Total Dissolved Solids Load Research Articles

A study of celestine equilibrium in marine sediments using the entire ODP/IODP porewater data base

The stability of celestine (SrSO 4) in marine sediments has been investigated through the calculation of its saturation index at the in situ temperature and pressure, using the entire ODP/IODP porewater composition data base (14,416 samples recovered from sediments collected during 95 ODP and IODP Legs) that has been thoroughly corrected for missing data and inconsistencies. The porewater in situ pressure has been obtained from depth data, and the in situ sample temperature has been calculated from the bottom seawater temperature and from the measured thermal gradient. When the latter is unavailable, a default value of 35 °C/km or an assumed gradient similar to that of a site located close to the study area has been used. Molarities have been converted to molalities through the calculation of the porewater densities, which have represented by an empirical function of the total dissolved solids load up to 150 g/L. Ocean bottom waters are largely undersaturated with respect to celestine. Yet sediment porewater saturation is not uncommon: it is reached in 83 boreholes (i.e. about 10% of all boreholes) drilled during 22 ODP/IODP Legs. Celestine equilibrium can be reached through two different non-exclusive causes: a strontium increase in porewater linked to the dissolution of Sr-rich aragonite or biogenic calcite and precipitation of Sr-poor calcite (carbonate recrystallization), or an increase in the strontium and sulfate porewater concentrations linked to a salinity increase due to the presence of brines. Sediments at most of the sites exhibiting celestine equilibrium share common characteristics such as a carbonate-rich lithology (typically higher than 80 wt.%) and a low organic carbon content (generally below 1 wt.%). These results indicate that modification of porewaters during burial diagenesis can easily lead to celestine saturation, especially in carbonate-rich sediments. We then briefly discuss former interpretations of the presence of celestine in ancient and recent marine sediments, as well as the consequences of the incorporation of celestine formation in diagenetic models using the porewater Sr content and Sr isotopic composition.

Chemical evolution of shallow playa groundwater in response to post-pluvial isostatic rebound, Honey Lake Basin, California–Nevada, USA

The 1,750-km2 endorheic Honey Lake basin (California–Nevada, USA) was part of the 22,000-km2 Pleistocene Lake Lahontan pluvial lake system which existed between 5,000 and 40,000 years BP. The basin consists of two subbasins separated by a low elevation divide. Groundwater in the western subbasin has a maximum total dissolved solids (TDS) content of only ∼1,300 mg/L; however eastern subbasin groundwater has a maximum TDS of ∼46,000 mg/L. This TDS distribution is unexpected because 94% of surface water TDS loading is to the western subbasin. In situ reactions and upwelling thermal groundwater contributing to groundwater chemistry were modeled using NETPATH. The TDS difference between the subbasins is attributed to post-Lake Lahontan isostatic rebound about 13,000 years ago. Prior to rebound the subbasins did not exist and the low point of the basin was in the eastern area where hydraulic isolation from the larger Lake Lahontan and frequent desiccation of the basin surface water resulted in evaporite mineral deposition in accumulating sediments. After rebound, the terminal sink for most surface water shifted to the western subbasin. Although most closed basins have not been impacted by isostatic rebound, results of this investigation demonstrate how tectonic evolution can impact the distribution of soluble minerals accumulating in shallow basins.

Assessing Uncertainty in Mass Balance Calculation of River Nonpoint Source Loads

Several sources of uncertainty are considered in using field data to perform mass balance calculations to estimate nonpoint source (NPS) loads of total dissolved solids (TDS) and selenium (Se) to two reaches along the Lower Arkansas River in Colorado. This approach renders stochastic models of the mass balance equations for each river reach, where the input variables and their associated parameters are treated as random variables described by probability distributions. A data set collected in an intensive field effort conducted over several years is used in developing the models. Monte Carlo simulation solves the stochastic mass balance equations to describe distributions of possible values of the NPS loads. Results indicate that uncertainty in these calculated loads is sizeable. Annual average coefficient of variation (CV) in calculated total NPS TDS loads for sample periods within the two reaches ranges between 0.15 and 2.76, averaging about 1.1. For the Se mass balance along the downstream reach, the average CV in calculated loads is 0.23. The 90% prediction interval width for total NPS TDS load averaged over the 58 sample periods along the upstream reach is 13,691 (kg/day)/km, compared to an overall average mean load of 8,383 (kg/day)/km. It is 8,545 (kg/day)/km averaged over the 61 sample periods downstream, compared to an overall average mean load of 11,183 (kg/day)/km. For the Se load, the overall average 90% prediction interval width is also substantial compared to the overall average mean: 0.028 (kg/day)/km compared to 0.038 (kg/day)/km. Change in stored solute mass within the river over sample periods is found to be a major contributing factor to the calculation of NPS loads. Also, sensitivity analyses are performed that yield information on the relative influence that the degree of uncertainty in each random parameter has on the uncertainty in the calculated solute loads.

Quantifying contributions to stream salinity using electromagnetic induction and hydrochemistry in a small Texas coastal-plain basin

Airborne, ground, and borehole electromagnetic (EM) induction measurements were combined with surface-water chemical analyses to determine the extent of salinization as well as identify salinity sources and migration mechanisms that elevate total dissolved solids (TDS), Cl −, and SO 4 2 - concentrations in Petronila Creek, a shallow stream that drains a small (1600 km 2) basin on the Texas coastal plain. A multifrequency airborne EM induction survey measured apparent electrical conductivity of the ground to depths of a few tens of meters along the axis of the stream and along parallel flight lines within a 150 km 2 area extending from where the stream is fresh to the estuarine mixing zone. Apparent conductivity sections and maps were analyzed to identify stream segments where high conductivity indicates near-surface salinization and where saline baseflow increases the salinity load. Elevated conductivities at shallow depths beneath the stream lie adjacent to extensive conductive areas in oil fields and along ditches that once carried brine produced from the oil fields. These highly conductive areas delineate salinization that dominantly is caused by past discharge of produced brine into ditches and pits, infiltration into sandy, permeable horizons, lateral subsurface migration, and eventual discharge into the stream. Streamflow measurements and chemical analyses show that the TDS load increased along two highly conductive streambed segments upstream from the estuarine mixing zone. Extensive salinization between the ditches and the stream could provide a continuing source of salinity. A third highly conductive segment coincides with the zone of estuarine mixing, where there is geophysical evidence of possible subsurface seawater intrusion. Multifrequency EM induction spectral images (the sectional depiction of apparent conductivity measured at multiple frequencies) along the stream axis, produced with minimal geophysical processing, helped identify stream segments that receive saline baseflow and guided surface-water sampling that allowed quantification of salinity loads. Apparent conductivity maps helped determine the salinization extent and identify salinity sources and migration mechanisms. Both the stream-axis and gridded airborne EM surveys were effective approaches to investigate salinization and interaction between ground water and surface water in this small basin, but multifrequency stream-axis images are a more practical alternative in larger basins where discrete salinity sources are poorly known.

SPECTRAL CHARACTERIZATION OF AQUATIC NUTRIENTS AND WATER QUALITY PARAMETERS IN MARINE ENVIRONMENT.

Water bodies are often induced with high concentrations of pollutants due to increased aquaculture and other development activities in marine zones. Remote sensing is an effective technique for monitoring marine environment. This study focuses on determining the appropriate spectral band for monitoring nutrients received from shrimp farms and other aquaculture activities and also from decomposed materials from mangrove forests. The study area considered was Ranong marine zone of western seaboard of Thailand. Appropriate spectral bands for monitoring major aquatic nutrients like Ammonia Nitrogen, Phosphate Phosphorous, Total Suspended Solids (TSS) and Total Dissolved Solids (TDS) were investigated using band suitability analysis. Spectral characterization of these parameters was done using image acquired by Landsat-5 TM and IRS 1C sensors for two different years: 1993 and 2000. The digital numbers of both images were analyzed for different pollution status. All these pollutant parameters were exponentially related to digital numbers whereas TSS was linearly related. Only TDS had negative and exponential correlation with the digital number. It was found that red, and SWIR are best suitable bands for tracking nutrients and TDS load by remote sensing.

Physical and chemical properties of the Sulphur Mountain thermal springs, Banff National Park, and implications for endangered snails

Nine thermal springs, in three groups, occur along the flank of Sulphur Mountain in Banff National Park. The principal recharge zone is suggested to be above 2000 m elevation on Mount Rundle, circulation depths are estimated to be 3.2 ± 0.6 km, and discharge is focused along the Sulphur Mountain Thrust. Springs show constant temperature and total dissolved solids load throughout the winter, whereas both drop in association with spring snowmelt. The degree and timing of temperature drops are a function of elevation, with the highest springs showing the earliest and most significant temperature drop. The highest elevation springs also show the greatest seasonal variability in water chemistry. Unusual seasonal flow stoppages of these springs are related to extreme low precipitation years. The biogeochemistry of the thermal springs and population fluctuations of the endemic and endangered Banff springs snail (Physella johnsoni) are strongly related to seasonal variability in flow rates. Changes in redox conditions associated with an influx of shallow groundwater during spring snowmelt negatively impact the microbial community that forms a principal food supply for the snail.

Short term fluctuations in dissolved organic matter concentrations in streamflow draining a forested watershed and their relation to the catchment budget

AbstractDissolved organic matter (DOM) concentrations in throughfall, throughflow, and runoff were recorded in a small (95 ha) woodland catchment in North Warwickshire for a period of eight weeks following a prolonged dry spell. DOM is shown to be positively related to stream discharge over the sampling period, although distinctive flushing effects were identified. The net contribution of DOM to total dissolved solids load carried in the river was only 2.4 per cent, and represented significantly less than published carbon losses by mineralization of soil organic matter. Throughfall inputs were some 100 times higher than streamflow outputs from the catchment.

Other side of the Ashulia wetland: a limnological purview

Limnology of a temporary wetland Ashulia was found highly seasonal. Fluctuations of water depth, water temperature, Secchi depth, pH, conductivity, total dissolved solids, dissolved oxygen and alkalinity were studied in three different stations for one year. Water depth showed a range of 1.5 - 4.2 m and Secchi disc transparency from 0.07 - 2.15 m. Annual ranges in respect of pH, conductivity, total dissolved solids (TDS), dissolved oxygen (DO) and alkalinity of water varied from 6.3 -7.2, 92 - 1028 μS/cm,43.4 - 491.0 mg/l, 4.3 - 28.9 mg/l, and 0.71 - 6.45 meq/l, respectively. The wetland showed a good to moderate water quality during rainy season because in this season visibility of water increased, TDS load, alkalinity and conductivity came down to their lowest. Dissolved oxygen content also showed an acceptable water quality value during rainy season. Key words: Wetland; Physical factors; Chemical factors; Limnology; Phytoplankton; Macrophytes DOI: http://dx.doi.org/10.3329/dujbs.v19i1.8940 DUJBS 2010; 19(1): 21-26