Reposted from Coastal Review Online

By Andy Wood

Last of two parts

Just when you thought it was safe to play in the swamp, along comes news about the state’s new mercury study that reminds you that something’s happening out there that we need to think about and work to correct.

I’ve spent much of my life exploring swamps and other aquatic realms and in that time I have come to know a great many interesting plants and animals. While alligators, eagles and other so-called “glamorous megafauna” grab headlines and dominate conservation efforts, I have long been attracted to the smaller beings in the world we share. Tiny crustaceans including dot-sized copepods, daphnia and even mosquito larvae are the things I seek, before I start looking for fishes, frogs, turtles or birds.

I could be equally charmed by protozoans and bacteria, since they inhabit every sample of pond water I examine, but the hand lens I carry can’t discern these tiniest of beings. Bacteria inhabit every ecosystem we have examined, and even though daily life functions require a diverse collection of bacteria inhabiting our body, these “animalcules” as they were first called, are rarely celebrated.

Bacterial activity drives entire ecosystems. Some kinds break down carbon compounds – the remains of once-living organisms– while others are chemical converters, nitrogen cycling for example. Some bacteria cycle chemicals as a metabolic activity required to expel wastes from their cell structure. As an example of this is found in coastal areas, where hydrogen sulfide, a waste product of sulfate-reducing bacteria, can be smelled when carbon-based organic sediments are exposed during low tide. The rotten egg smell is essentially the exhalations of marsh bacteria reducing carbon compounds.

While sulfate bacteria are processing organic compounds in sediments they may also bind up various chemicals, including mercury deposited from the atmosphere. The bacteria don’t necessarily seek out mercury, they simply encounter it. To rid themselves of this unneeded material, bacteria employ metabolic processing to convert the mercury to methylmercury, a chemical compound that bacteria can expel.

Mercury is a naturally-occurring element in the environment, though rarely in high concentrations. The mercury in thermometers and electronic switches is a highly refined product extracted from mercury-containing ores. While elemental mercury is a hazardous material, a more nuanced form, known as methylmercury (CH₃Hg), is far more insidious, hazardous, and unfortunately, inside each member of every community across the globe.

Mercury can be found wafting through the atmosphere attached to a water droplet, or adhered to a dust particle. Atmospheric mercury can originate from a volcano, but since we can’t do much about volcanoes, we focus on the mercury pollution generated by burning coal, manufacturing cement from limestone, incinerating medical and other wastes and processing various metals. Atmospheric mercury released from industrial smokestacks may stay aloft for thousands of miles before falling to earth, most likely landing in water.

In its elemental state mercury is unhealthy to higher forms of life, but methylmercury is even more insidious and harmful. Animals exposed to methylmercury, especially during early development stages, may suffer severe neurological damage and other health problems that inhibit full function and vigor. Adult animals are also at risk from methylmercury and none more than aquatic predators high up the food chain.

In the 1980s largemouth bass in North Carolina were included in a mercury advisory that warned people to limit consumption of this fish. The reason for the warning, still in place today, has everything to do with a process called biomagnification. Biomagnification refers to a natural concentration of compounds especially in the tissues of animals that are part of a complex food pyramid.

Picture a pyramid divided by horizontal layers, with each layer representing a step in a food chain. At the bottom of the pyramid we find primary producers known as plants. In the layer above plants are plant eaters. The next layers up are eaters of plant eaters and above them are eaters of eaters of plant eaters, and so-on to the top of the food pyramid; represented in this example by largemouth bass.

Mercury originating from coal combustion is deposited in sediments supporting the base of the food pyramid. Sulfate-reducing bacteria exposed to mercury convert it to methylmercury in order to rid themselves of the metal. Because it accumulates in muscle tissue in the “eat and be eaten” food pyramid, methylmercury is transferred from one organism to the next, magnifying with each level climbed. In this way methylmercury adhered to tiny copepods, daphnia and even mosquito larvae is passed to small fishes including mosquitofish and young sunfish. These in turn are eaten by slightly larger fishes that in their turn are eaten by still bigger fishes including bass, catfish, bowfin and others. This chain of events involving other players is also happening in the world’s ocean; hence the mercury advisories for tuna, swordfish and other so-called apex predators.

The study of methylmercury and its “lifecycle” is interesting and fraught with alarming revelations too important to ignore. So too is the study of the politics involved in regulating the discharge of mercury, the precursor to methylmercury.

When I hear complaints from industry members about the harm regulations put on their business, I am reminded of something a chemical plant manager shared with me many years ago. He said the chemical industry thrives best when it sees pollution as wasted product, and missed profit. In short, environmental protections are conservative measures that support best business practices. And when businesses behave well, communities thrive. It does not work the other way around.

Conservation educators often position a glamorous wild predator to illustrate the apex animal in a food pyramid, be it a shark, lion or bear. In truth, the top of the pyramid is reserved for but one species, and it is us. For this reason, it is in the interest of everyone that we put aside distracting arguments about economic well being and focus instead on the health of the ecosystems that support our economy.

This story is provided courtesy of Coastal Review Online, the daily news and feature service of the N.C. Coastal Federation.  http://www.nccoast.org/Article.aspx?k=e10f40af-81e1-430d-919c-e41339936c9a#.T7ux3Hvyc-g.facebook

Reposted from Coastal Review Online

By Wade Rawlins

First of two parts

State environmental officials say the state needs to reduce mercury levels by 67 percent by 2016 to protect North Carolina’s waters from mercury contamination, make fish safe to eat and ultimately lift the fish consumption advisories.

Mercury is a potent neurotoxin and reduction efforts are already underway. Unfortunately much of the mercury that contaminates the state’s rivers, lakes and coastal waters comes from power plants and sources in other states and even other countries, state officials say.

“It’s an issue that needs to be addressed,” said Kathy Stecker of the N.C. Division of Water Quality. “It’s a global problem. It’s not just a North Carolina problem. But that doesn’t mean we can’t start to work on it.”

The state currently lists all water bodies in the state as contaminated by mercury. The N.C. Department of Environment and Natural Resources is drafting a plan to quantify sources of mercury such as power plants and sewage treatment plants and propose steps to reduce mercury in North Carolina waterways. Having such a plan will make it easier to press other states that contribute to North Carolina’s pollution problem to cut mercury pollution, officials say.

As part of the process, state officials are developing an estimate of the maximum daily amount of mercury that waters may absorb without contaminating fish and posing a threat to humans. It’s known as a total maximum daily load, or TMDL, and it sets a target for reducing mercury. A public meeting is scheduled Wednesday in New Bern on the plan.

Coast Most Affected

“We see in Eastern North Carolina some of the highest mercury levels in the nation,” said Derek Aday, an ecologist at N.C State University who has done research on mercury deposition and affected fish. “It’s really variable from water system to system.”

Aday said the eastern portion of the state tends to have swamps and peaty, acidic soils that promote the formation of methylmercury, the toxic form that can build up in the tissue of fish and wildlife.

People in coastal North Carolina are exposed to mercury primarily by eating fish that contain methylmercury, a neurotoxin and can damage developing fetuses. Statewide health advisories warn about limiting consumption or avoiding certain species of freshwater and ocean fish that commonly have high levels of mercury.

The advisories warn that women of childbearing age, pregnant women and nursing mothers should avoid eating certain types of fish known to be high in mercury. Other people should limit consumption of these types of fish to no more than one meal a week.

Fish species vary greatly in the amounts of mercury they contain. The amount of mercury in fish depends on what the fish eat and how long they live. As a rule of thumb, longer-lived and larger predator fish, which devour smaller fish, typically accumulate higher levels of mercury in their tissues. Among saltwater fish listed as high in mercury are cobia, grouper, gag, king mackerel, greater amberjack, orange roughy, Spanish mackerel, shark, swordfish and albacore tuna.

Fish With High Levels

In recently published research, Aday and colleagues tested mercury levels in six commonly consumed fish caught by commercial and recreational fishermen in North Carolina. They found that king mackerel had the highest mercury concentrations. Grouper and wahoo also had high levels, while mahi mahi and triggerfish had the lowest levels.

Tests also have revealed high levels of mercury in freshwater fish such as black crappie caught east of Interstate 95 and in blackfish, catfish, chain pickerel and yellow fish caught east of Interstate 85, according to N.C. Department of Health and Human Services.

While largemouth bass caught throughout North Carolina have shown high levels of mercury, most of the high mercury concentrations occur in the eastern part of the state in the Cape Fear, Pasquotank, Lumber and Tar-Pamlico river basins. The highest mercury concentrations have been found in largemouth bass in the Lumber River basin.

If the U.S. Environmental Protection Agency approves the state’s mercury reduction plan, it could affect private industries that operate their own wastewater treatment plants —some of which have high levels of mercury in treated wastewater. They would be required to develop plans to minimize the discharge of mercury. But wastewater plants represent only about 2 percent of the overall mercury released in the state.

“There seems to be some kind of misunderstanding that we are only targeting wastewater plants,” Stecker said. “The reduction we are looking for is the same reduction as from the other source we identify. We are not asking them to get any more of a reduction than their fair share. “

Coal Burning and Mercury

Most of the mercury getting into the water and fish comes from airborne emissions. When power plants burn coal to generate electricity, the combustion releases mercury into the air. Coal-burning power plants are the largest source of mercury in the United States, according to the EPA. They account for more than half of mercury emissions.

Mercury in the air eventually settles into bodies of water or on land, where rain can wash it into the water. Microorganisms in the soil convert the mercury into methylmercury, a toxic form that builds up in fish and shellfish.

According to the state, power plants, steel mills and incinerators spewed approximately 5,300 pounds of mercury into the air in North Carolina in 2002, a year used as a baseline for measuring mercury. Two-thirds of the mercury came from coal-burning power plants operated by Duke Energy and Progress Energy.

Tom Mather, a spokesman for the N.C. Division of Air Quality, said the state anticipates additional reductions in mercury from the closure of some smaller coal burning plants and tighter federal regulations on industrial boilers. Mather said state computer estimates that only 16 percent of the mercury in the state comes from power plants and factories within the state. Most of the airborne mercury wafts into the state on wind currents blown from other states and even other countries.

“We’ve done a lot to reduce mercury emissions in North Carolina, and we expect further reductions,” Mather said. “But there is only so much we can do here if only 16 percent of our mercury is coming from sources within North Carolina.”

The Division of Air Quality has drawn up a list of options for achieving additional cuts in mercury air emissions. They include:

• Filing a legal petition to seek reductions in mercury emission from utilities outside North Carolina
• Setting a cap on statewide mercury emissions
• Reviewing industrial facilities’ pollution control technologies that would increase mercury emissions on a case-by-case basis

This story is provided courtesy of Coastal Review Online, the daily news and feature service of the N.C. Coastal Federation.  http://www.nccoast.org/Article.aspx?k=43c83f96-0a62-4388-97e3-b6677333f371