An introduction to Mike's Predict Conference 2015 Talk on Contaminants in Food – Hazards and Risks

1. Contaminants in Food –
Hazards and Risks
P. Michael Bolger Ph.D., D.A.B.T.
Washington, DC

2. Safety/Risk Assessment Paradigm
Risk Management
Risk Assessment
Science
Data
Inferences:
1. Adversity
2. Variability
3. Uncertainty
What is safe?
What is
the Risk?
Model
(Theory)

3. History of Safety/Risk Assessment
 A. Lehman and O. Fitzhugh - Quarterly Bulletin of
Assoc. Food & Drug Off. Vol. 28 (No.1): 33-35, 1954.
 Based on “No Effect Level” or “No Observed Adverse
Effect Level (NOAEL)”
 10-fold safety factor (SF) based on a comparative
analysis of fluorine and arsenic toxicity data in
laboratory animals and humans.
 Additional 10-fold SF to account for individual
variation
 Additional SF/UF up to 10 for differences in Dose
Duration as well as Modifying Factors (MF) for
inadequacy of data.

4. Non-Cancer - Dose-Response
Dose (mg/kg/day)
Response(%)
50%
100%
LOAEL
Uncertainty
Factor
RfD NOAEL

5. Safety/Risk Assessment
 First step in an iterative safety/risk process.
 An answer to a simple yes or no question - safe or
unsafe.
 Acceptable Daily Intake (ADI) / Tolerable Daily
Intake (TDI) / Reference Dose (RfD) / Minimal Risk
Level (MRL)
 Useful for screening out trivial public health problems.
 Does not describe the degree of the problem
quantitatively or provide basis for gauging level of risk
management remediation effort (e.g. , source
identification, issuance of public health advisories,
regulatory standards).

6. Methylmercury (MeHg) in Fish
 Mass poisoning episodes in Japan in the 1960s resulted
from environmental contamination and accumulation of
methylmercury in fish.
 Health effects included developmental abnormalities and
death.
 A second series of poisonings in Iraq in the 1970s
resulted from treated grain contaminated with MeHg.
 Several large scale epidemiological studies (Faroes and
Seychelles islands) have investigated subtle fetal effects.
 The level of MeHg in a given species of fish is dependent
on the animal’s diet, size, and age. Generally, levels are
below 0.4 mg/kg, but fish at the highest trophic levels
may contain MeHg at levels above 5 mg/kg.

7. MeHg Hazards
 MeHg is readily absorbed from the GI tract and
preferentially binds to hemoglobin resulting in high
erythrocyte to plasma ratios.
 MeHg crosses blood: brain barrier and placenta, resulting
in higher fetal brain MeHg concentrations as compared to
the maternal levels.
 Elimination is through the bile and feces, with neonatal
animals having a lower excretory capacity as compared to
adults.
 Hair and blood levels are the primary biomarkers of
exposure to MeHg.
 Most sensitive endpoint in humans occurring at lowest
doses is neurotoxicity which is dependent on dose and
duration of exposure.

8. MeHg and IQ
-2
0
2
4
6
8
10
0 2 4 6 8 10
Hair MeHg [ppm]
NetIQDecrease
Delayed Talking - Iraq
Delayed Walking - Iraq
Ryan - IQ - Faroe Islands
Ryan - IQ - Seychelles
Ryan - IQ - New Zealand
Cohen - IQ - Faroe Islands -
Log
Cohen - IQ - Faroe Islands -
Linear
Cohen - IQ - New Zealand
Cohen - IQ - Seychelles

9. Female Blood Mercury Levels in US Population in
Relation to Health Screening Values (2009–2010)
9

10. Fetal Neurodevelopment:
Net Effect Modeling Results
Summary
 Net adverse effects are probable for diets with high
MeHg fish.
 Because most commercial fish are low in MeHg, most
U.S. consumers experience a net benefit from
commercial fish consumption.
 Over 12 oz. fish/week can result and for most people
does result in a net benefit. However, the size of the
benefit is likely to decrease beyond 12 oz., especially
with higher MeHg fish.
 The size of a beneficial effect is dependent on amount
of MeHg in the fish.
 Low MeHg fish produce greater benefits than high MeHg
fish.
 Higher MeHg fish can attenuate the benefit and, in some
cases produce a net adverse effect, especially at higher
levels of consumption.
http://www.fda.gov/Food/FoodborneIllnessContaminants/M
etals/ucm393211.htm

11. Figure D-4: COMPARISON OF NET EFFECTS FOR IQ
FROM SALMON WITH TWO DIFFERENT DOSE
METRICS FOR NUTRITIONAL BENEFITS
11

12. Figure D-5: COMPARISON OF NET EFFECTS FOR IQ
FROM CANNED LIGHT TUNA WITH TWO DIFFERENT
DOSE METRICS FOR NUTRITIIONAL BENEFITS
12

13. Figure D-6: COMPARISON OF NET EFFECTS FOR IQ
FROM CANNED ALBACORE TUNA WITH TWO
DIFFERENT DOSE METRICS FOR NUTRITIONAL
BENEFITS
13

14. Figure D-7: COMPARISON OF NET EFFECTS FOR IQ
FROM SHARK WITH TWO DIFFERENT DOSE
METRICS FOR NUTRITIONAL BENEFITS
14

15. Fish: What Pregnant Women and Parents Should Know
Draft Updated Advice by FDA and EPA
June 2014
http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm393070.htm
Key Message
Eat 8 to 12 ounces of a variety of fish* each week from choices that are lower in mercury. The nutritional value of fish is important
during growth and development before birth, in early infancy for breastfed infants, and in childhood.
What to do
1. Eat 8-12 ounces of a variety of fish a week.
That’s 2 or 3 servings of fish a week.
For young children, give them 2 or 3 servings of fish a week with the portion right for the child’s age and calorie needs.
2. Choose fish lower in mercury.
Many of the most commonly eaten fish are lower in mercury.
These include salmon, shrimp, pollock, tuna (light canned), tilapia, catfish, and cod.
3. Avoid 4 types of fish: tilefish from the Gulf of Mexico, shark, swordfish, and king mackerel.
These 4 types of fish are highest in mercury.
Limit white (albacore) tuna to 6 ounces a week.
4. When eating fish you or others have caught from streams, rivers, and lakes, pay attention to fish advisories on those
waterbodies.
If advice isn’t available, adults should limit such fish to 6 ounces a week and young children to 1 to 3 ounces a week and not eat other
fish that week.
Why this advice is important
Fish contains important nutrients for developing fetuses, infants who are breastfed, and young children. Fish provides health benefits
for the general public. Many people do not currently eat the recommended amount of fish.
http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm393070.htm

16. Conclusions
 Effective food safety efforts for chemical contaminants
require a multi-dimensional and disciplinary approach,
involving surveillance and targeted monitoring and
toxicological and epidemiological studies.
 While the US food supply can be regional in nature
depending on the time of year, it has become a year round
global issue and therefore requires a global perspective.
 Proactive and constructive collaborative efforts between
local and national environmental and public health
agencies, as well as international collaborative efforts
between national, regional and international health
organizations are required for an effective food safety
program for chemical contaminants.