No abstract

This investigation was undertaken to determine the concentrations of cadmium, lead, mercury, zinc, copper and magnesium in six tea types used as children's tea. Six types of tea of different herbal composition used for children's consumption (T1, T2, T3, T4, T5 and T6) were analyzed in three subsequent collections. The analysis of cadmium showed that the concentration was very similar in all types of children's tea, ranging from 0.233 to 0.369 mg/kg. Lead concentrations were in the range of 0.340-1.564 mg/kg without any significant differences. The analysis of mercury detected very low concentration of this metal in all samples (0.002-0.004 mg/kg). In zinc, the values ranged from 36.633 to 71.711 mg/kg, with significant differences (p < 0.001) according to tea type. Copper concentration was 10.089-30.178 mg/kg with the highest value in T4. The concentration of magnesium was significantly higher in tea T1 and T2 (102.311 and 129.422 mg/kg) in comparison with other tea types where the level was 19.811-37.411 mg/kg. The maximum tolerable limit determined by Codex Alimentarius was not exceeded in any sample. In general, correlation analysis detected high positive correlation between cadmium and lead (r = 0.89), cadmium and mercury (r = 0.92) and between lead and mercury (r = 0.77).

Thermal weeding in Eastern Canadian agticulture is relatively new and being considered as a viable tool in organic food production. Hot water (HW), infrared (IR) and open flame (OF) thermal units were compared in terms of energy efficiency and effectiveness (percentage of weeds killed). The units were operated at ground speeds of 1.5, 2.5 and 3.5 km h-1 , and were tested on Amarantlws retroftexus L. (redroot pigweed), Chenopodium album L. (common lambsquru1ers), Persicaria maculata L. (ladysthumb), and Sinapis alba L. (white mustard) at growth stages of< 6, 6-8 and > 8 leaves. HW was also operated at I km h-1 • The energy consumption of lR was determined to be more than four times that of HW and OF, which consumed similar amounts per unit area. All units showed peak energy efficiency at 2.5 km h-1 speed; with the OF attaining the highest energy efficiency followed by IR, and then by HW, which was the least energy efficient. HW was also the least effective in controlling weeds, killing less than 48% of all four species. IR at speeds of 1.5 and 2.5 km h-1 killed I 00% of all weed species that were at growth stages of< 6 leaves. OF at 1.5 and 2.5 km h-1 killed I 00% of young redroot pigweed, common Iambsquarters, and ladysthumb, but not white mustard. OF at 2.5 km h-1 speed had the highest energy efficiency and effectiveness for most weed species that were at their early growth stage. Although IR at 3.5 km h-1 used higher energy input and had lower energy efficiency, it showed a potential for controlling a good number of the weed species as effectively or more effectively than OF at 1.5 km h-1 •

No abstract

No abstract