Nilotpal Das

Co-occurrence perspective of arsenic and fluoride in the groundwater of Diphu, Assam, Northeastern India

Considerable lacunae exists in As and F(-) co-contamination investigation in the Brahmaputra and Gangetic floodplains. Therefore we selected Diphu a township in the Karbi Plateau rising from the Brahmaputra floodplains for evaluation of As and F co-occurrence, correlation with coexisting ions of the aquifer system and elucidation of potential processes for releasing As and F(-) in the groundwater. Our initial appraisal used generic plots for identification of hydro geochemical processes and major water types. Subsequently, As and F(-) co-occurrence with pH, depth, HCO3(-), SO4(2-), Ca(2+) and Fe were probed for possible correlation followed by hierarchical cluster analyses to identify key processes for co-occurrence. Finally, saturation indices of groundwater minerals were calculated using MINTEQA2 to elucidate prospective As and F(-) release into groundwater. Results indicate F(-) and As presence in Ca-HCO3 rich water along with positive correlation between Ca(2+) and F(-) possibly due to limestone reserves in adjoining areas. Multivariate analyses suggest the presence of high concentrations of PO4(3-), and H4SiO4 either individually or in combination can enhance the mobility of both As and F(-) and possibly abet conditions conducive for co-contamination of aquifers. Initial release of As and F(-) from the parent rock seems driven by the anthropogenic activities while mobilization depends on chemical interactions and individual affinities of the elements. The results of speciation highlight further mobilization of As and F(-) into the groundwater which in turn require regular attention for sustainable management of scarce water resource present in the area.

Hydrogeochemical controls on mobilization of arsenic and associated health risk in Nagaon district of the central Brahmaputra Plain, India.

Abstract In recent years, elevated concentration of arsenic (As) in groundwater in the northeastern states of India has become a major cause of concern. Since many regions of the Brahmaputra plains are reported with groundwater As contamination, an attempt was made to study the As contamination and factors governing its release in the Nagaon district in Brahmaputra floodplain, based on various water types, relation of As with other major ions and with various depth profiles. The origin of groundwater mineralization and the processes responsible for As enrichment in groundwater was determined by calculating saturation index using PHREEQC code. Multivariate statistical analysis was carried out for identification of As-releasing mechanism based on rock–water interaction. Principle component analysis of physicochemical parameters revealed the association of As with SiO2 and Cl− in pre-monsoon and the fact that alkaline condition favors release of As. The relation between As and Fe shows that reductive dissolution of solid Fe oxide and hydroxide phases could be the source of As in Nagaon district. The result of hierarchical cluster analysis indicates that As release could also be associated with the agrochemicals application. Health risk assessment revealed that children are more susceptible to carcinogenic as well as non-carcinogenic health impact with consumption of As-contaminated drinking water. The male population is more susceptible to cancer as compared to females as the average water consumption is higher in case of male. Overall, the study highlights the health risk assessment is a matter of chief concern in this study as the younger generation are at higher risk.

Problem, Perspective and Challenges of Arsenic Contamination in the Groundwater of Brahmaputra Flood Plains and Barak Valley Regions of Assam, India

The problem of naturally occurring As pollution in groundwater is a burning issue which has now been recognised as one of the greatest environmental hazards, threatening the lives of the millions across the globe (Nickson R, McArthur JM, Burgess W, Ahmed KM, Ravenscroft P, Rahman M, Nature 395:338, 1998, Nickson RT, McArthur JM, Ravenscroft P, Burgess WG, Ahmed KM, Appl Geochem 15(4):403–413, 2000; Smith AH, Lingas EO, Rahman M, Bull World Health Organ 78(9):1093–1103, 2000; Berg M, Tran HC, Nguyen TC, Pham HV, Schertenlrib R, Giger W (2001), Environ Sci Technol 35:2621–2626, 2001; Anawar HM, Akai J, Mostofa KMG, Safiullah S, Tareq SM, Environ Int 27:597-604, 2002; Smedley PL, Kinniburgh DG, Appl Geochem 17(5):517–568, 2002; Guo HM, Wang YX, Shpeizer GM, Yan SL, J Toxicol Environ Health Part A, Environ Sci Eng Toxic Hazard Subst Control 38:2565–2580, 2003; Ravenscroft P, Burgess GW, Ahmed KM, Burren M, Perrin J, Hydrogeol J 13:727–751, 2003; Smedley PL, Zhang M, Zhang G, Luo Z, Appl Geochem 18(9):1453–1477, 2003; Li J, Wang Z, Cheng X, Wang S, Jia Q, Han L et al, Chin J Endem 24:183–185, 2005; Polya DA, Gault AG, Diebe N, Feldman P, Rosenboom JW, Gilligan E et al, Mineral Mag 69:807–823, 2005; Anawar HM, Akai J, Yoshioka T, Konohira E, Lee JY, Fukuhara H, Tari Kul Alam M, Garcia Sanchez A, Environ Geochem Health 28:553–565, 2006; Enmark G, Nordborg D, Arsenic in the groundwater of the Brahmaputra floodplains, Assam, India – Source, distribution and release mechanisms. Committee of Tropical Ecology ISSN 1653–5634 minor field study 131. Uppsala University, Sweden, 2001; Nriagu et al. Arsenic in soil and groundwater: an introduction. In: Bhattacharya P, Mukherjee AB, Bundschuh J, Zevenhoven R, Loeppert RH (eds), Arsenic in soil and groundwater environment: biogeochemical interactions, health effects and remediation, trace metals and other contaminants in the environment, vol 9, (Ser ed Nriagu JO). Elsevier, Amsterdam, 2007; Kumar M, Kumar P, Ramanathan AL, Bhattacharya P, Thunvik R, Singh UK, Tsujimura M, Sracek O, J Geochem Explor 105:83–94, 2010a, Kumar P, Kumar M, Ramanathan AL, Tsujimura M, Environ Geochem Health 32:129–146, 2010b; Bundschuh J, Litter MI, Parvez F, Roman-Ross G, Nicolli Hugo B, Jean J-S, Liu C-W, Maria Dina L, Armienta A, Guilherme Luiz RG, Cuevas AG, Cornejo L, Cumbal L, Toujaguez R, One century of arsenic exposure in Latin America: a review of history and occurrence from 14 countries, 429:2–35, 2012). Long-term ingestion of drinking water having As concentration beyond the permissible limit of 50 μg/L leads to detrimental effects on human health. Epidemiological studies have shown that inorganic As is a serious toxicant and can cause a variety of adverse health effects, such as dermal changes, respiratory, pulmonary, cardiovascular, gastrointestinal, haematological, hepatic, renal, neurological, developmental, reproductive, immunologic lead to cancer and other degenerative effects of the circulatory and nervous system (Golub MS, Macintosh MS, Baumrind N, J Toxicol Environ Health Part B 1(3):199-241, 1998; Lin T-H, Huang Y-L, Wang M-Y, J Toxicol Environ Health 53:85–93, 1998; NRC 2001; Ahamed S, Kumar Sengupta M, Mukherjee A, Amir HM, Das B, Nayak B, Pal A, Mukherjee CS, Pati S, Nath DR, Chatterjee G, Mukherjee A, Srivastava R, Chakraborti D, Sci Total Environ 370(2–3):310–322, 2006). In view of the above perspective WHO in 1993 has lowered its earlier permissible limit of 50 μg/L in drinking water to 10 μg/L. The BIS has also endorsed 10 μg/L as the permissible limit for As in drinking water.

Tracing the Significance of River for Arsenic Enrichment and Mobilization

Arsenic contamination of groundwater has been found to be prominent in many of the flood plain regions of the world where recent Holocene sediments are predominant (Berg et al. 2008; Kumar et al. 2010; Shah 2010). Reductive hydrolysis of metal (hydr)oxides, particularly those of Fe has been found to be the dominant mode of As mobilization in groundwater of such regions (McArthur et al. 2001; Smedley and Kinniburgh 2002; Berg et al. 2008; Kumar et al. 2010). Some of the most well known regions with high groundwater As, where the aforementioned conditions have been detected are Bangladesh, India, Vietnam and Cambodia (Bhattacharya et al. 1997; Acharyya et al. 1999; Smedley and Kinniburgh 2002; Ahmed et al. 2004; Berg et al. 2007, 2008).

An Evaluation of Antibiotic Profile, Molecular Characterisation and Risk Factors Associated with Carbapenem Resistant Non Fermentative Gram Negative Isolates in a Tertiary Care Centre

1 Department of Microbiology, Armed Forces Medical College, Pune, Maharashtra, India 2 Department of Microbiology, Dr D Y Patil Vidyapeeth Medical College, Pimpri, Pune-411018, India 3 Department of Lab Sciences & Molecular Medicine, Army Hospital R & R, Delhi, India 4 Department of Microbiology, Microbiology and HIC Sahyadri Speciality labs, Pune, India 5 Department of Microbiology, Shri Sathya Sai Medical College and Research Institute, Ammapettai, Kancheepuram608103, India 6 Gd Spl (Microbiology) Command Hospital, Kolkata, India *Corresponding author

Analysis of noise and its removal in nerve conduction study signal

Nerve Conduction Study (NCS) is a primary study for detection of motor and sensory nerve diseases. While acquiring the NCS data, various noises suppresses the signals like power line interference (PLI) and other high and low frequency noises. Although there are several research conducted for removal of noises from NCS data, this paper describes a novel technique of noise suppression in real time NCS data by using a battery operated system that include nerve stimulation, amplifier and the filter. Noise analysis both statistical and frequency analysis has been conducted and compared with conventional power supply systems acquired from AC mains.

Combining Ability Analysis for Bacterial Leaf Spot Resistance, Leaf Yield, and Agronomic Traits in Mulberry Clones

Combining ability effects for disease resistance, yield, and agronomic traits help in devising appropriate breeding strategies. Bacterial leaf spot (BLS) [Xanthomonas campestris pv.mori] is a destructive foliar disease of mulberry (Morus spp.). We evaluated crosses of useful mulberry clones to select good general combiners for resistance to BLS and to determine the genetics of important agronomic traits for mulberry improvement. Combining ability of six parents was estimated following a line × tester mating design. Established full-sib segregating progenies (440) derived from eight crosses, along with parents, were field-evaluated for leaf yield, agronomic traits, and resistance to BLS across two years. Significant negative (p < 0.01) general combining ability (GCA) effect of disease severity was found in genotype M. rotundiloba, which is desirable for BLS resistance; whereas significant positive GCA for leaf yield was observed in two parents, namely, M. multicaulis and C-2016. Moderately high narrow-sense heritability estimates (≥0.46), continuous frequency distributions, and moderately high genetic gains (19%–22%) were observed for traits such as primary shoot length, internodal distance, and petiole width. M. rotundiloba appeared to be a good general combiner for BLS resistance. Selection for primary shoot length, nodal distance, and petiole width should be effective for improving mulberry.