Assessment of trace metal contamination in a historical freshwater canal (Buckingham Canal), Chennai, India

The present study was done to assess the sources and the major processes controlling the trace metal distribution in sediments of Buckingham Canal. Based on the observed geochemical variations, the sediments are grouped as South Buckingham Canal and North Buckingham Canal sediments (SBC and NBC, respectively). SBC sediments show enrichment in Fe, Ti, Mn, Cr, V, Mo, and As concentrations, while NBC sediments show enrichment in Sn, Cu, Pb, Zn, Ni, and Hg. The calculated Chemical Index of Alteration and Chemical Index of Weathering values for all the sediments are relatively higher than the North American Shale Composite and Upper Continental Crust but similar to Post-Archaean Average Shale, and suggest a source area with moderate weathering. Overall, SBC sediments are highly enriched in Mo, Zn, Cu, and Hg (geoaccumulation index (Igeo) class 4– 6), whereas NBC sediments are enriched in Sn, Cu,Zn, and Hg (Igeo class 4–6). Cu, Ni, and Cr show higher than Effects-Range Median values and hence the biological adverse effect of these metals is 20%; Zn, which accounts for 50%, in the NBC sediments, has a more biological adverse effect than other metalsfound in these sediments. The calculated Igeo, Enrichment Factor, and Contamination Factor values indicate that Mo, Hg, Sn, Cu, and Zn are highly enriched in the Buckingham Canal sediments, suggesting the rapid urban and industrial development of Chennai MetropolitanCity have negatively influenced on the surrounding aquatic ecosystem

Groundwater quality evaluation using water quality index and geospatial techniques in parts of Anantapur District, Andhra Pradesh, South India

The main aim of this research is to evaluate the quality of groundwater in parts of Anantapur district, Andhra Pradesh, for drinking and irrigation purposes. Groundwater samples were collected from various locations in the study area during the post-monsoon season and were analyzed for different parameters including pH, EC, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, and NO3−. The results were then compared with the water quality standards of the World Health Organization (WHO). The major ions were found in the following order: Na+ > Ca2+ > Mg2+ > K+ = HCO3− > SO42− > Cl− > NO3−. The obtained data was then mapped using the Arc-GIS technique to show the spatial distribution pattern of physicochemical properties and major ion concentrations in groundwater. The water quality index showed that 69% of the samples are very poor, and 31% are unfit for drinking purposes due to effective leaching of ions, over-exploitation of groundwater, direct discharge of effluents, and agricultural impact. Based on the Gibbs diagram, the groundwater samples fall within the rock dominance region. The majority of the samples fell into the C3S1 category, which denotes water with high salinity and low sodium which is moderately suitable for irrigation purposes, according to the USSL diagram. According to the Wilcox classification, 27% and 2% of groundwater samples are deemed doubtful and unsuitable, respectively, while 69% of samples are deemed suitable for farming. In addition, most groundwater samples show moderate suitability for irrigation when evaluated for SAR, %Na, PI, RSC, MAR, and KR. Most of the samples, with the exception of a few spots, turned out to be suitable for irrigation. However, due to human activity, some samples had levels of contamination that were higher than allowed and needed to be treated before consumption