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Abstract At present, there are growing concerns over the increasing release of trace metals in the Sundarbans mangrove areas in Bangladesh due to nearby shipbreaking and metallurgical industries, untreated waste discharge, navigation activities, and other natural processes that deposit trace metals into soils. The current study investigated the spatial distribution, contamination level, and ecotoxicity of eight trace metals (Fe, Mn, Cu, Zn, Pb, Cd, Cr, Ni) in Sundarbans soils. Results revealed that all the trace metals except Cr were present in higher concentrations compared to Earth’s shale and/or upper continental crust. Principal component analysis and Pearson correlation showed strong positive correlations (p

From the beginning of the industrial revolution, metal refining industries using the pyrometallurgical process are generating remarkable emissions of heavy metals. As the main objective of these pollutants, a great number of soils are now contaminated over extensive areas depending on exposure level, and duration, and pose a major risk to human health worldwide. Biochar, a co-product of the pyrolysis process, can be used to nourish soil health, and remediate heavy metals. They are nowadays modified to enhance the sorption capacity of biochar and immobilization of heavy metals. Immobilization, as an in-situ application method, is a cost-effective method for environmental remediation of heavy metals in the soils. The research statistics on biochar and modified biochar influences on heavy metal remediation from the soil are scarce. Therefore, the purposes of this review are (1) to combine modification processes of biochar (2) to offer possible mechanisms associated with the reduction of heavy metals (iii) to combine the available data on the positive effects of biochars and modified biochars on heavy metal remediation(iv) identify researchable priorities.

Brick kiln is well known as one of the main sources of air pollution; however, the pollutants produced from it do not remain in the air, they ultimately fall down to the soil and pollute the surroundings, therefore, this study was carried out to assess the status of macro (N, P, K and S) and micro nutrients (Fe, Mn and Zn, Cu) in the agricultural environment near the brick kilns of Young Brahmaputra and Jamuna Floodplain soils. Composite soil and plant samples were collected from four distances such as 250 m, 500 m, 1000 m, and 1500 m in three different sites. Sulphur (2352–3378 mg kg−1), Zn (86–156 mg kg−1) and Cu (24.7–46.9 mg kg−1) are found in the elevated levels near brick kiln soils that is released due to burning of poor quality coal and fire woods. The alarming news is that plant uptake of S and micro nutrients in the nearest areas of the brick kilns are significantly higher than the areas far from the brick production and their concentration ranges from 23 mg kg−1 to 101 mg kg−1 for Zn, 10–41 mg kg−1 for Cu, 35–1309 mg kg−1 for Fe, 26–126 mg kg−1 for Mn and 2590–mg kg−1 for S. Data indicates both soil and plant received maximum amount of micronutrients and S concentrations within 500–1000 m distances from brick kilns. Iron and Mn concentrations vary within a permissible limit but the plant uptake is high. Nitrogen concentrations is increasing with the distance from the brick kilns in both soils and plants but no definite pattern of P and K accumulation was found. Research suggested avoiding agricultural practice nearby brick kiln soils due to micronutrient contamination in order to preserve adjoined agricultural environment.