Pore-Water Sample for Long-Term Monitoring Beneath Lakes and Streams

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Sewers as a Source and Sink of Chlorinated-Solvent Groundwater Contamination, Marine Corps Recruit Depot, Parris Island, South Carolina

2010 S.C. Water Resources Conferences - Science and Policy Challenges for a Sustainable Futur

Phytoscreening for Chlorinated Solvents using Rapid in Vitro SPME Sampling: Application to Urban Plume in Verl, Germany

Rapid Detection and Delineation of Contaminants in Urban Settings is Critically Important in Protecting Human Health. Cores from Trees Growing above a Plume of Contaminated Groundwater in Verl, Germany, Were Collected in 1 Day, with Subsequent Analysis and Plume Mapping Completed over Several Days. Solid-Phase Microextraction (SPME) Analysis Was Applied to Detect Tetrachloroethene (PCE) and Trichloroethene (TCE) to Below Nanogram/liter Levels in the Transpiration Stream of the Trees. the Tree Core Concentrations Showed a Clear Areal Correlation to the Distribution of PCE and TCE in the Groundwater. Concentrations in Tree Cores Were Lower Than the Underlying Groundwater, as Anticipated; However, the Tree Core Water Retained the PCE:TCE Signature of the Underlying Groundwater in the Urban, Populated Area. the PCE:TCE Ratio Can Indicate Areas of Differing Degradation Activity. Therefore, the Phytoscreening Analysis Was Capable Not Only of Mapping the Spatial Distribution of Groundwater Contamination But Also of Delineating Zones of Potentially Differing Contaminant Sources and Degradation. the Simplicity of Tree Coring and the Ability to Collect a Large Number of Samples in a Day with Minimal Disruption or Property Damage in the Urban Setting Demonstrates that Phytoscreening Can Be a Powerful Tool for Gaining Reconnaissance-Level Information on Groundwater Contaminated by Chlorinated Solvents. the Use of SPME Decreases the Detection Level Considerably and Increases the Sensitivity of Phytoscreening as an Assessment, Monitoring, and Phytoforensic Tool. with Rapid, Inexpensive, and Noninvasive Methods of Detecting and Delineating Contaminants Underlying Homes, as in This Case, Human Health Can Be Better Protected through Screening of Broader Areas and with Far Faster Response Times. © 2011 American Chemical Society

Phytoscreening and phytoextraction of heavy metals at Danish polluted sites using willow and poplar trees

The main purpose of this study was to determine typical concentrations of heavy metals (HM) in wood from willows and poplars, in order to test the feasibility of phytoscreening and phytoextraction of HM. Samples were taken from one strongly, one moderately, and one slightly polluted site and from three reference sites. Wood from both tree species had similar background concentrations at 0.5 mg kg(−1) for cadmium (Cd), 1.6 mg kg(−1) for copper (Cu), 0.3 mg kg(−1) for nickel (Ni), and 25 mg kg(−1) for zinc (Zn). Concentrations of chromium (Cr) and lead (Pb) were below or close to detection limit. Concentrations in wood from the highly polluted site were significantly elevated, compared to references, in particular for willow. The conclusion from these results is that tree coring could be used successfully to identify strongly heavy metal-polluted soil for Cd, Cu, Ni, Zn, and that willow trees were superior to poplars, except when screening for Ni. Phytoextraction of HMs was quantified from measured concentration in wood at the most polluted site. Extraction efficiencies were best for willows and Cd, but below 0.5 % over 10 years, and below 1 ‰ in 10 years for all other HMs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11356-013-2085-z) contains supplementary material, which is available to authorized users

Speciation of arsenic in sulfidic waters

Formation constants for thioarsenite species have been determined in dilute solutions at 25°C, ΣH(2)S from 10(-7.5 )to 10(-3.0 )M, ΣAs from 10(-5.6 )to 10(-4.8 )M, and pH 7 and 10. The principal inorganic arsenic species in anoxic aquatic systems are arsenite, As(OH)(3)(0), and a mononuclear thioarsenite with an S/As ratio of 3:1. Thioarsenic species with S/As ratios of 1 : 1,2 : 1, and 4 : 1 are lesser components in sulfidic solutions that might be encountered in natural aquatic environments. Thioarsenites dominate arsenic speciation at sulfide concentrations > 10(-4.3 )M at neutral pH. Conversion from neutral As(OH)(3)(0 )to anionic thioarsenite species may regulate the transport and fate of arsenic in sulfate-reducing environments by governing sorption and mineral precipitation reactions

Effect of carbon starvation on toluene degradation activity by toluene monooxygenase-expressing bacteria

Subsurface bacteria commonly exist in a starvation state with only periodic exposure to utilizable sources of carbon and energy. In this study, the effect of carbon starvation on aerobic toluene degradation was quantitatively evaluated with a selection of bacteria representing all the known toluene oxygenase enzyme pathways. For all the investigated strains, the rate of toluene biodegradation decreased exponentially with starvation time. First-order deactivation rate constants for TMO-expressing bacteria were approximately an order of magnitude greater than those for other oxygenase-expressing bacteria. When growth conditions (the type of growth substrate and the type and concentration of toluene oxygenase inducer) were varied in the cultures prior to the deactivation experiments, the rate of deactivation was not significantly affected, suggesting that the rate of deactivation is independent of previous substrate/inducer conditions. Because TMO-expressing bacteria are known to efficiently detoxify TCE in subsurface environments, these findings have significant implications for in situ TCE bioremediation, specifically for environments experiencing variable growth-substrate exposure conditions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45353/1/10532_2005_Article_9014.pd