URI researcher uses new study to monitor health of Narragansett Bay

10/02/08 - Many waterfront urban areas contain potentially harmful chemicals left over from years of industrial dumping, and now there might be a way to find out where they come from and in what concentrations they appear.Rainer Lohmann, a University of Rhode Island chemical oceanographer and researcher, is studying the effectiveness of sheets of light density polyethylene at detecting environmentally unsound compounds.

For his award-winning paper published last year in the Journal of Environmental Science and Technology, Lohmann was given a $300,000 grant from the National Oceanic and Atmospheric Administration through the Cooperative Institute for Coastal and Estuarine Environmental Technology at the University of New Hampshire.

In his paper, he showed how sheets of this common and cheap material could be used to find virtually any compound that dissolves in water. Polyethylene is the same material some plastic trash bags and painters' drop sheets are made of, and any substance that dissolves in water is absorbed into the material.

By pre-treating the sheets with certain chemicals, depending on the contaminant being searched for, density levels and patterns of contamination can then be extrapolated from the sheets relatively quickly.

This is not a new concept; the method has been used before in detecting other industrial chemicals, such as PCBs, dioxins and oil components in water. But the difference Lohmann demonstrated in his paper was that they are also useful in finding other relatively overlooked chemicals.

The main chemicals he mentioned were alkylphenols in certain cleaning products that can cause reproductive impairments to marine life, a disinfectant called triclosan found in many surface cleaners that when exposed to sunlight can form a toxic dioxin and flame-retardant chemicals.

The flame-retardant chemicals are especially dangerous, because like PCBs and certain dioxins, bioaccumulation occurs, during which the chemicals permanently accumulate in the fat cells of whatever organism they enter and are absorbed all the way up the food chain, possibly to humans. A fully formed dioxin is believed to work in the same way, according to the Environmental Protection Agency Web site.

This is why detecting, quantifying and finding the source of these chemicals as quickly as possible is imperative both to Lohmann and his research into the health of Narragansett Bay.

As opposed to the former method of detecting these compounds, Lohmann said this method allows more samples to be tested in less time.

"Let's say one student analyzed 50 samples within a year, in classical sample [gathering methods] it would have taken probably twice as long," Lohmann said.

He said more data means better and more accurate conclusions, leading to more informed responses to potential problems. The traditional sampling method, he said, involves taking a boat out, dropping a collector into the water, waiting for adequate depth and bringing the sample back to the lab.

Lohmann's preferred method takes fewer man-hours and less money because, instead of staying with the sampling device as it works, one can tie it to a buoy and leave it for however long is required, which varies from site to site.

"It depends on the contamination of the site," said Carey Lee Friedman, a graduate student working for her doctorate degree under Lohmann. "For more contaminated sites, they would need short periods of maybe a few weeks; less contaminated sites probably about several months."

This is important to the team because the chemicals they are looking for are endocrine disrupting chemicals (EDCs) that have been known to wreak havoc on the hormones of animals. Because hormones are so sensitive, there does not necessarily have to be a large amount of the chemicals in the water system to significantly affect the animals living there, so the added accuracy of the method helps a great deal.

Lohmann said that while this method is much more efficient, it takes more knowledge of the specific chemical reactions that occur when the polyethylene comes into contact with certain amounts of a particular compound. That is the only way they can be identified, and he said that a greater understanding of chemical processes is needed than the previous method required.

"On the positive side, we know that anything that goes into a sheet of plastic will also go into a shrimp, a crab or a fish," Lohmann said. "In a way we use it to understand bioaccumulation enrichment in the food chain."

Lohmann said he believes that the Environmental Protection Agency has not been thorough with its investigation into these compounds.

"I think basically it is because the EPA has been forced from the top not to be very active," he said. "And then obviously there's pressure from industry not to look at too many compounds."

Some of these EDCs have similar effects on wildlife as the pesticides discussed in last Friday's Cigar that can cause sexual irregularities in certain animals.

In a nutshell, these animals are very sensitive to certain hormones, so much so that when there are too many of one gender in the habitat, a number of them will switch sexes, much like the basis for dinosaur reproduction among a completely female population in the film, Jurassic Park.

"The EPA has been authorized by Congress to locate endocrine disrupting compounds, the ones we are looking at actually," he said. "And over the last 10 years, they haven't come up with a working way of doing it, for whatever reason. I think the EPA is staffed with many people, and politically they have been turned around into a business protection agency."

Christopher Deacutis, a university affiliate at the URI Coastal Institute, said that while there is not much activity in the EPA concerning these EDCs that does not mean it is intentionally ignoring them. He said that because many of these chemicals are so new, there is little research and information on even identifying them, let alone managing them.