MIBowhunter
06-29-2003, 09:59 AM
Mercury Pollution Poses Public Health Threat
By Laurie Walden, SCWF board of directors member
This article is the second in a series exploring mercury pollution in South Carolina and throughout the nation.
South Carolina Fish Advisories
In South Carolina, most of the attention so far has focused on unsafe levels of methylmercury found in fish throughout South Carolina waters. The state Department of Health and Environmental Control (SCDHEC) has issued warnings to residents to restrict the amount of fish they eat from nearly 2,000 miles of river, about 5 percent of the total, and from nearly 9 percent of all lake acreage, according to preliminary estimates from the South Carolina Wildlife Federation. Advisories also cover the entire coastline. Most of the advisories apply to largemouth bass and bowfin (mudfish) that feed on smaller fish that contain mercury. DHEC also advises residents not to eat any Atlantic King Mackerel over 39 inches in fork length.
DHEC’s mercury advisories cover almost a dozen lakes, including Lake Jocassee, Lake Marion, and Lake Moultrie. While most of the state’s major rivers are affected, they differ in the severity of the restrictions.
Anglers are advised not to eat more than one eight-ounce serving per week of bowfin caught from the Sampit River, yet the restrictions for fish caught in parts of the Great Pee Dee River are more severe: Individuals should not eat more than one eight-ounce meal of largemouth bass or bowfin a month.
Individuals should altogether avoid eating largemouth bass and bowfin caught from the Waccamaw River and restrict their consumption of chain pickerel, redear sunfish, bluegill and warmouth.
In the Santee System, advisories restrict the eating of bowfin and largemouth bass caught in parts of the Congaree, Saluda and Santee Rivers. While DHEC has imposed no restrictions on the consumption of largemouth bass caught in the Wateree and Cooper Rivers, residents are advised to limit the amount of bowfin they eat.
Residents are advised not to eat any bowfin caught from the Edisto River, or from its forks. Those eating fish caught in the Savannah River should restrict their consumption of largemouth bass, mudfish, channel and white catfish, redear and redbreast sunfish, bluegill and black crappie.
If an individual has eaten the maximum weekly amount of fish listed on the advisory, he or she should avoid eating other fish on the advisory.
Methlymercury cannot be removed by cleaning or cooking the fish, as it stays in the meaty portion of the fish.
SCDHEC uses a tiered approach in determining what levels of mercury are considered unsafe. For instance, levels of mercury as high as 1 part per million (ppm) trigger the “do not eat” advisory. Action levels of 0.6 ppm trigger the advisory to not eat more than one meal per month; and levels of mercury at 0.25 ppm trigger the 1 meal per week advisory.
State advisories also include a warning to pregnant women, women planning to become pregnant, infants and children: they should not eat any fish containing mercury. This warning is stronger than the latest advisory issued by EPA. The EPA recommends that these sensitive groups limit consumption of freshwater fish to one meal (an eight- ounce serving) per week. It also has ruled that fish with mercury levels as low as 0.25 ppm may be unsafe for consumption.
While EPA sets the recommendations for unsafe levels of mercury in recreational freshwater fish, the federal Food and Drug Administration (FDA) sets guidelines for saltwater fish and seafood sold across state boundaries. In January, 2001 the federal FDA advised young children, pregnant women and women planning to get pregnant not to eat shark, swordfish, mackerel and tilefish (also called golden or white snapper)
because samples of these fish were found with levels of methylmercury greater than 1 ppm. The agency said these vulnerable populations could safely eat up to 12 ounces a week of other cooked fish, including canned tuna, shellfish and smaller ocean fish.
Tuna Talks
The FDA decision was a controversial one since the agency did not warn the public of the dangers of eating too much canned tuna. Even though tuna fish generally used for canning (albacore and skipjack) typically falls below the 1 pp mercury limit (with levels of mercury averaging about 0.17 ppm), Americans tend to eat more of it.
In response to the controversy, the FDA convened an independent food safety advisory committee to review the agency’s earlier decision. The committee, in July, 2002, advised FDA to tell pregnant women to limit their consumption of canned tuna because of possible harmful mercury levels. The panel also called on the FDA to study more thoroughly how much tuna women can safely eat. While the advisory group did not specifically recommend that level of tuna consumption is safe for women and children, members praised Wisconsin’s advisory. That advisory recommends pregnant women limit their consumption to two six-ounce cans of tuna per week, or one six-ounce can plus six ounces of another fish.
Meanwhile, ten states in the Great Lakes and New England regions, have posted advisories warning pregnant women, and in some cases children, to limit consumption of canned tuna. The states include Maine, Massachusetts, Michigan, Minnesota, New Jersey, Vermont, Connecticut, Washington, New Hampshire and Wisconsin.
Besides tuna, other fish should be added to the FDA’s list of fish that are off limits to pregnant women and other sensitive groups. The Public Interest Research Group and Environmental Working Group have urged FDA to add the following fish, besides tuna, to its list: Gulf Coast and eastern oysters, largemouth bass, sea bass, halibut, marlin, pike and white croaker.
In addition, canned tuna, mahi-mahi , cod and pollack should not be eaten more than once a month, the groups said.
Mercury Background
Mercury has been in use since 1500 B.C., and has even been found in Egyptian tombs. The phrase “ mad as a hatter” came about during the 1800s when hat makers developed mercury poisoning when they rubbed the metal into felt cloth to preserve it.
The public became aware of the dangers of mercury when thousands of Japanese complained of symptoms of mercury poisoning after eating contaminated fish in the late 1950s and later in the mid-1960s. Later, more poisonings occurred in Iran, in 1960 and in Iraq in 1970, after residents there consumed grain that had been treated with a mercury-based fungicide. More than 6,500 people were hospitalized, and 459 people died.
By Laurie Walden, SCWF board of directors member
This article is the second in a series exploring mercury pollution in South Carolina and throughout the nation.
South Carolina Fish Advisories
In South Carolina, most of the attention so far has focused on unsafe levels of methylmercury found in fish throughout South Carolina waters. The state Department of Health and Environmental Control (SCDHEC) has issued warnings to residents to restrict the amount of fish they eat from nearly 2,000 miles of river, about 5 percent of the total, and from nearly 9 percent of all lake acreage, according to preliminary estimates from the South Carolina Wildlife Federation. Advisories also cover the entire coastline. Most of the advisories apply to largemouth bass and bowfin (mudfish) that feed on smaller fish that contain mercury. DHEC also advises residents not to eat any Atlantic King Mackerel over 39 inches in fork length.
DHEC’s mercury advisories cover almost a dozen lakes, including Lake Jocassee, Lake Marion, and Lake Moultrie. While most of the state’s major rivers are affected, they differ in the severity of the restrictions.
Anglers are advised not to eat more than one eight-ounce serving per week of bowfin caught from the Sampit River, yet the restrictions for fish caught in parts of the Great Pee Dee River are more severe: Individuals should not eat more than one eight-ounce meal of largemouth bass or bowfin a month.
Individuals should altogether avoid eating largemouth bass and bowfin caught from the Waccamaw River and restrict their consumption of chain pickerel, redear sunfish, bluegill and warmouth.
In the Santee System, advisories restrict the eating of bowfin and largemouth bass caught in parts of the Congaree, Saluda and Santee Rivers. While DHEC has imposed no restrictions on the consumption of largemouth bass caught in the Wateree and Cooper Rivers, residents are advised to limit the amount of bowfin they eat.
Residents are advised not to eat any bowfin caught from the Edisto River, or from its forks. Those eating fish caught in the Savannah River should restrict their consumption of largemouth bass, mudfish, channel and white catfish, redear and redbreast sunfish, bluegill and black crappie.
If an individual has eaten the maximum weekly amount of fish listed on the advisory, he or she should avoid eating other fish on the advisory.
Methlymercury cannot be removed by cleaning or cooking the fish, as it stays in the meaty portion of the fish.
SCDHEC uses a tiered approach in determining what levels of mercury are considered unsafe. For instance, levels of mercury as high as 1 part per million (ppm) trigger the “do not eat” advisory. Action levels of 0.6 ppm trigger the advisory to not eat more than one meal per month; and levels of mercury at 0.25 ppm trigger the 1 meal per week advisory.
State advisories also include a warning to pregnant women, women planning to become pregnant, infants and children: they should not eat any fish containing mercury. This warning is stronger than the latest advisory issued by EPA. The EPA recommends that these sensitive groups limit consumption of freshwater fish to one meal (an eight- ounce serving) per week. It also has ruled that fish with mercury levels as low as 0.25 ppm may be unsafe for consumption.
While EPA sets the recommendations for unsafe levels of mercury in recreational freshwater fish, the federal Food and Drug Administration (FDA) sets guidelines for saltwater fish and seafood sold across state boundaries. In January, 2001 the federal FDA advised young children, pregnant women and women planning to get pregnant not to eat shark, swordfish, mackerel and tilefish (also called golden or white snapper)
because samples of these fish were found with levels of methylmercury greater than 1 ppm. The agency said these vulnerable populations could safely eat up to 12 ounces a week of other cooked fish, including canned tuna, shellfish and smaller ocean fish.
Tuna Talks
The FDA decision was a controversial one since the agency did not warn the public of the dangers of eating too much canned tuna. Even though tuna fish generally used for canning (albacore and skipjack) typically falls below the 1 pp mercury limit (with levels of mercury averaging about 0.17 ppm), Americans tend to eat more of it.
In response to the controversy, the FDA convened an independent food safety advisory committee to review the agency’s earlier decision. The committee, in July, 2002, advised FDA to tell pregnant women to limit their consumption of canned tuna because of possible harmful mercury levels. The panel also called on the FDA to study more thoroughly how much tuna women can safely eat. While the advisory group did not specifically recommend that level of tuna consumption is safe for women and children, members praised Wisconsin’s advisory. That advisory recommends pregnant women limit their consumption to two six-ounce cans of tuna per week, or one six-ounce can plus six ounces of another fish.
Meanwhile, ten states in the Great Lakes and New England regions, have posted advisories warning pregnant women, and in some cases children, to limit consumption of canned tuna. The states include Maine, Massachusetts, Michigan, Minnesota, New Jersey, Vermont, Connecticut, Washington, New Hampshire and Wisconsin.
Besides tuna, other fish should be added to the FDA’s list of fish that are off limits to pregnant women and other sensitive groups. The Public Interest Research Group and Environmental Working Group have urged FDA to add the following fish, besides tuna, to its list: Gulf Coast and eastern oysters, largemouth bass, sea bass, halibut, marlin, pike and white croaker.
In addition, canned tuna, mahi-mahi , cod and pollack should not be eaten more than once a month, the groups said.
Mercury Background
Mercury has been in use since 1500 B.C., and has even been found in Egyptian tombs. The phrase “ mad as a hatter” came about during the 1800s when hat makers developed mercury poisoning when they rubbed the metal into felt cloth to preserve it.
The public became aware of the dangers of mercury when thousands of Japanese complained of symptoms of mercury poisoning after eating contaminated fish in the late 1950s and later in the mid-1960s. Later, more poisonings occurred in Iran, in 1960 and in Iraq in 1970, after residents there consumed grain that had been treated with a mercury-based fungicide. More than 6,500 people were hospitalized, and 459 people died.