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Re: [SANET-MG] Mercury poisoning
Michael asked for references so I am including two showing the link between
methyl mercury and developmental defects in children.The studies are on
children from the Faroe Islands.
In Michael's studies the links were dismissed rather summarily.
The political link is worth mentioning. The US opted for poor mercury
regulations to keep polluting coal fired energy facilities in the pollution
business. Some academics seem now to curry favor with government agencies by
arguing mercury is not harmful.
J Pediatr. 2004 Feb;144(2):177-83
Delayed brainstem auditory evoked potential latencies in 14-year-old children
exposed to methylmercury.
Murata K, Weihe P, Budtz-Jorgensen E, Jorgensen PJ, Grandjean P.
Division of Environmental Health Sciences, Akita University School of Medicine,
OBJECTIVE: To determine possible exposure-associated delays in auditory
brainstem evoked potential latencies as an objective measure of neurobehavioral
toxicity in 14-year-old children with developmental exposure to methylmercury
(MeHg) from seafood. STUDY DESIGN: Prospective study of a birth cohort in the
Faroe Islands, where 878 of eligible children (87%) were examined at age 14
years. Latencies of brainstem evoked potential peaks I, III, and V at 20 and 40
Hz constituted the outcome variables. Mercury concentrations were determined in
cord blood and maternal hair, and in the child's hair at ages 7 and 14.
RESULTS: Latencies of peaks III and V increased by about 0.012 ms when the cord
blood mercury concentration doubled. As seen at age 7 years, this effect
appeared mainly within the I-III interpeak interval. Despite lower postnatal
exposures, the child's hair mercury level at age 14 years was associated with
prolonged III-V interpeak latencies. All benchmark dose results were similar to
those obtained for dose-response relationships at age 7 years. CONCLUSIONS: The
persistence of prolonged I-III interpeak intervals indicates that some
neurotoxic effects from intrauterine MeHg exposure are irreversible. A change
in vulnerability to MeHg toxicity is suggested by the apparent sensitivity of
the peak III-V component to recent MeHg exposure.
Ambul Pediatr. 2003 Jan-Feb;3(1):18-23.
Neurotoxic risk caused by stable and variable exposure to methylmercury from
Grandjean P, White RF, Weihe P, Jorgensen PJ.
OBJECTIVES: To examine whether the dose-effect relationship for developmental
mercury neurotoxicity is affected by variable mercury exposure during
pregnancy. METHODS: The study was based on a birth cohort of 1022 children born
in the Faroe Islands between March 1986 and December 1987. Neurobehavioral
performance of 917 children (90%) was assessed at age 7. Intrauterine
methylmercury exposure was determined from mercury concentrations in cord blood
and 2 sets of maternal hair. Complete exposure information was available for
614 children (67%). RESULTS: In children with complete exposure data, 8 of 16
neuropsychological tests showed deficits significantly associated with the
cord-blood mercury concentration after confounder adjustment. Variable
intrauterine exposure was suggested by disagreement between mercury
concentrations in the 2 maternal hair samples. Removal of the 61 children (10%)
with the greatest degree of variable exposure had a minimal effect on most
exposure-effect relationships. However, the effect of the cord-blood
concentration on verbal learning and memory was greater after this exclusion.
CONCLUSION: The study supports previous findings from this cohort study that
maternal mercury exposure during pregnancy is associated with
neuropsychological deficits detectable at age 7 years and that this association
is evident in women with stable exposures throughout pregnancy. Thus the
association is not the result of variable exposures.
Quoting Michael Elvin <Marimike6@CS.COM>:
> An interesting question has just popped up concerning methyl mercury
> ingestion and developmental damage to fetuses. I was reading an article about
> Seychelles Study,
> that failed to prove any link between high mercury consumption by mothers (on
> these islands they eat more ocean fish than just about anywhere on earth) and
> observable retardation, autism or other measurable damage to their children.
> I reached for my e-pen to fire off a response, and could find no
> corresponding studies I could use to bolster the notion that a link had been
> between the two. Somehow, amid all the brouhaha, it would appear that no
> smoking gun
> has yet been found, and that the experts attest that at bottom, any such link
> is "still a mystery".
> Is this what we've been wasting all that worry for? I'm calling on Lion (of
> course) and anyone else with the time and interest to find some study,
> somewhere, that says "We found x number of mothers with abnormally high blood
> of methyl mercury, and they had y number of newborns who exhibited
> developmental difficulties later on-- said number being greater than the
> incidence in the
> general population".
> You would think this study had been done by now. Without it, the whole
> mercury scare falls apart. Please respond.
> Mike (of course it would be me) Elvin
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