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Environmental Site Assessments (ESA’s) are conducted by
professional consultants, with Vermont DEC oversight, and for all
EPA funded studies, EPA Quality Assurance screening. Thus there is a
“hands-off” system whereby the client commissioning the ESA cannot
influence the findings.
There are two levels of assessment:
The initial study performed at a site suspected to have
contamination issues is called a “Phase I Environmental Site
Assessment (ESA)”. The Phase I ESA is mostly a desktop study,
combining historical and deed research, interviews with past and
present owners/tenants and neighbors, site walkovers, database
reviews of areas of concern, and reviews of any available records,
resulting in an opinion as to whether or not there is the potential
for contamination at the site. If the Phase I ESA concludes that
past activities on or near the site could have led to contamination,
the report must be submitted to Vermont DEC, which will issue a
so-called “First Letter” to the site owner indicating that that a
workplan for a Phase II ESA be submitted within a specified
timeframe.
Phase II ESA’s establish the type, degree, and extent of
contamination through soil and groundwater testing using drill rigs,
soil sampling, sophisticated sampling techniques, and lab analysis.
These assessments are highly standardized and prescriptive, ensuring
a consistent format.
Before any assessment work can take place, a Phase II ESA
Workplan must prepared by a qualified consultant, and be approved by
Vermont DEC. If USEPA Brownfields grant money is to used, the
workplan must undergo a rigorous EPA Quality Assurance review before
the Phase II ESA can be performed.
Once a Phase II ESA Workplan is approved by Vermont DEC and EPA
Quality Assurance, consultants can commence field work, which is in
turn tracked and overseen by the Vermont DEC Site Manager. The Phase
II ESA may include soil sampling, groundwater sampling, and in some
cases, indoor air sampling, asbestos and lead analyses. Once the
Phase II ESA is completed, a draft report is submitted to Vermont
DEC. The report, and soil and water sample results are reviewed by
the Vermont DEC Site Manager assigned to the site. In some cases,
Vermont DEC may ask for additional sampling, or for a re-write of
portions of the report. Using tables of “Preliminary Remediation
Goal” levels for each hazardous substance, the Site Manager reviews
the recommendations made in the completed report, and issues a
“Second Letter” to the site owner indicating whether or not the site
needs additional work, and if warranted, orders that a Corrective
Action Plan for site cleanup be submitted, also within a specific
timeframe.
With the Phase I and II ESA’s complete, and the Second Letter in
hand, consultants craft a draft Corrective Action Plan for the site.
This plan covers all cleanup and future monitoring activities, and
is the working document for remediation.
There are generally three options is dealing with soil and
groundwater contamination, and many Corrective Action Plans employ a
combination of the below methods:
Leave Contamination in Place and Monitor
This can involve
monitoring only, or capping impacted areas with clean soil, and
often a Notice to Land Records is placed that permanently documents
contamination, and refers to the appropriate Vermont DEC file.. This
option is far more common with petroleum compounds, which break down
over time, and in areas where there are municipal water and sewer
systems.
Conduct On-Site (“in situ”) Remediation
This could mean pumping
and treating groundwater, using injected air (“sparging”) to
introduce oxygen to subsurface contaminants to promote degradation,
stockpiling soils to allow for natural atennuation, phytoremediation
(the use of plants for remediation), or other emerging technologies
– provide they receive approval from Vermont DEC before use in the
field.
Remove Contaminated Soils
Depending on the type, amount, and
toxicity of the contamination, soils can be removed and used for
landfill cover, recycled at an asphalt plant (petroleum soils),
incinerated, or placed in a lined landfill.
In almost all cases, post-cleanup monitoring is required to ensure
the effectiveness of a remedy. This can be taking water samples from
a monitoring well, soils samples from stockpiled soils, and/or other
measures. If contamination is left in place, it is common practice
to register a Notice to Land Records to permanently document the
presence of contamination.
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