& Recommendations for the Remediation of Historic Pesticide Contamination
- Final Report March 1999
of Soil Contaminated by Historic Pesticide Use
The management of
health risks involves the reduction or elimination of human exposure to
a contaminant. The remedial options described below reduce exposure to
soil contamination resulting from pesticide residues in surface soil.
While all the remedial options presented are protective, the remedial
options that employ engineering controls have additional, long term requirements
associated with them.
that cover or contain contaminated soil can reduce risk, provided, however,
that these exposure controls are maintained. If these controls are not
maintained, contaminated soil can be brought to the surface. Contaminated
soil brought to the surface must be properly disposed of or covered on-site.
regulations allow for various remedies for sites with contaminated soil.
The Department uses two different criteria for soil; the first are residential
use remediation criteria that are appropriate for any use, without the
placement of restrictions. The second soil criteria are referred to as
a non-residential use remediation criteria. A deed notice is imposed at
sites where non-residential criteria are applied as the remedy to ensure
that the site use continues to be appropriate.
by historical pesticide use, such as farmland, can be developed for any
site use, including residential use, using appropriate engineering and
institutional controls. For example, one foot of clean soil as a cap with
a vegetative cover to stabilize the cap and a deed notice may be sufficient
at many sites. Residential use remedies can be conducted at sites by excavating
and disposing of contaminated soil, replacing with clean top soil or by
blending contaminated soil with clean soil from on-site or from off-site
sources so that the residential use remediation criteria are met throughout
the soil column.
Existing Regulatory Framework
To put the report
recommendations into context, the Department presented to the Task Force
the following discussion of the Departmentís Site Remediation Program
procedures. The Site Remediation Program is charged with the identification
and remediation of discharges of hazardous substances and pollutants into
the environment. With the Departmentís oversight, the person conducting
the remediation evaluates environmental conditions at a site in relation
to applicable environmental regulations.
When remedial actions
have been completed at a site, the Department issues a No Further Action
Letter. The Departmentís No Further Action Letter is based on an evaluation
of the historical use of the site and other investigation deemed necessary
to determine that no contaminants are present at the site above the Departmentís
residential soil cleanup criteria or that contaminants have been remediated.
The No Further Action Letter describes the location of the site and the
type of remediation that has occurred at a site. It is important to understand
that the issuance of a No Further Action Letter does not necessarily mean
that no contamination remains at the site. A situation that can result
in contamination being left at a site is when the person conducting the
remediation chooses to remediate the site by leaving the contamination
in place and by controlling human exposure to contaminated media. Exposure
control can be a physical mechanism, such as a cap of clean soil, an asphalt
parking lot, or a building. Exposure can also be controlled with the imposition
of an institutional control, such as a deed notice. An institutional control
is a mechanism that serves to control the type and location of activities
at a site.
It should be
noted that the Department does not regulate metals that are determined
to be naturally occurring and therefore, it does not require their remediation.
When naturally occurring metals come to the Departmentís attention during
the remediation of a discharge, the Department will include information
about the concentrations measured at the site within the No Further Action
Letter for the property ownerís and county health departmentís information.
A deed notice is required at sites
where contamination remains after a remedy is implemented above the Departmentís
residential soil cleanup criteria. This notice ensures protection of public
health, disclosure of site conditions to future owners, and maintenance
of required engineering controls. See the Technical
Requirements for Site Remediation N.J.A.C. 7:26E for deed
notice and biennial reporting requirements.
The Task Force evaluated
a wide range of possible remedial actions for reducing or eliminating
human exposure to contaminated soil based upon land use. The selection
of remedial options should include considerations such as site layout
and construction plans. In addition, it may be appropriate to implement
more than one remedial option at a site.
Remedial Option 1 - Contaminated soil can be consolidated
and covered on-site under buildings, roads, or other areas approved by
the Department. Contaminated topsoil may not have the appropriate physical
properties to be used under some structures making engineering review
of this option important. The use of grass and landscaping as an exposure
control should only be allowed for as part of an exposure control strategy
when approved by the Department. This option would require the filing
of a deed notice.
Remedial Option 2 - Contaminated soil can be capped with clean
topsoil (caps are typically one foot or more thick). It may be difficult
and costly to find and test sufficient quantities of "clean"
soil. See Addendum
4 for the Departmentís testing protocol for "clean"
soil. The term "clean" soil means that the soil does not contain
any constituent/contaminant at concentrations greater than the Departmentís
residential soil cleanup criteria. Remedial option 2 would require the
filing of a deed notice.
Remedial Option 3 - Contaminated soil can be blended with clean
soil within the contaminated area (the area of concern). The area of concern
is as defined in N.J.A.C.
7:26E. Blending may be done with clean soil from within
or outside the area of concern to achieve concentrations at or
below the Departmentís residential soil cleanup criteria for all contaminants.
Blending involves the physical mixing of contaminated surface soil with
uncontaminated soil within a given area of concern. This strategy may
not be feasible in areas of the state with high background arsenic concentrations.
Blending may not be a practical option if contaminant levels are very
elevated because large amounts of clean soil would be needed to achieve
the cleanup criteria or if there are potential ground water impacts. This
option would not require the filing of a deed notice.
Remedial Option 4 Ė Contaminated soil may be blended
with clean soil outside the area of concern, but within the site. The
site is as defined the boundaries of the real property under development.
Blending may be accomplished by physically mixing contaminated soil with
clean soil from within or outside the site. For arsenic, the cleanup goal
is to achieve concentrations that exist in the uncontaminated areas of
the site within the area of concern and across the site. For the organochlorine
pesticide residues, blending outside the area of concern must achieve
concentrations at or below the Departmentís residential soil cleanup criteria.
Blending outside the area of concern involves the physical mixing
of contaminated surface soil with uncontaminated soil within the site.
Blending may not be a practical option if contaminant levels are very
elevated because large amounts of clean soil would be needed or if there
are potential ground water impacts. This option would not require the
filing of a deed notice.
Blending represents a significant
departure from Department policy but members of the Task Force agree that
it may be used to mitigate risk as a practical matter, by helping reduce
the cost of remediation at some sites. Blending contaminated soils with
clean soil outside the area of concern could increase the concentrations
of these contaminants in previously clean areas, but the concentrations
will never be increased above the Departmentís residential soil cleanup
criteria. The Task Force accepts blending as a remedial option and acknowledges
the potential for a slight increase in risk that may result from its use.
Remedial Option 5 Ė Contaminated soil can be removed
from the site and disposed of as a waste or reused with the Departmentís
approval and be replaced with soil that meets the Departmentís residential
soil cleanup criteria. This option includes additional costs and problems
associated with the handling and disposal of contaminated soil. This option
would not require the filing of a deed notice.
Remedial Option 6 Ė The treatment of contaminated soil to the
Departmentís residential soil cleanup criteria is not considered to be
a practicable option for a number of reasons. Treatment technologies do
exist, but would be cost prohibitive in that the cost of treatment would
in most cases be greater than the value of the land. Treatment technologies
would be very intrusive in residential settings and the resulting soil
quality would be poor and may even be unable to support vegetation without
substantial amendment. If the Departmentís residential soil cleanup criteria
were met, this option would not require the filing of a deed notice.