Cleaning the river Damodar (India): impact of COVID-19 lockdown on water quality and future rejuvenation strategies

Globally, it is established that the partial lockdown system assists to improve the health of the total environment due to inadequate anthropogenic actions in different economic sectors. The ample research on fitness of environment has been proved that the strict imposition of lockdown was the blessings of environment. The river Damodar has historical significance and lifeline for huge population of Jharkhand and West Bengal state of India but in the recent years the water quality has been deteriorated due to untreated industrial effluents and urban sewage. The main objective of this study is to examine the water quality of river Damodar during and prelockdown phase for domestic use and restoration of river ecosystem. A total of eleven (11) effluent discharge sites were selected in prelockdown and during lockdown phase. A new approach of water quality assessment, i.e., water pollution index (WPI) has been applied in this study. WPI is weightage free, unbiased method to analysis of water quality. The result shows that the physical, chemical and heavy elements were found beyond the standard limit in prelockdown period. The cation and anion were arranged in an order of Na²⁺ ?>?K⁺ ?>?Ca²⁺ ?>?Mg²⁺ and Cl^??>?So₄^??>?No₃^??>?F^? in both the sessions. WPI of prelockdown showed that about 100% water samples are of highly polluted. WPI of lockdown period showed that around 90.90% samples improved to ‘good quality’ and 9.10% of samples are of ‘moderately polluted.’ Hypothesis testing by ‘t’ test proved that there was a significant difference (ρ?=?0.05%) in values of each parameter between two periods. Null hypothesis was rejected and indicated the improvement of river water quality statistically. Spatial mapping using Arc GIS 10.4 interpolation (IDW) helps to understand spatial intensity of pollution load in two periods. This research study should be helpful for further management and spatial diagnosis of water resource of river Damodar.

     

Perchlorate contamination of groundwater from fireworks manufacturing area in South India

Perchlorate contamination was investigated in groundwater and surface water from Sivakasi and Madurai in the Tamil Nadu State of South India. Sensitive determination of perchlorate (LOQ?=?0.005 μg/L) was achieved by large-volume (500 μL) injection ion chromatography coupled with tandem mass spectrometry. Concentrations of perchlorate were <0.005–7,690 μg/L in groundwater (n?=?60), <0.005–30.2 μg/L in surface water (n?=?11), and 0.063–0.393 μg/L in tap water (n?=?3). Levels in groundwater were significantly higher in the fireworks factory area than in the other locations, indicating that the fireworks and safety match industries are principal sources of perchlorate pollution. This is the first study that reports the contamination status of perchlorate in this area and reveals firework manufacture to be the pollution source. Since perchlorate levels in 17 out of 57 groundwater samples from Sivakasi, and none from Madurai, exceeded the drinking water guideline level proposed by USEPA (15 μg/L), further investigation on human health is warranted.     

Oxidative destabilization of dissolved organics and E. coli in domestic wastewater through immobilized cell reactor system

Domestic wastewater contains a considerable amount of pathogenic organisms besides non-biodegradable organics. The conventional technologies followed for the treatment of domestic wastewater are less efficient in removing pathogenic organisms despite substantial removal of dissolved organics. The focal theme of the present investigation was to use a chemo-autotrophic activated carbon oxidation (CAACO) system, an immobilized cell reactor using chemoautotrophs (Bacillus sp.) for the treatment of domestic wastewater. The oxidation of organics and Escherichia coli in wastewater is controlled by the parameters space time, O(2)/COD, bed height and cod loading. The scheme comprised of anaerobic treatment, sand filtration and CAACO treatment removed BOD. COD, Total organic carbon (TOC), dissolved protein, total Kjeldhal nitrogen (TKN) and bacterial count (most probable number (MPN)) by 81%, 92%, 84%, 94%, 93% and 99.9997%, respectively. The low concentration of E. coli in the CAACO-treated wastewater was completely eliminated through UV irradiation in 3 min at 254 nm.     

Investigation of groundwater quality in hardrock terrain using Geoinformation System

Two hundred sample sites were selected systematically and samples were taken for a baseline study to understand the geochemistry of the groundwater and to assess the overall physicochemical characteristics. Sampling was carried out using pre-cleaned polyethylene containers. The physical and chemical parameters of the analytical results of groundwater were compared with the standard guideline values recommended by the World Health Organization for drinking and public health standards. Thematic maps pertaining to TDS, EC, Cl, NO₃, SO₄, and Na were generated using Arc View 3.1 platform. Results showed that most of the locations are contaminated by higher concentration of EC, TDS, K^?+?, and NO $_{3}^{\;-}$ . Major hydro-chemical facies were identified using Piper trilinear diagram. Based on US salinity diagram, most of the samples fall in the field of C3-S1 indicating high salinity and low sodium water, which can be used for almost all types of soil with little danger of exchangeable sodium. Majority of the samples are not suitable for domestic purposes and far from drinking water standards. However, PI values indicate that groundwater is suitable for irrigation.     

Fluorine contamination in groundwater: a major challenge

Fluoride in high concentration in groundwater has been reported from many parts of India. However, a systematic study is required to understand the behavior of fluoride in natural water in terms of local hydrogeological setting, climatic conditions, and agricultural practices. The present study is an attempt to assess hydrogeochemistry of groundwater in parts of Palar river basin pertaining to Kancheepuram district Tamil Nadu to understand the fluoride abundance in groundwater and to deduce the chemical parameters responsible for the dissolution activity of fluoride. The study area is geologically occupied by partly sedimentary and partly crystalline formations. A total of 50 dug cum borewell-water samples, representing an area of 2,628.92 km². The results of the chemical analyses in September 2009 show fluoride abundance in the range of 1 to 3.24 mg/l with 86% of the samples in excess of the permissible limit of 1.5 mg/l. Presence of fluoride-bearing minerals in the host rock, chemical properties like decomposition, dissociation, and dissolution, and their interaction with water are considered to be the main causes for fluoride in groundwater. Chemical weathering with relatively high alkalinity favors high concentration of fluoride in groundwater. Villagers who consume nonpotable high fluoride water may suffer from yellow, cracked teeth; joint pains; and crippled limbs and also age rapidly.     

Major ion chemistry and hydrochemical studies of groundwater of parts of Palar river basin, Tamil Nadu, India

Groundwater is almost globally important for human consumption as well as for the support of habitat and for maintaining the quality of base flow to rivers, while its quality assessment is essential to ensure sustainable safe use of the resources for drinking, agricultural, and industrial purposes. In the current study, 50 groundwater samples were collected from parts of Palar river basin to assess water quality and investigate hydrochemical nature by analyzing the major cations (Ca, Mg, Na, K) and anions (HCO(3), Cl, F,SO(4), NO(3), PO(4),CO(3), HCO(3), and F) besides some physical and chemical parameters (pH, electrical conductivity, alkalinity, and total hardness). Also, geographic information system-based groundwater quality mapping in the form of visually communicating contour maps was developed using ArcGIS-9.2 to delineate spatial variation in physicochemical characteristics of groundwater samples. Wilcox classification and US Salinity Laboratory hazard diagram suggests that 52% of the groundwater fall in the field of C2-S1, indicating water of medium salinity and low sodium, which can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. Remaining 48% is falling under C1-SI, indicating water of low salinity and low sodium.     

The fetal circulation

Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow. Copyright © 2004 John Wiley & Sons, Ltd.     

Immobilized reactor for rapid destruction of recalcitrant organics and inorganics in tannery wastewater

The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic activated carbon oxidation(CAACO) reactor, an immobilized cell reactor using chemoautotrophs for the treatment of tannery wastewater. The treatment scheme comprised of anaerobic treatment, sand filtration, and CAACO reactor, which remove COD, BOD, TOC, VFA and sulphides respectively by 86%, 95%, 81%,71% and 100%. Rice bran mesoporous activated carbon prepared indigenously and was used for immobilization of chemoautotrophs. The degradation of xenobiotic compounds by CAACO was confirmed through HPLC and FT-IR techniques.     

Synthesis of SnO2 quantum dots mediated by Camellia sinensis shoots for degradation of thiamethoxam

Abstract

A novel method of synthesis of tin dioxide quantum dots employing Camellia sinensis shoots as reducing agent and stabilizer is presented. The quantum dots were characterized by UV spectroscopy, X-Ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The crystalline tin dioxide quantum dots with an average size of 4.3?nm were of flake like morphology capped by phenolic compounds of Camellia sinensis. The quantum dots were employed for the photocatalytic degradation of thiamethoxam resulting in 57% degradation within 45 mins.