Amrit Kumar Dutta

The current study aims to assess the infusion pattern of three important micronutrients namely copper (Cu), iron (Fe), and zinc (Zn) contents from black tea samples produced in Assam (India) and Thohoyandou (South Africa). Average daily intakes and hazardous quotient were reported for these micronutrients. Total content for Cu, Fe, and Zn varied from 2.25 to 48.82 mg kg⁻¹, 14.75 to 148.18 mg kg⁻¹, and 28.48 to 106.68 mg kg⁻¹, respectively. The average contents of each of the three micronutrients were higher in tea leaves samples collected from South Africa than those from India while the contents in tea infusions in Indian samples were higher than in South African tea samples. Results of this study revealed that the consumption of 600 mL tea infusion produced from 24 g of made tea per day may be beneficial to human in terms of these micronutrients content. Application of nonparametric tests revealed that most of the data sets do not satisfy the normality assumptions. Hence, the use of both parametric and nonparametric statistical analysis that subsequently revealed significant differences in elemental contents among Indian and South African tea.

A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18′ 48.02″ N and 88° 39′ 29.0″ E) and Lakshmikantapur (22° 06′ 16.61″ N and 88° 19′ 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5–100 mg L⁻¹). The average rate coefficient (k _avg) and half-life (t _1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t _1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (E _a) values, Cd sorption in acidic pH (14.76 ± 0.29 to 64.45 ± 4.50 kJ mol⁻¹) is a surface control phenomenon and in alkaline pH (9.33 ± 0.09 to 44.60 ± 2.01 kJ mol⁻¹) is a diffusion control phenomenon The enthalpy of activation (ΔH ^∓) values were found to be between 7.28 and 61.73 kJ mol⁻¹. Additionally, higher positive energy of activation (ΔG ^∓) values (46.82 ± 2.01 to 94.47 ± 2.36 kJ mol⁻¹) suggested that there is an energy barrier for product formation.