Heating is one of the most commonly used methods of food preparation in homes and industries and prolong use of oil for this purpose causes changes in its physical and chemical properties. The effects of changing temperature on various chemical and physical characteristics of sesame seed oil were studied. The oil was extracted using soxhlet apparatus with nhexane as extraction solvent. The seeds of sesame (Sesamumindicum) were found to have high oil content. Both the chemical and physical characteristics were investigated within a temperature range of 25-290°C. At room temperature (25°C), the results revealed the chemical characteristics as follows: acid value (AV) (5.61mg/g); peroxide value (PV) (4.42 Meq/kg); free fatty acid (FFA) (5.89%). The physical characteristics were: moisture content (MC) (5.50%); density (0.99g/cm 3); refractive index (RI) (1.47). At elevated range of temperatures (170-290°C), there were corresponding changes in both chemical and physical parameters as follows: AV (5.61-5.91mg/g); PV (4.44-6.05 Meq/kg); FFA (5.91-6.06%); MC (3.98-0.71%); density (0.95-0.69g/cm 3); RI (1.46-1.40). The study showed that there was gradual increase in chemical properties with increase in temperature whereas, the physical properties decreased gradually with increase in temperature.

Soil pollution by heavy metals is a global environmental problem. The need to keep the environment clean is increasingly becoming a global concern. Heavy metals are one group of pollutants that are widespread in our environment. They tend to persist indefinitely once they enter the soil. Their mobility and toxicity depend on their forms and oxidation states in the soil. This research presents the speciation, mobility and potential toxicity of Cr, Co, Cu and Mn in soils from some dumpsites in Kano, using a six-step sequential extraction method and AAS analysis. The results revealed the pH of the soils to range from 6.20-7.80. Percentage composition of clay and organic matter ranged from 6.00-16.58 % and 0.48- 4.30 % respectively. The results showed that the metals are bioavailable at different forms evident from their distribution pattern in the different fractions and therefore the soils should not be used for cultivation to avoid the metals getting into the food chain. The mobility factor values ranging between 14.38 % and 61.48 % for dry season; 15.63 % and 74.74 % for rainy season showed the metals to be very mobile especially Co, Cu, and Mn. This could lead to potential pollution of the agricultural produce and ground water in this area and hence have toxic effects on human lives. This result can serve as a guide to researchers on the appropriate method to reclaim the soils in this area based on the pattern of distribution of the metals in different geochemical phases.

Mankind quest for better life has led to advancements in modern technologies which include a number of manufacturing processes and methodologies. Some of these processes and methodologies often release harmful substances into the environment including heavy metals which lead to pollution. These heavy metals are non-biodegradable and therefore need to be removed. Attention has been devoted to emerging technologies which are relatively cheap, for the removal of heavy metal ions from contaminated waters. Adsorption of heavy metal ions using biological materials is one such technologies. As such, the adsorption of Cr(vi), Cd (ii), Zn (ii) and Ni(ii) from synthetic solution by activated carbon from Khaya senegalensis was studied in a batch experiment as a function of pH, metal concentration, adsorbent dose and contact time. Solutions after the batch experiments were analyzed using atomic absorption spectrophotometer. The result revealed dependency of adsorption process on pH. The optimal metal removal occurred at pH 6 for Cd (ii), Zn (ii) and Ni (ii) and 3 for Cr (vi). Maximum adsorption of 82.2 %, 78.9 %, 87.2 % and 83.3 % was attained for Cr (vi), Cd (ii), Zn (ii) and Ni (ii) respectively. Adsorption capacity of the adsorbent improved with initial metal concentration. Ion exchange seemed to be the major mechanism of adsorption in this study. The data collected was were modelled by the Langmuir isotherm over the entire concentration range, suggesting a monolayer coverage. The result showed that, sulphurised Khaya senegalensis is effective in removing heavy metal ions from aqueous solution.