Major-Ion Chemistry and Quality of Water in Rivers of Northern West Siberia

This study reports a synthesis of years-long hydrogeochemical monitoring in northern West Siberia, performed by the Russian Meteorological Service (Rosgidromet) and several academic institutions. Natural factors and intensive human economic activity lead to the disruption of the ecosystems of the northern territories of Western Siberia. The aim of this study is to estimate the background water chemistry parameters in the rivers of northern West Siberia in the beginning of the 21st century. The mean values hydrochemical and geochemical indicators were determined with STATISTICA software, which can be used as background values in assessing the actual and allowable anthropogenic impact on water bodies. We revealed four water chemistry provinces: western Ob Gulf and Ob estuary catchments (I); eastern Ob Gulf and Taz Gulf catchments, except for the Taz River and its tributaries (II); Taz River catchments (III); Yenisei River catchments, right bank (IV). The major-ion chemistry of the sampled river waters records a combination of geological, geomorphological, and hydrological conditions in the four provinces. The features typical of the northern West Siberian Plain are especially prominent in province II, which has the lowest average total of major ions (Σmi), the highest chemical oxygen demand (potassium dichromate COD), and the highest contents of Fe and phosphates. The Σmi value is the highest in province IV. The river waters from four provinces share similarity in quite high organic contents (both potassium dichromate and permanganate COD), as well as high NH4+ and Fe. The long-term average Σmi of the waters is predicted not to change much in the coming one or two decades, though it may decrease slightly in the winter season but increase in the fall and spring time.

Machine Learning Can Assign Geologic Basin to Produced Water Samples Using Major Ion Geochemistry

Understanding the geochemistry of waters produced during petroleum extraction is essential to informing the best treatment and reuse options, which can potentially be optimized for a given geologic basin. Here, we used the US Geological Survey’s National Produced Waters Geochemical Database (PWGD) to determine if major ion chemistry could be used to classify accurately a produced water sample to a given geologic basin based on similarities to a given training dataset. Two datasets were derived from the PWGD: one with seven features but more samples (PWGD7), and another with nine features but fewer samples (PWGD9). The seven-feature dataset, prior to randomly generating a training and testing (i.e., validation) dataset, had 58,541 samples, 20 basins, and was classified based on total dissolved solids (TDS), bicarbonate (HCO3), Ca, Na, Cl, Mg, and sulfate (SO4). The nine-feature dataset, prior to randomly splitting into a training and testing (i.e., validation) dataset, contained 33,271 samples, 19 basins, and was classified based on TDS, HCO3, Ca, Na, Cl, Mg, SO4, pH, and specific gravity. Three supervised machine learning algorithms—Random Forest, k-Nearest Neighbors, and Naïve Bayes—were used to develop multi-class classification models to predict a basin of origin for produced waters using major ion chemistry. After training, the models were tested on three different datasets: Validation7, Validation9, and one based on data absent from the PWGD. Prediction accuracies across the models ranged from 23.5 to 73.5% when tested on the two PWGD-based datasets. A model using the Random Forest algorithm predicted most accurately compared to all other models tested. The models generally predicted basin of origin more accurately on the PWGD7-based dataset than on the PWGD9-based dataset. An additional dataset, which contained data not in the PWGD, was used to test the most accurate model; results suggest that some basins may lack geochemical diversity or may not be well described, while others may be geochemically diverse or are well described. A compelling result of this work is that a produced water basin of origin can be determined using major ions alone and, therefore, deep basinal fluid compositions may not be as variable within a given basin as previously thought. Applications include predicting the geochemistry of produced fluid prior to drilling at different intervals and assigning historical produced water data to a producing basin.

A Study on Groundwater Quality Based on Major Ion Chemistry of Jharkhand State in India: A Review

Groundwater is prime and major source of drinking water in our world. Groundwater in Jharkhand is also used for drinking, domestic, irrigation, mining and industrial etc. purposes. In Jharkhand some population are suffering from scarcity of pure drinking water and some population have partial facility with drinking water as groundwater of many area of Jharkhand are contaminated with fluoride, arsenic, heavy metals and iron etc. dangerous chemicals. This review paper focuses on current status of groundwater and contamination of different water quality parameters based on major ion chemistry in Jharkhand. The discussed water quality parameters in this study are water temperature, pH, electrical conductivity, total dissolved solid, total hardness, calcium, magnesium, iron, sodium, potassium, chloride, fluoride, arsenic, carbonate, bicarbonate, phosphate, nitrate and sulphate.

Sensitivity Analysis of Ion Channel Conductance on Myocardial Electromechanical Delay: Computational Study

It is well known that cardiac electromechanical delay (EMD) can cause dyssynchronous heart failure (DHF), a prominent cardiovascular disease (CVD). This work computationally assesses the conductance variation of every ion channel on the cardiac cell to give rise to EMD prolongation. The electrical and mechanical models of human ventricular tissue were simulated, using a population approach with four conductance reductions for each ion channel. Then, EMD was calculated by determining the difference between the onset of action potential and the start of cell shortening. Finally, EMD data were put into the optimized conductance dimensional stacking to show which ion channel has the most influence in elongating the EMD. We found that major ion channels, such as L-type calcium (CaL), slow-delayed rectifier potassium (Ks), rapid-delayed rectifier potassium (Kr), and inward rectifier potassium (K1), can significantly extend the action potential duration (APD) up to 580 ms. Additionally, the maximum intracellular calcium (Cai) concentration is greatly affected by the reduction in channel CaL, Ks, background calcium, and Kr. However, among the aforementioned major ion channels, only the CaL channel can play a superior role in prolonging the EMD up to 83 ms. Furthermore, ventricular cells with long EMD have been shown to inherit insignificant mechanical response (in terms of how strong the tension can grow and how far length shortening can go) compared with that in normal cells. In conclusion, despite all variations in every ion channel conductance, only the CaL channel can play a significant role in extending EMD. In addition, cardiac cells with long EMD tend to have inferior mechanical responses due to a lack of Cai compared with normal conditions, which are highly likely to result in a compromised pump function of the heart.

Groundwater quality assessment of domestic shallow dug wells in parts of Tanah Merah district, Malaysia

Groundwater resources have become an important fresh water supply due to its increasing demandsfor agricultural, drinking and industrial uses. Groundwater is often contaminated by the process ofindustrial development and suburbanization that has gradually advanced over time without anyconcern for environmental consequences. The objective of this study is to analyse the groundwaterquality of shallow dug wells in parts of Tanah Merah district by conducting quality assessment ofgroundwater using WHO and MHO guide lines. Groundwater samples were collected from dugwells uniformly spread out across the study area to investigate the major ion chemistry of thegroundwater as well as physical parameter. The major ion being investigated are sodium,magnesium, calcium, potassium, sulphate, nitrate, chloride and bicarbonates. Various methods havebeen were employed to determine the major ions concentration in the samples such as atomicabsorption spectrophotometer for cations, gravimetric method for sulphates, titration method forchloride and bicarbonates and colorimetric method for nitrate ion. From the analysed data’s, mostwells are safe for drinking purpose although quite a small amount of ion concentration has surpassedthe permissible limit set by WHO and MOH. The graphical presentation of major ion chemistryaids in identifying two types of groundwater. Ionic species such as Na-K-HCO3 and mixed typewaters are likely to occur in the groundwater system. The analysed major ions concentrationsindicates that majority of the shallow dug wells reported adequate or lower values compared topermissible limit which are safe and can be utilized for various domestic purposes includingdrinking. Several recommendations has been suggested to proliferate the groundwater quality suchas strictly monitoring and supervising the dissipation of waste such as pesticides, industrial effluentand domestic sewage into the aquifer.