Remediation: Techniques and Cost - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 409

TABLE 11.5
Total Cost and Mass Remediated by Media

Percentage
of Total Cost

Percentage of Total
Mass Recovered Remediated Media or Phase

Soil 24.3 17.6

Groundwater 41.6 2.0

Free product 34.1 80.4

Total 100 100

Table 11.5 displays the percentages of total cost and mass recovered by the media reme-
diated, and also highlights the cost inefficiency of remediating groundwater. Although
41% ($238 million) of the total cost was devoted to remediating groundwater, only 2% of
the total contaminant mass was recovered. This cost disparity highlights the difficulty of
cost effective remediation once groundwater has become impacted.
Table 11.6 shows the cost to remediate a kilogram of contaminant by soil type. Data
on arsenic, chlordane, mercury, and perchlorate are not provided due to the lack of an
adequately sized data set. Figure 11.32 displays these data graphically.

TABLE 11.6
Cost of Remediating a Kilogram of Contaminant
by Soil Type

Remedial
Cost ($/kg) Contaminant Geology

Chromium VI Clay 1,000

Silty clay 1,500

Sandy and silty clay 1,500

Sand 77,633

DNAPL Clay 721

Silty clay 1,366

Sandy and silty clay 3,263

Sand 66,024

LNAPL Clay 319

Silty clay 518

Sandy and silty clay 778

Sand 527

PCBs Clay 4,700

Silty clay 4,800

Sandy and silty clay 5,500

Sand 5,700

PAHs Clay 922

Silty clay 843

Sandy and silty clay 303

Sand 442

Lead Clay 68

Silty clay 230

Sandy and silty clay 538

Sand 445