Poly(methyl methacrylate) thin films were prepared through solvent casting method followed by thermal treatment to completely remove the residual solvent. All three different tactic PMMAs were studied; the PMMA solution was made in chloroform at various concentrations, with 0.1wt% QDs added against the polymer mass in the polymer solution. PMMA-QDs thin films as well as the pristine PMMA thin film (as control sample) were characterized using a variety of analytical techniques to probe their structure, functionalities, and respective physicochemical properties including thickness, surface wettability, fluorescence emission, and biocompatibility using HeLa mammalian cell as a model cell line. The fluorescence emission steadily increased when the concentration of PMMA increases. The wettability test showed i-PMMA to be more hydrophilic with a smaller contact angle than the other tacticity, while a-PMMA showed to be more hydrophobic with a larger contact angle than the other tacticity. All PMMA-QDs thin films used in co-culturing with HeLa cells supported their growth and proliferation.
This study was carried out in ten (10) different locations within River Gongola, its Dam, and Dadinkowa Dam, Gombe State, Nigeria during the wet and dry season to study the water quality in terms of physicochemical properties to ascertain the levels of contaminants due to flooding and anthropogenic activities and the levels of heavy metals (Cr, Cd, Pb, and Ni) in the two species of fish (Clarias gariepinus and Bagrus docmak). A total of 200 water and 360 fish samples comprising two different species were collected in the month of March-June 2017 (Dry season) and July-October 2017 (Wet Season). The results of physicochemical properties obtained ranges between Temperature 29.0-30 0C and 30-32 0C, pH 5.4-7.8 and 6.0-6.9, Conductivity 93.3-161 μS/cm3 and 104.9-128 μS/cm3, Dissolved oxygen 1.2-3.98 mg/l and 0.4-3.1 mg/l, Total Suspended Solids 10-860 mg/l and 13-1180 mg/l, Total Dissolved Solids 46.5-80.5 mg/l and 54.2-76.5 mg/l, Turbidity 424.7-783.5 NTU and 11.15-442.1 NTU, Phosphate 1.82-7.23 mg/l and 0.00-0.11 mg/l, and Nitrate 2.25-8.82 mg/l and 2.68-6.81 mg/l during wet and dry season respectively. The result reveals that turbidity, PO43, DO, TSS, and TDS were above the acceptable permissible limits of WHO While the mean concentration levels of heavy metals in Clarias gariepinus and Bagrus docmak revealed that Cr was below the detectable limit while Cd ranges between 0.5-7.75 µg/g, Pb rangesbetween 3.9-35.6 µg/g during the wet and dry season. The mean concentrations of all the studied metals were above the permissible limit of WHO with a higher concentration during the dry season.
Soil is a vital environmental, ecological and agricultural resource that has to be protected from further degradation as an adequate supply of healthy food is needed for the world’s increasing population. Heavy metals’ accumulation in the soil is of great concern in agricultural production due to the adverse effects on food quality, crop growth and environmental health. The concentration of heavy metals [Zinc (Zn), Iron (Fe), Lead (Pb), Copper (Cu), Cadmium (Cd) and Chromium (Cr)] in vegetables (Tomato fruit and Spinach leaves) and soils (Tomato and Spinach soils) were collected from different farmlands in Mamudo, Potiskum L.G.A of Yobe State and analyzed using Atomic Absorption Spectrometer (AAS). The results revealed all the heavy metals were detected in all the samples with Zn (7.2), Fe (7.5), Pb (4.0), Cu (113.9), Cd (29.1), Cr (4.7) mg/kg respectively for the tomatoes samples and Zn (7.1), Fe (18.3), Pb (21.8), Cu (95.7), Cd (50.8), and Cr (2.7) mg/kg respectively for the spinach. The concentration of the heavy metals were within the normal range World Health Organization (WHO) and Food and Agricultural Organization (FAO) safe limits of 20 – 100, 400 – 500 and 0.5 – 30 for Zn, Fe and Pb respectively in plants samples. But the concentration of the heavy metals were above the normal range WHO/FAO safe limits of 2.5 < 2.4 and < 0.1 – 1 for Cu, Cd, and Cr respectively in plants samples. The high concentration level of Cu, Cd and Cr could be attributed to the high level of metal work, vehicular emissions, addition of fertilizers, pesticides, herbicides and other chemicals to the soil to enhance the agricultural crops. Therefore, the vegetables samples are not safe for consumption with regards to Cu, Cd and Cr.
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