Description and use of Schellencandona rhodanensis sp. n. (Ostracoda, Candoninae) to locate groundwater upwelling zones in rivers and wetlands

This study explores the extent and possible sources of heavy metal (Cd, Cr, Cu, Fe, Mn, Pb, Zn and Ni) contamination in the bed sediments of the Gomti River performing principal component analysis on the five years (Jan. 1994–Dec. 1998) data set obtained through continuous monitoring of the river water and bed sediments at eight selected sites and water/wastewater of its tributaries/drains. Influence of anthropogenic activities on metal contamination of the bed sediments was evaluated through computing the geoaccumulation index for various metals at studied sites. PCA performed on combined (river bed sediment, water, suspended solids, water/wastewater from tributaries/drains) data set extracted two significant factors explaining more than 58% of total variance. Factor loadings suggested the presence of both natural as well as anthropogenic sources for all these metals in the river bed sediments. Among all the sites, the sites 4 and 5 are more contaminated with Cd, Cu, Cr and Pb, which was supported by the geoaccumulation indices computed for metals. Factor scores revealed presence of seasonal (monsoon-related) differences in metals profiles for river water and suspended solids and absence of seasonal differences for bed sediment and wastewater. Further, the metal contamination of the bed sediment was also evaluated using biological thresholds. Results suggested that the river bed sediments are contaminated with heavy metals, which may contribute to sediment toxicity to the freshwater ecosystem of the Gomti River.

Understanding the molecular make-up of recalcitrant organic matter (rSOM) is important to postulate the capability of soil organic matter (SOM) to sequester carbon and mitigate climate change. Humic acid (HA) extracted from the river bed sediment (RS) from the West Holland river was analyzed, aiming to characterize and quantify the fused ring aromatic structures (FRA) portion. FARs can be formed through condensation and polymerization reactions and act as an important skeletal structure of the rSOM which has a mean residence time >1000 years. We conducted a series of nuclear magnetic resonance (NMR) experiments, 13C Direct Polarization Magic Angle Spinning (DP-MAS) NMR spectroscopy, and Dipolar dephased (dd) DPMAS NMR, chemical shift anisotropy (CSA) cross-polarization (CP) total sideband suppression (TOSS) NMR experiment and a dd-CSA filtered CPTOSS to accurately quantify the proportion of FRAs in the sediment HA sample. We compared the proportions of the functional groups of the RS with the surface (0-20 cm, TS) and deep (>90 cm, CS) soil HAs of the nearby Holland Marsh, Muck Crops Research Station to understand the linkages and the transformations of SOM happened while transportation (wind erosion and horizontal seepage) to the muck river sediment. We found that 90% of the aromatic C in the RS is non-protonated, and 32% of the aliphatic region was non-protonated. The DPMAS spectral comparison between RS, TS and CS clearly showed that RS contains characteristic peaks of both TS and CS. Moreover, the proportion of non-protonated aliphatics in RS (32%) is high compared to TS (18%) and CS (29%). Our results indicate that in muck river sediment soil HA, non-protonated aliphatics (CRAM-like structures) contribute to the rSOM more than FRAs, while in TS and CS, FRAs' contribution is higher than the non-protonated aliphatics. Collectively our results show the link between terrestrial organic matter transportation to the river sediment and the transformation that occur in the rSOM fraction in the river sediment SOM. This new knowledge allows us to understand the structural changes that happen in the sequestered carbon in different soil environments.

In the Hanford Reach of the Columbia River, a thin layer of recent alluvium overlies the sedimentary formations that comprise the unconfined groundwater aquifer. Experimental and modelling studies have demonstrated that this alluvial layer exerts significant control on the exchange of groundwater and surface water (hydrologic exchange flux), and is associated with elevated levels of biogeochemical activity. This layer is also observed to be strongly heterogeneous, and quantifying the spatial distribution of properties over the range of scales of interest is challenging. Facies are elements of a sediment classification scheme that groups complex geologic materials into a set of discrete classes according to distinguishing features. Facies classifications have been used as a framework for assigning heterogeneous material properties to grid cells of numerical models of flow and reactive transport in subsurface media. The usefulness of such an approach hinges on being able to relate facies to quantitative properties needed for flow and reactive transport modelling, and on being able to map facies over the domain of interest using readily available information. Although aquifer facies have been used in various modelling contexts, application of this concept to riverbed sediments is relatively new. Here, we describe an approach for categorizing and mapping recent alluvial (riverbed) sediments based on the integration of diverse observations with numerical simulations of river hydrodynamics. The facies have distinct distributions of sediment texture that correspond to variations in hydraulic properties, and therefore provide a useful framework for assigning heterogeneous properties in numerical simulations of hydrologic exchange flows and biogeochemical processes.

Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological indicator that provides results within 60 minutes with three conventional, 24-hour biological indicators for monitoring flash sterilization and three chemical indicators. Conventional biological indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical indicators tested included Comply, Incheque, and Thermalog S. Survival at 132 degrees C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56 degrees C for the three conventional biological indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological indicator, and color change for the chemical indicators. Each exposure time was replicated four times with 10 of each biological and chemical indicator per run. The conventional biological indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The chemical indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. The sensitivity of the Attest Rapid Readout parallels the conventional biological indicators. These data suggest that a 60-minute rapid readout biological indicator is equivalent to the 24-hour biological indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.

Sediment characteristics influence the distribution and bioavailability of phosphorus (P) in river sediments. In this study, we analyzed different P fractions in the sediments of the Bronx River, New York City, NY, using sequential extraction. The results showed that the average P pool rank order was HCl−P > NaOH−P > NaHCO3−P > residue−P, and their relative proportions were 3.7: 2.0: 1.4: 1 in sediments collected in 2006, while HCl−P > NaOH−P > residue−P > NaHCO3−P, with their relative proportions of 27.8:6.2:2.7:1 in the sediments obtained in 2007. The strong correlation between microbial P and organic P (OP), along with the changes in microbial P over time indicate that most of the OP in the river bed sediments is potentially bioavailable. The sediment transport, deposition, assimilation, the exchange of P between sediments and water columns, the land use changes, raw sewer discharge, gas spill, construction, fertilizer application, etc., as well as the hydro‐climatic changes could result in the spatial and temporal variations in P bioavailability in the river bed sediments. The estimations of P pools and their bioavailability in river bed sediments could help determine the spatial and temporal variations in P transport and impacts of land use on water quality, in turn, help regulate P in the river's watershed.

Summary Combination of high-resolution seismic and GPR surveys were developed for mapping river bed morphology and characterizing the river bed sediments. Careful survey execution and processing of the recorded data results not only centimeter accurate map of the river bed morphology, but also delineates sediment units with different reflectivity. Calibrating the geophysical attributes with sediment and rock samples collected at the river bottom results a three-dimensional input dataset for dynamic modelling of river bed evolution and sediment transport. Shallow river sections from the Hungarian part of river Danube were selected as study areas and were surveyed with combined seismic and underwater GPR technology.

The Mobilization of Heavy Metals in River Sediment by Nitrilotriacetic Acid (NTA)

Prediction of dissolved organic nitrogen via spectroscopic fingerprint in the shallow riverbed sediments of effluent-dominated rivers: A case study in Xi’an, northwest China

Performance evaluation of chemical, biological and physical indicators in the process of sterilization under the effect of non-condensable gases

This study was carried out to determine the concentration of phosphorus in six rivers from agricultural and urban rivers and to compare the bioavailable phosphorus (BAP). Nutrients entering rivers are divided into suspended and dissolved state. In this study, BAP was measured by using ultrasonic extraction method. A 100 L sample was collected from six rivers, three agricultural rivers and three urban rivers to compare their BAP concentration. Measurement for two weather conditions, rain and no rain were taken. The results showed that BAP concentrations were high in Nishino river followed by Hamada, Umeda, Yagyu, Asakura and Uchibari river, with the concentration ranging from 0.1 to 1.00 mg/L. Agricultural rivers for both rain and no rain events were high in total phosphorus (TP) with the concentrations ranging from 0.50 to 1.09 mg/L. Particulate phosphorus (PP) concentration in the river sediment (RS) after a rain event was high compared to the PP during a no rain event. However, PP in river bed sediment (RBS) was high during a no rain event compared to the concentration of PP in the river sediment (RS). This may due to the accumulated and attached PP in the RBS (low flow of river water). Concentration of particulate bioavailable phosphorus (PBAP) in RS was ranging from 0.70 to 10.94 mg/g. In this study, it was found that the BAP concentration from agricultural rivers were high than the BAP concentration in urban rivers.

The ultimate fate of inorganic phosphorus in natural waters is to a large degree determined by interactions with sediments. The interactions in river bed sediments have been investigated by a combination of methods using surface sediments, <2 mm in diameter, collected from a 55 km stretch of the River Swale in Yorkshire, UK. The sediments were analysed by digestion (Fe, Ca and P), clay mineralogy and their equilibrium phosphate concentration. All the equilibrium phosphate concentrations were below 2 μmol dm−3, which is much less than the concentration in the overlying water and indicates a net uptake of phosphorus by the sediments. Experiments in a fluvarium channel with a coarse sediment also showed that the release and uptake of soluble phosphorus was towards a steady-state concentration in the overlying solution, consistent with measurements of the equilibrium phosphate concentration. A kinetic model describing the net uptake of soluble reactive phosphorus by river sediments was applied to chemical data collected during an intensive monitoring exercise in the catchment. Copyright © 1999 John Wiley & Sons, Ltd.

There are so many ISO documents to understand and utilize for validation studies and routine control. A biological indicator (BI) is essential for conducting sterilization validation and routine control. ISO 11138-1 and ISO 14161 are the major documents to follow for BI manufacturers and BI users, respectively. In ISO 11138-1, BI manufacturers must utilize a BI with 106 CFU/carrier as an initial population for validation studies. For routine control, it is approved to use an initial BI population of 105 CFU/carrier according to ISO 11138-1. In ISO 14161 BI users need not imitate BI manufacturers and less than 106 CFU/carrier BI is approved for use in validation studies and routine control. According to ISO 14161 for BI users, the initial population must be identical for validation studies and routine control. For the BI user, there are four types of procedures for sterilization validation and routine control. These are the half-cycle, over-kill, combined BI/bioburden and the absolute bioburden methods. A BI with An initial population of 106 CFU/ carrier must be used for validation studies by BI manufacturers according to ISO 11138-1, but BI users can elect to use a commercially available BI with more than 103 CFU/carrier as the BI for validation studies and routine control as described in ISO 14161. The approved SAL was defined to be 10-6 and this is unchanged for both BI users and BI manufacturers. Therefore, from the initial population of 106 CFU (colony forming unit)/carrier to a SAL of 10-6, the survivor curve must be straight and tailing is not allowed as described below (ISO 11138-1). The BI used for gas plasma sterilization, spores of Geobacillus stearothermophilus ATCC 7953, has characteristics that do not result in a tailing phenomenon. A linear survival curve is obtained from an initial population of 106 CFU/carrier to a SAL 10-6 for all sterilization procedures tested, demonstrating that inactivation kinetics are first order and allowing calculation of the D (decimal reduction) value from the dose or time to decrease 1 log. Chemical indicators (CI) are not approved for use in validation studies; only the use of BI is approved. CIs are only approved for use as a supporting method during routine control according to ISO 11140-1 and 14161. Only a BI is approved for both validation studies and routine control according to ISO 14161.

Vertical and temporal distribution of paniculate organic matter (POM) in river bed sediments was observed in two different stations in the Morava River. Samples of river sediments from 0–70 cm depths were taken by inserting a steel cylinder with a special grab. The main type of organic matter found in bed sediments was fine particulate organic matter (FPOM < 1 mm). The organic matter had a variable distribution in the hyporheic zone. Generally, the concentration of organic matter was higher in the top 0–40 cm of sediment. The annual mean storage of buried organic matter (0–70 cm depth) was 5352.13 g AFDW.rn−3. The exchange of organic matter between surface sediments and deep river bed sediments is influenced mainly by flooding activity. The maximum storage of organic matter in the hyporheic zone appears in the spring when floods are decreasing.

The Second Songhua River was subjected to a large amount of raw or primary effluent from chemical industries in Jilin city in 1960s to 1970s, resulting in serious mercury pollution. However, an understanding of other trace metal pollution has remained unclear. The objective of this study was to investigate trace metal contamination in the sediment of the river. Bottom sediment samples were taken in the river between Jilin city and Haerbin city in 2005. An uncontaminated sediment profile was taken in the Nen River at the same time. Total concentrations of Al, Fe, Mg, Ca, K, Na, Ti, Mn, V, Sc, Co, Cu, Cr, Ni, Pb and Zn in the sediment samples were measured by ICP-MS or ICP-OES, following digestion with various acids. Concentrations of Co, Cu, Cr, Ni, Pb and Zn in the surface sediments were 5.1-14.7, 18.5-78.9, 2.4-75.4, 7.2-29.0, 13.5-124.4, and 21.8-403.1 mg/kg, respectively, generally decreasing along the course of the river from Jilin city to Haerbin city. Background concentrations of trace metals were reconstructed by geochemical normalization to a conservative element scandium. Results showed that concentrations of Co, Cr, and Ni in the sediment were generally only slightly higher than or equal to their background values, while concentrations of Cu, Pb, and Zn in the some sediment samples were significantly higher than their background values. In detail, the sediment at Jilin city was moderately contaminated by Cu, and the sediment of the Second Songhua River was moderately contaminated by Pb and Zn. The top layer (0-10 cm depth) and bottom layers (30-46 cm depth) of one sediment profile at Wukeshu town were generally moderately polluted by Pb and Zn. Synthetically, the surface sediment in the studied river section was classified as natural sediment without ecological risk by the sediment pollution index (SPI) of Cu, Cr, Ni, Pb and Zn. Only the 30-45 cm depth of the sediment profile at Wukeshu town was classified as low polluted sediment by the SPI of these metals, recording a historical contamination of the river in the 1960s to 1970s. This buried contamination of trace metals might pose a potential risk to water column under disturbance of sediment.

Taraxerol and Rhizophora pollen as proxies for tracking past mangrove ecosystems