Heavy metal pollution in the environment is a critical issue, engendering ecosystem deterioration and adverse effects on human health. The main objective of this study was to evaluate heavy metal adsorbents by modifying industrial byproducts. The bottom ash was sintered and evaluated for Cd and Pb sorption. Three adsorbents (bottom ash, sintered bottom ash (SBA), and SBA mixed with microorganisms (SBMA)) were tested to evaluate the sorption kinetics and mechanism using a lab-scale batch experiment. The results showed that the highest sorption efficiency was observed for Cd (98.16%) and Pb (98.41%) with 10% SBA. The pseudo-second-order kinetic model (R2 > 0.99) represented the sorption kinetics better than the pseudo-first-order kinetic model for the SBA and SBMA, indicating that chemical precipitation could be the dominant sorption mechanism. This result is supported by X-ray photoelectron spectroscopy analysis, demonstrating that -OH, -CO3, -O, and -S complexation was formed at the surface of the sintered materials as Cd(OH)2 and CdCO3 for Cd and PbO, and PbS for Pb. Overall, SBA could be utilized for heavy metal sorption. Further research is necessary to enhance the sorption capacity and longevity of modified industrial byproducts.
There is an increasing concern over heavy metal(loid) contamination of soil in agricultural areas including paddy soils. This study was conducted to monitor the background levels of heavy metal(loid)s, arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) in major rice growing soils and its accumulation in brown rice in Korea. The samples were collected from 82 sites nationwide in the year 2012. The mean and range values of As, Cd, Cu, Hg, Ni, Pb, and Zn in paddy soils were 4.
The current study was carried out to investigate total and inorganic arsenic (As) concentrations in 112 rice samples (husked rice and polished rice) grown around the abandoned mining areas and to estimate the potential health risk through dietary intake of rice in Korea. Mean concentrations of total As in husked rice and polished rice were 0.23 and 0.13 mg kg -1 , respectively. Also, average inorganic As concentrations in husked rice and polished rice were 0.09 and 0.05 mg kg -1 , respectively. These levels are lower than the standard guideline value (0.2 mg kg -1 ) for inorganic As in polished rice recommended by Korea Ministry of Food and Drug Safety and Codex. For health risk assessment, the average values of cancer risk probability was 5.7×10-5 which was less than the acceptable cancer risk of 10 -6~1
0-4 for regulatory purpose. Also, hazard quotient values were lower than 1.0. Therefore, these results demonstrated that human exposure to inorganic As through dietary intake of rice collected from abandoned mining areas might not cause adverse health effects.Key words: Total arsenic, Inorganic arsenic, Rice, Risk assessment, Abandoned mining areaInorganic arsenic (As) concentrations in 112 rice samples collected from abandoned mining areas.
The physical properties of horticultural substrate are important for optimal plant growth. The physical properties should be properly maintained during the crop growing season for producing higher yield.
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