close

Вход

Забыли?

вход по аккаунту

?

L. Williams-Health Effects

код для вставкиСкачать
Health Effects of Methylmercury and
North Carolina’s Advice on Eating Fish
Luanne K. Williams, Pharm.D.
Toxicologist
NC Department of Health and Human Services
Objectives
пЃ¬
Accumulation of methylmercury in fish
пЃ¬ Health effects in children and adults
пЃ¬ Health benefits of eating fish
пЃ¬ Issuance of NC and US fish advisories
 NC’s advice on eating fish
пЃ¬ Basis for issuance of fish advisories
Accumulation of
Methylmercury in Fish
Mercury пѓћ methylmercury пѓћ invertebrates пѓћ fish
пЃ¬ Deposited in water from air and biotransformed by
bacteria
пЃ¬ Invertebrates consume methylmercury
пЃ¬ Small fish consume invertebrates
пЃ¬ Large fish consume small fish
пЃ¬ Builds up to high levels in predatory fish
пЃ¬ Methylmercury binds to protein or meat of fish
and cannot be removed by cooking or cleaning
Fish High in
Methylmercury
Levels higher in long-lived predator fish
пЃ¬ Regional environmental pollution and
conditions influence levels in fish
пЃ¬ Fish high in methylmercury 0.4 ppm and
greater
пЃ¬
– ocean fish like shark, swordfish, king
mackerel, and tilefish
– freshwater fish like blackfish (bowfin),
largemouth bass, and jack fish (chain
pickerel)
Health Effects
пЃ¬
Methylmercury well absorbed
пЃ¬ Measured in blood and hair
пЃ¬ Half-life 2 to 3 months
пЃ¬ Developing fetus 3 times more sensitive
than adults- affects the way they think,
learn, and problem solve
Health Effects
on Adults
пЃ¬
Significantly less sensitive than children
пЃ¬ Numbness of lips, tongue, fingers, and toes
пЃ¬ Blurred vision
Issuance of Fish Advisories
пЃ¬
45 states issued fish advisories due to high
levels of methylmercury in some fish
пЃ¬ NC statewide advisory consistent with US
EPA and FDA national advisories
пЃ¬ NC recommends avoiding or limiting
consumption of 7 fish with high
methylmercury levels
пЃ¬ Positive message as well - recommends
consumption of fish with low
methylmercury levels
N.C. Advice
Sensitive populations
0 meals/week fish high mercury
2 meals a week fish low mercury
General public
1 meal a week fish high mercury
4 meals a week fish low mercury
http://www.epi.state.nc.us/epi/fish
Ocean Fish High in MethylMercury
shark
King mackerel
swordfish
tilefish
NC Freshwater Fish
High in Methylmercury
South and East of I-85
Bowfin or blackfish
Largemouth bass
Chain pickerel or jack
Fish Low In Methylmercury
пЃ¬ farm-raised
fish
пЃ¬ canned fish including tuna, fish sticks
пЃ¬ shrimp, crab, lobster, clams, oysters,
scallops
пЃ¬ spot, croaker, king fish (sea mullet),
speckled trout (spotted trout), flounder,
mahi mahi, salmon, cod, whitefish,
pollock, ocean perch, halibut, haddock,
herring trout, crappie, sunfish, perch,
bream
Health Benefits of
Eating Fish
пЃ¬
Low-fat, high-protein food
пЃ¬ Reduces risk of coronary heart disease
пЃ¬ Reduces cholesterol and triglyceride levels
пЃ¬ Inhibits platelet aggregation
пЃ¬ May reduce blood pressure
пЃ¬ Omega-3 fatty acids important for optimal
brain and nervous system development in
developing fetuses and infants
Fish - Good for Brain
and Nervous system
Development and
Heart
Women of childbearing age and children could
consume 2 meals a week of fish low in
methylmercury (<<0.4 mg/kg)
General public could consume 4 meals a week of
fish low in methylmercury
Studies in 50s, 60s and 70s
Human Health Effects
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
High dose seafood poisonings in Japan in 50s and
60s and high dose bread poisoning in Iraq in 70s
Health effects on developing neurological system
of greatest concern
Children born with mental retardation, cerebral
palsy, deafness, and blindness
Adults with numbness and tingling lips, tongue,
fingers, toes
Led to studies of methylmercury effects on
developing children after prenatal exposure
Two Large Epidemiology
Fishing Village Studies
1980s -1990s
пЃ¬
Evaluated child neurodevelopment from to birth
to several years old
пЃ¬ Children from mothers who consumed fish or
whale meat on a routine basis during pregnancy
пЃ¬ Seychelles Islands, Indian Ocean near Africa
пЃ¬ Faroes Islands, North Atlantic between Scotland
and Iceland
Seychelles Islands
Univ Rochester
School of Medicine and
Dentistry
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
1989 - 740 mother-infant pairs
12 meals/wk of fish low levels avg <0.3 ppm
Less than NC’s 7 advisory fish 1 ppm
Mercury levels mothers’ hair during pregnancy
Avg hair levels 6.8 ppm (0.5 - 27 ppm)
Children broad range of cognitive-behavioral
tests approx 6 months, 1 1/2 yrs, 2 1/2 yrs, 5 1/2
yrs and 9 years and NO EFFECTS
Faroes Islands
Harvard School
of Public Health
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
1986 - 700 mother-infant pairs
1 - 3 meals/wk of fish low levels avg < 0.3 ppm
1 meal/mo pilot whale high levels avg 1 ppm and
> similar to NC’s 7 advisory fish 1 ppm
Mercury levels mothers’ hair during pregnancy
and cord blood
Avg hair levels 4.3 ppm (0.2 - 39 ppm) similar to
Seychelles
Maternal hair 10 ppm and cord blood 58 ppb
10% risk dysfunction in language, attention, and
memory when children evaluated at 7 years
Differences
in
Results
пЃ¬ Faroes - weekly consumption of fish with
low levels but monthly consumption pilot
whale meat high levels > 1 ppm resulted in
a high peak or bolus dose
пЃ¬ Seychelles - weekly consumption of fish
with low levels and no monthly
consumption of fish with high levels
пЃ¬ American Academy of Pediatrics monthly
bolus doses Faroes children received during
critical developing periods may be more
likely to cause neurodevelopmental damage
than the same doses given cumulatively
over several months
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
US EPA and
National Academy of Sciences
Reviewed the studies
Faroe Islands study - study of choice to assess
risk from consumption of fish containing
methylmercury
A dose of 1.0 microgram per kilogram per day
maternal consumption = 10% risk to child having
abnormal neuropsychological test scores
A safety factor of 10 applied to account for
variability in susceptibility and uncertainty in
long-term effects later on in life
Derived health-protective dose of 0.1 microgram
per kilogram per day for fish consumption
Risks to Developing Child
Following Prenatal Exposure
from Maternal Consumption of Fish
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
Maternal consumption of 5 meals a week of fish
Containing 0.4 mg/kg (our action level)
Corresponds to a 10% risk to child
Neurological effects
Child may have problems with the way they
think, learn, and problem solve later on in life
Minimize risks to developing child, NC
recommends WCB and children under 15 yrs
avoid fish with high mercury - shark, swordfish,
king mackerel, tilefish, and largemouth bass,
bowfin and chain pickerel caught S and E I-85
Summary
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
High methylmercury levels in some fish
Concern largely for developing child
Health risks for developing child following
prenatal exposure from maternal consumption of
fish high in methylmercury as supported by
Faroes Islands Study
Women of childbearing age and children avoid
fish high in methylmercury
Benefits of eating fish - brain and nervous system
development and heart
Maternal consumption of fish low in
methylmercury is safe as supported by the
Seychelles Islands Study
Faroes Islands Sunset
Документ
Категория
Презентации
Просмотров
1
Размер файла
820 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа