Appraisal of probabilistic human health risks of heavy metals in vegetables from industrial, non-industrial and arsenic contaminated areas of Bangladesh.

Monitoring of heavy metal content in commonly consumed vegetables is of high priority for food safety, and public health risk assessment. Vegetables were collected from industrial, non-industrial, arsenic contaminated region and one of popular vegetable markets of Bangladesh for analyzing heavy metals (As, Cd, Pb, Cu and Zn) using Atomic Absorption Spectroscopy (AAS) with standard digestion procedure. Results showed significant variations of heavy metal content among vegetables and most of cases the metals (except Cu and some of Zn) revealed several times higher concentrations than that of maximum permissible level (MPL) values, which indicated the vegetables were contaminated through either natural or anthropogenic activities. The dietary intake of metals are responsible for association of health risk that evaluated by target hazard quotient (THQ), hazard index (HI), and target carcinogenic risk (TR) calculations. Estimated daily intake (EDI) for all metals were below the maximum tolerable daily intake (MTDI) values of all vegetables. The THQs for single metals were less than 1 (except As and Pb for few vegetables), indicating the inhabitant would not possess health hazard for single metal through vegetables consumption. However, the total target hazard quotient (TTHQ) of all metals were >1 (except Cu and Zn for industrial and non-industrial sites), suggesting potential health risk. HI values were found more than 1 (36.24 for industrial site, 16.74 for non-industrial site, and 15.03 for local market) representing the selected vegetables intake might be affected quality of food safety of densely populated Bangladesh. The probabilistic risk, individual, and total cancer risk (TR) for As and Pb were exceeded the threshold level (10-4) and safe limit (10-6), respectively, indicating peoples who have been consuming these vegetables long time, they might be exposed by lifetime cancer risk. Sensitivity analysis revealed that the metal concentration has high influence on carcinogenic risks.

Cadmium contamination in agricultural soils of Bangladesh and management by application of organic amendments: evaluation of field assessment and pot experiments.

In recent years, cadmium (Cd) contamination in agricultural soils and its subsequent transfer to crops is one of the high-priority environmental and public health issues of global concern, especially in densely populated developing countries like Bangladesh. However, no effective strategy has been introduced or implemented yet to manage Cd-contaminated soils in order to sustain agricultural production with no human health risks. In this study, agricultural soil samples were collected from 60 locations of 10 upazilas from Tangail district to assess the extent of soil Cd contamination. The Cd concentration ranged from 0.83 to 4.08 mg kg-1 with a mean of 2.17 mg kg-1 in topsoil (0-15 cm), and from 0.67 to 3.74 mg kg-1 with a mean of 2.10 mg kg-1 in subsoil (16-30 cm). The values of contamination factor (CF) indicated that all the sampling locations were found to be highly contaminated with Cd. Pot trials with the application of different doses of biochar and vermicompost in Cd-contaminated soil (0.8 mg kg-1 Cd) revealed that integrated application of biochar (5 t ha-1) and vermicompost (5 t ha-1) was the best treatment that significantly (p < 0.05) reduced plant Cd concentration (72%) and increased the biomass of experimental crop, Red amaranth (Amaranthus cruentus). This combined treatment also significantly reduced the uptake of Cr (37%) when co-contamination was present. The study suggests the application of biochar (5 t ha-1) in combination with vermicompost (5 t ha-1) to reduce human health risk and increase crop production when the soil is loamy sand in texture.

A Study of the Particle-Level Fabric and Morphology of Granular Soils under One-Dimensional Compression Using Insitu X-ray CT Imaging.

The particle morphology and fabric of a granular soil influence its mechanical behavior. This study focuses on the evolution of the particle-level fabric and morphology of a uniformly graded sand sample subjected to one-dimensional compression up to 64 MPa. The microstructural changes with increased stresses were captured using in situ high-resolution X-ray computed tomography (X-ray CT) imaging. The processed images of particles were separated using the Monash Particle Separation Method (MPSM) for subsequent fabric and morphological analyses. The variations of various fabric parameters were studied using the separated particle volumes. New methods of assessing the morphology and crushability of particles were introduced including a comprehensive algorithm for determining coordination number, branch and contact normal vectors. Results of all fabric parameters were analyzed and discussed with reference to observed changes. Potential mechanisms were identified and relevant correlations were developed where warranted.

A New Cluster Analysis-Marker-Controlled Watershed Method for Separating Particles of Granular Soils.

An accurate determination of particle-level fabric of granular soils from tomography data requires a maximum correct separation of particles. The popular marker-controlled watershed separation method is widely used to separate particles. However, the watershed method alone is not capable of producing the maximum separation of particles when subjected to boundary stresses leading to crushing of particles. In this paper, a new separation method, named as Monash Particle Separation Method (MPSM), has been introduced. The new method automatically determines the optimal contrast coefficient based on cluster evaluation framework to produce the maximum accurate separation outcomes. Finally, the particles which could not be separated by the optimal contrast coefficient were separated by integrating cuboid markers generated from the clustering by Gaussian mixture models into the routine watershed method. The MPSM was validated on a uniformly graded sand volume subjected to one-dimensional compression loading up to 32 MPa. It was demonstrated that the MPSM is capable of producing the best possible separation of particles required for the fabric analysis.

Determination of Elemental Composition of Malabar spinach, Lettuce, Spinach, Hyacinth Bean, and Cauliflower Vegetables Using Proton Induced X-Ray Emission Technique at Savar Subdistrict in Bangladesh.

The concentrations of 18 different elements (K, Ca, Fe, Cl, P, Zn, S, Mn, Ti, Cr, Rb, Co, Br, Sr, Ru, Si, Ni, and Cu) were analyzed in five selected vegetables through Proton Induced X-ray Emission (PIXE) technique. The objective of this study was to provide updated information on concentrations of elements in vegetables available in the local markets at Savar subdistrict in Bangladesh. These elements were found in varying concentrations in the studied vegetables. The results also indicated that P, Cl, K, Ca, Mn, Fe, and Zn were found in all vegetables. Overall, K and Ca exhibited the highest concentrations. Cu and Ni exhibited the lowest concentrations in vegetables. The necessity of these elements was also evaluated, based on the established limits of regulatory standards. The findings of this study suggest that the consumption of these vegetables is not completely free of health risks.