Metal Contamination in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 332

TABLE 9.7 (continued)
Mean Concentrations of Heavy Metals by Geologic Unit and Land Use

Subsurface
mg/kg

GW/Surface
Ratio

Surface
mg/kg

Subsurface
mg/kg

GW/Surface
Ratio Surface mg/kg GW mg/L GW mg/L

Sand 0.4 0.5 0.006 0.015 0.5 1.0 0.0068 0.014

Sc 0.96 0.75 0.073 a 0.076 1.23 2.7 0.013 0.011

Clay 1.85 1.1 0.04 0.022 1.72 0.41 0.033 0.019

Land use
Commercial

0.6 0.8 0.047 0.078 0.5 0.6 0.008 0.016

Industrial 1.9 0.9 0.029 0.015 2.3 2.2 0.02 0.009

Residential 0.8 0.35 0.005 0.006 0.8 0.5 0.009 0.011

Zinc (MCL = 5.0)

Geologic unit
Moraine

49.0 Na 0.23 0.005

Outwash 49.0 Na 0.11 0.002

Ssc 138.0 42.0 0 03 0.000

Sand 160.0 26.0 0.08 0.001

Sc 221.0 77.0 0.34 0.002

Clay 251.0 84.5 0.45 0.002

Land use
Commercial 130.0 67.0 0.31 0.002

Industrial 257.0 60.0 0.34 0.001

Residential 120.0 66.0 0.1 0.001

Note: MCL in mg -l .
a Concentration > MCL.