The fate of Dr. Bruno Soffientino’s summer-long experiment sits in a row of tightly-sealed jars stuffed with contaminated marine sediment samples in the chemistry lab of Dr. Rainer Lohmann at the University of Rhode Island’s Bay Campus.
Contributed by Community College of Rhode Island Marketing & Communications Department
Soffientino, an Associate Professor in Biology for the past seven years at the Community College of Rhode Island, and a Wakefield, RI, resident, hopes the results unearth a better understanding of how certain pollutants can be broken down by naturally-occurring bacteria, possibly leading to a more effective way to get rid of them faster.
With funding from the Rhode Island IDeA Network for Excellence in Biomedical Research (RI-INBRE), Soffientino spent this past summer carrying out a laboratory experiment to further study the breakdown of dangerous substances known as Medium-Chain Chlorinated Paraffins (MCCPs).
The work involves chemistry and biology components: Simon Vojta, a postdoctoral researcher in the Lohmann lab, measured concentrations of MCCPs in the bottled sediments, while Soffientino monitored the numbers of bacteria potentially capable of breaking down MCCPs.
The sediments come from various contaminated and non-contaminated areas in New Jersey and Staten Island, including sites within earshot of the Newark International Airport and Passaic River. Samples are divided into separate jars, each containing different levels of MCCPs, and Soffientino then introduces substances, such as cellulose and chitin, that fuel the growth of microbes – tiny, microscopic life forms such as bacteria, viruses and fungi, some of which 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. There’s an added element in the classroom, too, as he plans to implement details of his research in his teachings this fall, specifically to students interested in studying DNA sequencing. Likewise, he’ll offer those looking to get involved in a research project the opportunity to work with him in the lab as the experiment continues.
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 affected by these and other chlorinated chemicals. That, for now, is a longshot – the focus today is first figuring out what happens to MCCPs once they get in the sediment.
“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.
“There are a lot of people interested in how microbes break down chlorinated chemicals, and a lot of money is invested everywhere to see if we can implement techniques to stimulate microbes to do the clean-up naturally.”
Because of their versatility – among their most attractive qualities, they are unreactive, non-flammable, stain and chemical resistant, and flexible at low temperatures – MCCPs have become the compound of choice by companies that manufacture everyday products. They are used as plasticizers in garden hoses, which need to maintain elasticity in cold temperatures, and in paints, sealants and coatings, all of which need to be resistant to both water and chemicals while remaining pliable. 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.
But the same qualities that make MCCPs useful in the manufacturing industry also make them difficult to decompose in the environment. These chemicals, Soffientino says, 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 by the Environmental Protection Agency discovered they caused cancer in addition to adverse skin, liver and developmental effects in humans.
MCCPs, while not quite as deadly as PCBs, are still troublesome. When discharged into bodies of water, they seep into soil and aquatic sediments, and are known to have toxic effects on animals, plants and humans. Researchers in Europe have expressed concern over the possibility of metalworking fluids containing MCCPs resulting in an increased risk of kidney toxicity in humans.
There are other ways to decontaminate polluted sediment, such as dredging, which involves scooping debris and sediment from the bottom of lakes and rivers, but that can actually be counterproductive, Soffientino says, because the sediment can spread and wind up contaminating an even larger portion of the area.
The perfect solution is a natural one that does not harm the environment and helps reverse decades of damage done by the commercial use of toxic MCCPs during a time in which their effects were largely unexplored. Soffientino’s research could prove groundbreaking. The answer is in those jars.
“There is urgency for understanding where these MCCPs go,” Soffientino said, “and how they break down.”