Transcript Biomonitoring Non-Human Species for Ecological and Human

Exposure Assessment,
Conceptual Modeling,
Biomonitoring and
Environmental Regulations
Conrad (Dan) Volz, DrPH, MPH
Assistant Professor
Department of Environmental and Occupational
Health
Co –Director for Exposure Assessment, University
of Pittsburgh Cancer Institute, Center for
Environmental Oncology
Occupational/Environmental Exposure
Definition
Contact over time and space between a
receptor (human or ecological) and a
biological, chemical or physical hazard.
Components of Environmental and
Occupational Health Exposure Pathways
 Source (s)—Often with unique
fingerprint(s).
 Rate(s) of contaminant emissions.
 Transport route(s) through environmental
media.
 Route(s) of exposure.
 Exposure concentration(s).
Factors Influencing Human
Exposure
 The duration, frequency and intensity of
contact with the contaminant.
How Long/Often and Much?
 Identification of individual activity patterns,
population distributions and susceptible
populations.
Definition of Environmental
Media  Air
 Surface Water
 Groundwater
 Sediment
 Soil
 Subsurface area
 Food Chain
What is a Conceptual Site
Model?
 A written and/or pictorial representation of
an environmental system and the biological,
physical and chemical processes that
determine the transport and fate of
contaminants through environmental media
to environmental receptors.
Components of a Complete
Conceptual Site Model
 Sources of contaminants (can be multiple sources
as well as species on a site).
 Pathways of environmental transport.
 Indications of any barriers or remedies that exist
or are proposed.
 Pathways to ecological and human receptors.
Why develop a Conceptual Site
Model?
 Pull together technical data concerning a site from
numerous sources.
 Support the selection of sampling locations to
establish background concentrations of identified
contaminants.
 Identify data needs and gaps.
 Describe and integrate the processes that
determine contaminant release, migration and
receptor exposure.
Why develop a Conceptual Site
Model (continued)?
 Determine exposure routes (inhalation,
ingestion and/or dermal absorption).
 Identify uncertainties in the model that need
further study.
 Preliminarily evaluate the risk to human and
ecological receptors (CERCLA NPL status
is based on a significant risk to human
health or the environment).
Why develop a Conceptual Site
Model (continued)?
 Facilitate the selection of remedial
alternatives and evaluate the effectiveness
of remedial actions to reduce exposure.
 For use a a communication tool in the
decision-making process involving experts
from exposure assessment, human and
ecological health, remediation engineers
etc.
 As a risk communication tool for the public.
Conceptual Site Model for a Former Manufactured
Gas Plant
Required Component of CERCLA Site Assessment
Modeling –Mercury in New Jersey Wells
“Biomonitoring”and
“Biomarkers” -Definitions
 “Biomonitoring” is the analytical measurement
of biomarkers in specified units of tissues or
body products (blood, urine, etc.)
(Environmental Health PerspectivesNovember, 2006).
 “Biomarkers” are any substances, structures,
or processes so measured that indicate an
exposure or susceptibility or that predict the
incidence or outcome of disease (Toniolo et
al. 1997).
Examples of National
Biomonitoring Programs
 National Health and Nutrition
Examination Survey (NHANES)Centers for Disease Control and
Prevention
 CDC National Environmental Public
Health Tracking Program, UPACE –
Center of Excellence
 Interagency National Children’s Study
 Farm Family Exposure Study
(University of Minnesota)
Examples of Human Biomonitoring
for Exposure Assessment
 Phthalates
 The organophosphorus pesticides are
malathion and chlorpyrifos.
Reasons for Biomonitoring NonHuman Species
 Can sample in a naturalistic environment, without
IRB clearances (retains ecosystem complexity).
 Initially test hypothesis regarding conceptual
models of contaminant fate and transport.
 Establish a baseline of contaminants in biomass as
part of an ongoing monitoring program (important
for assessing the need for or failure of site
remediation ie, Superfund, RCRA, DOE-NNSA).
Reasons for Biomonitoring NonHuman Species-Continued
 Establish the exposure and thus risk to humans
from consumption of contaminated foodsespecially fish (incredibly important to tribal
groups and vulnerable sub-populations- Amish,
immigrant Asians, African Americans).
 To establish the efficacy of and use aquatic and
other species as sentinels for human health effects.
 To determine population risk from contaminant
exposure to a species or an ecosystem.
The Basis for Biomonitoring
Ecological Receptors
 Microbial Oxidation of Anthropogenic Compounds-
Biotransformation, Biodegradation, Mineralization
- Tremendous variety of microorganisms that have the
ability to use pollutants such as alcohols, fuels and solvents
as well as natural organic detritus as a source of energy.
- - The rate of microbial degradation decreases for
contaminants with;
 Increasing molecular weight.
 Lower solubility in water.
 Increasing number of aromatic rings.
 Increasing numbers of branches.
 The number of halogen atoms in their make-up
(chlorine, fluorine, bromide etc.)
The Basis for Biomonitoring
Ecological Receptors-Continued
 Increasing concentrations of contaminants in sediments
and water leads to bioconcentration and accumulation in
aquatic organisms.
-Bioconcentration – The process of aquatic organisms accumulating
chemicals from water only.
-Bioaccumulation - The process of aquatic organisms accumulating
chemicals from both water and food.
-Bioconcentration Factor- (BCF) – The ratio of the concentration of a
chemical in an organism to the concentration of that chemical in
seawater, freshwater or brackish water.
Thereforemg of chemical/kg of organism
__________________________ = Liter/kg
mg of chemical in solution/Liter
Bioconcentration and
accumulation modeling
 BCF can be an observed ratio or be the prediction of a
partitioning model.
- ModelingAssumptions
 1.
Pollutant chemicals partition in passive way between
water and the organism.
 2.
Chemical equilibrium exists.
These assumptions are most valid for lipophilic
(hydrophobic) chemicals- they are more rapidly exchanged
between the water and organism than they are excreted or
biodegradated by the organism.
Bioconcentration and accumulation
modeling-continued

Fish Model- Fish is a bag of oil and tissue water.Chemical partitions
between the bag and surrounding water according to:
1.
Kow which is the reciprocal of the chemicals water solubility.
2.
The lipid content of the fish.
--log BCF = 2.791 – 0.564 log S where S is Water Solubility in ppm This
formula has been determined using Brook and Rainbow Trout,
Sunfish, Flathead Catfish

Bioaccumulation Models are Kinetic and depend on the dynamics
of intake, storage, metabolic transformation and excretion of
specific chemicals in specific organisms.
-Use a first order kinetic model to estimate the depuration
(cleansing) or partial removal of a contaminant from a fish given a
specific contaminant concentration so
- C = Co e-kt Where C is the concentration at any time t, Co is the
initial concentration, k is the first order rate constant and t is the
time.
White Bass-Hg in Filet, ppm-95% CI
.16
.14
.12
.10
95% CI Hg ppm
.08
.06
.04
.02
N=
45
10
Pittsburgh Pool
Storebought
Pittsburgh Pool vs Other
Barium in White Bass fillet in ppm, 95% CI
.14
.12
.10
.08
.06
95% CI Ba ppm
.04
.02
0.00
-.02
N=
45
10
Pittsburgh Pool
Storebought
Pittsburgh Pool vs Other
Channel Catfish, Hg in fillet, 95% CI
TYPE_FIS:
1 Channel Catfish
.4
.3
95% CI Hg ppm
.2
.1
0.0
-.1
N=
39
11
13
Pittsburgh Pool
Storebought
Kittanning
Pittsburgh Pool vs Other
Occupational and Environmental
Health Legislation
 Occupational Safety and Health Act of 1970-
Adopted the 1968 American Conference of
Governmental Industrial Hygienists (ACGIG),
Threshold Limit Values (TLV’s) for airborne
contaminants.
- A TLV is an exposure concentration that most
workers can be exposed to 8 hours/day, 40
hours/week over a working lifetime with no
adverse effect.
Occupational and Environmental
Health Legislation

Comprehensive Environmental Response,
Compensation and Liability Act of 1980
(CERCLA)- commonly called Superfund
-To provide for remediation of sites not cleaned-up
by the responsible party.
-To establish priorities for the clean-up of the
nation’s worst toxic and radiological waste sites.
CERCLA continued.
- Conduct human and ecological risk
assessments through the Agency for Toxic
Substances and Disease Registry (ATSDR).
- Conduct remedial investigation and
feasibility studies.
Occupational and Environmental
Health Legislation
 Resource Conservation and Recovery Act of
1976 (RCRA)
- Creates cradle to grave regulatory scheme to
manage, store, transport and dispose of
hazardous waste.
- Designed to prevent current hazardous waste
disposal from causing future environmental
health problems.