Determination and risk assessment of heavy metals in raw foodstuffs sold from open markets in Zambia; a comparison of Kabwe, Kitwe, and Lusaka towns.

The research focused on risk assessment of some heavy metals in common vegetables and fish sold on open markets in three towns of Zambia. The mean level of heavy metals ranged as follows (mg/kg): 1.9 to 662.7, 3.0 to 3472.3 and 2.0 to 1698.7 of cadmium (lowest) and aluminium (highest) for samples from Kabwe, Kitwe and Lusaka, respectively. Statistical analysis indicated that the concentrations of samples from Kitwe and Lusaka towns were similar, P > 0.05. However, there were noteworthy differences in the mean amounts of heavy metals in samples from Kitwe and Kabwe, and samples from Kabwe and Lusaka towns, P < .0167. The health risk analysis indicates possible non-carcinogenic and carcinogenic risks to the consumer. This is because the hazard index (HI) for all metals in all samples from all towns was greater than 1 and the cancer risk (CR) for cadmium was above 10-4 in all samples from all towns.

Degradation of methyl orange on Fe/Ag nanoparticles immobilized on polyacrylonitrile nanofibers using EDTA chelating agents.

Bimetallic nanoparticles are effective for the removal of organic pollutants from environmental water samples through catalytic degradation reactions. Hence, this work reports on the preparation of Fe/Ag bimetallic nanoparticles immobilized on electrospun polyacrylonitrile nanofibers (PAN NFs) pre-functionalized with EDTA and ethylenediamine (EDA) chelating agents. Characterization techniques included attenuated total reflectance coupled to Fourier transform infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The liquid chromatography coupled to a mass spectrometer (HPLC-MS) was used to investigate the degradation by-products. The impregnation of EDTA-EDA chelating agents imparted changes on the pristine PAN NFs as evidenced by increased nanofiber's average diameter and surface chemistry. The zero valent Fe and Ag NPs were successfully immobilized on PAN NFs and their catalytic activity was tested for the degradation of azo dyes. Results showed efficient decolourization of methyl orange dye molecules from synthetic water samples after four (4) cycles of reuse (e.g. >96% removal efficiency). The hydrogenation of methyl orange was found to be the removal mechanism due to the presence of hydrogenated methyl orange by-products in the treated water samples. Therefore, the fabricated nanocomposites exhibit potential application for the remediation of textile wastewater.