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Heavy metals such as cadmium (Cd), arsenic (As), and lead (Pb) pose significant health risks, particularly in Asia, where rice is a staple for nearly three billion people. Despite their known dangers and environmental prevalence, studies addressing their concentrations in rice across different regions and the associated health implications remain insufficient. This review systematically examines the occurrence and impact of these toxic elements, filling a critical gap in the literature. Data from seven countries indicate mean concentrations in the order of Pb > As>Cd, with values of 0.255 ± 0.013, 0.236 ± 0.317, and 0.136 ± 0.150 mg/kg, respectively. Uncertainty analysis shows extensive variability, especially for Cd, with a 95% confidence interval range from 0.220 to 0.992 mg/kg. The typical daily intake of heavy metals through rice consumption, in the order of As>Cd > Pb, frequently exceeds safe limits. Generally, data obtained from various studies showed that children were more prone to heavy metal contamination through rice consumption than adults. This review is fundamental for ongoing monitoring, future research, and management strategies to reduce heavy metal contamination in rice.
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Graphene-based aerogels are among the lightest materials in the world and have been extensively studied for environmental remediation. In this work, an Fe3O4/graphene aerogel material was synthesized using the co-precipitation method. The prepared material was characterized using X-ray diffraction (XRD), scanning electron microscopy/X-ray energy dispersive spectroscopy (FESEM/EDX), infrared spectroscopy (FT-IR), and vibration sample magnetization (VSM). The results showed that the Fe3O4 nanoparticles with a particle size of less than 100 nm were well-distributed on the surface of the graphene aerogel. The prepared Fe3O4/graphene aerogel showed effective removal of 2,4-D herbicide from the aqueous solution with a maximal adsorption capacity of approximately 42.918 mg g-1. The adsorption isotherms and kinetics were investigated to study the adsorption behaviour of the resultant material. The saturation magnetism value of the aerogel was determined to be about 20.66 emu g-1, indicating that the adsorbent could be easily collected from the solution using an external magnet. These results implied that the prepared Fe3O4/graphene aerogel could be a promising adsorbent for the removal of 2,4-D herbicide from water.
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The failure of the centralized water supply system forced XY community to become more dependent on uncertain and unstable water sources. The results of surveying 50 households showed that 89.18% of total households depended on water collected from rivers, which contributed 58.3% of the total water volume used for the domestic demands. The average water volume consumed was 19.5 liters/person/day (l/p/d), and 86.5% of households used more than one source; 13.5% of households collected water only from rivers, and 45.94% of families had rainwater harvesting (RWH) for their activities (domestic water demand); however, RWH only provided 9.9% of total water consumption. In this study, basic methods were applied to calculate the storage tanks necessary to balance the water deficit created by drought months. Three levels of water demand (14, 20, and 30 l/p/d) can be the best choices for RWH; for a higher demand (40 and 60 l/p/d), small roof area (30-40 m2), and many people (six to seven) per family, RWH might be impractical because of unsuitable rainfall or excessively large storage tanks.
Assuntos
Chuva , Água , Conservação dos Recursos Naturais , Humanos , Incerteza , Abastecimento de ÁguaRESUMO
In this manuscript, biological durability, cytotoxicity and MRI image contrast effect of chitosan modified magnetic nanoparticles were investigated. The result of durability study shows that the asprepared sample with average size of about 30 nm had a high stability under pH conditions in range of from 2 to 12 and at salt concentration in range of from 0 to 300 mM. The cytotoxicity testing indicates that the obtained Fe3O4@CS ferrofluid revealed a low cytotoxicity. After 48 h of test on the line of prostate tumor cells of Sarcoma 180, collected IC50 value was 178.5±22 (µg/ml), 7.5 to 27.9 times less cytotoxicity than that of reported ferromagnetic fluids. MRI data shows that the transverse relaxation rate (r2) of the ferrite nanoparticles was 130.32 (mM-1s-1), 2 and 1.44 times larger than that of the commercial products of Sinerem (AMI-227) and Ferumoxytol products, respectively. Invivo test in rabbit shows that the picture of body parts was clearly observed after the injection of the Fe3O4@CS ferrofluid. With these outstanding properties, this magnetic fluid based on the chitosan modified Fe3O4 nanoparticles had great potential for enhancing the image contrast in image diagnosis by MRI magnetic resonance imaging technique.