Kali Prasad Sarma

Removal of As(III) from Aqueous Solution Using Functionalized Ultrafine Iron Oxide Nanoparticles

Arsenic toxicity has become a major concern worldwide. Remediation of this problem needs the development of technology with improved materials and systems with high efficiency. We have demonstrated a simple and efficient method for the absolute removal of As(III) from high concentration As(III) treated water with a low contact time period. The process of As(III) adsorption follows pseudo-second-order kinetic model. The mechanism for high-adsorption efficiency is attributed to fatty acid binding domain-mediated surface conjugation of ultrafine Fe2O3 nanoparticles with As(III). We have also ensured the simultaneous separation of arsenic sorbed nanoparticles by entrapping them in hydrophilic calcium alginate beads and thereby a pure arsenic free solution has been obtained.

Distribution and solid-phase speciation of toxic heavy metals of bed sediments of Bharali tributary of Brahmaputra River

Heavy metal (Fe, Mn, Zn, Cu, Ni, Pb, and Cd) concentrations and their chemical speciations were investigated for the first time in bed sediments of Bharali River, a major tributary of the Brahmaputra River of the Eastern Himalayas. Levels of Fe, Mn, Pb, and Cd in the bed sediments were much below the average Indian rivers; however, Cu and Zn exhibit levels on the higher side. Enrichment factors (EF) of all metals was greater than 1 and a higher trend of EF was seen in the abandoned channel for most metals. Pb showed maximum EF of 32 at site near an urban center. The geoaccumulation indices indicate that Bharali river is moderately polluted. The metals speciations, done by a sequential extraction regime, show that Cd, Cu, and Pb exhibit considerable presence in the exchangeable and carbonate fraction, thereby showing higher mobility and bioavailability. On the other hand, Ni, Mn, and Fe exhibit greater presence in the residual fraction and Zn was dominant in the Fe–Mn oxide phase. Inter-species correlations at three sites did not show similar trends for metal pairs indicating potential variations in the contributing sources.

Source contributions of Polycyclic Aromatic Hydrocarbons in soils around oilfield in the Brahmaputra Valley.

Surface soils from Borholla oilfield in the upper Brahmaputra Valley in India were studied for the USEPAs 16 priority Polycyclic Aromatic Hydrocarbons (PAHs). Analysis of PAHs was carried out by high performance liquid chromatography (HPLC) system equipped with an UV detector. Seasonality in PAHs concentrations was evident and the concentrations were found to be greater in post-monsoon season. There has been a dominance of low molecular weight PAHs (80-90% of total PAHs) indicating recent deposition from combustion sources. The concentration profiles appeared in the decreasing order of 3-ring >2-ring >4-ring >5-ring >6 ring PAHs. The sources of PAHs were identified using isomer pair ratios and Principal Component Analysis-Multiple Linear Regression (PCA-MLR) and Positive Matrix Factorisation (PMF). The ratios of diagnostic pairs indicated for both pyrogenic and petrogenic input of PAHs. The PCA-MLR modelling revealed that the <16% of contribution came from petrogenic origin and the rest 85% was found to be from pyrogenic sources. The PMF model also shown that <19% of PAHs source were petrogenic origin whereas rest from pyrogenic origin. The correlations of black carbon (BC) with PAHs also supported the pyrogenic contribution. The analysis of air mass back trajectories revealed that there has been contribution of both local and distant sources, through long range transport of pollutants, which were deposited to the site.

Diversity, Uses and In vitro Propagation of Different Bamboos of Sonitpur District, Assam

Bamboos are the tallest and largest member of the grass family and widely distributed in India and abundantly occur in northeast region. A few species are also found scattered in other parts of the country both in the hills and the plains. Bamboos play an important role in the day to day lives of common people of Assam and become an integral part of the cultural, social and economic traditions of the State. Besides, it is an essential component of forest ecosystem and commonly found in the traditional home gardens of Assam. Study was carried out in 62 randomly selected home gardens of Sonitpur district of Assam. The maintenance of bamboo diversity in home gardens fulfills the household necessity and also contributes to the rural economy. The commonly found bamboos are B. tulda, B. balcooa, B. pallida, B. nutans, B. bambos, Dendrocalamus strictus, D. hamiltonii, Melocanna baccifera etc. Home garden based bamboos have also great demand as a construction materials, fencing, fodder and also as a source of fiber for paper industry. Tissue culture technique is also applied in three selected Bamboos for large scale production of plantation stocks for commercial cultivation. Rural employment can be generated by proper cultivation and management of bamboos in traditional home gardens thereby helps in conservation of bamboo diversity without much care and effort.

Spatial and Seasonal Variations of Water Soluble Ions in PM10 of Mid-Brahmaputra Plain of Assam Valley

A year-long study on water soluble ionic constituents of PM10 was conducted at mid-Brahmaputra plain during 2012-2013. Water soluble ions associated with PM10 viz. SO4 2-, NO3 -, Cl-, F-, NH4 +, K+, Ca2+, Na+ and Mg2+ were analyzed using Ion chromatograph (Metrohm 882 Compact IC Professional) for three representative sites. Marked differences were observed regarding PM10 loading and concentrations of major ions in three different sites, with maximum PM10 (71.1±56 μg/m 3) at urban site. Among anions, dominance of SO4 2and Clwere observed and Na+, NH4 + and K+ were found to be predominant cations. An explicit seasonal variation of ionic constituents was observed during the study period with maximum abundance of ions during winter season, and SO4 2was the most abundant ion during all the seasons. Pre-monsoon season showed influence of crustal input with high mass concentrations of Ca2+ and Na+ in PM10.The equivalent ion balance reveals the fact that except winter season, all other seasons experienced alkaline nature of particulates in the atmosphere. Influence of anthropogenic activities to the ionic constitutions of PM10 was revealed by calculating ionic ratios and enrichment factor. HYSPLIT trajectory analysis showed influence of long-range transport of pollutants to this region.

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).