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Using
Multiple Lines of Evidence to Demonstrate that Elevated
Arsenic Groundwater Concentrations are Naturally Occurring
Gail L. Batchelder, Loureiro Engineering Associates,
Inc., Plainville, CT
Derivation
of Site-Specific Arsenic Background in Soil: A Case Study
Matt Mortefolio, NYSDEC, Albany, NY
James A. Ridenour, NYS Department of Health, Troy, NY
Risk
and Background Evaluation for Arsenic in Soil at a Planned
Residential Development
Christopher Teaf, Florida State University,
Tallahassee, FL
Living
with Arsenic in Hawai'i - Case Study of a Former Sugar
Cane Plantation
R. John, Peard, Hawai'i Department of Health, Honolulu,
HI
Novel
Technique for Sustainable Brownfield Remediation of
Arsenic Contaminated Soils
Rene van Herwijnen, University of Surrey, Surrey, UK
Using
Multiple Lines of Evidence to Demonstrate that Elevated
Arsenic Groundwater Concentrations are Naturally Occurring
John
R. Nelson, P.G., Massachusetts Water Resources Authority,
100 First Avenue, Charlestown Navy Yard, Boston, MA
02129, Tel: 617-788-2782, Fax: 617-788-1295, Email:
john.nelson@mwra.state.ma.us
Gail L.
Batchelder,
Ph.D., Loureiro Engineering Associates, Inc., 100
Northwest Drive, Plainville, CT 06062, Tel: 860-747-6181, Fax: 860-747-8822, Email:
gbatchelder@loureiro.com
Mark E. Radville, P.G., Massachusetts Water Resources
Authority, 100 First Avenue, Charlestown Navy Yard,
Boston, MA 02129,
Tel: 617-788-2759, Fax: 617-788-1295, Email: mark.radville@mwra.state.ma.us
Sherry A. Albert, P.E., Weston & Sampson Engineers,
Inc., Five Centennial Drive, Peabody, MA
01960, Tel: 978-532-1900, Fax: 978-977-0100, Email:
alberts@wseinc.com
It has been widely
documented that in many parts of New England, background
concentrations of arsenic in groundwater may exceed
existing and/or proposed standards. Consequently, the need
to document that concentrations detected above the
standard values are, in fact, representative of naturally
occurring arsenic concentrations and not the result of an
anthropogenic release of arsenic to the environment has
become increasingly important in recent years.
The study site is located
in central Massachusetts, adjacent to a tributary to a
public water supply reservoir. During the course of an investigation to evaluate the
potential for subsurface discharge of non-contact cooling
water, groundwater samples were collected from overburden
and bedrock aquifers. Laboratory analysis indicated that elevated concentrations of
arsenic were present in several samples.
At some of those locations, detected concentrations
in overburden and bedrock groundwater exceeded the
reportable concentration for arsenic under the
Massachusetts Contingency Plan of 0.050 mg/l (subsequently
decreased to 0.010 mg/l), which triggered the need for
further evaluation of subsurface conditions.
In this study, multiple
lines of evidence were used to support the position that
elevated concentrations of arsenic were due to natural
dissolution of arsenic-bearing minerals in the overburden
and bedrock aquifers.
These lines of evidence included:
historical information that did not support any use
or disposal of arsenic-bearing materials; available
geologic mapping; field observations of overburden and
bedrock encountered during well drilling; total
concentrations of arsenic, iron, and manganese and
microprobe analyses indicating the presence of
arsenic-bearing minerals in overburden materials; and
evaluation of geochemical characteristics (pH, dissolved
oxygen, oxidation/reduction potential) of groundwater
samples.
Derivation
of Site-Specific Arsenic Background in Soil: A Case Study
Matt
Mortefolio, P.E.,
NYSDEC, 9th Floor, 625 Broadway, Albany, NY
12233
James
A. Ridenour, NYS Department of Health, Troy, NY
During
the course of environmental investigations of sites where
arsenic is one of the principal contaminants, it often
becomes necessary to determine arsenic background in soil
in order to define the extent of the arsenic contamination
from the site and, in many cases, to help establish an
appropriate cleanup level.
Arsenic background in soil often has two
components, one being Anatural@
background from the formation of the earth=s
crust, and the other being Aanthropogenic@
background from human activities not associated with the
site. For
sites located in mostly pristine areas, it is likely that
only natural background is involved, which in the eastern
half of the United States is fairly consistent over a very
limited range of arsenic concentrations.
For these sites, arsenic background in soil can be
established fairly easily through use of existing regional
data or from a limited sampling of soil in areas
unaffected by the site.
However, for sites where the arsenic contamination
is extensive over a large off-site area and other
anthropogenic sources are suspected to have contributed to
arsenic levels within that area, the determination of
arsenic background applicable to the site becomes more
complex. This
case study describes how arsenic background in soil was
established at one such site.
Arsenic
based pesticides were produced or handled at the New York
site from the 1930s through the 1970s.
During that period arsenic released through air
emissions was deposited on soil in areas surrounding the
site, and arsenic was also discharged into a nearby stream
which contaminated sediment and floodplain soils. The land surrounding the site has historically been used for
residential and agricultural purposes (including
orchards). Due
to the possibility of historic arsenic pesticide usage in
area orchards and other possible non-site related sources
of arsenic in the area, it was necessary to consider other
anthropogenic sources in evaluating arsenic background for
this site.
This
case study will discuss how land use categories were
established based on suspected degrees of historic arsenic
usage and the development of a soil sampling strategy
based on the relative size of each land use type in the
area surrounding the site.
The arsenic results from the background sampling
will be presented for each land use category, and
differences discussed.
The statistical methodologies used to help estimate
the arsenic background concentrations for this site will
be presented along with an uncertainty analysis.
Finally, the case study will explore the
complexities involved in estimating arsenic background for
use as a cleanup criterion, where human health and
environmental risks must be considered.
Risk
and Background Evaluation for Arsenic in Soil at a Planned
Residential Development
Christopher
M. Teaf,
Center for Biomedical & Toxicological Research,
Florida State University, 2035 E. Dirac Dr., Tallahassee,
FL, 32310, Tel: 850-644-3453, Fax: 850-574-6704,
Email: cteaf@mailer.fsu.edu
Douglas J. Covert, Hazardous Substance
& Waste Management Research, Inc., 2976 Wellington
Circle West, Tallahassee, FL, 32309, Tel: 850-681-6894,
Fax: 850-906-9777, Email: dcovert@hswmr.com
R. Marie Coleman, Hazardous Substance & Waste
Management Research, Inc., 2976 Wellington Circle West,
Tallahassee, FL, 32309, Tel: 850-681-6894, Fax: 850-906-9777,
Email: dcovert@hswmr.com
Michael Petrovich, Hopping
Green & Sams, P.A., 123 S. Calhoun Street,
Tallahassee, FL, 32301, Tel: 850-222-7500, Fax:
850-224-8551, Email: MikeP@hgslaw.com
R.S. Murali, Langan Engineering, 7900
Miami Lakes Drive Suite 102, Miami, FL, 33016, Tel:
305-362-1166, Fax: 305-362-5212, Email: rsmurali@langan.com
Vince Yarina, Langan Engineering, 7900
Miami Lakes Drive Suite 102, Miami, FL, 33016, Tel:
305-362-1166, Fax: 305-362-5212, Email: vyarina@langan.com
Arsenic
soil concentrations at many Florida environmental
investigation sites have been reported above the current
U.S. Environmental Protection Agency (EPA) soil screening
level (0.4 mg/kg) and above the recently modified Florida
default residential exposure Soil Cleanup Target Level (SCTL)
of 2.1 mg/kg.
At a site in west central Florida, arsenic soil
concentrations were observed site-wide during early
routine sampling.
In a Chen et al. (2001) study of background
concentrations of arsenic in Florida soils, 27 out of the
51 Florida counties that were evaluated contained arsenic
soil concentrations above the EPA soil screening level.
Ten out of the 51 counties that were evaluated had
arsenic concentrations in soil regularly above the
contemporary residential exposure SCTL of 0.8 mg/kg.
That study also identified elevated arsenic
concentrations above FDEP’s residential exposure SCTL in
a geographic “belt” from Leon and Madison counties in
NW Florida to Lee and Charlotte counties in SW Florida.
This belt includes Hillsborough County, in which
the Site is located.
Based on a very extensive database for surface and
subsurface soil, it was apparent that the observed arsenic
concentrations at the Site represent a naturally occurring
condition (2.4 mg/kg average and 2.8 mg/kg 95% UCL
concentration drawn from over 2,000 samples collected
across the Site).
The close agreement between the mean and the 95%
UCL concentrations indicates a low degree of statistical
variability across the Site, and is supportive of the
conclusion that the observed distribution represents
naturally occurring background.
Further, while the 2.8 mg/kg UCL exceeds the
Florida default residential cleanup target of 2.1 mg/kg,
it does not represent a significantly increased human
health risk.
While there was no regulatory involvement,
preparation of the initial background survey, a site risk
evaluation, and a local background evaluation allowed the
Site owner and prospective developer to determine that the
site was suitable for residential improvement.
Living
With Arsenic in Hawai’i – Case Study of a Former Sugar
Cane Plantation
R.
John Peard,
Hawai’i Department of Health, 919 Ala Moana Blvd,
Honolulu, Hawai’i 96814, Tel: 1-808-586-4249, Fax:
1-808-586-7537, Email: john.peard@doh.hawaii.gov
Roger C. Brewer, Hawai’i Department of Health, 919 Ala
Moana Blvd, Honolulu, Hawai’i 96814, Tel:
1-808-586-4249, Fax: 1-808-586-7537, Email:
roger.brewer@doh.hawaii.gov
Barbara A. Brooks, Hawai’i Department of Health, 919 Ala
Moana Blvd, Honolulu, Hawai’i 96814, Tel:
1-808-586-4249, Fax: 1-808-586-7537, Email: barbara.brooks@doh.hawaii.gov
Bill Cutler, Environmental Resources Management, 733
Bishop Street, Suite 1872, Honolulu, Hawai’i 96813, Tel:
1-808-521-4404, Fax: 1-808-521-4404, Email: william.cutler@erm.com
Environmental
investigations at a planned hotel site and former sugar
plantation camp in Kea’au, Hawai’i led to the
discovery of significant arsenic contamination in soil
(>500 mg/kg total arsenic).
The arsenic is related to the use of sodium
arsenite in sugar cane fields during the early 1900s. During this time, over 100,000 acres of land were under
cultivation for sugar cane.
The arsenic is sorbed to iron hydroxyoxide,
allophane and imogolite particles in thin Andesols.
The soil investigation was expanded to include
multi-incremental sampling of eighteen other areas in
Kea’au. The
highest levels of total arsenic were reported for
community gardens (mean 331 mg/kg), followed by
undeveloped land adjacent to residential subdivisions
(mean 278 mg/kg), parks (mean 121 mg/kg) and schools (mean
37.0 mg/kg). Background total arsenic is typically <20 mg/kg.
The
elevated arsenic posed several initial concerns, including
leaching and impacts to groundwater, uptake in produce and
direct exposure of residents.
Elevated levels of arsenic have not been reported
in local water supplies.
Lab-based leaching studies are underway.
Total arsenic in produce from community gardens is
similar to marketplace data compiled by the USFDA.
Bioaccessibility tests were conducted on soil
samples to further evaluate direct-exposure concerns.
Reported bioaccessibility ranges from 1.5% to 22%,
with the highest levels of bioaccessible arsenic reported
for the hotel site (186 mg/kg) and the community gardens
(111 mg/kg). Bioaccessible
arsenic in other areas ranges from <1 mg/kg to 27
mg/kg. An
in-vivo study carried out on soils from the hotel site
yielded a bioavailability of only 5-6%, however, or
approximately 35 mg/kg bioavailable arsenic.
A urine investigation carried out on residents
appears to rule out unusual arsenic exposure from living
in the area. Measures
are being taken to minimize long-term exposure and educate
the community on chronic risks posed by high arsenic in
soils.
Novel
Technique for Sustainable Brownfield Remediation of
Arsenic Contaminated Soils
Vishnu
Priya Gadepalle, University of Surrey, School of
Engineering, Guildford, Surrey, GU2 7XH, United Kingdom.
Tel: 0044-1483-689543, Fax: 0044-1483-450984, E-mail: v.gadepalle@surrey.ac.uk
Sabeha
K. Ouki, University of Surrey, School of Engineering,
Guildford, Surrey, GU2 7XH, United Kingdom. Tel:
0044-1483-686633, Fax: 0044-1483-450984, E-mail: s.ouki@surrey.ac.uk
René
van Herwijnen,
University of Surrey, School of Engineering, Guildford,
Surrey, GU2 7XH, United Kingdom, Tel: 0044-1483-686633,
Fax: 0044-1483-450984, E-mail:
cvs1rv@surrey.ac.uk
Tony
R. Hutchings, Forest
Research, Land Remediation and Urban Greening Group, Alice
Holt Lodge, Farnham Surrey, GU10 4LH, United Kingdom. Tel:
0044-1420-22255, Fax: 0044-1420-520180, E-mail: Tony.hutchings@forestry.gsi.gov.uk
Contaminated
land is increasingly becoming an important issue
worldwide. Many metal contaminants are persistent in soil for a large
number of years. Immobilisation
of metals has proven to be a challenging task and a
cost-effective, non-invasive and socially acceptable
technology is required for its remediation. The present
study involves the in-situ
immobilisation of heavy metals using compost enhanced
with iron oxide and/or zeolite (up to 20% w/w) the
assessment of their effectiveness with respect to metals
containment and greening capability.
The preliminary results illustrated that the
combination of compost/iron oxide yielded better results
for reducing the leaching of
As (95%), Cu (97%), and Cd (73%) and the compost/zeolite
treatment has reduced the leaching of Zn (97%), whereas
compost treatment alone reduced leaching of Pb (90%) from
the contaminated soils.
The
sequential extractions results show that the untreated
soils contain Cu, Zn, Co and Cr associated with the
organic bound fractions (42-81%) whereas Cd, Fe, As and Pb
are predominant in the residual fractions (41-82%). All
the metal fractions were associated with a lesser extent
to the exchangeable fractions, indicating that the metals
are not relatively mobile. It
was also evident from the nursery trials that higher
biomass production was achieved when using compost/zeolite
amendments. Overall, this study has demonstrated that
zeolite/iron enhanced composts amendments have a
significant potential in reducing leaching of metals and
improving plant growth.
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