Mercury contamination is so widespread that people are regularly exposed to or consume levels that exceed U.S. Environmental Protection Agency health advisory levels, according to a new study co-authored by the Biodiversity Research Institute in Gorham.
The report, “Global Mercury Hotspots,” includes data relevant to the Gulf of Maine but also documents the need to reduce mercury contaminants internationally. It emphasizes that humans and marine ecosystems around the world are contaminated with mercury, and that toxins in humans and fish are at levels that pose health risks for humans.
“The thing that surprised me was, wherever we looked around the world, the (human) hair samples exceeded the EPA reference dose,” demonstrating that “most people have more mercury in their bodies than they should,” said David Evers, the Gorham institute’s executive director and chief scientist.
The institute produced the report in collaboration with the International POPs Elimination Network, an organization focused on reducing toxins in the environment. “POP” stands for “persistent organic pollutants.”
The two groups released the findings in advance of the United Nations Environment Programme’s first international treaty conference on the environment in more than a decade. The meeting will convene next week in Geneva, Switzerland, and delegates will have a chance to review the report. The meeting is the final negotiating session leading to a mercury treaty.
“There’s a lot at stake,” Evers said. “The big question (is) how strong a treaty, how strong the language” can be forged.
The report “brings together new data on mercury concentrations in fish and human hair samples and identifies, for the first time, a set of global biological hotspots where elevated levels of mercury are sufficient to pose serious threats to both ecosystems and human health,” he said.
Advocacy groups, including the International POPs Elimination Network, a European-based global network of more than 700 public interest organizations worldwide, are concerned that the current proposed treaty is not sufficient to prevent continued health damage from mercury or to reduce global levels of mercury in fish.
Scientists have identified Indonesia, Thailand and Japan as “hot spots” of mercury contamination, according to the report.
While mercury levels in the Gulf of Maine are lower than in some parts of the world, the report strikes a cautionary note that echoes earlier studies that indicate mercury levels in fish from the Gulf of Maine are “about average,” compared to other marine ecosystems. One recent Biodiversity Research Institute study indicated the harm to humans from methylmercury – an especially toxic form of the substance that is readily absorbed into the body when consumed in fish – is occurring at lower levels than those considered safe just a few years ago.
Much of the fish in the Gulf of Maine have concentrations of mercury that “are right in the middle” of the highs and lows documented by the new data that comprise the report, Evers said. Species with lower concentrations of mercury here include haddock, cod and salmon, while Pacific bluefin tuna and swordfish, available in grocery stores nationwide, tend to show higher concentrations.
Within hours of the release of the report, the Natural Resources Council of Maine in Augusta joined the call for further reductions in mercury and greater efforts to correct problems that the toxin’s contamination still poses in the state.
“The evidence just keeps piling up,” said NRCM’s Toxics Project advocate Abby King. “We need to take action at every level – state, federal, and international – to eliminate sources of mercury exposure.”
King said Maine “has made good progress in eliminating root sources of mercury in products sold in the state, as well as handling them safely when they are thrown away.”
Among the highlights of the report:
- Mercury contamination exists virtually everywhere in marine and freshwater systems around the world.
- Biological mercury “hot spots” are common globally and are related to a variety of human activities, including chlorine production, contaminated sites, coal-fired power plants, small-scale gold mining and mixed-used chemical industry sites.
- Fish samples from around the world regularly demonstrate mercury concentrations exceeding EPA human health advisory guidelines.
In the study, 40 to 100 percent of fish samples from nine countries revealed mercury contamination severe enough to warn consumers to limit consumption to one fish meal of six ounces per month. Mercury concentrations in fish from sites in Japan and Uruguay were so high that people are advised to eat no fish from the tested waters.
More than 82 percent of human hair samples from eight countries exceeded EPA reference dose levels of 1.0 parts per million. In Thailand, 20 out of 20 individuals living near an industrial site had unsafe levels; 19 out of 20 Indonesians at a gold mining site exceeded EPA recommended levels; and 18 out of 20 individuals in Tokyo had similarly high levels.
Studies have shown exposure to high levels of mercury can permanently damage the brain and kidneys. Harmful effects also can be passed from a pregnant woman to her developing fetus and can result in brain damage, mental retardation, blindness, seizures and an inability to speak.
Staff Writer North Cairn can be reached at 791-6325 or at: