When he was in college, David Caldwell knew he wanted to find a job where he could do something good for the environment.

At Charlotte-Mecklenburg Storm Water Services - County Water Quality, he's been doing exactly that now for nearly 20 years.

This summer, Caldwell's job took him to the area's lakes to do some high-tech fishing, literally.

"Last Summer, there were some articles in the paper about fish consumption," Caldwell recalls. "Actually, the state did some testing. I guess the Catawba Riverkeeper did some testing on Mountain Island Lake. They found PCBs in channel catfish at levels that were high enough that the state issued fish consumption advisories."

PCBs, or Polychlorinated biphenyls, are a class of organic compounds that were widely used as dielectric and coolant fluids, for example in transformers, capacitors, and electric motors, according to Wikipedia. Due to PCBs' toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001.

Caldwell said even though they were banned in 1979, "They don't go away - once they are in the environment they are there forever."

"We contacted the state because we were getting a lot of questions from citizens about other species like crappie. They were wanting to know if these fish were safe," said Caldwell, a Mooresville resident. "We really hadn't tested those fish enough to draw any conclusions so we sent a proposal to the state division of water quality."

Mecklenburg County agreed to pay $27,000 for lab analysis and provided labor; the State provided the expertise and equipment, such as an electro shocking boat, which is used to bring fish to the surface.

In addition to PCBs, they would test for mercury, arsenic, and selenium.  

So Caldwell and his colleagues in Water Quality started a fishing expedition, of sorts, with staff at the North Carolina Division of Water Quality.

They began fishing for four samples each of crappie, channel catfish, blue catfish, and white perch from Lake Norman, then moved to Lake Wylie and Mountain Island Lake. On Lake Wylie, they also sought samples of largemouth bass, but not blue catfish; on Mountain Island Lake, they did not look for samples of channel catfish.

"For each species you have to have four fish of the same species of the same size class to make up one sample," Caldwell said. "You don't want to sample one fish. If I'm looking for blue catfish, I want to catch at least four of the size that people might want to eat. It's a lot harder than you just go out and catch fish and you are done."

They haven't yet collected all the fish samples they need; some of the fish that they need are difficult to collect in the summer due to the hot water temperatures, which push the fish into deeper water. They will continue sampling in the fall when the water temperatures come down.

But they've collected what they could so far and worked with Jeff Deberardinis of the NC Division of Water Quality who took the fish collected so far back to his lab in Raleigh and prepared them into samples.
 
The samples were then shipped to a laboratory in Wilmington for testing; the results of the initial tests should be known sometime this fall.

Caldwell loves the fact that his job is helping keep people safe.

"I've always been interested in the environment and I wanted to be in a field where I felt like I was doing something to help the environment," he said.
 
For more information about how pollutants end up in fish, click here: http://portal.ncdenr.org/c/document_library/get_file?uuid=5ad6b4dd-1780-4051-ab53-9aabfa5d202b&groupId=38364.

For more information about the tests, click here: http://portal.ncdenr.org/web/wq