Lake Chapala Water/Fish Study

[Guest PalapaGirl]

http://news.harvard.edu/gazette/story/2014/10/the-mystery-of-the-lake/

Fascinating & informative.

[Snafu]

What a switch. Now it's safe to eat fish from the lake and dangerous to eat fish from the Pacific. Who'd a thunk it.

[vetteforron]

My internet is too slow here in Roca Azul Rv park to open the study but, I live on the lake in two places and will never eat fish (knowingly) from this lake.

[snowyco]

For people who can't open the file or don't like to read research studies, here's a summary:

The upcoming research results from Harvard exactly meet the predictions of experts who know mercury pollution & the food chain in Lake Chapala. Mercury moves into the food chain from microbes in the muck at the bottom of the lake, where microbes convert mercury contamination into a bioavailable form of mercury called "methyl mercury" in the bottom sediments. This means that mercury is able to move into the food chain through bottom feeding fish (carp) and through the predatory fish that eat the bottom feeders - as the predators concentrate the mercury throughout their lives. (Which is why tuna, swordfish, and other predatory ocean fish are generally high in mercury.)

In Lake Chapala: The common food fish are tilapia and charales - which are not bottom feeders nor predators. - Carp from Lake Chapapa however are considered to potentially be bottom feeders.-

Mercury is very easy to test in fish, the mercury test methods are very very sensitive finding even trace amounts of mercury, and mercury results from fish testing have been very reliable for over 50 years.

The study was large enough, and it covered the fish that people eat, and is hence likely very reliable.

The study also tested the abilities of small children whose mothers ate a lot of fish and who themselves regularly eat fish. Babies and small children are the most susceptible humans to mercury damage. Harvard experts checked the children's neurosystem development using standard tests - to determine if past consumption of Chapala fish by their mothers and by the children had affected the children.

Here is a key excerpt from the article that describes the major scientific conclusions about mercury risks from eating fish from Lake Chapala:

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:"Cifuentes and his co-authors aver that eating Lake Chapala white fish like tilapia and charales at least once a week is healthy for women of reproductive age and for pregnant mothers.

Other people can (safely) eat fish more often than that.

“That reflects a global consensus on the consumption of fish during pregnancy,” said Cifuentes, who for several years traveled to the lake region, often with Harvard and Guadalajara graduate students in tow. They helped collect fish, lake sediments, and medical samples.

As for the study’s developmental testing, it revealed no negative effects on cognition, language, or motor skills among infants.
That result, said University of Guadalajara psychologist Leonor Lozano, was “very positive news for the people of the communities surrounding Lake Chapala.”

But the study did say that women of childbearing age should avoid eating carp, carnivorous fish, and bottom feeders that may contain elevated levels of mercury. In hundreds of fish assayed, said Cifuentes, only carp — and just a few of those — showed risky levels of mercury.

“Fortunately, we have very good news,” he said of the three-year study’s bottom line. “Keep eating fish. But women of childbearing age should eat only the right ones.”
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From a scientific perspective, these preliminary results from Harvard say that tilapia and charales from Lake Chapala are safer than US tuna.