scholarly journals Arsenic mobilization in shallow aquifer of Bengal Delta Plain: role of microbial community and pathogenic bacteria

Author(s):  
P. Ghosh ◽  
D. Chatterjee
Author(s):  
Md. Shajedul Islam ◽  
M. G. Mostafa

Abstract Arsenic contamination of alluvial aquifers of the Bengal delta plain causes a serious threat to human health for over 75 million people. The study aimed to explore the impacts of chemical fertilizer on arsenic mobilization in the sedimentary deposition of the alluvial Bengal delta plain. It selected ten comparatively higher affected Districts and the least affected two Divisions as a referral study site. The countrywide pooled concentration of arsenic in groundwater was 109.75 μg/L (52.59, 166.91) at a 95% confidence interval, which was double the national guideline value (50 μg/L). The analysis results showed a strong positive correlation (r ≥ 0.5) of arsenic with NO3, NH4, PO4, SO4, Ca, and K, where a portion of those species originated from fertilizer leaching into groundwater. The results showed that PO4 played a significant influence in arsenic mobilization, but the role of NO3, SO4, and NH4 was not clear at certain lithological conditions. It also showed that clay, peat, silt-clay, and rich microbial community with sufficiently organic carbon loaded soils could lead to an increase in arsenic mobilization. Finally, the study observed that the overall lithological conditions are the main reason for the high arsenic load in the study area.


2020 ◽  
Vol 1 (8) ◽  
pp. 372-382
Author(s):  
Pinaki Ghosh ◽  
Ayan Das ◽  
Madhurina Majunder ◽  
Samir Kumar Mukherjee ◽  
Debashis Chatterjee

In Bengal Delta Plain (BDP), shallow aquifer (<50 m) is often contaminated with Arsenic (As). The phenomenon is wide spread in nature thought the BDP notable in Nadia district of west Bengal. The present study highlights a primary screening of As, Fe, MPN and FC in monitored shallow wells. The study designed for two different sites (site-A, High As and site-B Low As area). The water quality monitoring results suggest that high As concentration (Range- 103-171 μgL-1) has been noticed in site A when compared with site B (range-53-99 μgL-1). In sites A, the Fe concentration is high and low in site B. The correlation study (r2) between arsenic and iron are also determined. The value of r2 is 0.94 for site A and 0.73 for site B. The water quality results suggest that the nature of the monitor aquifer is anoxic in nature with low Eh, DO absent and low NO3- and SO4+. Major anion is HCO3- (376 mgL-1) followed by Cl- (28 mgL-1). However chloride concentration is largely varying in the monitored tube well. Microbial study (MPN & FC count) also indicates some relationship among MPN (r2-0.32) and Fe (r2 -0.24). However the relationship is scatter when As concentration is low. The linear trended has also obtained when both As, MPN and FC are high. The physical observation of plate count (Color reaction in Chromo colt Agar) has also been observed. This is a clear indicator of fecal coli form contamination. The study indicates that the microbial mobilization of As is the key factor for enrichment of As in ground water. The possible sources of the microbes are local land-use pattern (notable pit-latrine). Finally, the study highlights the role of coli forms bacteria (Both facultative and non-facultative) are wide spread in shallow rural aquifer of Bengal. Thus microbial process possibly enriches arsenic in shallow ground water.


2005 ◽  
Vol 69 (5) ◽  
pp. 855-863 ◽  
Author(s):  
A. G. Gault ◽  
F. S. Islam ◽  
D. A. Polya ◽  
J. M. Charnock ◽  
C. Boothman ◽  
...  

AbstractArsenic mobilization and Fe(III) reduction in acetate-amended sediments collected from a range of depths from an aquifer with elevated groundwater arsenic concentrations in West Bengal were monitored over a 1 month period. Significant arsenic release was noted in sediment collected from 24 m and 45 m depth, with some Fe(III) reduction also observed in the 24 m sample. The structure of the microbial communities present in the sediments prior to incubation showed marked differences down the sediment column. Profiling of the microbial community in the 24 m and 45 m samples revealed a relatively complex make-up, with Acinetobacter species comprising the bulk of the 24 m sedimentary bacterial population, but no previously characterized As(V)-reducers were detected in either sample.


Author(s):  
Pramod Dhakal ◽  
Ankit a Achary ◽  
Vedamurthy Joshi

Bioenhancers are drug facilitator which do not show the typical drug activity but in combination to enhance the activity of other molecule in several way including increase the bioavailability of drug across the membrane, potentiating the drug molecules by conformational interaction, acting as receptor for drug molecules and making target cell more receptive to drugs and promote and increase the bioactivity or bioavailability or the uptake of drugs in combination therapy. The objective of the present study was to evaluate the antibacterial and activity of combination in Azadirachta indica extract with cow urine distillate and pepper extract against common pathogenic bacteria, a causative agent of watery diarrhea. It has been found that Indian indigenous cow urine and its distillate also possess bioenhancing ability. Bioenhancing role of cow urine distillate (CUD) and pepper extract was investigated on antibacterial activity of ethanol extract of Azadirachta indica. Antibacterial activity of ethanol extract neem alone and in combination with CUD and pepper extract were determined the ATCC strains against Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and E-coli by cup plate diffusion method. Ethanol extract of neem has showed more effect on P. aeruginosa, E-coli than S. aureus and K. pneumonia with combination of CUD and pepper extract. CUD and pepper did not show any inhibition of test bacteria in low concentration. The antibacterial effect of combination of extract and CUD was higher than the inhibition caused by extract alone and is suggestive of the bioenhancing role of cow urine distillate and pepper. Moreover, inhibition of test bacteria was observed with less concentration of extract on combining with CUD


2016 ◽  
Author(s):  
Jishnu Adhikari ◽  
◽  
Debashis Chatterjee ◽  
Shilajit Barua ◽  
Thomas R. Kulp

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