Part IV - Gold Rush Series

In part three of our Mercury blog series, we focused on the different types of Mercury. In part four, we will cover the effects of mercury on the human body.

As was described in part two of our series, mercury is a metal that is used in a variety of consumer products, from light bulbs to thermometers. While it is beneficial and useful for these applications, it is poisonous and can harm the environment, as well as any animals and humans that are exposed to it.

Part II – Gold Rush: What is Mercury?

Having taken a look at Gold Rush era mercury use and its modern consequences in our last blog it only seems logical to discuss what mercury is and why it poses such great human health risks.  Because mercury and its associated risks is a broad topic, part three of our series on mercury will only look at mercury’s most well known forms.

Having taken a look at Gold Rush era mercury use and its modern consequences in our last blog it only seems logical to discuss what mercury is and why it poses such great human health risks.  Because mercury and its associated risks is a broad topic, part three of our series on mercury will only look at mercury’s most well known forms.

The following is Part I of a multi-part series of posts about Mercury

Overview

A recent series of articles in the The Tribune, a newspaper covering San Luis Obispo, Calif. and surrounding communities, highlighted the legacy of California’s mountain of gold and the environmental hazard leftover from the intense mining of the era. The articles reminded me of a 2013 report¹ in USA Today about the findings of high levels of mercury in sites along the California’s Yuba River. While mercury emissions and environmental contamination is not a new topic, I was surprised to learn that the origins of the mercury were traced to the immense piles of Gold Rush-era mining debris in the river valley.  As one subject is often interwoven with another, I eventually found myself digging up mining practices of 1848, sifting through fact sheets explaining mercury’s various forms and health effects, and finally examining statistics and perspectives on how researchers are addressing mercury contamination today.

Part III – Gold Rush: Mercury and its Various Forms

In part two of our Mercury blog post, we described Mercury and provided some initial details on the various forms of the element. In this post, we will go into more detail elemental, inorganic and organic forms of mercury.

Elemental Mercury

Mercury in elemental form is a silver-colored liquid that remains liquid at room temperature. Inorganic mercury is mined and processed to generate elemental mercury[i]. It is poorly absorbed by ingestion and contact with skin, and ingested elemental mercury is not absorbed in significant quantities[ii]. Because elemental mercury is absorbed slowly, a majority of it passes the digestive system without doing significant harm.

Less than 40 years ago in 1978, the Communist dictator of Romania ordered the 400 families living in the small village of Geamana to leave their homes so that the country could build a copper mine. Unfortunately, the people did not have much choice as the village was to become an artificial lake for the toxic waste from the Rosia Poieni, one of Europe’s largest copper mines. The water that covers Geamana is laced with cyanide and other chemicals, making the area uninhabitable. Recently, the website Roadtrippers published several pictures from the abandoned village.

Unfortunately, the fate of Geamana is not uncommon. In the United States, the area around Treece, Kansas and Picher, Oklahoma was ranked in 1981 by the Environmental Protection Agency as the most contaminated in the country. The contamination was the result of extensive lead and zinc mining. In the 1920s, the area was the number one producer of the elements in the United States, supplying the metals for ammunition during the World Wars. While the metals were extracted, the waste was piled up around the town into mounds of contaminated gravel that still litter the landscape. A New York Times article from May 2012, describe the conditions:

More than 144 homes in a two-square mile southeast of Los Angeles County are the focus of lead contamination test after the California Department of Toxic Substances Control detected high levels of lead in soil near a temporarily closed battery recycling plant. In the fall of 2013, elevated levels of lead at 39 homes and a preschool near the plant were blamed on air pollution from the plant and prompted local officials to issue health warnings and push for additional testing. State regulators expanded the lead soil testing to include more than 144 homes in Vernon, California.

Recently more 750 scientists from around the world gathered at the Animal Behavior Society meeting at Princeton University. They gathered to discuss… you guessed it… animals; all kinds of animals, from fish to birds. Among the topics of discussions was the impact of liquid metal mercury, even small doses, on the animal kingdom, particularly in birds. In humans, large doses of mercury can cause lethargy and depression, while smaller amounts can lead to dementia. In animals that are much smaller, the impact can be even more significant.

Researchers at the College of William and Mary conducted an experiment where they exposed zebra finches to mercury levels consistent with a contaminated environment. Rather than lethargy or depression, the finches exhibited symptoms more on the side of dementia. The birds were “bolder and hyperactive,” and “spent less time feeding” compared with birds that had not been exposed to the metal. Because of this behavior, the finches could be at risk of increased predation. Unfortunately, they discovered some other disturbing trends.

Where does roughly half of all mercury that enters public water treatment systems come from?

If you answered dental offices, you would be correct.

According the U.S. Environment Protection Agency 120,000 dental offices use or dispose of amalgam fillings, which contain a mixture of mercury and other metals used in dental fillings.  Most of these offices are attached to public sewer systems. The amalgam waste is flushed at the point-of-care down chair-side drains. When the amalgam is discharged into the sewer systems, it can be transformed into methylmercury, which is a highly toxic neurotoxin that impairs brain and nervous system development and function. Methylmercury can build up in fish, shellfish and fish-eating animals, which can be harmful to humans who consume the fish.

We thought it might be helpful for those of you with questions regarding EPA Method 245.7 to create a blog post addressing some of these questions.  If you have any questions regarding EPA 245.7 that we haven't addressed here, please let us know and we will do our best to provide you with the answer.