??????? ??? ?? ??? ?? The status and prospect of risk assessment for environmental pollutants

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??????? ??? ?? ??? ?? The status and prospect
of risk assessment for environmental pollutants
????? ???? ?????? ? ? ?
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Topics

• Introduction to Risk Assessment
• Frame of Risk Assessment
• Prospect of Risk Assessment
• Status and Future Works of Risk Assessment in
  Korea

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Risk Assessment
???????? ??? ??? ??? ???? ????? ??? ? ??
????? ??? ???? ??? ?? (Process from the
identification of hazard potential up to the
quantitative characterization of risks)
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Risk (??)

• ????? ????? ??? ???? ??? ?? ??? ??? ???
  ??(probability) ?? ???(likelihood)
• (NAS, 1983)

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Chloroform Risk

• Chloroform
• ?? ??? (q1) 6.84x10-3
• ????? 1.95x10-7
• ??? ???? 5 ppb

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Excess Cancer Risk

• Hypothetical Number (morbidity or mortality)
  supported by scientific bases and logical process

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The RED BOOK (NRC, 1983)

• Risk Assessment in the Federal Government
  
• Managing the Process

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Traditional Risk Assessment Process

• 4 Steps of Risk Assessment

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Hazard Assessment - 1
Step 1

• What health problems are caused by the
  pollutants?
• ??? ?? ????? ????? ??, ?? ??? ??? ??????? ?????
  ???? ??
• ????? ??, ???? ?? ???? ??
• ?? ????
• ????? ?? ????
• ?? ??? ?? ? ??? ?? ??

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Hazard Assessment - 2
Step 1

• ??? ?? ??? ??? ?? ?? ?? ?????? ????? ???? ????
  ?????? ????? ?? ???? ??? ?? ?? ?????? ????.

(International Agency for Research on
Cancer,Lyon, France 1987)
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Hazard Assessment for Dioxin
Step 1 ??
Step 1. Hazard Assessment
EPA IARC TCDD IS A HUMAN CARCINOGEN Dioxin IS A LIKELY HUMAN CARCINOGEN CLASS 1 (FEBRUARY 1997)
Evidences Sufficient evidence of animal carcinogenicity (rats, mice, hamsters, medaka) Limited () evidence of human carcinogenicity (occupations cohorts SEVESO) Mechanistic data
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?? ??? ?? ??????
Step 1. Hazard Assessment
Step 1 ??
??? ???? ?? TCDD ?? (pg/g lipid) ?? ??
?? ?? (1942-1984) 12? ??? ?? 5,172? ??? ?? 233 (1987) ?? ??? 114? ??, ? ? ???? 40? ?? ?? ? SMR 1.5 (1.2-1.8), ?? SMR 1.4 (1.0-1.9)
BASF ?? (1952-1984) BASF ?? ?? ??? 247? ???? 15.4 (1988-1992) ?? ??? 18? ??, ? ? ???? 7? ?? ?? ? SMR 1.9 (1.1-3.0), ?? SMR 2.4 (1.0-5.0)
?? ?? (1952-1984) 4? ??? ?? 2,479? ??? ?? 141.4 (1985-1994) ?? ??? 105? ??, ? ? ???? 33? ?? ?? ? SMR 1.3 (1.0-1.5), ?? SMR 1.4 (1.0-2.0)
???? ?? 2? ??? ?? 2,074? ??? A ?? ?? 53 (1993) ?? ??? 51? ??, ? ? ???? 14? ?? ?? ? SMR 1.5 (1.1-1.9), ?? SMR 1.0 (0.5-1.7)
IARC ??? ?? 12??, 36? ?? 21,863? ???? 3-389 (7??, 574?) ?? ??? 394? ?? ?? ? SMR 1.2 (1.1-1.3)
??? ?? (1976-1996) A ?? 804? B ?? 5,941? R ?? 38,624? ????232,745? A 447 73.3 B 94 12.4 R 48 (1977) ???? 5.5 (1994) ?? ??? 745?(A? B ??) ?? ?? ? RR 1.3 (1.0-1.7), ?? RR 1.3 (1.0-1.7), ???? RR 4.9 (1.5-16.4), ??? RR 3.8 (1.2-12.5)
?? ???? (Meta ??) - - ?? ? SMR 1.3 (1.2-1.5) (??? ??? ??)
SMR standardized mortality ratio RR
rate ratio Sample collected in 1977 and 1994
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Dose-Response Assessment - 1
Step 2

• What are the health problems at different
  exposure?
• ???? ??? ??? ????? ??? ?? ????? ???? ?????? ?????
  ???? ??
• ????? ???????? ???? ??

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Dose-Response Assessment - 2
Step 2

• Carcinogens
• Decisions on dose response assessment approaches
  for the range of extrapolation

Data to support
Biologically based or case-specific model yes no no no No
Linearity yes no yes No
Nonlinearity no yes yes No
Extrapolation used Specific model Default- linear Default- nonlinear Default-linear nonlinear Default-linear
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Dose-Response Assessment - 3
Step 2

• Mathematical Model for extrapolation of carcinogen

Statistical models--tolerance distribution models Statistical models--tolerance distribution models
Probit (sublinear) a lognormal tolerance model P(d) a b log(d)
Logit (sublinear) characterizes tolerance distribution with a logistic function P(d) 1/ (1 exp(-a b log(d) )
Weibull time to tumor distribution P(d) 1 - exp(-a bd)
Stochastic or hit models Stochastic or hit models
One-hit Derived from Poisson statistics P(d) 1 - exp(-a - b d)
Multi-stage Based on the stage theory of cancer as first proposed by Armitage and Doll P(d) 1 - exp(-a - b1d - b2d2 - b3d3 )
Linearized Multistage the b1 parameter is replaced by its upper confidence limit.
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Additive? multiplicative ??? ????? ???? ??? ?? ??
?? ???
Step 2. Dose-Response Assessment Cancer Potency
Step 2 ??
???? ?? ?? ?? ?? ??? (1 pg/kg/day)-1 LADD intake 95 ?? ?? ??? (1 pg/kg/day)-1 LADD intake 95
???? ?? ?? Lower Maximum Limit Likelihood Estimates
Fingerhut ? (1991) Additive Multiplicative 0 0 1.1X10-4 5.7X10-5
Manz ? (1991) Additive H-M-L scenario Chlorance or not Multiplicative H-M-L scenario Chlorance or not 0 0 0 0 1.0X10-3 2.0X10-3 6.1X10-4 1.3X10-3
Zober ? (1990) Multiplicative 0 7.6X10-5
All studies combined Additive Multiplicative 3.7X10-6 1.5X10-5 1.1X10-4 5.9X10-5
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?? ? ????? ??? ?? EPA? q1 ?? ????
Step 2. Dose-Response Assessment Cancer Potency
Step 2 ??
? ? ? ???? ??? ???? q1(pg/kg/day)-1
Kociba ? (1978) Squire (1980) US EPA (1985) Sauer Goodman (1992) ???? ???? ???? ???? ? ? ?? ? ? LMS Multistage Weibull LMS LMS 0.5X10-4 3.1X10-4 1.6X10-4 0.8X10-4
Zoger ? (1990), Manz ? (1991), Fomgerhut ? (1991) ???? ? ?? ? Additive Multiplicative Addutuve Multiplicative 1.1X10-4 5.9X10-5 6.0X10-4 3.4X10-4
US EPA proposed (1998) US EPA proposed (1994) US EPA currently proposed (2000) - - - - - - - - - 1.0X10-5 1.0X10-4 1.0X10-3
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Exposure Assessment - 1
Step 3

• How much of the pollutant do people inhale,
  ingestion or dermal contact during a specific
  time period ? How many people are exposed?
• ??? ??? ??(??, ???, ?? ?)? ?? ???? ??? ????? ??
  ??? ?????? ???? ??
• ????
• ?? ?? ??
• ?? ?? ????
• ?? ?? ????
• (exposure biomarkers)

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Exposure Assessment - 2
Step 3

• ??????
• ? ???? ???? ????, ? ??? ??????? ???? ??

• ??????
• ? ????? ??? ???? ?? ?? ??? ?? ?? ???? ???? ??

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• Conc. x IR x ET x EF x ED
• Dose
• BW x AT

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Exposure Assessment - 4
Step 3

• Human Exposure Assessment through Multimedia and
  Multipathway

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Exposure Assessment - 5
Step 3

• The average daily intake dose based on dioxin
  concentration of human tissue

• ADDmother(pg/kg/day) Average daily intake dose
  of the mother
• Chuman tissue(TEQ pg/kg fat) Concentration in
  human tissue such as breast milk, blood, and
  adipose tissue
• h(day) Half-life of dioxin in adults (7 year)
• f1 Proportion of mother's weight that is fat
  (30)
• f2 Proportion of ingested dioxin that is
  stored in fat (90)

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Dioxin Exposure Assessment
Step 3. Exposure Assessment
Step 3 ??
???? ?? ??? ????? ???3) ????? ???3) ?? ??? ???
PCDDs/DFs PCBs (pg/kg/day) ()
?? (g/day) (pg-TEQ/g) (pg-TEQ/g)
?? ?? ??? ??? ?? ?? ??? ??? ???? ??? ?? 350.91) 28.91) 306.21) 179.11) 52.31) 14.01) 51.91) 11.01) 28.81) 27.31) 20.51) 0.015 0.014 0.015 0.006 0.142 0.123 0.011 0.015 0.005 0.027 0.044 0.000 0.002 0.000 0.000 0.000 0.165 0.002 0.008 0.003 0.001 0.011 0.088 0.008 0.076 0.019 0.123 0.067 0.011 0.004 0.004 0.013 0.019 17.7 1.6 15.3 3.8 24.8 13.5 2.2 0.8 0.8 2.6 3.8
?? ???? (m3/day) 13.32) (pg-TEQ/m3) 0.283 (pg-TEQ/m3) NA.4) 0.063 12.8
?? ???? ?????? (g/day) 0.0502) 0.0122) (pg-TEQ/g) 0.324 0.324 (pg-TEQ/g) NA.4) NA.4) 0.001 0.000 0.1 0.0
? ? 0.496
1) ???? ?? (2064?)? ? ??? ?? ?? ???
(?????,2000) 2) ?? ??? ?? ?? ???, ?? ???, ??? ??
??? ?? (US EPA, 2000) 3) ?? ?? ??
????????(1999), Hashimoto ?(1998), ??? ?(2000) ??
? ?? ???????(2000,2001) 4) NA not available,
?? ?? ? ????? PCBs ?? ??? ??
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?? ? ?? ???? ??? ??
Step 3. Exposure Assessment
Step 3 ??
(pg-TEQ/g fat) ?? ??
(n) (15) (78)
?? SD 15.13 13.49 11.17 7.66
(?? ??) (4.83 58.81) (0.16 35.93)
???? 1998 2002-2004
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????? ?? ?? ??? ??
Step 3. Exposure Assessment
Step 3 ??
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Risk Characterization - 1
Step 4

• What is the extra risk of health problems in the
  exposed population?
• ??? ??, ??-???? ? ?????? ??? ??? ???? ???????
  ????? ????? ??, ???? ?????? ??? ??(? ?)? ??? ???
  ???? ??

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Risk Characterization - 2
Step 4

• ?? ?? ?? ??? (excess cancer risk)
• ECR ??? (ug/m3. L, kg) X ????? (ug/m3. L, kg)
  -1
• ????? (mg/kg-day) X ????? (mg/kg-day)
  -1
• ECR gt ?????? ?? ?? ??? ???? ??? ??
• ?? ??? (Hazard Quotient)
• HQ ??? / ?????(RfD,RfC)
• HQgt1 ?? ?? ??? ???? ??? ??

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Risk Characterization - 3
Step 4
10-3
????? ?? ????? ?? ????? ?? ????? ??
10-4
???? ?? ???? ?? ???? ?? ???? ?? ???? ?? ???? ?? ???? ?? ???? ??
10-5
???? ???? ???? ????
10-6
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No risk
??? ? ?? ??? ? ?? ??? ? ?? ??? ? ??
?? ??? ?? ??? ?? ??? ?? ???
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????? ?? ?? ?? ?? ??
Step 4. Risk Characterization
Step 4 ??
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National Human Exposure Assessment Survey (NHEXAS)
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Risk Assessment Science Policy
Science Policy
Policy
Science
Facts Affected by Personal Values
Judgments Affected by both Personal and
Societal Values
Policies Affected by Societal Values

• Effect on generating, analyzing and interpreting
  facts
• Effects on assumptions, inferences, and
  extrapolations
• Effects on attitudes and approaches to uncertainty

• Effect on goals, objectives and priorities
• Effects on decision about acceptability or
  unacceptability of risks
• Effects on decision about tradeoffs (e.g, costs
  vs. benefits)

• Effect on decisions about the use of science in
  the formulation
• Effects on decision about the development of
  policy for science

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PUBLIC HEALTH GOALS
Reduce Adverse Effects (Secondary prevention)
Treat Adverse Effects (Tertiary prevention)
Prevent Adverse Effects (Primary prevention)
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2
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S A F E G U A R D I N G E N V I R O N M E N
T A L H E A L T H
ASSESSING MANAGING AND COMMUNICATING RISKS
Research and Surveillance
Knowledge and Understanding
Risk Assessment
Risk Management

• Estimating the magnitude Likelihood, and
  uncertainty of risks

• Deciding about which risks are unacceptable
• Deciding about what actions to take

• Epidemiology
• Toxicology
• Clinical studies
• Cell/Tissue experiments
• Computational methods
• Monitoring
• Exposure analysis

• Exposure
• Effects
• Link between exposure and effects

Risk Communication

• Explaining risks to important stakeholders
• Responding to stakeholders concerns and questions

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Risk Assessment in Korea
1990
??? ? THM? ?? ??? ??
??? THM ?? ??
?? ????? ?? ??? ??
??? ??? VOCs (??, TCE ?) ?? ??
1995
??? ? ???? ?? ??? ??
??? ???(???) ??? ?? ??
2000
????? ????? ? ??? ???? ?? ??
?? ????? TDI ? ?? ?? ?? ?? ?
??, ????? ?? ????? ?? ??? ?? ??? ??
?? ??? ?? ?? ?? ?? ?
?????? ?? ? ?? ?? ??
?? ?????? ?? ?? ??
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Future works for Risk Assessment in Korea
??? ?? ? ?? (Risk Assessment Management)
?? ?? (Environmental Problems)
?? ??
??? (EMF)
??-?? ??
Endocrine Disruptors
Pesticides

• ????
• ???
• ??????

?? ??
Nano Particles
On Going
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