Got PCDDs?

Chemistry Professor Investigates Carcinogen Found in Car Exhaust, Smoke and, Eventually, Coastal Waters

January 20, 2009

By Russ L. Hudson

Chemicals known as polychlorinated dibenzo-p-dioxins, or PCDDs, are just about all around us.

Found in car exhaust, smoke, pesticides, solvents, food preservatives and in every phase of electronics manufacture, the carcinogen eventually makes its way into waters off the California coast and into the tissue of marine life that humans eat. Long lasting in the body, PCDDs can affect fertility, the nervous system and cause acne, yet the toxicity level for humans is still an unknown.

Although scientific literature abounds on sources of PCDDs and where they concentrate in the body, facts on harmful thresholds is difficult to find, according to Fu-Ming Tao, professor of chemistry and biochemistry at Cal State Fullerton.

Scientists won’t know the carcinogen's toxicity until they understand its chemical properties, said Tao, who is now focusing his research on finding the highest concentrations of PCDDs off the Southern California coast. Once determined, marine life can be studied to determine the harm done at different concentrations and how quickly PCDDs break down in the ocean. That can go a long way toward unlocking the chemical properties, the researcher noted.

Not surprisingly, the heaviest concentrations are near ports.

Tao and Keith Maruya of the Southern California Coastal Water District Project are working with a two-year, $34,962 grant from the district project. Results from the study could help Tao discover how to break down the PCDDs before the chemical enters the ocean.

“After they’re in the water, they’re almost impossible to treat,” he said. “The most likely approach is to oxidize it first. Oxidizing destabilizes most chemical compounds. Once destabilized, they’re easier to break down. But that means addressing the issue before the PCDDs get into the water.”

Tao anticipates it will take a series of research projects by several scientists to address the PCDD problem.

“First we need to determine the chemical properties, and studying how bad it is is part of that. By that, I mean, how much is already out there off the coast and where it is worst and how it behaves. Next is how to break it down chemically to something harmless, so it doesn’t pollute. Following that is how to break it down once it’s in the body.

“This is a worldwide problem,” Tao said. “PCDDS are everywhere. What we learn here can be applied globally.”

The Fullerton resident received his doctorate in chemistry from Boston College, his master’s in chemistry from Suzhou University in China, and his bachelor’s in chemistry from the University of Science and Technology of China. He has won a dozen major awards internationally for his research and teaching and has authored 108 peer-refereed publications.