字幕列表 影片播放 列印英文字幕 Francisco Artigas- Meadowlands Environmental Research Institute We have a legacy of contamination in the district…organic pollution is very prevalent. We are coming out of a cycle of 60, 70 years - I could go even further back - of industrialization. I mean this is the quintessential, post-industrial landscape in New Jersey low lands. People just dumped here. Narrator Francisco Artigas is talking about the Kearney (Carney) Marsh located in the Meadowlands of northern New Jersey. Once a salt water marsh, it was drained and used as a land fill. Later, a fresh water marsh was established on top of the dump. And while wildlife still remains here today, Kearney Marsh faces other threats than those from below. During rainy periods, sewage overflows into the swamp. Runoff from nearby landfills is also a problem. The result is a marsh laden with toxins. For Donna Fennel, this is a perfect place- for she is a soil explorer. Donna Fennell-Rutgers University A lot of people have heard about PCB’s. That’s Polychlorinated Biphenyls. These are compounds that were produced as industrial chemicals and used for electrical insulators. They were used in carbonless copy paper. Their production was banned in the 1970’s after it became apparent that these things were an environmental problem. PCBs are very hydrophobic so they like to stick to soil particles. Soil particles are the recipients of many types of pollutants. Some of these soil particles get pushed into aquatic systems and form the basis of the sediment that forms in the bottoms of rivers, lakes, harbors and coastal areas.Organic matter contained in soil is sort of an attractant for these more problematic pollutants like PCB’s and dioxins. Narrator Today, Fennell and assistant Val Krumins are going against convention. The standard method for eliminating such toxins is to dredge, physically remove the polluted sediments from the aquatic environment. This is not only costly, but the muck collected then needs to find a safe home so that the toxins don’t spread further.But Donna and her Rutgers colleagues believe they have a better idea. Donna Fennell Our techniques are intended to work naturally within the sediment. We’re really focused on treating the pollutants where they are … We are looking at microorganisms that occur naturally in the sediment or which we may introduce to the sediment to transform and detoxify these compounds. That way, we can detoxify the sediment in place and the excavation or dredging, if it occurs later as a normal course of management of aquatic sediments, would not result in a new distribution of pollutants. Narrator The microbes that the Rutgers staff inject into the polluted sediments are tiny bacteria - ones that, in order to live, absorb chlorine from toxins like PCBs. Donna Fennell What these microorganisms do is they use the chlorinated compounds as their oxygen. They’re breathing chlorine, so to speak. Narrator The marsh experiment has several steps. First, a barrel is set down into the sediment to isolate it from the rest of the bottom. The de-chlorinating microbes are then injected into the sediment. Then a second blue barrel is fitted into the first. This allows the scientists to funnel in materials from the boat. The last step is to cap off the embedded barrel with a gel-like clay seal. Donna Fennel This capping idea is something that has been used for some time for treating sediments. What we want to do is study how the microbial process under the cap can be stimulated, and how it can work in conjunction with capping. The loading is about 16.5 pounds per square foot. Narrator Back on shore, the Rutgers team examines the sample just brought in from the boat. CSREES helped fund this research along with a grant from the Department of Defense. Scientist- This stuff is really soggy. Donna Fennell Finding that that organisms de-chlorinated … dioxins to me was a very incredible moment. I think the organic matter content was like 40%. I believe we are at the point where knowing something about the microorganisms, we have the chance to make a breakthrough so that biological treatment of sediments is going to be possible. Narrator With the samples safely preserved in liquid hydrogen, the serious sediment is transferred back to Rutgers where the rigorous lab work begins. It is here that Fennell is discovering the intricacies of the de-chlorinating microbes used at Kearney Marsh. Donna Fennell We put the sediments in the bottles. We amend them with certain things to stimulate the bacterial de-chlorination of the PCB’s. Were growing more bacteria, and we watch the fate of those PCB’s over time in our bottles. It has only been in about the last five years that we know the identities of the microorganisms - the bacteria - that are doing the de-chlorination of the PCB’s and dioxins. And we are just beginning to look at the genetics that controls that process. Only by using molecular DNA technologies can we have hope of detecting those microorganisms. Extracting the DNA and using molecular markers that are specific for the bacteria that we are interested in, we can pin point members that only make up an small percentage of that population. I have a 3 year old in my house. I am very concerned about the impact that environmental pollutants have. We are starting to break down these barriers. What happens in sediments? What can degrade or bio-degrade these pollutants? We’re developing technologies to deal with these legacy pollutants, and we can sort of right the wrongs from that done in the past. It is recovering our environmental legacy and our heritage and making that a resource for future generations.