M. Sowmya

Bio: M. Sowmya is an academic researcher from Indira Gandhi Centre for Atomic Research. The author has contributed to research in topics: Water quality & Computer network. The author has an hindex of 3, co-authored 4 publications receiving 58 citations.

Formation and speciation characteristics of brominated trihalomethanes in seawater chlorination.

Abstract: Formation character of brominated-trihalomethanes (Br-THMs) in chlorinated seawater and its dependence on applied chlorine dose, reaction time, and temperature were investigated in the laboratory. Seawater was collected from the east coast of India and a chlorine dose of 1, 3, 5, and 10 ppm was each applied at a temperature of 20, 30, and 40 degrees C to investigate the yield and kinetics of Br-THMs formation. Qualitative and quantitative estimation of THM formation at various intervals of time ranging from 5 min to 168 h was determined by a gas chromatograph equipped with an electron capture detector (GC-ECD). Chlorine dose, chlorine contact time, and reaction temperature positively affected the load of THMs. The ratio of chlorine dose to halogen incorporation decreased from 12% to 5% with increasing applied chlorine dose from 1 to 10 ppm. Significant levels of THMs were found to be formed within 0.5 h of reaction, followed by a very slow rate of formation. Elevated temperature favored both increased rate of formation and overall THM yield. The formation order of different trihalomethane species at all studied temperatures was observed to be bromodichloromethane (CHCl2Br) < dibromochloromethane (CHClBr2) < bromoform (CHBr3). Formation of chloroform was not observed, and bromoform was the dominant (96% to 98%) among the three THM species formed.

Groundwater nitrate contamination and use of Cl/Br ratio for source appointment

Abstract: Source appointment for groundwater nitrate contamination is critical in prioritizing effective strategy for its mitigation Here, we assessed the use of Cl/Br ratio and statistical correlation of hydro-chemical parameters to identify the nitrate source to the groundwater A total of 228 samples from 19 domestic wells distributed throughout the study area were collected during June 2011–May 2012 and analyzed for various physicochemical parameters Study area was divided into three spatial zones based on demographic features, viz, northern, southern, and central part Nitrate concentration in 57 % of samples exceeded the prescribed safe limit for drinking stipulated by the World Health Organization (WHO) and Bureau of Indian standards (BIS) The central part of the study area showed elevated nitrate concentration ranging from below detection limit (BDL) to 2635 mg/l as NO3 − and demonstrated high attenuation within the immediate vicinity thereby restricting diffusion of the nitrate to the adjacent parts Resolution of correlation matrix as statistical indicator for nitrate contamination was poor Seventy-seven percent of samples with high nitrate concentration (>45 mg/l as NO3 −) showed strong association with high Cl/Br mass ratio (350–900), indicating mixing of sewage and septic tank effluents with groundwater as a primary source for the nitrate in the studied area Nitrate level during monsoon (BDL, 2299 mg/l as NO3 −), post-monsoon (BDL, 2635 mg/l as NO3 −), and pre-monsoon (05–2231 mg/l as NO3 −) indicated additional contribution of surface leaching to groundwater

Fluoride in ground water: a comment on "Fluorine contamination in ground water: a major challenge" published in Environmental Monitoring and Assessment, (2011) 173, 955-968.

Abstract: The objective of this paper is to highlight the erroneous map used in depicting the sampling locations, reported high fluoride values, and other minor mistakes published by Dar et al. (2011) for the benefit of the scientific community. It is estimated that about 80% of the diseases in the world are attributed to poor quality of drinking water, and fluoride contamination in drinking water is responsible for 65 % of endemic fluorosis in the world (WHO 1984). Fluorosis is a non curable disease so far, and its severity depends on the fluoride concentration and the intake. In India, more than 90 % of the villages use groundwater for drinking and 50 % of these sources are contaminated with fluoride. In fact, a prevalence of dental fluorosis is responsible to affect more than 40 million people in India (Karthikeyan et al. 2005). Therefore, fluoride concentration in groundwater needs to be monitored to assess its suitability for consumption. Occurrence of high fluoride content in groundwater can be associated with diverse geological environments; ranging from sedimentary rocks (Battaleb-Looie et al. 2012) to crystalline rocks (Jacks et al. 2005; D’Alessandro et al. 2008) and to volcanic aquifers (Gaciri and Davies 1993; Ashley and Burley 1995; Tekle-Haimanot et al. 2006; Vivona et al. 2007; Rango et al. 2009). Considering the value attached to the fluoride contamination in ground water, any monitoring investigation must be carried out with high scientific standards at each stage such as sampling, analysis, interpretation and data presentation. A paper entitled “Fluorine contamination in ground water: a major challenge” published in Environmental Monitoring and Assessment by Dar et al. (2011) reported the groundwater fluoride concentration for Kancheepuram district of Tamil Nadu, India. In this paper, some of the locations have been implicated to contain relatively high fluoride content. A close scrutiny of the paper revealed error with regard to the sampling location itself. Considering the importance of the investigated site and their fluoride content for the public and government, it is essential to clarify the mistakes. In this paper, we have discussed the drawbacks such as (a) the use of erroneous sampling locationmap resulting inwrong implications on the outcome of the study, (b) non-conformance of hydrochemical data with respect to ionic balance, a prerequisite in water quality analyses and (c) reported high fluoride values for a specific site which has subsequently been studied by us. Spatial presentation of data in water quality monitoring studies has considerable scientific and management implication. Name of the sampling locations (village/town) may be familiar to a limited researcher belonging to the same area; however, for important geographical information to universal readers, providing the correct map of the sampling sites is a scientific need. Thus, any error in identifying sampling points in the map greatly distorts the study results and hence nullifies the very purpose of the study. Errors in the sampling location map used by Environ Monit Assess (2014) 186:2159–2163 DOI 10.1007/s10661-013-3525-4

Mobile Ad-hoc Networks: A Survey on multipath routing protocols

Abstract: A Mobile Ad Hoc Network (MANETs) connects mobile nodes without any base station. These nodes in the network can change the topology dynamically and transfer the data among themselves. The nodes in the MANET are categorized based on the resource factors like memory, computation, and power levels. The dynamic change in route makes the connection of the destination node more complex. Sometimes, it results in link failure, and hence the primary route is failed, which means an alternative route is required to transmit the packets. It required multiple paths from the source node to destination node with a stable path connecting the source node. This issue makes MANET routing a crucial task. To address these problems, multipath routing in MANET is discussed in this paper. Multipath routing provides various paths for a single source node to a single destination node. It is more important to consider load balancing and fault tolerance when establishing the multipath routing mechanism. This paper describes the various type of challenges along with their respective multipath routing protocols in MANETs.

GIS-based evaluation of groundwater geochemistry and statistical determination of the fate of contaminants in shallow aquifers from different functional areas of Agra city, India: levels and spatial distributions

Abstract: The quality of groundwater is very important in Agra because groundwater is the main source of water for drinking, domestic, agricultural and industrial uses. A groundwater geochemistry study was conducted in Agra where 28 samples were collected from shallow aquifers in May 2016 from different sites. The aim of this research was to assess the quality of groundwater for drinking purposes in the study area. Arc-GIS has been used to prepare geographic information system-based spatial distribution maps of different major elements. The groundwater quality was analyzed for various physico-chemical parameters, major cations and anions and some trace metals. The observed values were compared with BIS and WHO standards. Statistical parameters such as the mean, median, standard deviation, skewness and kurtosis were used to analyze the hydrogeochemical characteristics of the groundwater. Correlation coefficient analysis and principal component analysis (PCA) were performed to identify the sources of the water constituents. Our results showed that most of the samples exceeded the acceptable limit for drinking water standards. The sequence of abundance of the main cations was generally Na+ > Ca2+ > Mg2+ > K+, while the anions in order of abundance were HCO3− > Cl− > SO42− and NO3− > F−. All of the trace metals were within the permissible limit except for iron and manganese. The hazard index value of 5.7 × 10−2 indicated that there was no potential health risk in the study area. Ca2+, Mg2+, Cl− and SO42− were the dominant hydrogeochemical facies in the majority of the groundwater samples. Most of the parameters such as TDS, Cl−, HCO3−, SO42−, NO3−, Ca2+, Mg2+, Na+, K+ and TH showed strong correlations with each other, which were due to natural processes such as weathering, exchangeable ions and reduction/oxidation, as well as anthropogenic activity around the study area. The water quality index indicated that the water quality was poor at 46.43% of the sampling sites, very poor at 28.57% of the sites and unsuitable for drinking purposes at 25% of the sampling sites. Gibbs diagrams suggested rock weathering as a major driving force for controlling the groundwater chemistry in the study area, along with evaporation as a minor influence.