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The Connecticut Department of Environmental Protection (DEP) has finalized significant new guidelines which modify the procedure for collecting and preserving soil and sediment samples targeted for volatile organic compounds (VOCs) analysis. The final guidance, entitled “Guidance for Collecting and Preserving Soil And Sediment Samples For Laboratory Determination Of Volatile Organic Compounds” was issued February 28, 2006. DEP expects that all new soil samples collected for VOC analysis on or after March 1, 2006 will be collected and preserved in accordance with the new procedures.
What’s driving the
change?
The purpose of the new DEP procedure is to reduce the loss of VOCs from soils
during the sampling and testing process. The DEP believes that up to 90% of
VOC concentrations are lost during the collection and analysis of soil
samples.
What
impact will this change have on environmentally impacted properties?
The new soil sample preservation guidance issued by the DEP will generally
increase the costs of soil investigations in Connecticut, as a result of the
additional field time and sampling equipment necessary to collect and preserve
soil samples in accordance with the new procedure. Total VOC concentrations
measured in soils at release sites Statewide can be expected to increase due
to the changes in to the collection and preservation methods recommended in
the guidance. This increase in total VOCs will likely result in more
properties exceeding the respective Pollutant Mobility Criteria (PMC) of the
Connecticut Remediation Standard Regulation (RSR). In order to demonstrate
compliance with the PMC at these sites, or to determine if remedial action is
necessary, select soil samples will need to be re-analyzed for leachable
concentrations of VOCs using SPLP or TCLP extraction methods, leading to
further increased analytical testing costs.
The increase in VOC detection in soil samples may also enlarge the size of release areas where remedial actions are necessary to comply with the RSR. Larger release areas may translate into increased remediation, post-remediation sampling, and/or groundwater monitoring costs.
Am
I grandfathered for active investigation and remediation projects?
These changes are only required for samples collected for VOC analysis in
Connecticut on or after March 1, 2006. Soil and sediment samples collected for
VOC testing using other methods and procedures prior to the effective date of
the new guidance are generally acceptable to the DEP. Therefore, re-sampling
will not typically be required for sites that initiated investigation or
remediation prior to March 2006, unless future testing results obtained
using the new procedure change the understanding of the VOC distribution in
soils or sediments.
What
are the actual changes in sampling procedure?
The guidance specifies procedures for collecting “undisturbed samples”
from the subsurface, obtaining representative “sub-samples” from the
undisturbed samples, and preserving “sub-samples” at the time of
collection to minimize VOC loss due to volatilization and biodegradation. This
requires that appropriate containers and/or “sub-samples” be preserved,
and in some instances weighed, in the field to ensure appropriate ratios of
soil “sub-sample” to preservative. In accordance with the guidance
document, and depending on the containers and preservative utilized, samples
must be frozen to -7 to -15 degrees Celsius or analyzed within 48-hours.
However, in practice, samples should be frozen within 32-hours of collection
to allow laboratories sufficient time to thaw and analyze them (about 16
hours).
How
does this change affect the clients of HRP Associates?
HRP has been using similar procedures for VOC sample collection in
Massachusetts and at select sites in Connecticut where specific regulatory
programs have required the use of similar soil and sediment field preservation
methods. Our Connecticut office is equipped with a digitally temperature
controlled freezer and NIST traceable datalogger to preserve samples within
1-day of collection, maintain sample temperatures, and validate sample
quality.
As with
most sampling programs, it is vital that the client’s objectives are
absolutely clear before an appropriate soil sampling work scope is prepared.
In this manner, the use of field screening methods can be evaluated to
reduce sampling and fixed laboratory analytical costs.
For more information contact Scot Kuhn, LEP at (800) 246-9021.