Transitions - Sustainable Design: The Science of Sustainability and Green Engineering - page 102

limit (40 CFR 261). For example, the TLCP limit for lead is 5 mg L − 1 .Any
exceedence of this federal limit in the soil or sand on a site must be reported.
Initial monitoring and chemical testing should be conducted to target those
contaminants that may have resulted from a spill or dumping. More general
surveillance is also needed to identify a broader suite of contaminants. This is
particularly important in soil and groundwater, since their rates of migration
are quite slow compared to the rates usually found in air and surface water
transport. Thus, the likelihood of finding remnant compounds is greater in
soil and in groundwater. Also, in addition to parent chemical compounds,
chemical degradation products should be targeted, since decades may have
passed since the waste was buried, spilled, or released into the environment.
The originally released chemicals may have degraded, but their breakdown
products may remain; many of which can be as toxic or more toxic than
the parent substance. For example, the fungicide vivelozolin may break down
readily if certain conditions and microbial populations are present in the soil.
However, its toxic byproducts butenoic acid and dichloroanaline can remain.
An important part of the preliminary investigation is the identification of
possible exposure, both human and environmental. For example, the investiga-
tion should document the proximity of a site to schools, parks, water supplies,
residential neighborhoods, shopping areas, and businesses.
One means of efficiently implementing a hazardous waste remedial plan
is for the present owners (and also past owners, for that matter) to work
voluntarily with government health and environmental agencies. States often
have voluntary action programs that can be an effective means of expediting the
process, which allows companies to participate in, and even lead, the RI/FS
consistent with a state-approved work plan (which can be drafted by the state's
consulting engineer).
The feasibility study delineates potential remedial alternatives, comparing
the cost-effectiveness to assess each alternative approach's ability to mitigate
potential risks associated with the contamination. The feasibility study includes
a field assessment to retrieve and chemically analyze (at a state-approved labora-
tory) water and soil samples from all environmental media on the site. Soil and
vadose-zone * contamination will probably require that test pits be excavated
to determine the type and extent of contamination. Samples from the pit are
collected for laboratory analysis to determine general chemical composition
(e.g., in a total analyte list ) and TCLP levels (which indicate the rate of leaching ,
i.e., movement of the contaminants).
An iterative approach may be appropriate as the data are derived. For exam-
ple, if the results of the screening (e.g., total analytical tests) and leaching tests
indicate that a site's main problem is with one or just a few contaminants, a