Arsenic-induced health crisis in peri-urban Moyna and Ardebok villages, West Bengal, India: an exposure assessment study.

Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7 % of the sampled tube wells contain As concentrations above 10 µg/L, while 57.7 % contain As concentrations above 50 µg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51-99 µg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region.

Spatio-temporal variability and source identification for metal contamination in the river sediment of Indian Sundarbans, a world heritage site.

Metal pollution is a subject of growing concern as it affects the whole food chain of an ecosystem by bioaccumulation. Growing industrialization and anthropogenic intervention have put tremendous pressure on self-sustaining ecosystems worldwide. Sundarbans mangrove estuary, being a UNESCO World Heritage site, suffers severely from anthropogenic stress, urbanization, ecotourism, overexploitation of natural resources and discharges of industrial as well as municipal waste products. Our study unfolds the extent of metal pollution in the sediment of this estuarine mangrove ecosystem and also investigates the source and distribution of these metals. Extensive samplings were performed during three major seasons, namely pre-monsoon, monsoon, and post-monsoon for two consecutive years at ten sampling stations along the major river networks of the mangrove estuary. Seasonal variations of these metals, physicochemical properties, and soil texture studies were performed to explore the sediment quality of the study area. Positive correlation was observed between the pollutants and siltation. Several environmental indices were investigated to explore the degree of metal pollution which revealed contamination of Cd, Cr, and Pb to cross the permitted safe index in the study area. Pollution load index indicates the spatial as well as seasonal variation of eco toxic metal load along the course of the rivers. Statistical analyses such as principal component analysis and correlation matrix identified different sources for metal contamination. Almost 700 tannery industries are located in the upstream region of the rivers, and several small- and large-scale battery industries seem to be the main possible source for Cd, Cr, and Pb pollution. Analysis of the results indicates the alarming condition of this heritage site. The metal concentrations beyond toxicity thresholds are responsible for gradual deterioration of this estuarine mangrove which may only be protected by developing sustainable management planning.

Metagenomic exploration of the bacterial community structure at Paradip Port, Odisha, India.

This is a pioneering report on the metagenomic exploration of the bacterial diversity from a busy sea port in Paradip, Odisha, India. In our study, high-throughput sequencing of community 16S rRNA gene amplicon was performed using 454 GS Junior platform. Metagenome contain 34,121 sequences with 16,677,333 bp and 56.3% G + C content. Metagenome sequences data are now available at NCBI under the Sequence Read Archive (SRA) database with accession no. SRX897055. Community metagenome sequence revealed the presence of 11,705 species belonging to 40 different phyla. Bacteroidetes (23%), Firmicutes (19%), Proteobacteria (17%), Spirochaetes (10%), Nitrospirae (8%), Actinobacteria (7%) and Acidobacteria (3%) are the predominant bacterial phyla in this port soil. Analysis of metagenomic sequences unfolded the interesting distribution of several phyla which pointed to the significant anthropogenic intervention influencing the bacterial community character of this port.

Pyrosequencing based profiling of the bacterial community in the Chilika Lake, the largest lagoon of India.

Brackish water lake is the most extraordinary reservoir for bacterial community with an adaptability of tolerance to saline stress. In the present study, metagenomic approach was implemented utilising 454-pyrosequencing platform to gain deeper insights into the bacterial diversity profile of the soil sediment of Chilika Lake, Odisha, India. Metagenome contained 68,150 sequences with 31,896,430 bp and 56.79% G + C content. Metagenome sequences data are now available at NCBI under the Sequence Read Archive (SRA) database with accession no. SRX753382. Bacterial community metagenome sequences were analysed by MG-RAST server representing the presence of 16,212 species belonging to 45 different phyla. The dominating phyla were Proteobacteria, Chloroflexi, Firmicutes, Acidobacteria, Actinobacteria, Bacteroidetes and Planctomycetes. The analysis of bacterial community datasets obtained from two different saline soil sediments revealed significant differences in bacterial community composition and diversity value providing better understanding of the ecosystem dynamics of Chilika Lake.

In vitro assessment on the impact of soil arsenic in the eight rice varieties of West Bengal, India.

Rice is an efficient accumulator of arsenic and thus irrigation with arsenic-contaminated groundwater and soil may induce human health hazard via water-soil-plant-human pathway. A greenhouse pot experiment was conducted on three high yielding, one hybrid and four local rice varieties to investigate the uptake, distribution and phytotoxicity of arsenic in rice plant. 5, 10, 20, 30 and 40 mg kg(-1) dry weights arsenic dosing was applied in pot soil and the results were compared with the control samples. All the studied high yielding and hybrid varieties (Ratna, IET 4094, IR 50 and Gangakaveri) were found to be higher accumulator of arsenic as compared to all but one local rice variety, Kerala Sundari. In these five rice varieties accumulation of arsenic in grain exceeded the WHO permissible limit (1.0 mg kg(-1)) at 20 mg kg(-1) arsenic dosing. Irrespective of variety, arsenic accumulation in different parts of rice plant was found to increase with increasing arsenic doses, but not at the same rate. A consistent negative correlation was established between soil arsenic and chlorophyll contents while carbohydrate accumulation depicted consistent positive correlation with increasing arsenic toxicity in rice plant.