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In this study, the spatial distribution and hydrochemistry of arsenic (As) in shallow alluvial aquifers of Bidyananda and Nazimkhan Union of Rajarhat opazilla, Kurigram district of Bangladesh have been evaluated. Nineteen groundwater samples (depth: 10 to 50 m) were collected from the studied area for physical and chemical analysis. Based on analytical data of chemical analysis, a Piper trilinear diagram have been prepared which revealed that the groundwater of the studied area is CaHCO3 type, where Ca is the dominant metal. Physical data and permeability index values indicate good quality of the groundwater for drinking and irrigation. The concentrations of Fe, Mn and As in almost all samples exceed the WHO and Bangladesh national standard indicating significant pollutions. Groundwater As concentrations in the aquifer (10–50 m of depth) ranged from

Pimpinella anisum L. seeds of the two cultivars were assessed for their nutritional quality and safety assessment through proximate, chemical and pharmacological studies. The proximate composition along with rich mineral elements as well as minor level of toxic elements indicated the good quality of seeds. The GC–MS analyses of hydro distilled volatile oils of two cultivars contained 16 constituents. The main constituents in BSRC (Bangladesh Spice Research Centre) seeds were trans-anethole (83.67%), fenchone (5.29%) and 1,2-diisopropenylcyclobutane (6.31%) whereas, trans-anethole (69.94%), fenchone (11.184%) and d-limonene (13.007%) were the main constituents in local market seeds. The IC50 values of DPPH antioxidant activity showed at 48.71 and 52.48 mg/mL, in BSRC and local market seeds cultivars essential oils respectively. The antimicrobial activity of the essential oils showed moderate activity in both cultivars against Gram-positive, Gram-negative bacteria and fungi. Both oils had some similarity in physiochemical properties and antimicrobial activity. The brine shrimp cytotoxic activity of the essential oils exhibited weaker activity than the standard drug at 3.06 and 2.86 μg/mL (IC50) in BSRC and local market seed cultivars respectively. The present investigation demonstrated good nutritional quality with rich bioactive phytoconstituents as well as low level of toxic elements of anise seeds. The research findings can open up a new possibility for exportation of indigenously cultivated spices as well as recommendations for food and pharmaceutical industries.

Heavy metal pollution in agricultural soils and food crops around the ship breaking area is of great environmental and human health concern. In this work, we have spectroscopically determined the concentrations of Cd, Pb, Fe, Mn, Zn, Cr, Cu, and Ni in agricultural soils and commonly consumed vegetables, fruits, and rice grain collected from the Sitakunda ship breaking area of Chittagong, Bangladesh, in order to evaluate their contamination levels and probable human health risk with a multivariate statistical approach. Multivariate analyses such as principal component analysis and cluster analysis of the analytical data indicate a significant metal contamination in the samples which could be attributed to industrial activities such as ship breaking. The results of soil contamination evaluation indices such as enrichment factor, geo-accumulation index, and contamination factor demonstrated that the soils around the ship breaking area are mainly contaminated by Cd, Pb, Zn, and Cu while food crops were mostly contaminated by Zn, Cr, and Cu. The Pb contaminated the olive and teasle gourd while Cd contamination in rice grain was at the threshold limit for health hazard. Mn was slightly accumulated in banana. Transfer coefficient values of Cd, Zn, and Cu for almost all food crops were higher than other metals, and Cd showed the highest transfer. Estimated daily intake values for Ni exceeded the standard limit (1.3 μg kg−1 day−1). Target hazard quotient values of Cu, Zn, Pb, and Cd indicate that the local inhabitants who consume the contaminated food crops are being exposed to potential health risks.

Arsenic (As) concentration and geochemical analysis of groundwater as well as core sediments of 20 tube wells revealed the uppermost aquifer (20–40 m of depth) groundwater As concentrations ranging from 2.34 to 586.96 μg L−1, and groundwater geochemical conditions change from oxidized to gradually more reduced as higher concentrations of As increased with depth. The highest sediment As levels (25 mg kg−1) were found within the shallow depth (15 m). The groundwater of the study area is of Ca-HCO3 type, where Ca is the dominant metal with high concentrations of As, Fe, and Mn but low levels of NO3− and SO42−. The trace elements Fe, Mn, and As exceed the WHO and DoE standard in groundwater which clearly indicated As contamination except some few areas where less Fe and Mn are released in aquifer water from sediment. The contaminated As zone also corroborated with the GIS study. Considerable variability with depth and location is noted in the levels of As, Fe, and Mn in groundwater, and from these levels it can be seen that the groundwater of Rajarampur village of Chapai Nawabganj Paurasava is more reduced than the groundwater of Baragharia. Groundwater in Baragharia village contains low concentration of As below the WHO standard (

Hydrochemistry in parts of the Lower Tista Floodplain in northwest Bangladesh is dominated by alkalies and weakly acid, having highest concentration of sodium cations and bicarbonate anions respectively. Groundwater is characterized by sodium-calcium and sodium-potassium cation and bicarbonate-chloride-sulphate anion facies, and genetically ‘normal chloride’, ‘normal sulphate’, and ‘normal carbonated’ type, and soft to saline. Based on electrical conductivity values, the area is divided into northern fresh and southern saline groundwater zone, and values like salinity, Na%, SAR, and RSC and a good correlation between Na+ and Cl−, and Cl− and salinity reveals increasing salinity with depth indicating a mixing of fresh and saline bodies due to marine transgression (?) during Holocene period in the Bengal delta. The rock weathering is likely to affect the groundwater quality by dolomite dissolution and calcium precipitation, representing reverse softening process and is brine seawater. Water extracted from shallow zone (from 20 to 30 m) has suitability for drinking purpose, livestock consumption and irrigation purposes, and partially suitable for industrial use, but that from deeper zone (from 30 to 50 m) is generally poor and unsuitable especially for irrigation purposes with low alkali and moderate to high salinity hazard. So groundwater can be used for irrigation in the area of fine textured soil with proper management practices.