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A
Review of Risk Assessment Methods to Demonstrate Potential
Risk from Exposure to Asbestos in Soil
Lisa
Bailey, Menzie-Cura & Associates, Inc., 8 Winchester
Place, Suite 202, Winchester, MA 01890, Tel:
781-782-6147, Fax: 781-756-1610, Email: lbailey@menziecura.com
Miriam Weil, 8 Winchester Place, Suite 202, Winchester, MA
01890, Tel: 781-782-6148,
Fax: 781-756-1610,
Email: mweil@menziecura.com
Deborah Murray, 8 Winchester Place, Suite 202, Winchester,
MA 01890, Tel: 781-782-6140,
Fax: 781-756-1610,
Email: d-murray@menziecura.com
Standard
analytical methods do not exist to measure asbestos fibers
in soil. Analytical
methods, including Transmission Electron Microscopy (TEM),
developed to measure asbestos in bulk material, have been
applied qualitatively to the soil matrix to determine the
type and degree of asbestos contamination in soil. Current
quantitative risk assessment practice relies on TEM
analysis of soil samples, in combination with dust
generation estimates, to model an asbestos concentration
in air, the exposure pathway of concern.
However, uncertainty is introduced when modeling
TEM results from soil to an airborne asbestos
concentration in respirable dust due to the heterogeneity
of asbestos types and soil types. As a result, this method may not reliably quantify asbestos
exposure points for use in quantitative risk assessment.
An analytical method more directly related to
exposure and risk assessment for asbestos, the Draft
Modified Elutriator Method for the Determination of
Asbestos in Soils and Bulk Material (D. Wayne Berman and
Anthony Kolk, 2000), measures the amount of asbestos
released to the air in respirable dust from
asbestos-contaminated soil. These measurements can be used directly to quantify risk from
inhalation of asbestos in air thereby eliminating the need
to model asbestos soil concentrations to dust.
A challenge that risk assessors will meet when
applying the Modified Elutriator method to asbestos risk
assessments is how to use these estimates to
back-calculate an asbestos soil concentration that is
protective of human health.
Part of this challenge will be to determine how the
amount of asbestos released to the air in respirable dust
compares to the amount of asbestos measured in soil, given
the heterogeneity of both asbestos types and soil types.
A comparison of asbestos risk assessment methods is
presented.
Assessing
the Toxic Risk of Polychlorinated Biphenyl (PCB) Congeners
Using the Bluegill Sunfish Immune System
Jessica E. Duffy, New York University School of Medicine,
Department of Environmental Medicine, 57 Old Forge Road,
Tuxedo, NY 10987, Tel: 845-731-3632, Fax: 845-351-5472,
Email: jessd2000@yahoo.com
Yun Li, New York University School of Medicine, Department
of Environmental Medicine, 57 Old Forge Road, Tuxedo, NY
10987, Tel: 845-731-3632,
Fax: 845-351-5472, Email: yunli@env.med.nyu.edu
Judith T. Zelikoff, New York University School of
Medicine, Department of Environmental Medicine,
57 Old Forge Road, Tuxedo, NY 10987, Tel: 845-731-3528,
Fax: 845-351-5472, Email: judyz@env.med.nyu.edu
The immune system, sometimes overlooked as a sensitive and
frequently-targeted organ for chemical-induced toxicity,
is an essential component in maintaining overall good
health of an organism.
Any alteration in normal immune function can
disrupt homeostasis and result, ultimately, in increased
susceptibility to disease.
For these reasons, studies examining
chemical-induced immunotoxicity in residing species are
essential for accurately predicting the health of an
ecosystem. The objective of this study was to examine the impact of a
widespread aquatic contaminant (i.e., PCBs) on the immune
response of a feral fish species to determine its
sensitivity for predicting PCB-induced immunotoxicity.
The effects of a single intraperitoneal exposure of
bluegill sunfish (Lepomis macrochirus) to either a potent coplanar (PCB 126) or
environmentally-relevant noncoplanar (PCB 153) PCB
congener on host immunocompetence was determined by
examining non-specific and cell-mediated immune
parameters. Cytochrome
P-4501A (CYP1A) induction, typically measured as a
biomarker of PCB exposure, was also examined.
Phagocyte-mediated oxyradical production and
mitogen-stimulated lymphocyte proliferation were examined
using kidney/spleen cells recovered from laboratory
exposed fish on 3, 7, 14 or 21 d post-PCB exposure.
While both congeners enhanced extracellular
superoxide production by kidney phagocytes 3 d
post-exposure, only PCB 153 had significant effects on
lymphoproliferation.
Proliferation of both T- and B-lymphocytes was
suppressed (compared to controls) as early as 3 d and up
to 14 d post-PCB 153 exposure.
Hepatic CYP1A was only induced in fish
treated with PCB 126.
Given the lack of CYP1A induction associated with
PCB 153 exposure, immunosuppression may prove a more
relevant biomarker for predicting exposure to- and health
risks from- noncoplanar PCB congeners. Results reveal the sensitivity of the fish immune response
for assessing PCB-induced immunodysfunction and
demonstrate the utility of such a system for assessing
risks to exposed populations, and for predicting ecosystem
health. Supported
by a Hudson River Foundation Graduate Fellowship and
USACEHR No. DAMD 17-99-9011.
Factors
Affecting the Bioaccumulation of DDE from Soil by 3
Earthworm Species
Jason
W. Kelsey, Ph.D., Program in Environmental Science and
Dept. of Chemistry, Muhlenberg
College, Allentown, PA
18104, Tel: 484-664-3144,
Fax: 484-664-3546, Email: kelsey@muhlenberg.edu
Allison Colino, Program in Environmental Science,
Muhlenberg College, Allentown, PA
18104, Tel: 484-664-4535,
Email: Sweper21@aol.com
Jason C. White, Ph.D., Dept. of Soil and Water, The
Connecticut Agricultural Experiment Station, 123
Huntington St., New Haven, CT
06504, Tel: 203-974-8523, Fax:
203-974-8502, Email:
jason.white@po.state.ct.us
The
uptake of pollutants by soil organisms is controlled by a
number of biological, chemical, and physical variables.
Factors affecting the extent to which a compound
such as DDE (a persistent product of the metabolism of
DDT) is biologically available are important because
knowledge of them could inform the evaluation and
management of contaminated sites. We studied the effects of species differences, soil
concentration and residence time of the contaminant, and
interactions with a plant, on the bioaccumulation factor (BAF;
dry-weight ratio of contaminant concentration in the
tissue to that in the soil) of DDE for earthworms.
In 4 field-weathered soils, the BAF for Eisenia
foetida, an epigeic species (surface habitat), was
approximately 10-fold higher than those for Lumbricus
terrestris, an anecic species (deep habitat) and Aporrectodea
caliginosa, an endogeic species (habitat within the
soil profile). Within
the range tested (82 ppb to 405 ppb), the data indicate
that BAF may decline with increasing pollutant
concentration in soil.
Residence time of DDE did not significantly alter
the BAF for A. caliginosa, but the BAF for E.
foetida was lower in weathered soils relative to that
in spiked soils. The
presence of a single plant also affected the BAF of E.
foetida and L. terrestris.
Bioaccumulation by E. foetida grown with Curcubita
maxima was over 3-fold lower than that by the worms
grown alone. Growth
with Curcubita maxima led to a modest decrease in
the BAF for L. terrestris.
These data suggest that risk assessments of
contaminated sites should consider the differences in
bioavailability of soil toxins to different species and
the environmental factors that control uptake by
organisms. Total
chemical concentration alone is not a reliable indicator
of the toxicological significance of a contaminated soil.
Applying
a Spatially Explicit Wildlife Exposure Model to Improve
Remedial Efficiency:
The SEEM Case Study
Charles
A. Menzie, Menzie-Cura & Associates, Inc., 8
Winchester Place, Suite 202, Winchester, MA
01890, Tel: 781-756-1600, Fax: 781-453-7260, Email:
camenzie@menziecura.com
W.
Theodore Wickwire, Menzie-Cura & Associates, Inc., 477
Congress Street, 5th Floor, Portland, ME
04011, Tel: 207-773-0881, Fax: 207-773-8597, Email:
wickwire@menziecura.com
Dimitriy Burmistrov, Menzie-Cura
& Associates, Inc., 8
Winchester Place, Suite 202,
Winchester,
MA 01890,
Tel: 781-756-1600, Fax: 781-453-7260, Email: dburmist@menziecura.com
Mark S. Johnson, Health Effects Research Program, US Army
Center for Health Promotion and Preventive Medicine, ATTN:
MCHB-TS-THE, 5158 Blackhawk Road, Aberdeen Proving Ground,
MD 21010-5403,
Tel: 410-436-5081,
Fax: 410-436-6710, Email:
mark.s.johnson@us.army.mil
The
development of wildlife exposure models that incorporate
the impact of chemical distribution, habitat distribution
and the foraging behaviors of the assessed species, not
only insert realism into the risk assessment, but also
insure that remedial actions focus on the areas where
habitat and chemicals intersect.
The Spatially Explicit Exposure Model (SEEM) is
being developed for the US Army to improve the realism of
wildlife exposure modeling. SEEM tracks exposures for all individuals in a
user-defined population rather than evaluating a single
representative individual.
Foraging for each individual is guided by habitat
suitability preferences.
As a result, individuals are less likely to forage
in areas where the habitat suitability is low.
Also, users may select two different foraging
strategies, a free-ranging strategy and a static home
range strategy. In
the free-ranging strategy individuals move across the
landscape guided by habitat suitability.
Foraging each day is bounded by the home range,
however each day that home range boundary shifts based on
the path followed the previous day.
In contrast, in the static home range strategy,
individuals move out from a central location (e.g. a nest)
to forage a user-specified number of times bounded by the
home range. The
home range boundary remains in the same location
throughout the modeling period. In both strategies individuals forage a user-specified number
of times per day. The
model is run for a specified number of days.
The model generates population-effects curves.
In combination with area-effect curves, users may
develop remedial strategies that balance risk reduction
with loss of habitat due to remediation and remedial
efficiency. SEEM
assists in developing remedial strategies that reduce
site-wide risk, while avoiding the application of a single
PRG to all areas of site.
SEEM is being developed for inclusion within the US
Army Risk Assessment Modeling System (ARAMS).
Risk
Assessment and Heavy Metals Bioavailability in Soil
Audil
Rashid, Environmental
Biology Lab., Department of Biological Sciences,
Quaid-i-Azam University, Islamabad, Pakistan, Tel:
92-51-4472551, Email: audil@comsats.net.pk
Dr. Tahira Ahmad, Environmental
Biology Lab., Department of Biological Sciences
Quaid-i-Azam University, Islamabad, Pakistan, Tel: 92-51-2277014,
Email: taqau@yahoo.com
Dr. Najma Ayub, Environmental Biology Lab.,
Department of Biological Sciences, Quaid-i-Azam
University, Islamabad, Pakistan, Tel: 92-51-2824846,
Email: Najma_ayub@yahoo.com
Dr. Abdul G.
Khan, University of Western Sydney, School of Science,
Food & Horticulture, College of Science, Technology
& Environment, Penrith South DC, N.S.W. 1797,
Australia, Tel: 61-2-46203237,
Fax: 61-2-46203025, Email: a.khan@uws.edu.au
Heavy
metal (HM) contamination of soil and groundwater is not at
all uncommon today. They interact with soil matrix and may
persist for a long period of time creating long-term
hazards. Their bioavailability in soil is increasingly
used as key indicator of potential risks that contaminant
pose to both the environment and human health. Hence the
most exciting technical area in risk assessment and
remediation field today is contaminant bioavailability.
Given that ‘Risk Based Land Management’ is
increasingly being adopted as a cost effective management
strategy for contaminated sites in terrestrial ecosystem,
this research work was designed to assist regulatory
bodies (Federal and Provincial EPAs) to define risk posed
by contaminated sites. The present study was conducted in
some industrial areas of Punjab province (Pakistan). Metal
toxicity to mycorrhizal fungi and plant uptake of
contaminants was assumed a reflection of HM
bioavailability. Soils with high reaction capacity were
observed to have low bioavailable fraction. A strong
correlation between soil texture and contaminant sorption
was observed. The binding capacity of soil is limited to
available clay and organic fraction of soil. The reduced
toxicity of HM (Cr, Cd) to mycorrhizal fungus was
attributed to increase binding of contaminants to soil
colloids. However, reduced calcium in soil promoted the
dispersion of clay particles and raised the
bioavailability of metals in soil interstitial water.
Consequently elevated HM concentrations in soil lead to
enhanced plant uptake. Thus contaminated sites revealed
poor plant growth and diversity by restricting the natural
vegetation to few species compared to reference sites.
Studies further show that edaphic factors (pH, electrical
conductivity etc) can influence contaminant
bioavailability pool in soil. We believe that these
findings have greater implications for remediation of HM
contaminated soils and the natural attenuation of
contaminants in terrestrial ecosystems in relation to risk
assessment.
Human
Health and Ecological Risk Assessment of a PCB-Impacted
Former Radar Station in Atlantic Canada
Robert
D. Willis, Cantox Environmental Inc., 5121 Sackville
Street, Suite 506, Halifax, Nova Scotia, Canada, B3J 1K1,
Tel: 902-429-0278, Fax: 902-429-0279, Email: robw@cantoxenvironmental.com
Christine E. Moore, Cantox Environmental Inc., 5121
Sackville Street, Suite 506,
Halifax, Nova Scotia, Canada, B3J 1K1, Tel:
902-429-0278, Fax: 902-429-0279, Email: cmoore@cantoxenvironmental.com
Eugene Lee, AMEC Earth & Environmental, Bonaventure
Place, 95 Bonaventure Avenue, P.O. Box 2035, St. John`s,
Newfoundland, Canada, A1C 5R6, Tel: 709-722-7023, Fax:
709-722-7353, Email: Eugene.Lee@na.amec.com
Kevin Edwards, Transport Canada, Airports Group, John
Cabot Building, 10 Barters Hill, St. John’s,
Newfoundland, Canada, A1C 6H8, Tel: 709-772-2102, Fax:
709-772-5127, Email: edwardk@tc.gc.ca
Margaret Whyte, Transport Canada, Airports Group, Heritage
Court, 95 Foundry Street, P.O. Box 42, Moncton, New
Brunswick, Canada, E1C 8K6, Tel: 506-851-7319, Fax:
506-851-7542, Email: whytem@tc.gc.ca
A
human health and ecological risk assessment was conducted
on a former remote radar station site that was
contaminated with elevated soil concentrations of PCBs.
The site is adjacent to a frequently used
recreational trail. Adjacent lands include forested habitat and a stream.
PCBs were identified as the only chemical of
potential concern for the human health and terrestrial
ecological risk assessment (ERA).
A number of metals, and petroleum hydrocarbons were
assessed in addition to PCBs for the aquatic ecological
risk assessment. The
multipathway human health risk assessment (HHRA) focused
on a recreational exposure scenario and included potential
exposures from wild berry and game consumption.
In the ERA, a variety of ecological receptors,
including freshwater aquatic life, small mammals and
carnivores were evaluated.
Probabilistic exposure analysis techniques were
used to estimate PCB exposure in both human and ecological
receptors. Results
and risk management options will be presented.
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