Risk Assessment
Eva Holt (holt@recetox.muni.cz)
Risk Assessment Outline
• Objectives
• What is risk?
• Human health and ecological risk
assessment definitions
• Risk assessment basics
• Where can we use risk assessment?
• Case studies
– Human exposure to particle-bound PAHs from
traditional cooking practices and potential
carcinogenic risk
– Biota exposure to toxic levels of uranium
downstream of a mine
Objectives
• Introduce you to the concept of risk as it relates to
environmental chemistry/science/management
• Describe the risk assessment process for human health
and ecological risk assessment
• Show examples of human health and ecological risk
assessment
What is risk?
• “(Exposure to) the possibility of loss, injury, or
other adverse or unwelcome circumstance; a
chance or situation involving such a
possibility.” [Oxford English Dictionary]
• In an environmental science context risk can
be defined as the “chance of harmful effects
to human health or to ecological systems
resulting from exposure to an environmental
stressor*”. [US EPA]
*Stressor = can be physical,
chemical, or biological; may
induce an adverse response.
Term ‘agent’ is also sometimes
used.
http://blog.statefoodsafety.com
(accessed 19/11/2015)
Human health and ecological Risk
assessment definitions
• Human health risk assessment:
estimating the nature and probability of
adverse health effects in humans
potentially exposed to environmental
stressors, in the past, now and in the
future
• Ecological risk assessment: determining
risk (magnitude and likelihood) posed
by a stressor to ecosystem health
• Sometimes we see the term
environmental risk assessment used
instead of ecological risk assessment
Risk Assessment Basics
Risk Assessment
1. Identify problem: Describe the
environment; What are the potential
stressors? What are the exposure pathways?
2. Analyse information: Assess extent and
effects
3. Risk Characterisation: Probability of
occurrence and severity; uncertainties
Risk
Management
Monitoring
Framework for conducting risk analysis
Adapt risk assessment
over time based on
monitoring
Adapt risk
management
based on
monitoring
results
Risk
Communication
Risk
Communication
Risk Assessment Basics
Establish
the scope
and
objectives
Identify the
type and
nature of
the adverse
effect
Qualitative
and
quantitative
description
of inherent
properties
of stressor
Evaluate
how much
of the
stressor
reaches the
human
Estimate
the risk
posed to
human
health
Risk assessment paradigm (US EPA model)
Planning
Hazard
identification
Exposure
assessment
Risk
characterisation
Hazard
characterisation
Ecological
Determine
which
organisms
are at risk
Determine
what is
exposed, to
what degree
and whether
exposure is
harmful
Problem
formulation
Analysis
Estimate
the risk
posed to
ecological
entities
Risk
characterisation
Establish
the scope
and
objectives
Planning
Humanhealth
Risk Assessment Basics
• Planning
Questions we need to ask at the beginning
• Who/what/where is at risk?
• What is the environmental hazard of
concern?
• Where do these environmental hazards
come from?
• How does exposure occur?
• What is the fate of the hazard in the body
and impact of, e.g., age, sex, etc.
• What are the health/ecological effects?
• How long does it take for hazard to cause a
toxic effect? Does it matter when the
exposure occurs in the lifetime of a
human/organism?
“…..and that in a nutshell is the plan, any
questions?
Risk Assessment Basics
• Human health risk assessment
Hazard identification
Determine whether
exposure to a stressor can
cause an adverse effect
Carcinogenic or non-
carcinogenic
Available data
Clinical or epidemiological
studies (human)
Other animal studies
QSAR
TOXNET – toxicology data
network; focused mainly on
chemical hazards
Work platform is
unstable and
unsecured leading to
a fall – breaking
bones, etc.
Fire hazard –
burns, smoke
inhalation
(suffocation)
Frayed leads close
to water – electric
shock
Spilled oil slipping
hazard – physical injury
(broken….anything)
Heavy load – back
injury
Metal fragments
from grinding – eye
damage
Compressed air
applied to the
skin/bloodstream –
embolism!
Risk Assessment Basics
• Human health risk assessment
Hazard identification
Determine whether
exposure to a stressor can
cause an adverse effect
Carcinogenic or non-
carcinogenic
Available data
Clinical or epidemiological
studies (human)
Other animal studies
QSAR
TOXNET – toxicology data
network; focused mainly on
chemical hazards
Hazard characterisation
Describe the likelihood and
severity of adverse effect
with amount and
condition(s) of exposure to,
e.g., chemical agent
Use existing, or develop
guidelines
Dose-response or
concentration-response
Available data
As for hazard identification
Objectives, standards or
guidelines (e.g., WHO, EU)
https://toxlearn.nlm.nih.gov/
(accessed 20/11/2015)
or
e.g., from Graphpad Prism
(accessed 20/11/2015)
Adverse effects
Hazard characterisation
Describe the likelihood and
severity of adverse effect
with amount and
condition(s) of exposure to,
e.g., chemical agent
Use existing, or develop
guidelines
Dose-response or
concentration-response
Available data
As for hazard identification
Objectives, standards or
guidelines (e.g., WHO, EU)
Risk Assessment Basics
• Human health risk assessment
Exposure assessment
Measure or estimate the
magnitude, frequency and
duration of exposure to,
e.g., biological agent
Considers exposure
pathway and route, as well
as size, nature and type of
populations exposed
Available data
Measured directly/estimated
using environmental
concentrations + fate/
transport + estimated intake)
Hazard identification
Determine whether
exposure to a stressor can
cause an adverse effect
Carcinogenic or non-
carcinogenic
Available data
Clinical or epidemiological
studies (human)
Other animal studies
QSAR
TOXNET – toxicology data
network; focused mainly on
chemical hazardshttp://epa-sdcc.ornl.gov/sdcc_owok_dust_tot.html
(accessed 20/11/2015)http://www.slideshare.net/AngelAlhamad/different-route-ofexposure-of-toxicant
(accessed 20/11/2015)
Properties of the
chemical – effects how
they enter the body
e.g., External
exposure to
dust (US EPA)
What’s missing/isn’t included
in the example?
Risk Assessment Basics
• Ecological risk assessment
Problem formulation:
 Define an assessment end-point to
determine what ecological entity is
important to protect
 Identify and determine what entity
you are protecting and what
attributes of entity are at risk
 Your ecological entities might
include: Species (polar bear),
ecosystem (stream), valued habitat
(wetland), etc.
What to protect?
Think of ecological relevance,
susceptibility to stressors and relevance
to management goals
Process based on two major
elements:
 characterization of effects
 characterization of exposure
Outcomes:
 Assessment end-points
 Conceptual models
Risk Assessment Basics
• Ecological assessment
Problem formulation:
 Define an assessment end-point to
determine what ecological entity is
important to protect
 Identify and determine what entity
you are protecting and what
attributes of entity are at risk
 Your ecological entities might
include: Species (polar bear),
ecosystem (stream), valued habitat
(wetland), etc.
What to protect?
Think of ecological relevance,
susceptibility to stressors and relevance
to management goals
Analysis:
 Characterisation of exposure and
ecological effects
 Degree of exposure and ecological
responses of plants and animals
exposed to stressors
 Guidelines can be used or can also
be developed
- ECTOX database has ecotox data
 Determining exposure levels
- Area use/home range; food
ingestion; bioaccumulation rates;
bioavailability; life stage
Risk Assessment Basics
• And finally……risk characterisation
risk characterisation = risk estimation + risk
description
• Risk estimation: using the results of preceding
steps in risk assessment estimate the risk
• Risk description: an interpretation of risk
results. The level of harmful effects, as well as
likelihood/probability of adverse effects, on
humans or other organisms
• It is very important to include how the risk
was assessed, the degree of confidence in the
risk estimates, any assumptions made, as well
as summarise limitations and uncertainties
• Citations must be used to support risk
estimates and any interpretation of adverse
effects
• Information is used for decision making
Risk characterisation
• Risk characterisation can be quantitative
or semi-quantitative assessment (e.g.,
ranking risk)
− Quantitative: case study examples
− Semi-quantitative risk assessment
o Helps set priorities when assessing
multiple stressor risks and considers
uncertainties.
o Needs to be scrutinised and reviewed
by experts
e.g.,3 Risk matrix of impact versus
probability
e.g., 2 Risk matrix of consequences versus likelihood
e.g., 1 null hypothesis testing and
likelihood estimation
U limit = 6µg/L
Risk Assessment Basics
Risk Assessment
1. Identify problem: Describe the
environment; What are the potential
stressors? What are the exposure pathways?
2. Analyse information: Assess extent and
effects
3. Risk Characterisation: Probability of
occurrence and severity; uncertainties
Risk
Management
Monitoring
Framework for conducting risk analysis
Adapt risk assessment
over time based on
monitoring
Adapt risk
management
based on
monitoring
results
Risk
Communication
Risk
Communication
Risk Assessment Basics
• Further reading
− For guidance on conducting risk assessment or risk analysis refer to
government or non-government agencies (within your study region is
best)
− Some places to start on the web:
 US EPA (http://www2.epa.gov/risk)
 World Health Organization (WHO) (2010) WHO Human Health Risk
Assessment Toolkit: Chemical Hazards (ISBN 978 92 4 154807 6)
 UK Department for Environment, Food and Rural Affaris (DEFRA)
(https://www.gov.uk/government/uploads/system/uploads/attachment_da
ta/file/69450/pb13670-green-leaves-iii-1111071.pdf) – has some good case
studies
− Good journal source:
 Environmental Health Perspectives
Where can we use risk assessment?
• Human health
 Will an upgrade of a sewage treatment plant increase nuisance odours and
pose a risk to health of the local community through recreational activities?
 What is the risk to children from lead dust exposure near to a smelter?
• Ecological
 How would construction, operation and decommissioning of a gold mine
impact downstream aquatic ecosystems?
 Will invasive species increase during construction of a pipeline?
Case study 1:Carcenogenic risk from
exposure to particle-associated PAHs
• Planning
− The scope is people using primitive or
traditional cooking practices in
residences or commercial kitchens in
Pakistan. PAH associated to dust is the
stressor. Potential adverse effect of
cancer was nominated as a health
effect.
− An assessment endpoint was devised
and used to evaluate impacts from
potential particle-bound polycyclic
aromatic hydrocarbon (PAH) exposure in
the vicinity of primitive or traditional
cooking
− Assessment endpoint = reduction in
incidence of disease. Disease measured
as cancer incidence over a lifetime for
residents or kitchen workers in vicinity of
primitive or traditional cooking, Pakistan.
Case study modified from Kamal et al. 2015
(Environ Sci Pollut Res (2015) 22:12644–12654, DOI
10.1007/s11356-015-4444-4)
https://www.globalgiving.org
(accessed 20/11/2015)
Case study 1:Carcenogenic risk from
exposure to particle-associated PAHs
• Hazard identification and characterisation
− Solid fuel combustion a major source of household energy in Pakistan. When burnt
solid fuel produces particulate matter, particularly when stoves are poorly functioning
and ventilation is bad.
− Wood and coal identified as a major source of PAHs. PAHs are toxic to humans
(assigned a toxic equivalency factor (TEF) relative to benzo(a)pyrene).
• Exposure assessment
− Exposure wasn’t directly measured. Instead levels of PAHs in samples of dust from
workplace and domestic kitchens in Pakistan with primitive or traditional cooking
practices were determined. An equivalent toxicity was calculated for each dust
sample.
+ +
WHO information used for exposure estimation
exposure routes considered
Case study 1:Carcenogenic risk from
exposure to particle-associated PAHs
• Risk characterisation
− Probabilistic incremental lifetime cancer risk
(ILCR)
− The ILCR model can be used in estimating
the incremental probability an individual
develops a tumour over an average lifetime
(70 years)
− ILCR compared to US EPA acceptable risk
range (1x10-6 – 1x10-4 or 1 per 1,000,000 or
1 per 10,000)
http://www.iarc.fr/
Case study 1:Carcenogenic risk from
exposure to particle-associated PAHs
• Risk characterisation
− Cancer risk over a lifetime
Average - Adults and
children >1/1000
Worst case – (adults,
workplace cooking) >1/100
1.E-09
1.E-07
1.E-05
1.E-03
1.E-01
Adult
Children
Adults
Children
Adults
Children
Adults
Children
Dermal Inhalation Ingestion Total
ILCR
Workplace cooking - Ave Residential cooking - Ave
Average
scenario
total ILCR
exceeds
acceptable
risk
1.E-08
1.E-06
1.E-04
1.E-02
1.E+00
Adult
Children
Adults
Children
Adults
Children
Adults
Children
Dermal Inhalation Ingestion Total
ILCR
Workplace cooking - Max Residential cooking - Max
▬US EPA guide 1x10-6 (1 per
1,000,000)
▬US EPA guide 1x10-4 (1 per 1
per 10,000)
Worst case
scenario
total ILCR
exceeds
acceptable
risk
− Unacceptable risk of
cancer in adults and
children exposed to
particle associated PAHs
derived from primitive
cooking stoves
Magela Creek
Biota exposure to toxic levels of uranium
(U) downstream of a mine
Case study modified from Australian Government Department of the Environment
• Planning and problem formulation
− Scope is an aquatic ecosystem downstream of a U mine. Stressor is available U.
Potential adverse effects include death, illness or change in behavior.
− Surveys conducted to establish aquatic species present (ID: sensitive species)
− An assessment endpoint was devised and used to evaluate impacts from potential
uranium contamination downstream of the mine
− Assessment endpoint = conservation of biological diversity of the region. Species
abundance in Alligator Creek catchment surveyed during the mine operation and
decommissioning
U
U
U
U
U
U
abc.net.au (accessed 19/11/2015) (https://www.environment.gov.au/science/supervising-
scientist/research/ecological-risk)
Biota exposure to toxic levels of uranium
downstream of a mine
• Analysis
− Exposure estimated using
environmental U concentrations
measured in Magela Creek
− Effects observations measured using
ecotoxicity tests (6 native species;
NOEL)
− A U limit was derived to using the
ecotox data (99% species protection)
• Risk characterisation
− Null hypothesis testing and likelihood
estimation based on frequency
information for effects and exposure
U limit = 6µg/L
− Risk of adverse effects from exposure
to U as a result of mine discharge was
assessed to be low
Cumulative probability
for exposure to U in
Magela Creek, and for
potential effects of U
on 6 species of native
species (NOEL)
Questions/discussion/tea break?
International conventions for persistent,
toxic, mobile and bioaccumulative
chemicals
Eva Holt (holt@recetox.muni.cz)
International conventions for PTMB
chemicals
• Objectives
• Basic concepts of PTMB chemicals
• Key conventions dealing with PTMB chemicals
• Global monitoring of PTMB chemicals
Objectives
• PTMB chemicals
• Describe some of the main international conventions
dealing with PTMB chemicals
• Highlight global monitoring programs for PTMB
chemicals and what the monitoring data is used for
Basic concepts of PTMB chemicals
• You will remember these from a previous lecture(s)
– What is persistent?
Lasting for years or even decades before degrading into less dangerous
forms. High resistance to degradation (abiotic and biotic)
– Which toxic compounds?
Everything is, right? Even water? High toxicity at very low concentrations
– How mobile?
Moves to remote areas far from sources
– What is bioaccumualtive?
Toxic substance taken up at a higher rate than being removed from an
organism. Lipophilic compounds (they like lipids).
Biomagnification through the food web
results in higher trophic organisms
accumulating more PBTs through
consumption of lower trophic organisms
Basic concepts of PTMB chemicals
• Transboundary movement
Tracking the Distribution of
Persistent Organic Pollutants
Wania & Mackay, VOL. 30, NO. 9,
1996 Environmental Science &
Technology (News)
Basic concepts of PTMB chemicals and
transboundary movement
Some PTB contenders
Hg
Those that
are also
mobile
PAHs
Pesticides
HCB
PBDEs PCDD/Fs
PFCs
Key conventions dealing with PTMB
chemicals
• Question for the group – what international
environmental conventions do you know about?
Rio earth summit (1992):
United Nations Framework Convention on Climate
Change
Convention on Biological Diversity
United Nations Convention to Combat Desertification
A clue
Key conventions dealing with PTMB
chemicals
• Why mention Rio?
Principle 15 of the Rio Declaration on Environment and
Development
“In order to protect the environment, the precautionary
approach shall be widely applied by States according to
their capabilities. Where there are threats of serious or
irreversible damage, lack of full scientific certainty shall not
be used as a reason for postponing cost-effective
measures to prevent environmental degradation.”
Key conventions dealing with PTMB
chemicals
Global treaties to protect human health and the environment from
chemicals
• Stockholm Convention (SC) on Persistent Organic Pollutants
(POPs)
– Reduce exposure by eliminating or reduce use and emissions
– Requires parties to:
• Restrict, prohibit and/or eliminate the
production and use, import and export
intentionally or unintentionally produced
POPs
• Promotes the use of best available
techniques and best environmental
practices for preventing releases of POPs
into the environment.
• Ensure POPs stockpiles and wastes
managed safely and in an environmentally
sound manner
• To target additional POPs /list new ones
Key conventions dealing with PTMB
chemicals
SC on POPs - parties
Key conventions dealing with PTMB
chemicals
• Stockholm Convention (SC)
on Persistent Organic
Pollutants (POPs)
– A POP by definition share
these properties:
 highly toxic
 persistent
 travel long distances
 accumulate in fatty tissue
Key conventions dealing with PTMB
chemicals
• Basel Convention on the Control of Transboundary
Movements of Hazardous Wastes and their Disposal
– Under which framework was set up for controlling movement of
hazardous wastes across international borders
– Criteria developed for “environmentally sound management” of
hazardous wastes
Key conventions dealing with PTMB
chemicals
• Basel Convention on the Control of
Transboundary Movements of
Hazardous Wastes and their Disposal
− The provisions of the Convention center
around the following principal aims:
 the reduction of hazardous waste generation and the
promotion of environmentally sound management of
hazardous wastes, wherever the place of disposal;
 the restriction of transboundary movements of
hazardous wastes except where it is perceived to be
in accordance with the principles of environmentally
sound management; and
 a regulatory system applying to cases where
transboundary movements are permissible.”
[http://www.pic.int/]
Key conventions dealing with PTMB
chemicals
• Rotterdam Convention on the Prior
Informed Consent Procedure for Certain
Hazardous Chemicals and Pesticides in
International Trade
– “Objectives of the convention are:
• to promote shared responsibility and cooperative efforts
among Parties in the international trade of certain
hazardous chemicals in order to protect human health
and the environment from potential harm;
• to contribute to the environmentally sound use of those
hazardous chemicals, by facilitating information
exchange about their characteristics, by providing for a
national decision-making process on their import and
export and by disseminating these decisions to Parties.”
[http://www.pic.int/]
Key conventions dealing with PTMB
chemicals
• Rotterdam Convention
– “The Prior Informed Consent (PIC)
procedure – The PIC procedure is a
mechanism for formally obtaining
and disseminating the decisions of
importing Parties as to whether they
wish to receive future shipments of
those chemicals” listed in the
Convention or “for ensuring
compliance with these decisions by
exporting Parties.”
– “Information Exchange - The
Convention facilitates information
exchange.” Notification required
“when taking a domestic regulatory
action to ban or severely restrict a
chemical.”
Global monitoring of PTMB chemicals
• Example - The Global Monitoring Plan on Persistent
Organic Pollutants (GMP)
– Article 16 of SC on POPs: requires effectiveness of measures
adopted by the Convention regularly evaluated
GMP: aims at collecting comparable, harmonized and reliable information on POP
levels in core environmental matrices (air, breast milk/blood and water).
Flow chart of activities so far
Global monitoring of PTMB chemicals
• Available Global Monitoring Plan (GMP) data
What happens to POPs levels over time? Are measures to eliminate or reduce
emissions working?
- Time series analysis
- Active air samples
- γ-HCH
- Median and 5-95th percentile
- Chicago
Global monitoring of PTMB chemicals
• Available Global Monitoring Plan (GMP) data
Which countries have the highest exposure to POPs? How are people exposed
and what are the risks? Do levels decrease over time?
p,p-DDT, pooled breast milk
p,p-DDE, pooled breast milk
Global monitoring of PTMB chemicals
• Available Global Monitoring Plan (GMP) data
Do we know anything about spatial trends? Where are the highest POPs
contaminations? Can we figure out why? Are the POPs mobile?
The end…..any questions?