et al. 2009). The measured extents of contamination listed
in the rightmost column represent contaminants at concentrations exceeding the appli-
cable regulatory action level from an identified anthropogenic source. As predicted by the
computed CRF GW /CRF SOIL ratios, the average extents of contamination were the largest for
chromium VI and DNAPL compounds.