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The present study was conducted to determine the heavy metal contamination in soil with accumulation in edible parts of plants and their subsequent changes in biochemical constituents due to wastewater irrigation. Though the wastewater contains low levels of the heavy metals (Fe, Mn, Pb, Cd, and Cr), the soil and plant samples show higher values due to accumulation. The trend of metal accumulation in wastewater-irrigated soil is in the order: Fe > Pb > Mn > Cr > Cd. Of the three species Colocasia esculentum, Brassica nigra, and Raphanus sativus that are grown, the order of total heavy metal accumulation in roots is Raphanus sativus > Colocasia esculentum, while in shoots the order is Brassica nigra > Colocasia esculentum > Raphanus sativus. The enrichment factor (EF) of the heavy metals in contaminated soil is in the sequence of Cd (3) > Mn (2.7) > Cr (1.62) > Pb (1.46) > Fe (1.44), while in plants EF varies depending upon the species and plant part. C. esculentum and R. sativus show a higher EF for Cr and Cd. All plants show a high transfer factor (TF > 1) for Cd signifying a high mobility of Cd from soil to plant whereas the TF values for Pb are very low as it is not bioavailable. Results of the biochemical parameters show decrease in total chlorophyll and total amino acid levels in plants and an increase in amounts of soluble sugars, total protein, ascorbic acid, and phenol except B. nigra for protein in plants grown in soil irrigated with wastewater as compared to control site.

Remote sensing and GIS play a vital role in exploration and assessment of groundwater and has wide application in detection, monitoring, assessment, conservation and various other fields of groundwater-related studies. In this research work, delineation of groundwater potential zone in Birbhum district has been carried out. Various thematic layers viz. geology, geomorphology, soil type, elevation, lineament and fault density, slope, drainage density, land use/land cover, soil texture, and rainfall are digitized and transformed into raster data in ArcGIS 10.3 environment as input factors. Thereafter, multi-influencing factor (MIF) technique is employed where ranks and weights, assigned to each factor are computed statistically. Finally, groundwater potential zones are classified into four categories namely low, medium, high and very high zone. It is observed that 18.41% (836.86 km 2 ) and 34.41% (1563.98 km 2

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The assessment of groundwater vulnerability is essential especially in developing areas, where agriculture is the main source of the population. In the present study, four different overlay and index method, namely, DRASTIC, modified DRASTIC, pesticide DRASTIC and modified pesticide DRASTIC are implemented with a view to identifying the most appropriate method that predicts the vulnerable zone to groundwater pollution. Sensitivity analysis reveals that net recharge is the most influential parameter of the vulnerability index. Cross comparison of model output shows the highest similarity of 97% is observed between drastic and modified drastic while the maximum difference in models prediction of 49% is observed between modified drastic and pesticide drastic. Reported nitrate concentrations in groundwater are considered for validation of model-generated final output map. The prediction power of the models are assessed using success and prediction rate method and it highlights DRASTIC model as the most suitable model with 89.69% and 84.54% of the area under area under the curve (AUC) for success and prediction rate respectively.

In this study, variations in physicochemical parameters and heavy metal contamination in water-sediments of a natural stream in the Durgapur industrial zone have been investigated. pH, COD, Cl − , CN − and heavy metals, viz. Pb, Hg and Fe concentrations in channel water, are higher than Indian standards. Metal concentrations in sediments are many folds higher than background value, where Pb, Cd, Hg and Cr contents exceed the sediment quality guidelines. Contamination factor (C f) value of channel water follows the order of Hg > Pb > Fe > Cr > Cd > Cu > Ni, whereas enrichment factor and geoaccumulation index (I geo) values in channel sediments are in the order of Hg > Cr > Ni > Pb > Cd > Fe > Cu. The assessment of contamination index (C d), modified contamination index (mC d) and pollution load index indicates that channel water and sediment samples in the study area are strongly contaminated by heavy metals. Sediment samples based on PELQ and ERMQ are highly toxic, with high degree of potential ecological risk at all the monitored stations. Multivariate analysis infers that heavy metals in channel water and sediments are majorly sourced from industrial discharge.

In this study multi-hazard risk assessment is carried out in Arithang ward, one of the major wards within Gangtok Municipal Corporation, with the objectives of (a) landslide and earthquake hazard mapping of Gangtok city with analytical hierarchy process (b) vulnerability mapping in Arithang ward and (c) semiquantitative and semiqualitative risk analysis. Landslide hazard zonation (LHZ) depicts that very high and high hazard zone occupies 6% and 17% of the Gangtok city whereas 60% and 18% of area falls under medium and low hazard category respectively. With respect to seismic hazard susceptibility 13% and 22% of area falls under very high and high category respectively. Semiquantitative risk analysis reveals that majority of the residential buildings are concentrated in low earthquake and landslide hazard zone followed by 39% and 35% within medium class. Only 0.6% and 7% of residential buildings are found in high earthquake and landslide hazard zones. Bamboo and wood made buildings are found to cluster within very high class of landslide hazard. About 61% of multistoried buildings are placed within low zone of LHZ. Risk analysis reveals that buildings at the eastern and western part of Arithang ward come under high risk with respect to earthquake and landslide.