Article published Feb 5, 2008

Evidence suggests that any additional mercury is too much

By M. CALANTHE WILSON-PANT

Should we worry about mercury? Let's look at the evidence.

Mercury in larger amounts has been known to be toxic to the brain since milliners used mercury vapors to shape hats, as evidenced by Lewis Carroll's "Mad Hatter." But the question facing us now is, "What amount of mercury is safe?"

Initially we thought that "the solution to pollution is dilution." Mercury refutes that concept. Instead of diluting, mercury concentrates in the environment. In water, methylmercury concentrates in fish, and travels up the food chain to the largest fish. The American College of Obstetricians and Gynecologists have recommended limiting amounts of fish eaten during pregnancy because of the risk of mercury in the fish affecting brain development in the fetus.

The data come from studies of island populations who live primarily on large fish. Two long term-studies have shown that children of mothers with higher levels of mercury have lower IQs. An attempt has been made using these studies to determine the lowest safe level of methylmercury.

A recent report, done at nine years of follow-up indicates that the level that causes effects is lower than the level indicated from the previous analysis. Hence it may take many years before we have any definite answers. Other studies in fish indicate that higher levels of mercury in the mother fish also affects the offspring of fish, decreasing the adaptive abilities of the juvenile fish which would result in decreased survival.

One argument is that there are large amounts of natural mercury in the Montana environment. It is true that forest fires release mercury from burned wood that is washed into the water supply. Mammoth Hot Springs also releases a large amount of mercury. However, these are actually arguments to further limit man-made sources, because we see that it is cumulative amounts that count. The higher the natural sources of mercury, the less we can afford to add. Mercury from Montana will affect fish all the way through the American water system — the Missouri, the Mississippi, the Gulf of Mexico, the Atlantic Ocean.

What about airborne mercury? A 2006 study of the Bay Area indicated that a higher atmospheric level of inorganic mercury may be related to a higher incidence of autism. The majority of current research does not support the association of either mercury amalgams or vaccines with autism. However, there is other research that does indicate that high blood levels of mercury, probably from other sources, in children are associated with autism and ADHD.

The situation is complex and exposure is only one possible explanation of the apparent association. In addition, airborne inorganic mercury is converted to organic mercury when it reaches a marine environment, so it also contributes to the contamination of fish.

Doctors have given up mercury thermometers and blood pressure cuffs. Mercury in any quantity is considered hazardous material for clean-up purposes. The research shows an association between lower IQs and maternal mercury levels. The research involving inorganic mercury is still inconclusive and, most important, early.

We are at a similar point in this research to where we were in the early '80s in regards to fetal alcohol syndrome. Twenty-plus years later, we know that alcohol during pregnancy causes birth defects, but we still do not know how little is too much; we still do not know the full effects, or who is at greatest risk. We do not even have ideal methods of diagnosing FAS.

How little mercury is too much? We don't know. Would you consume anything during your pregnancy that might cause your baby to have a lower IQ — even if that was "only a few points?"

Many questions remain about mercury in childhood neurological diseases. Mercury is also being investigated for roles in breast cancer and neurodegenerative diseases such as Parkinson's, Alzheimer's, and ALS.

So what about the proposed coal plants? CFB technology releases much higher levels of mercury than IGCC technology. Further, gold-mine tailing ponds, which have high levels of mercury, have shown increased mercury resistance in bacterial populations. Would the circulating fluid bed be subject to similar effects? Metals are used to combat bacteria when antibiotics no longer work.

We must demand technology that will minimize mercury, and that will be most amenable to future modification should we find that the mercury levels released by the plant are too high.

We owe this to our children and ourselves. Shouldn't SME and Electric City Power want to use technology that is least likely to cause health problems for their neighbors and citizens, especially our children? Are 75 jobs worth putting ourselves at risk — especially when alternative technology exists to reduce that risk, yet would still create jobs and economic benefits?

Cost benefit analyses must include the possibility of higher rates of autism, ADHD, mental retardation, dementia, cancer and bacterial resistance; allowing for the increased medical costs and the decreased productivity that would result.

Economic development is no longer a case of simply creating jobs and luring new industry; it is a careful weighing of complex issues to create long term economic stability with a minimum of "side effects."

Hmmm, it sounds a lot like managing human disease — where we now are focusing on applying the evidence to the best of our ability. Shouldn't we make all complex decisions based on best available evidence?