Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment.

The Jordan River is a major source of water, solutes, and allochthonous particles to Lake Kinneret contributed by the river tributaries as well as through leaching and erosion of soils and leakage of effluents. Those external nutrient loads impact the Lake Kinneret ecosystem. The current chapter presents a processed time series of material loads for 1971-2012 based on discharge measurements at the "Pkak Bridge'', located on the Jordan River downstream of all tributaries and the Hula Valley. Also presented are chemical analyses performed on water samples collected at the same place. During the early 1990s, water sampling was gradually changed from being manual to an automatic sampling method, with an overlap period from 1991 to 1996 during which both methods were widely applied. Discrepancies between the two sets of parallel data obtained during the years of overlap were analyzed, with conclusions used to produce a single coherent corrected long-term record. Robust trend analysis performed on the corrected time series revealed significant long-term declines in the loads of nitrogen and phosphorus compounds, and suspended matter, while total nitrogen to total phosphorus ratio remained unchanged. The time series also reflects a wide range of anthropogenic activities in the watershed, such as increasing population and effluents in the 1970s, the peat area reclamation by the "Hula Project" since 1994, and the various watershed management actions implemented to vigorously eliminate pollution sources in the Lake Kinneret watershed.

Introduction Uranium (U) contamination is widespread in the U.S., particularly at Department of Energy (DOE) sites. The Hanford site in Richland, WA is underlain by Hanford (HF) and Ringold (RG) silts and sands and the CaCO3-cemented Plio-Pleistocene (PP) unit. Recent studies have identified a “new” aqueous complex, Ca2UO2(CO3)3. These related Hanford samples provide an opportunity to investigate the coupled fate and transport of U(VI) in unconsolidated silts and sands compared to CaCO3-cemented sediments. Results and discussion Kinetic batch studies demonstrated signficantly greater sorption of U onto PP (Kf = 3.59) in comparison to the HF and RG (Kf = 1.67 and Kf = 1.19, respectively). U sorption is generally associated with Fe-oxides, but measured Fe contents are not consistent with the observed U sorption (Table 2). Thus there are three hypotheses regarding increased sorption in PP: higher surface area, organic-facilitated sorption, and/or differential sorption of the Ca2UO2(CO3)3 complex (Table), which is likely to form given the high carbonate content of the caliche. In support of hypothesis 3 is the observation of increased U sorption in the presence of 2 mM CaCl2 for all sediments.

This study is focused on gas‐water displacement through fracture networks. First, we investigated the flow patterns in fracture branches following a fracture intersection. Laboratory experiments were conducted to qualitatively identify the gas‐water flow patterns in intersecting fractures. A mathematical model consistent with the actual phenomena observed in the laboratory was then formulated. The mathematical model is represented by a nonlinear system of partial differential equations, which is solved by an iterative numerical method. In the second part of the study, investigations of a vertical cross section of a fracture network were conducted. Two sets of fractures were assumed to intersect orthogonally, as characteristic of some granites. The angles of the fractures with the horizontal direction were either 45° or 135°. Fracture intersection centers, fracture lengths, and fracture openings were generated according to statistical distributions. Simulations were carried out under constant pressure boundary conditions at top and bottom as might be found at offshore radioactive repositories. The present study, which accounts for a gas‐water slug, shows that the flow of water reaches quasi‐steady state with continuous gas release.