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To view all previously funded research, please visit our Annual Report Archive
Fiscal Year 2007
The influence of flooding cycles and iron oxides on arsenic retention in contaminated, planted microcosms in comparison with phosphate retention
Luke MacDonald with Professor Peter Jaffe
Department of Civil and Environmental Engineering
Princeton University
This research aims to better predict the behavior of phosphate and arsenic under changing iron and sulfur redox conditions. Accordingly, this study investigates the potential for iron oxides, sulfides, and iron sulfides to capture phosphate and arsenate, and the influence of plants and hydrology on this process. The specific problem that this research investigates is: will iron oxides or sulfides effectively capture arsenic and phosphate under the redox conditions we expect to find in wetlands and retention ponds, how do plants impact the capture of these pollutants, and what role do wetting and drying cycles play? Competing redox driven processes influence the solubility and sorption of phosphate and arsenic. These dynamic redox processes may have opposite effects on the capture of these pollutants, making it difficult to determine the optimal conditions for arsenic and phosphate capture, and the goal of this research is to help unravel this mystery. 
Figure 1. Photograph of the greenhouse experiment. Each microcosm receives influent water from the blue 55-gallon drums. The water enters at the bottom port, and contains nine sample ports equally spaced throughout the microcosm. The system is permanently flooded, with a free water surface. Sand is present in all microcosms to ensure adequate flow rates and sample volumes.
Contact information:
Luke MacDonald
Princeton University
Telephone: (609) 258-7819
E-mail: Lmacdona@princeton.edu
Professor Peter Jaffe
Princeton University
Telephone: (609) 258-7819
E-mail: Jaffe@princeton.edu
Development of Microscale Membrane Extraction for Trace Monitoring of Pesticides and Other Emerging Pollutants in Water
Kamilah Hylton with Professor Somenath Mitra
Department of Chemistry and Environmental Science
New Jersey Institute of Technology
In a 2004 Environmental Science and Technology Article (1), a USGS study revealed the presence of a large number of “emerging contaminants,” such as antibiotics and households chemicals, in the drinking water of many homes in the New York metropolitan area, including New Jersey. According to Stackleberg (1), synergism between these chemicals could increase their impacts on human health. In light of health concerns and the absence of regulation of these compounds, studies are needed that allow us to determine the amounts actually reaching the environment and consequently how much additional treatment may be required.
Measurement of these trace compounds is challenging because many are acidic, basic or polar. Recent reviews (2-4) have all listed solid phase extraction (SPE) as the only sample pretreatment technique, followed by separation and detection with liquid chromatography/mass spectrometry (LC/MS), liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) or gas chromatography/mass spectrometry (GC/MS). While these techniques are capable of detecting trace amounts of contaminants, they are expensive and require multiple steps, long analysis time and large amounts of solvents. Also, most SPE is done off-line which makes continuous monitoring difficult. Petrovic et. al. (3) laments that the lack of more effective methods for trace determination of these new pollutants limits their measurement. Clearly, there is a need for the development of simple, inexpensive techniques that allow for quantification of these pollutants at low levels in environmental samples with the possibility of on-line analysis.
Figure 1. (a)Experimental set-up for microextraction of N-methyl carbamates;
(b) Schematic diagram of the barrier film system.
Conclusions
A mixed solvent membrane extraction in conjunction with a barrier film was developed for the analysis of N-methyl carbamate pesticides in water that precluded the need for post column derivatization. All the pesticides could not be extracted with any one solvent, so the use of a mixed solvent was absolutely necessary for extending the range of compounds studied with high sensitivity. The presence of the barrier film reduced solvent loss, allowing higher stirring rates and extraction times that led to enhanced enrichment and lower limits of detection. This used small sample volumes, and was simple and environmentally friendly.
References:
1. Thacker, P.D., Pollutants in New Jersey’s drinking water, Environmental Science and Technology Online, December 8, 2004. Accessed September 23, 2006.
2. Petrovic, M., Gonzalez, S., Barcelo, D., Analysis and removal of emerging contaminants in wastewater and drinking water, Trends Anal. Chem. 22 (2003) 685.
3. Zwiener, C., Frimmel, F. H. LC-MS analysis in the aquatic environment and in water treatment - A critical review: Part II: Applications for emerging contaminants and related pollutants, microorganisms and humic acids. Anal. Bioanal. Chem. 378 (2004) 862.
4. Richardson, S., Environmental mass spectrometry: Emerging contaminants and current issues. Anal. Chem. 78 (2006) 4021.
Contact Information:
Kamilah Hylton
New Jersey Institute of Technology
Telephone: (973) 642-7645
E-mail: ksh4@njit.edu
Professor Somenath Mitra
New Jersey Institute of Technology
Telephone: (973) 596-5611
E-mail: mitra@njit.edu
Phosphate and Thermal Stabilization of Dredged Sediments for Reuse as Construction Material
Peter Nbida with Professor Lisa Axe
Department of Civil and Environmental Engineering
New Jersey Institute of Technology
Sediments are continuously deposited in rivers, lakes, and shorelines through the natural processes of erosion, transport, and deposition. Because of their capacity to adsorb contaminants, sediments act as an important sink (Vdovic et al., 2006); their contamination can adversely affect the health of organisms impacting the aquatic food chain (Lyman et al., 1987; Peplow and Edmonds, 2005). Navigable waters and harbors are regularly dredged to maintain and sometimes extend water depths. The amount of material excavated can be enormous. Such large quantities of contaminated sediments naturally raise the question of disposal.
Treatment and reuse of dredged sediments as an alternative to disposal is highly desirable as it reduces the cost of disposal and conserves natural resources. Existing treatment technologies have been, for the most part, adopted from technologies applied on contaminated soil and in the mining industry; however, comparatively, sediment treatment is more expensive because of the high water content (over 50%) and the large quantities involved. Consequently, few existing technologies are actually commercially used (Mulligan et al., 2001). With the need for further development, a novel method is proposed for sediments dredged from the Passaic and Hackensack Rivers: phosphate addition and thermal treatment at 700oC, where organics are mineralized with the off-gas treated by carbon adsorption, and heavy metals are stabilized into sparingly soluble hydroxylapatites (Kribi et al., 2004). If the treatment is found to be successful, the stabilized sediments can potentially be used as construction material.
References
1. Kribi, S., A. Nzihou, P. Sharrock. 2004. Stabilization of heavy metals from dredged sediment. Tailoring of residue properties. InProc. pro40: the use of recycled materials in buildingsand structures; Vázquez, E.; Hendriks, Ch. F.; Janssen, G. M. T. Eds.; ISBN: 2-912143-52-7, e-ISBN: 2912143756., 2, 824–832.
2.
Lyman, W.J., A.E. Glazer, J.H. Ong, S.F. Coons. 1987. An overview of sediment quality in the United States, prepared for U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, D.C.
3.
Mulligan, C.N., R.N. Yong, B.F. Gibbs. 2001. An evaluation of technologies for the heavy metal remediation of dredged sediments, J. Hazard. Mater., 85 (2), 145–163.
4.
Peplow, D., R. Edmonds. 2005. The effects of mine waste contamination at multiple levels of biological organization. Ecolog. Engin., 24 (1–2), 101–119.
5.
Vdovic, N., G. Billon, C. Gabelle, J. Potdevin. 2006. Remobilization of metals from slag and polluted sediments (Case Study: The canal of the Deule River, northern France), Environ. Poll., 141 (2) 359–369.
Contact Information:
Peter Nbida
New Jersey Institute of Technology
Telephone: (973) 596-6077
E-mail: pkn4@njit.edu
Professor Lisa Axe
New Jersey Institute of Technology
Telephone: (973) 596-2477
E-mail: Axe@ADM.njit.edu
Restored oyster reef habitat use by the American Eel (Anquilla rostrata) in the Lower Delaware Bay
Jaclyn Taylor with Assistant Professor David Bushek
Haskin Shellfish Research Laboratory
Rutgers, The State University of New Jersey
A preliminary small-scale oyster restoration project was funded in summer 2006 through a Rutgers University Research Council grant, and demonstrated the potential for creating oyster habitat in the intertidal zone of the lower Delaware Bay. Preliminary minnow trap sampling data showed an increase in macrofauna abundance associated with the shell bag reefs compared to adjacent control sand areas. Of the 27 total fish caught on the shell bag reefs, the American eel (Anguilla rostrata) accounts for 25% of this total, while no eels were caught on the adjacent sand areas. Interestingly, the total length of A. rostrata increased from 35cm to 55 cm during the June through October sampling season. The preliminary catch and length data from the Cape Shore reefs reported above corresponds with the predicted migration time of A. rostrata. These findings imply that oyster reef habitat use by American eels in the lower Delaware Bay is important for successful migrations.
The present study was designed to test the hypothesis that yellow phase American eels, Anguilla rostrata, utilize oyster reefs and oyster aquaculture racks in the intertidal zone of lower Delaware Bay during their migration season. The objectives were as follows: 1) Provide novel documentation on the ecological importance of restored oyster beds as habitat for yellow phase Anguilla rostrata in the lower Delaware Bay, 2) Determine abundance and length-weight relationship of A. rostrata associated with shell restoration and aquaculture sites, 3) Determine the relationship between period of maximum abundance of A. rostrata and their migration season, and 4) Determine if A. rostrata are resident or transient species associated with restoration sites and aquaculture racks through mark-recapture efforts.
Contact Information:
Jaclyn Taylor
Rutgers University
Telephone: (856) 785-0074 X4332
E-mail: jaclynt@eden.rutgers.edu
Assistant Professor David Bushek
Rutgers University
Telephone: (856) 785-0074 X4327
E-mail: bushek@hsrl.rutgers.edu
Using assimilated 13C-DNA to fingerprint active microorganisms in methylmercury demethylation by staple-isotope probing
Riqing Yu with Professor Tamar Barkay
Department of Biochemistry and Microbiology
Rutgers, The State University of New Jersey
Methylmercury (CH3Hg or MeHg), a lipophilic form of Hg that is a potent neurotoxin, could be readily accumulated by aquatic organisms and severely affect public health via food chain accumulation. The New Jersey Mercury Task Force (NJMTF, 2002) reported that mercury levels in water (e.g. the Hudson-Raritan Estuary) and sediment (e.g. 75% of the NY-NJ Harbor sediment) were found to exceed the related criteria or effect range, respectively. They also found that 43–56% of freshwater fish contained Hg concentrations higher than the FDA Action Level of 0.5 ppm.
Microbial degradation of MeHg (demethylation), a naturally occurring process of which little is known, plays an important role in mercury biogeochemical cycling and detoxification. To date, two pathways for the degradation of MeHg have been documented (Oremland et al., 1991; Marvin-Diapsquale et al., 2000; Barkay & Wagner-Dobler, 2005). Both pathways imply the conversion of the C1 moiety to gaseous products, either methane or carbon dioxide. The possibility that MeHg is degraded by microbes which utilize the C1 as a carbon source has not been examined and may be a major pathway for MeHg degradation. The proposed approach will explore this possibility by applying stable-isotope probing (SIP), a recently developed method to taxonomically and functionally characterize microbial species that are active in degradation and bioremediation processes of organic pollutants (Madsen, 2006). Thus, this project will investigate if microorganisms that are grown in the presence of 13CH3Hg assimilate the heavy carbon isotope into their DNA during demethylation and can consequently be distinguished by SIP. From the 13CH3Hg enrichment with environmental samples, 13C–DNA (or RNA) extracted from the target group of microbes that actively participate in 13CH3Hg demethylation could be characterized taxonomically by SIP. This study will first test if and how the C1 group from MeHg is assimilated into nucleic acids in the cell. If this approach is feasible, identification of the specific groups of microorganisms that degrade MeHg will be possible.
Literature Cited:
1. Barkay T., I. Wagner-Dobler. 2005. Microbial transformations of mercury: potentials, challenges, and achievements in controlling mercury toxicity in the environment. Adv Appl. Microbiol. 57: 1-54.
2. Oremland R. S, C. W. Culbertson, M. R. Winfrey. 1991. Methylmercury decomposition in sediments and bacterial cultures: involvement of methanogens and sulfate reducers in oxidative demethylation. Appl. Environ. Microbiol. 57: 130-137.
3. Madsen E. L. 2006. The use of stable isotope probing techniques in boreactor and field studies on bioremediation. Curr. Opin. Biotechnol. 17: 92-97.
4. Marvin-Diapsquale M. C., J. Agee, C. McGowan, R. S. Oremland, M. Thomas, D. Krabbenhoft, C. C. Gilmour. 2000. Methylmercury degradation pathways: a comparison among three mercury-impacted ecosystems. Environ. Sci. Technol. 34: 4908-4917.
5. New Jersey Department of Environmental Protection. 2002. The NJ Mercury Task Force (http://www.state.nj.us/dep/dsr/mercury_task_force.htm).
Contact Information:
Riqing Yu
Rutgers University
Telephone: (732) 932-9763 X334
E-mail: rqyu@eden.rutgers.edu
Professor Tamar Barkay
Rutgers University
Telephone: (732) 932-9763 X333
E-mail: barkay@aesop.rutgers.edu
Fiscal Year 2006
The Potential Impact of the Asian Isopod, Synidotea laevidorsalis (Miers 1881), on the Delaware Bay, USA
Sean Boyd with Assistant Professor David Bushek
Haskin Shellfish Research Laboratory
Rutgers, The State University of New Jersey
The non-indigenous isopod Synidotea laticauda1 was first documented in Delaware Bay in 1999 and recent data indicates extremely high seasonal abundances. These observations suggest a potentially strong impact on the local ecosystem. To better understand the extent of any impact and the potential for further spread we need to know how S. laticauda is distributed in Delaware Bay and how its niche characteristics are likely to influence further establishment. This study is the first to address issues relating to the presence of S. laticauda in Delaware Bay, and was conducted during its establishment rather than after the fact.
The specific objectives of this study were:
1. Catalogue the distribution and abundance of S. laticauda with respect to environmental parameters of the isopod
2. Determine environmental tolerances to temperature and salinity as a mechanism for identifying potential limits to its aquatic distribution
3. Identify potential food resources for S. laticauda in Delaware Bay
4.
Identify potential predators of S. laticauda in Delaware Bay
 |
An example of Synidotea laticauda |
Synidotea laticauda was documented along portions of both the New Jersey and Delaware coastlines of Delaware Bay. However, they were only present in areas where the salinity was between 2 and 20 psu and were generally associated with anthropogenic structures, particularly marinas. Isopods were not observed along the Atlantic coast of New Jersey. At the present time it is unlikely that the northern range of S. laticauda in the bay will expand into freshwater portions of the estuary. Isopods experienced very little mortality at 5ºC; however, high mortality was experienced above 30ºC. The normal upper temperature limit for Delaware Bay appears to be close to upper limit for this isopod, but is not likely to be limiting.
Several trophic interactions between S. laticauda and the biota of Delaware Bay were identified through this study. Single-choice feeding trials identified nine different native fauna and flora that were readily consumed and establish S. laticauda as an omnivore capable of exploiting multiple food resources within the Bay. Gut content analysis of fish collected from the Maurice and Nantuxent Rivers indicate that at least four predatory species may consume S. laticauda, although the isopod did not appear to be an important component of their diets.
1During the course of this research the taxonomic classification of the species investigated was changed from S. laevidorsalis to S. laticauda
Contact Information:
Assistant Professor David Bushek
Rutgers, The State University of New Jersey
Telephone: (856) 785-0074 x4327; Fax: (856) 785-1544
Email: bushek@hsrl.rutgers.edu
Advancing the characterization of fractured bedrock aquifers using electrical geophysical methods: application to water resources evaluation in the New Jersey Highlands
DeBonne N. Wishart with Associate Professor Lee Slater
Department of Earth and Environmental Sciences
Rutgers, The State University of New Jersey - Newark Campus
This project initiates hydrogeophysical research in the New Jersey Highlands directed towards improving water resources management and reducing aquifer vulnerability in the region. Rather than relying solely on traditional collinear (symmetric) azimuthal resistivity surveys alone to characterize fracture anisotropy as was done in previous investigations, asymmetric azimuthal arrays of ASP and ARS measurements are coupled with hydrologic measurements to characterize fractures at the laboratory and extended to the field scale. Two-thirds of the research completed has allowed us to (1) improve the effectiveness of electrical geophysical methods in the hydrogeologic characterization of fractured bedrock aquifers, (2) devise a method to delineate hydraulically-active fractures, (3) extend bench-scale laboratory research to the field sites, and (4) apply methods to improve understanding of fracture geometry in the north New Jersey Highlands. The program of research investigates how integrated geoelectric measurements can be used to distinguish hydraulically-conductive fractures and to infer direction (and possibly rates) of groundwater flow based on the electrokinetic phenomena associated with “streaming" or self potential (SP).
The results of laboratory investigations suggest that azimuthal SP measurements can potentially advance the geoelectrical characterization of hydraulic anisotropy in fractured rocks. Laboratory ASP surveys on a fracture block model show that ASP measurements are capable of distinguishing hydraulically-active fractures from electrically-conductive fractures, and are diagnostic of flow direction and flow rates in fractures. In contrast, electrical resistivity measurements that are sensitive to the anisotropy in electrical current flow through fractures may not necessarily be equivalent to groundwater flow as previously indicated by earlier authors.
Recent laboratory data shows that the polarity of the SP anomaly associated with a fracture set indicates the direction of groundwater flow within the fracture set. Limited data obtained from field study sites (primarily surface water flow directions) is consistent with this being borne out at these field sites. These data suggest simple field-scale electrical measurements can define not just hydraulic anisotropy, but delineate the direction of groundwater flow.
These results show distinct differences between ARS and ASP surveys and highlight apparent advantages of ASP.
In conclusion, preliminary field measurements in a fractured rock environment suggest that this work could improve the characterization of fracture systems in bedrock aquifers and promote understanding of regional groundwater resources in fracture-dominated systems required for the design of groundwater remediation strategies.
Contact Information:
Associate Professor Lee Slater
Department of Earth and Environmental Sciences
Rutgers, The State University of New Jersey - Newark Campus
Telephone: (973) 353-5109; Fax: (973) 353-1965
Email: lslater@andromeda.rutgers.edu
Nitrate removal in urban wetlands: examining the roles of vegetation, soils, and hydrology in the creation of 'hot spots' and 'hot moments' of denitrification
Monica Marie Palta with Professor Joan Ehrenfeld
Department of Ecology, Evolution and Natural Resources
Rutgers, The State University of New Jersey
The scale at which “hot spots” and “hot moments” of nitrogen (N) removal occur via denitrification has not been well-defined, and there has been little work relating plant biology, hydrologic regime, and soils with N removal function in floodplain restoration efforts. The role of riparian vegetation, particularly Phragmites australis, in nitrate (NO3-) removal from surface and groundwater in particular is poorly understood. Additionally, differences in hydrologic conditions and soils between wetland areas may lead to differences in N removal ability of Phragmites.
This project took advantage of a 17 ha site (Teaneck Creek Conservancy, Bergen County) in which monospecific Phragmites stands are located on adjacent patches of clayey, silty, and organic soils. The presence of these adjacent patches enabled the researcher to isolate the effects of soil type and soil-generated differences in hydrology on the spatial and temporal distribution of “hot spots” and “hot moments” of NO3- removal. The goal was to determine the temporal and spatial variability in denitrification within and among replicate areas within each of these three soil types, thus both helping to define the dimensions of “hot spots” and “hot moments” in N removal and examining the drivers behind such phenomena.
The hypotheses were (1) there will be significant differences in both spatial and temporal variability among the three soil types that will be correlated with their hydraulic properties, thus demonstrating that differences in soil texture are a source of patchiness in dentrification within wetlands; (2) further, the high water retention capacity of the clay soils will result in less within-patch variability and less variability over time than in the silty soil or peaty soil, thus resulting in larger “spots” and longer “moments” in the clays and smaller “spots” and shorter “moments” in the silt and peat; (3) finally, the dimensions of both “spots” and “moments” will be correlated with the abundance and distribution of organic matter available in the soil.
The subset of data processed and analyzed thus far largely supports the hypotheses originally proposed. Significant differences in denitrification rate were found between soil types (indicating “hot spots”) and between and within seasons (indicating “hot moments”). Further, these differences do appear to be driven, at least in part, by moisture conditions, which influence nitrification rates; the latter is a key process driving denitrification. This study therefore provides important evidence that differences in soil texture are a source of patchiness in denitrification within wetlands, and that restoration projects aiming for higher levels of denitrification within wetlands must carefully consider texture and drainage of wetland soils in their design.
Contact Information:
Monica Marie Palta
Rutgers, The State University of New Jersey
Telephone: (732) 932-1050
E-mail: mpalta@eden.rutgers.edu
Professor Joan Ehrenfeld
Rutgers, The State University of New Jersey
Telephone: (732) 932-1081; Fax: (732) 932-8746
E-mail: ehrenfel@rci.rutgers.edu
Cranberry Agriculture as Wildlife Habitat in the Pine Barrens Wetland Ecosystem
Department of Ecology, Evolution and Natural Resources
Rutgers, The State University of New Jersey
As the need for agricultural development continues to grow, it is imperative to maintain or increase the ecological function of agroecosystems while minimizing negative influences on the surrounding environment. The cranberry farms located in the Pine Barrens of New Jersey provide an excellent opportunity to study this issue. Cranberries have been cultivated in this area for about 150 years. The 3,600 acres of active farms, as well as numerous abandoned bogs, are embedded in the riverine wetlands, where a great variety of lowland plants and animals live. This is a unique opportunity to study wildlife distribution in farmland habitat as well as the response of animal communities to plant succession after agricultural abandonment.
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Cranberry farm at the Whitesbog, Burlington County. |
Objective 1. To study bird and frog distributions within the farm with different habitat factors (vegetation, hydrology and landscape factors).
Objective 2. To study the seedbank composition in cranberry beds with different water-table depth, and their germination under different hydrological conditions.
Contact Information:
Ai Wen
Rutgers, The State University of New Jersey
Telephone: (732) 932-1050
Email: aiwen@eden.rutgers.edu
Professor David Ehrenfeld
Rutgers, The State University of New Jersey
Telephone: (732) 932-9553
Enhancing the remediation of Trichloroethene (TCE) using double-walled carbon nanotubes (DWNT)
Sarat Kannepalli with Assistant Professor Donna E. Fennell
Department of Environmental Sciences
Rutgers, The State University of New Jersey
The chlorinated organic solvent trichloroethene (TCE) is one of the most commonly detected groundwater contaminants. Widespread application in vapor degreasing of fabricated metal parts (80% use) and in the production of organic chemicals and pharmaceuticals (5% use), resulted in increased production from 260,000 lbs in 1981 to 320 million lbs in 1991.
The low viscosity, low interfacial tension with water, high volatility and existence as a non-aqueous-phase liquid make many physical and chemical methods of TCE remediation either ineffective or uneconomical. Furthermore, many hydro-geologic formations make remediation difficult. Reliable, cost effective methods for remediation of TCE contaminated groundwater are still needed.
The proposed research aimed to combine chemical-physical concentration and sequestration using carbon nanotubes and subsequent biodetoxification by dechlorinating bacteria to increase the efficiency of TCE removal from groundwater. The specific objectives of this study were two-fold: (1) What is the sorptive capacity of double walled carbon nanotubes (DWNT) for TCE? and (2) Is carbon nanotube-sequestered TCE bioavailable to dehalogenating bacteria? We hypothesized that TCE sorbed on DWNT is bioavailable to bacteria and this sorption/concentration may increase the dechlorinating efficiency of the bacteria. If feasible, a more efficient remediation technology for TCE contaminated groundwater may be developed.
Contact Information:
Sarat Kannepalli
Rutgers, The State University of New Jersey
Telephone: (732) 932-5546; Fax: (732) 932-8644
Email: skannepalli@envsci.rutgers.edu
Assistant Professor Donna E. Fennell
Rutgers, The State University of New Jersey
Telephone: (732) 932-9800 x6204; Fax: (732) 932-8644
Email: fennell@envsci.rutgers.edu
Fiscal Year 2005
Lab-on-a-chip device for monitoring trace level arsenic
Kamilah Hylton with Professor Somenath Mitra
Dept. of Chemistry and Environmental Science
New Jersey Institute of Technology
This study aims to develop a low cost, lab-on-a-chip field instrument that is capable of determining the total inorganic arsenic concentration in water samples in a rapid, continuous, reproducible, and accurate manner. The approach also precludes the tedious hydride generation methods used in conventional methodologies. By using a chelating agent and Supported Liquid Membrane Extraction (SLME) on a micro-scale platform, researchers propose to extract and concentrate arsenic from aqueous samples, allowing for faster analysis and lower detection limits.
Contact Information:
Kamilah Hylton
New Jersey Institute of Technology
Telephone: (973) 642-7645
E-mail: ksh4@njit.edu
Professor Somenath Mitra
New Jersey Institute of Technology
Telephone: (973) 596-5611
Email: mitra@njit.edu
Examining Effects of Soil Compaction on Pollutant Removal Efficiency and
Lifespan of a NJ Approved Stormwater Best Management Practice
Michael Mak with Assistant Professor Christopher C. Obropta
Department of Environmental Sciences
Rutgers, The State University of New Jersey
The bioretention system, an alternative to conventional stormwater Best Management Practice (BMP) structures such as stormwater wetlands or riparian forest buffers, is common to suburban settings. It is used for treatment of runoff from impervious surfaces such as residential and commercial roofs and parking lots. The design of a bioretention system must account for soil compaction within the basin.
Compaction in soil influences plant growth in multiple dimensions, primarily based on the degree of compaction. Accidental soil compaction will lead to a reduction of pollutant removal and eventually diminish the lifespan of the basin. For example, after approximately 15 to 20 years, metals may accumulate to levels where ecosystem risks may be heightened. However, the effects of soil compaction on the efficiency and lifespan of bioretention systems remain highly undefined.
This research seeks to determine the ideal degree of soil compaction for pollution removal efficiency of bioretention systems and confirm the effects of soil compaction on the system.
Contact Information:
Assistant Professor Christopher Obropta
Rutgers, The State University of New Jersey
Telephone: (732) 932-9800 X6209; Fax: (732) 932-8644
Email: obropta@envsci.rutgers.edu
Resistance of fractured rock dechlorinating bacteria
to pressure from heavy metals
Eun-Kyeu Son with Assistant Professor Donna E. Fennell
Department of Enviromental Sciences
Rutgers, The State University of New Jersey
Chlorinated ethenes such as tetrachloroethene (PCE) and trichloroethene (TCE), frequently used as degreasers, are the most frequently found groundwater contaminants. Chlorinated ethene contamination is widespread in the northern portion of New Jersey, and remediation of aquifers contaminated with these compounds is a difficult proposition that is further complicated by the presence of heavy metal co-contaminants.
Microbial reductive dechlorination, utilizing bacteria which transform chlorinated ethenes to the benign product ethene, is an attractive remedial process for contaminated aquifers and has been used as an alternative to chemical or physical methods. Only one genus of bacteria, Dehalococcoides, has been identified which is capable of the complete dehalogenation, or breakdown, of these contaminants.
The primary goal of this study is to investigate the effect of heavy metals on the dechlorination potential in groundwater contaminated with both chlorinated ethenes and heavy metals under anaerobic, or oxygen-deficient, conditions utilizing this bacteria for remediation.
Contact Information:
Eun-Kyeu Son
Rutgers, The State University of New Jersey
Telephone: (732) 932-9800 X6806
E-mail: eunkyeu@eden.rutgers.edu
Assistant Professor Donna E. Fennell
Rutgers, The State University of New Jersey
Telephone: (732) 932-9800 X6204; Fax: (732) 932-8644
E-mail: fennell@envsci.rutgers.edu
The Influence of Urbanization on Watershed Nitrogen Cycling Watersheds
Bernice Rosenzweig with Professor Peter Jaffe
Dept. of Civil and Environmental Engineering
Princeton University
As the amount of land devoted to urban and suburban use increases, understanding the impact of this type of development on ecosystem processes will become increasingly important. This issue is one of particular urgency in the state of New Jersey, where 27% of the total land area was categorized as urban at the end of the 20th century, and approximately 16,600 acres of land are converted to urban development each year. In spite of its importance, the study of nutrient cycling in urban watersheds is still in its infancy.
The proposed research will investigate the coupled hydrologic and nitrogen cycles in an urban watershed and how they are modified by urban land use. Understanding the dynamics of nitrogen is particularly important because, when transported in excess to coastal ecosystems, this nutrient can lead to harmful coastal eutrophication (oxygen depletion due to nutrient enrichment).
This research focuses on the role of stormwater detention ponds in nitrogen cycling in urban watersheds. It is motivated by the idea that watershed-scale nitrogen retention and export is dominated by spatial “hot spots” and temporal “hot moments” of activity that are created by variations in water flux. The work will test the following hypotheses:
- Urban land use leads to modifications in the mechanisms of runoff production
- Urban stream channels are incised and widened in response to increasing flood peaks
- As a result, urban stream channels have reduced capacity for nitrogen retention and can no longer function as watershed-scale hotspots of nitrogen removal and retention
- Stormwater detention ponds function as hot spots of nitrogen retention in urban watersheds
Contact Information:
Bernice Rosenzweig
Princeton University
Telephone: (609) 258-5646
Email: brosenzw@princeton.edu
Professor Peter Jaffe
Princeton University
Telephone: (609) 258-4653
Email: jaffe@princeton.edu
Microbial degradation of MTBE in anaerobic environments
Laura K.G. Youngster1 with Professor Max M. Häggblom2
1Department of Microbiology and Molecular Genetics
2Department of Biochemistry and Microbiology
Rutgers, The State University of New Jersey
Methyl tert-butyl ether (MTBE) is a synthetic chemical which is added to gasoline as an oxygenate to reduce carbon monoxide emissions and formation of ozone. Since the passage of the Clean Air Act, which mandates the use of fuel oxygenates, MTBE has been used extensively, with the largest per volume production of any organic chemical. Consequently, MTBE has been detected in groundwater as well as surface water across the United States. Common sources of MTBE contamination in water resources include fuel spills, leaking underground storage tanks and pipelines, storm runoff, precipitation, and motorized watercrafts.
New Jersey has been aware of the presence of MTBE in groundwater since the mid-1980s when it was detected during a drinking water survey. MTBE has proven to be persistant in the environment, and is now routinely detected in private wells sampled in New Jersey, especially wells near gasoline stations and other uses of gasoline. MTBE is also frequently detected in New Jersey surface water. Studies of the potential health hazards have been inconclusive, but the U.S. EPA currently lists MTBE as a possible human carcinogen. The concentration allowed in drinking water is also held to a low level due to the chemical’s easily detectable unpleasant taste and odor.
When MTBE is spilled, it is likely to dissolve in water and migrate quickly throughout the water system without hindrance by volatilization or adherence to soil. It is unfortunately also less prone to biodegradation. MTBE was initially thought to be entirely unsusceptible to microbial attack and now is known to be degraded by only a few cultures of microorganisms, most of them aerobic.
In the Haggblom laboratory, anaerobic MTBE-degrading microcosms have been established using inocula from various sites including sediments from areas in New Jersey. These are the first, and very likely only, stable MTBE-utilizing anaerobic enrichment cultures available for more detailed microbial analysis.
This research proposes to characterize the microbial community structure of these enriched bacterial cultures in order to understand their role in MTBE degradation. The information uncovered by the project can be used to create guidelines for proper management of MTBE-contaminated environments and highly contaminated anaerobic waterways as well as subsurface aquifers.
Contact Information:
Laura K.G. Youngster
Department of Microbiology and Molecular Genetics
Rutgers, The State University of New Jersey
Telephone: (732) 932-9763 X222
Email: lyoungster@optonline.net
Professor Max M. Häggblom
Department of Biochemistry and Microbiology
Rutgers, The State University of New Jersey
Telephone: (732) 932-9763 X326
Email: haggblom@aesop.rutgers.edu
Fiscal Year 2004
Soil Moisture Regimes and Nitrate Leaching in Urban Wetlands
Emilie K. Stander with Professor Joan G. Ehrenfeld
Department of Ecology, Evolution and Natural Resources
Rutgers, The State University of New Jersey
Nitrogen is one of the most widespread and pervasive pollutants present in surface waters throughout the United States. Excess nitrogen can cause eutrophication and zones of hypoxia in receiving water bodies and drinking water pollution in surface waters. It is a widely held belief that wetlands systems serve as sinks of nitrate from upland land use owing to their ability to remove nitrate through the process of denitrification. As a result, wetlands are increasingly being used as a management tool to combat the problem of excess nitrogen in urban watersheds. However, due to hydrological alteration resulting from urban land use, urban wetlands in northeastern New Jersey may experience lowered water tables, overall dryer conditions, and wet-dry cycles that may reduce nitrate removal capacity. In wetlands with lowered water tables, the biologically active zone of the soil where roots and microbial populations are located no longer experiences frequent saturation. As a result denitrification is inhibited. Conversely, aerobic conditions in wetland soils are well known to be conducive to high rates of nitrification. This results in the accumulation of high concentrations of nitrate and the potential for its movement through leaching to surface waters. Thus, the frequent occurrence of unsaturated conditions in urban wetlands may actually cause wetlands to become a source of nitrate to surface waters, rather than a sink.
Another issue which emphasizes the need to study nitrate removal in urban wetlands is the significant input of nitrogen into the system through atmospheric deposition. The density of urban development and amount of vehicular traffic in close proximity to many urban wetlands suggests that nitrogen deposition rates are significantly elevated, perhaps above regional averages, as documented along an urban-rural gradient from New York City to outlying suburbs. Several studies have explicitly linked atmospheric nitrogen deposition with eutrophication of coastal waters in the Northeast United States.
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The throughfall collector is very visible even from far away. Since vanadalism is always a concern for ecologists working in urban areas, this collector will have to be camouflaged by painting or spraypainting it brown and green. |
The aim of this study is to document nitrogen inputs and outputs in forested swamps along a gradient of urban to suburban conditions. To do this the researcher will collect "throughfall" (i.e., rain which has filtered through the tree canopy) and soil leachate (i.e., soil water which has leached down below the rooting zone towards the shallow groundwater) at eight forested wetlands along an urban to suburban gradient in northeastern New Jersey. The researcher will collect monthly for the course of one year, and will also sample weekly for one month of each season to capture temporal variability on a finer scale. Samples will be analyzed for nitrate and ammonium concentrations in the laboratory.
This study will allow researchers to determine whether nitrogen outputs are correlated with nitrogen inputs (i.e., do sites with higher nitrogen inputs have higher nitrogen outputs). This study will also demonstrate whether inputs are higher in areas with a higher intensification of urban land use. Also, using data collected from previous work partially funded by NJWRRI, the researcher will be able to determine whether outputs are higher in sites with altered hydrology and in sites with higher rates of nitrogen cycling processes such as nitrogen mineralization and nitrification.
Contact Information:
Professor Joan G. Ehrenfeld
Rutgers, The State University of New Jersey
Telephone: (732) 932-1081; Fax: (732) 932-8746
E-mail: ehrenfel@rci.rutgers.edu
Dechlorination of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans by Dehalorespiring Bacterial Cultures
Fang Liu with Assistant Professor Donna E. Fennell
Department of Environmental Sciences
Rutgers, The State University of New Jersey
A mixed culture containing D. ethenogenes strain 195 was shown to dechlorinate 1,2,3,4-tetrachlorodibenzo-p-dioixn (1,2,3,4-TeCDD) both with and without the addition of tetrachloroethene (PCE) as a co-substrate. 1,2,3,4-TeCDD was dechlorinated to 1,2,4-trichlorodibenzo-p-dioxin (1,2,4-TrCDD) and 1,3-dichlorodibenzo-p-dioxin (1,3-DCDD). Rates of daughter product formation were initially slower in PCE-amended cultures relative to cultures with no added PCE. At the end of the incubation, the extent of 1,2,3,4-TeCDD dechlorination was very similar in both treatments. It seems that PCE addition did not affect the dechlorination of 1,2,3,4-TeCDD. We further transferred the pre-grown culture at 10% v/v ratio spiked with 1,2,3,4-TeCDD alone or together with PCE addition. The results also showed that 1,2,3,4-TeCDD was dechlorinated in both treatments at a similar rate. The 1,2,3,4-TeCDD dechlorination and 1,3-DCDD formation did not show significant differences in both treatments. Although the first transfer results agree with that of the pre-grown culture, we have not yet confirmed that 1,2,3,4-TeCDD is a growth substrate by strain 195.
The dechlorination of 1,2,3,4,7,8-HxCDF was observed after one month of incubation. A penta-CDF was detected in all three active sets: the set spiked with 1,2,3,4,7,8-HxCDF as the only halogenated substrate, the PCE-amended set and the 1,2,3,4-TeCB-amended set. The most extensive dechlorination occurred in the 1,2,3,4-TeCB-amended set where the penta-CDF was further dechlorinated to two tetra-CDF congeners. We examined the dechlorination products and found that no 2,3,7,8-substituted penta- or tetra-CDF congeners were formed. This indicates that this dechlorination process detoxifies 1,2,3,4,7,8-HxCDF and forms non-2,3,7,8-substituted congeners. These results suggest that there is potential for using the mixed culture to bioaugment contaminated sites.
Contact Information:
Assistant Professor Donna E. Fennell
Rutgers, The State University of New Jersey
Phone:(732) 932-9800 X6204; Fax: (732) 932-8644
E-mail: fennell@envsci.rutgers.edu
Use of stable isotope ratios of mercury to track and differentiate
between sources of mercury pollution
Kritee1 with Professor Tamar Barkay2
1Dept. of Molecular and Microbial Genetics
2Dept. Biochemistry and Microbiology
Rutgers, The State University of New Jersey
The extreme toxicity of mercury (Hg) compounds warrants the search for new methods that can be used to track sources of Hg and dominant pathways leading to formation and bioaccumulation of methylmercury. Since Hg has seven stable isotopes (0.15 – 30% abundance; mass spread of 4%) and its compounds have a high degree of covalent character, it may undergo stable isotopic fractionation, and if so, the isotopic signatures of Hg may attest to its origin and/or redox history.
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Figure 1. The biogeochemical cycle of Hg. Solid arrows indicate uptake or transformation of Hg and hollow arrows indicate transport pathways. The width of hollow arrows reflects the relative importance of different fluxes. Scheafer et al., 2002. |
The purpose of this study was to determine the extent of mercury isotopic fractionation during the reduction of Hg(II) to Hg0 by mercuric reductase, an enzyme found in a broad range of Hg resistant bacteria from diverse environments. We measured the isotopic composition of Hg0 formed by pure cultures of Escherichia coli and Bacillus cereus, as a function of the extent of Hg substrate utilized using MC-ICPMS. We found that Hg(II) supplied as NIST 3133 undergoes Rayleigh fractionation with a fractionation factor (alpha) of ~1.0006 per amu during its reduction by E. coli (see graph below) and B. cereus at 37oC. Alpha values of similar magnitude were observed when Hg0 was produced by a natural microbial community following enrichment of Hg(II) reducing microbes.
This is the first evidence of biologically induced mass dependent fractionation of Hg, the heaviest metal for which biological fractionation has been detected to date. This report opens up the possibility of use of Hg isotope fractionation for identifying its sources and sinks in the environment, in situ pathways leading to its toxicity, and the nature and evolution of redox reactions in both modern and paleo environments.
Contact Information:
Professor Tamar Barkay
Dept. Biochemistry and Microbiology
Rutgers, The State University of New Jersey
Telephone: (732) 932-9763 X333
E-mail: barkay@aesop.rutgers.edu
Efficiency of Bioretention Systems to Reduce Fecal Coliform Counts in Stormwater
Gregory Rusciano1 with Assistant Professor Christopher C. Obropta2
1Department of Bioresource Engineering
2Department of Environmental Sciences
Rutgers, The State University of New Jersey
Currently, 7,742 water bodies in the nation are impaired for pathogenic bacteria, viruses and/or parasites (14.4% of all reported water bodies), more than for any other impairment (USEPA, 2003). Impairments result in large part from nonpoint sources of pollution carried by urban and agricultural stormwater runoff. Fecal coliform (FC) counts are commonly used as an indicator of pathogens and are used by governmental agencies to help manage drinking water quality and recreational activities such as swimming, boating and fishing. The study seeks to evaluate the ability of bioretention systems to effectively reduce fecal coliform colony counts. Bioretention systems were modeled in the laboratory with columns with representative depths of gravel, sand and soil. Panicum virgatum, typically used in bioretention systems, was integrated into the columns.
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Photo of a bioretention bolumn |
Typical rainfall conditions for New Jersey were mimicked in the laboratory with regard to rainfall intensity and frequency and stormwater composition (bacterial colony counts). The drainage area received by a typical bioretention system was estimated to determine the appropriate flow rate of water input into the system. The maximum percolation rate was observed to be approximately 37 mL/minute. Ponding occurred in the top of the column during every simulated storm event, although its maximum height never surpassed 12 inches. Total suspended solid (TSS) removal was generally high with an average ratio of 92.3% and range of 82.5-99.4%. FC count reductions were generally high, with an average ratio of 87.8% and a range of 54.7-99.7%. The turbidity was observed to be significantly lower in leachate samples. On average, the pH and temperature of the influent was 7.14 and 25.4oC, respectively. The pH and temperature of the leachate was 4.71 and 22.9oC, respectively. In addition to filtration and adsorption mechanisms, other mechanisms are responsible for acting directly on the bacteria regardless of their association with particulates. The primary mechanism is the pH. It is also likely that predation of FC bacteria by other microorganisms was a factor. Since bioretention is increasingly being implemented as a primary watershed management tool across the United States, this research will provide data to help optimize its effectiveness in the field and improve regulatory guidance for the future.
Contact Information:
Assistant Professor Christopher C. Obropta
Rutgers, The State University of New Jersey
Telephone: (732) 932-9800 X6209
Email: obropta@envsci.rutgers.edu
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