Mercury in Seafood
An NGO perspective
Kimberly A. Warner, Ph.D.
C MERC Workshop
September 8, 2010
Seafood Contamination Campaign:
Two objectives:
Reduce exposure:
Control Sources:
Protect at-risk
populations
Hg-based Chlor-alkali
Landscape 2005
•Updated 2004 FDA/EPA fish advisory
–First time tuna included
•New proposed Hg regulations: CAMR, etc.
•Push-back by industry, free-enterprise
groups
–Cast doubt on science on Hg fate and effects
Structure of Anti-regulation
Positions
•There are no health problems with MeHg
•If there are problems, not our fault
•Regulations will do nothing to solve
imaginary problem
•Pushed science to respond: e.g.
–METALICUS
–NHANES
–Mercury 2006 consensus statements
Nutritionists/
Seafood Interests Pushback
2005 NOAA Seafood and Health Conference
•Question MeHg RfD and uncertainty
•Omega research: neurodevelopment, cardiovascular health, etc,
etc.
•Selenium
•FDA Risk Benefit update
•Launch of Fish Scam
Science needed:
Methylmercury risk
•Update MeHg RfD; constrain uncertainty?
•Cardiovascular risks nil?
•Selenium modification?
•Interaction of multiple contaminants
•More transparent risk-benefit studies
–Open, transparent dialogue between
nutritionists, toxicologists, modelers
–Examine specifics, not just averages
Hair mercury levels positively related to
fish consumption (p < 0.0001)
Hair Hg (ppm)
2.5
2
1.5
1
0.5
0
1-2
3-4
5-6
Fish meals per month
7-8 or more
Oceana survey in 2005 found high levels of fish
consumption and mercury in some popular sport fish
Consumption Rates
High
Medium
Fish Mercury levels
Cobia (Ling) (8)
Low
King Mackerel (19)
Barracuda (29)
Bonito (Little Tunny) (28)
Crevalle Jack (23)
Spanish Mackerel (5)
Blackfin Tuna (7)
Amberjack (11)
Black Drum (13)
Wahoo (21)
Gafftopsail Catfish (24)
Bluefish (25)
Ladyfish (30)
Red Snapper (1)
Grouper (all) (4)
Gray Snapper (16)
Gag Grouper (14)
Hardtail (Blue Runner)
(31)
Yellowfin Tuna (2)
Flounder (3)
Speckled Trout
(Spotted Seatrout) (6)
White Trout (Sand
Seatrout) (10)
Dolphin (12)
Gray Triggerfish (15)
Vermilion
Snapper(17)
Sheepshead (9)
Scamp Grouper (18)
Blackfish (Tripletail) (26)
Hg exposure
Median Hair Mercury Level (ppm)
Regional Differences in:
0.7
0.6
(A) Hair Mercury
0.5
0.4
0.3
0.2
0.1
0
Northern AL
Coastal AL
12
Seafood consumption rates
Fish servings per month
(B) Fish consumption
10
8
6
4
2
0
Hg levels in top consumed fish
•Northern: catfish, salmon, cod
•Coastal: snapper, flounder, grouper
National: shrimp, canned tuna, salmon
Top Fish Mercury Level mean (ppm)
Northern AL
Coastal AL
0.35
0.3
(C) Mercury in Top Fish
0.25
0.2
0.15
0.1
0.05
0
Northern AL
n= 59
Coastal AL
n= 65
Science needed:
Consumer protection
•ID at-risk populations
–Geo-, ethno-, demo- graphic differences
•Effective communication strategies on
seafood risk/benefit messages
•Effectiveness of point of sale signs
•More monitoring of nutrient/contaminant
levels in seafood supply
–Target harvest areas, size class, etc.
Science needed:
Reduce seafood contamination
•Ocean
–What Hg sources methylated?
–Where is Hg methylated?
–Food chain, location studies
–Climate change effects
–Multiple contaminant effects
•Oil, emerging contaminants, POPs
–Sustainability concerns
Temporal Trends?
Mean Hair Hg (ppm)
6
all
5
4
3
2
1
0
Mobile Register 2001
n= 65
Rodeo 2006
n=65
female