ON THE WACCAMAW RIVER - After more than a decade of measuring mercury in fish, water and air, Carolinas officials will seek grants this week to test a final frontier: people.

Thousands of people on the coastal plain, where mercury most commonly takes a toxic form, would be tested if the Centers for Disease Control and Prevention approves the grants. Many in Piedmont counties east of Charlotte would be tested, too.

Even without a CDC grant, South Carolina hopes to forge ahead with plans to test 12,000 toddlers, who are at special risk.

In North Carolina, a state toxicologist estimates 7,400 children born each year are already at risk from mercury. In its most toxic form, it can cause neurological damage to developing fetuses and harm the way children think, learn and problem-solve.

A naturally occurring metal, mercury also blows out of industrial smokestacks, mostly coal-fired power plants and incinerators. Released into the air, mercury falls back to earth in rain. A national study released last month indicated average concentrations of mercury in rainfall in the Carolinas were at least twice as high as the Environmental Protection Agency says is safe in surface waters.

The chemistry of the Carolinas' blackwater rivers on the coastal plain transforms mercury into a highly toxic form. Called methylmercury, it works its way up the food chain from tiny organisms to the largest fish. People are most often exposed to it by eating contaminated fish.

Most previous estimates of mercury's health impact in the Carolinas have been projected from concentrations measured in fish and water. Testing people is a direct approach.

"Blood doesn't lie," said Karen Brazzell of the S.C. Department of Health and Environmental Control's biomonitoring unit.

Each year the Carolinas update advisories on what fish species and waterways to avoid. The growing list now covers the half of North Carolina south and east of Interstate 85, and 53 rivers and lakes in South Carolina.

Because of the potential damage to developing babies, pregnant women are especially cautioned not to eat fish known to be high in mercury.

But some officials worry the warning isn't reaching the people who most need it.

Many of the coastal plain's poor rely on fish for a substantial part of their diet. They may also be less likely to read newspapers, brochures or Web sites where mercury information is posted.

Neither state budgets money for public outreach. North Carolina sends fact sheets to doctors, clinics and health departments, but hasn't spent the $42,000 it would cost to print and mail posters and brochures -- information women could take home and post on the refrigerator.

South Carolina mails 30,000 to 40,000 information booklets a year. "We do the best we can within the scope of no resources," said Tracy Shelley, a state environmental toxicologist.

Mercury news misses many

The Waccamaw River flows between the two states, a tea-brown syrup oozing downstream from Lake Waccamaw in southeastern North Carolina to Winyah Bay at Georgetown, S.C.Tests of people who live along the N.C. portion of the river, in 1993, found 10 times more mercury in frequent fish eaters. Some concentrations were among the highest in the nation.

Despite fish-consumption advisories out for several years, mercury is still news to some local people.

"I haven't heard anything about that, and I've been here nearly two years," said Myra Ward, who owns a bait-and-tackle store near the Waccamaw. "I see a truck come here and test the water ever so often, but they haven't said anything to me about it."

North Carolina advises limiting consumption of three freshwater predators -- largemouth bass, blackfish and chain pickerel. State advisories also include the saltwater species shark, swordfish, tilefish and king mackerel.

Michael Best, 40, who regularly fishes the Waccamaw, knows about mercury -- he believes he has seen it in largemouth bass and bream. It looks like pockets of the silvery liquid in oral thermometers, Best said.

Biologists say mercury isn't visible in fish. Best said he cleans out the mystery substance and eats the fish. "It ain't never bothered me yet," he said.

Regulatory questions

Interest in mercury is growing in Washington, Raleigh and Columbia.

North Carolina's Clean Smokestacks Act, enacted last summer, is expected to reduce mercury emissions by 55 percent by 2013 as power plants install pollution controls for ozone and haze-forming chemicals.

The Bush administration says its Clear Skies Initiative would, by 2010, reduce mercury in Carolinas rainfall by up to 25 percent. N.C. power plant emissions would drop 56 percent and S.C. emissions 64 percent by 2020.

The Natural Resources Defense Council -- an advocacy group critical of Bush's proposal -- estimates the Bush proposal would let power plants release five times as much mercury for a decade longer than the Clean Air Act now does.

Scientists, meanwhile, aren't able to say how much of the contamination in water and fish comes from industry.

"The big question is what concentration coming out of a smokestack is going to equal what concentration in a bass that you're going to pull out of a lake and eat?" said Todd Crawford of the N.C. Division of Air Quality. "There's so much that happens between that smokestack and that fish that it's a daunting question."

The state has measured mercury in rain at two spots in Eastern North Carolina, Lake Waccamaw and Pettigrew state parks, since 1996 without drawing a clear picture of whether more or less mercury is falling.

S.C. fish consumption advisories rose rapidly in the early l990s as state officials expanded their tests of fish and waterways, said Butch Younginer, aquatic biology manager for the S.C. Bureau of Water.

"In the last three years the numbers and intensity of mercury in fish have pretty well leveled off," he said.

The N.C. air-quality division is also studying the amount of mercury in Charlotte's air.

An Environmental Protection Agency study, based on computer modeling, predicted in 1996 that Mecklenburg County would be in the top 5 percent of counties nationally. Air samples, to be collected through fall, will tell whether the EPA estimate was accurate.

Even at high levels, Crawford said, it's doubtful airborne mercury -- in a different form than methylmercury -- would be harmful.

An ongoing study of fish, water and sediment in 13 sites across Eastern North Carolina has found levels of methylmercury similar to those in other parts of the Southeast, said Michelle Woolfolk of the N.C. Division of Water Quality. Southeastern levels tend to be higher than in the rest of the nation.

Using analytical equipment that can detect mercury at levels 1/400th that of previous methods, the study will let researchers use water samples to estimate more accurately the levels of methylmercury in fish.

Human testing

In September, the CDC plans to award $5 million in grants to states that want to begin testing humans for environmental contaminants. Future funding will allow some of the projects to last nearly five years.North Carolina would use its grant to test for mercury in blood, urine, hair and toenails in fish-eaters from 14 counties, ranging from Union, Cabarrus, Stanly and Anson eastward to Brunswick and Columbus in the state's southeastern corner. One hundred people from each county would initially be tested, but state officials say the number could eventually expand to as many as 18,000 over 20 years.

Starting in March, South Carolina would test blood samples for methylmercury from 1-year-olds in 23 counties. Children of that age are already tested for lead.

The state has partnered with the Medical University of South Carolina, which is studying the prevalence of autism and developmental disabilities in coastal and Pee Dee counties. Researchers want to learn whether there is a link to the prevalence of mercury, and whether developmental problems crop up at certain doses.

Scientists are increasingly concerned about environmental contaminants, said Dr. Jane Charles, a developmental pediatrician at MUSC who studies autism and mental retardation.

"If you have a whole county full of children whose IQs are a few points lower than you would normally expect, what kind of effect does that have on the state?" she said.

Mercury on the Web

For fish-consumption advisories, visit the N.C. Department of Health and Human Services: www.schs.state.nc.us/epi/fish/

index.html or the S.C. Department of Health and Environmental Control: www.scdhec.net/eqc/ admin/html/fishadv.html

For more on mercury, see the EPA's site: www.epa.gov/ mercury/index.html