The fate of Bruno Soffientino’s summerlong experiment sits in a row of tightly sealed jars stuffed with contaminated marine sediment samples in a chemistry lab at the University of Rhode Island’s Bay Campus.
Soffientino, of Wakefield, an associate professor in biology at the Community College of Rhode Island, hopes to better understand how certain pollutants can be broken down by naturally occurring bacteria.
With funding from the Rhode Island IDeA Network for Excellence in Biomedical Research, Soffientino carried out a laboratory experiment to study the breakdown of dangerous substances known as medium-chain chlorinated paraffins.
Simon Vojta, a postdoctoral researcher in the lab of Rainer Lohmann at the Bay Campus, measured the paraffins in the bottled sediments, while Soffientino monitored the numbers of bacteria potentially capable of breaking them down.
The sediments come from areas of New Jersey and Staten Island, some within earshot of the Newark International Airport and Passaic River. The samples are divided into jars, each containing different levels of MCCPs, and Soffientino introduces substances, such as cellulose and chitin, that fuel the growth of microbes, including some that are used in the breakdown of plastics or to clean up oil spills.
“Over time, we’ll take some jars and open them, measure MCCP concentration, and extract the DNA so we can analyze the abundance of microbes and come up with an understanding of the process,” Soffientino said. “Are some treatments breaking down MCCPs faster than others? If so, are there more microbes? And do cellulose or chitin make a difference? There is a lot of waiting involved, but while you’re waiting, you’re processing previous samples.”
Soffientino’s study will take at least a year as he checks in every three months to see just how quickly – if at all – the chemicals are breaking down with the help of microorganisms found naturally in the sediment, a process known as bioremediation. He plans to use details of the research in his teaching this fall, specifically to students interested in studying DNA sequencing. Some students will get the opportunity to work with him in the lab.
The ultimate goal is to find an organic solution to breaking down dangerous chemicals that is both cost-effective and safe for the environment. If successful, Soffientino’s research could help in the development of a bioremediation technique to decontaminate toxic sites.
“I’m looking specifically at the MCCPs because they are poorly studied,” Soffientino said. “Hardly anything is known about whether or not — and which — microbes might be breaking them down.”
The MCCPs are unreactive, nonflammable, stain and chemical resistant, and flexible at low temperatures — qualities that have made them useful in the manufacture of everyday products. They are used as plasticizers in garden hoses, and in paints, sealants and coatings. They are also used as coolants or lubricants in metal cutting and other high-temperature applications, or as flame-retardant plasticizers in rubbers and fabrics.
Those same qualities make them difficult to decompose. Soffientino said that MCCPs were popularized more than 30 years ago as replacements for polychlorinated biphenyls, or PCBs, which were banned in the United States in 1979 after studies found they caused cancer and other health problems.
When discharged into bodies of water, the MCCPs seep into soil and aquatic sediments, and are known to have toxic effects on animals, plants and humans. There are other ways to decontaminate polluted sediment, such as dredging, but that can actually be counterproductive, Soffientino said, because the sediment can spread and end up contaminating larger areas.
The perfect solution would be a natural one that does not harm the environment and helps reverse decades of damage. So Soffientino’s research could prove groundbreaking. The answer could be in the jars.