Mercury Levels in High-End Consumers of Fish.

[Guest guest]

Poster's Comment: I can't believe this .... It is not an 'if' 'or' 'maybe'

They actually know they have this technology. " The further tragedy is that

we have the technology today to be able to use coal without letting that

mercury escape, but the political process puts higher value on cheap electricity

than on avoiding neurological damage to children and other adverse health

effects. " We could avoid all this mercury in our air but they put profits

above

the health of our children???

Hightower, JM. 2003.

Mercury Levels in High-End Consumers of Fish.

_Environmental Health Perspectives_

(http://ehpnet1.niehs.nih.gov/docs/2003/5837/abstract.html) _

doi:10.1289/ehp.5837_

(http://ehpnet1.niehs.nih.gov/docs/2003/5837/abstract.html)

_http://www.protectingourhealth.org/newscience/learning/2002/2002-1031hightowe

r.htm_

(http://www.protectingourhealth.org/newscience/learning/2002/2002-1031hightower.\

htm)

 

Physician Jane Hightower reports that patients in her medical practice in

the San Francisco Bay Area who consume large predatory fish like tuna and

swordfish carry high levels of methylmercury in their blood and/or hair and are

likely to report various medical symptoms consistent with low-level mercury

poisoning. The good news is that when they stopped eating fish contaminated

with

mercury, their blood mercury levels went down over a period of 20+ weeks.

For the most part these patients were socially and economically advantaged

people for whom cost was not an issue in determining what fish to eat.

What did she do? Hightower interviewed patients on patterns of fish

consumption and also about other sources of mercury exposure (mecury amalgam

fillings, thimerosal in vaccinations). Those whose fish diet indicated a

possibility

of high mercury exposure were then asked to participate in a study that

involved sampling blood or hair mercury levels over time, during which they

were

also encouraged to lower their predatory fish consumption.

What did she find? Approximately 140 out of 720 patients surveyed had fish

consumption patterns suggesting high mercury exposure. Of these 116 allowed

blood measurements; another with 7 allowed hair analysis. Mercury averaged 14

µg/L in serum. Hair levels ranged from 1.55 to 14.81 µg/g. EPA and the

National Academy of Sciences recommend not allowing mercury levels to rise

above 5

µg/L and hair not above 1 µg/g. Four of Hightower's patients had blood levels

in excess of 50 µg/g.

Data from eighty-nine patients were put through more detailed statistical

analysis to look for relationships among fish consumption patterns and mercury

level. Among these patients, mercury ranged from 2 to 89.5 µg/L, with a mean

of 14.5 µg/L. 82 subjects had levels above 5 µg/L and sixteen subjects had

levels above 20 µg/L. The estimates of fish consumption were based on

questionnaire responses about past histories and therefore subject to

considerable

uncertainty. The only strong pattern revealed by this analysis was for

swordfish: the more frequently a patient ate swordfish, the higher their

mercury

levels.

Hightower tracked 67 patients over time to see if reducing fish consumption

reduced mercury levels. As evident in the graph below, all but two of these

patients reduced their levels to under 5 µg/L after 41 weeks; the two

exceptions continued to eat large predatory fish.

Serum mercury levels in patients after beginning a diet with reduced

predatory fish intake. Two patients did not comply fully.

from Hightower 2003

 

What does it mean? The bad news is that some of the fish currently consumed

by Americans is sufficiently contaminated by mercury to elevate levels far

beyond thresholds of concern. This is not a new story. The twist that attracted

_media attention_

(http://www.protectingourhealth.org/newscience/learning/2002/2002-1031hightower.\

htm#mediaattention) to Hightower's research is that her

patients tend to come from tonier economic backgrounds and many are eating

fish-rich diets because they thought it was good for them.

Hightower does not expect her findings to be unique to the San Francisco

area: " It would be expected that places such as New York, Maine, Florida,

Hawaii, Martha’s Vineyard Massechusettes, and Los Angeles, Monterey, Santa

Cruz,

San Diego, California could demonstrate similar data. "

The good news is that not all fish creates this risks, and that by avoiding

mercury-laden fish even people with high mercury levels can bring them down

(assuming no other sources).

The tragedy is that we have allowed mercury to escape into the environment

which now means people must avoid important sources of protein. This mercury

comes from multiple sources, the most pervasive of which is generation of

electricity from coal contaminated by mercury. The further tragedy is that we

have the technology today to be able to use coal without letting that mercury

escape, but the political process puts higher value on cheap electricity than

on avoiding neurological damage to children and other adverse health effects.

Like many other state agencies, Washington State's Department of Health

provides _recommendations_ (http://www.doh.wa.gov/fish/FishAdvMercury.htm) for

limits to consumption of different type of fish because of mercury

contamination. For example, they would limit consumption of canned tuna to 2

oz. per week

for a child weighing 50 pounds. That's one third of a can.