Volume 17 - 2015

The United Arab Emirates (UAE) is one of the leading countries in the per capita bottled water consumption. This seems to be in controversy with adherences of local water authorities to stringent municipal water standards. A public survey (n= 891) was conducted to ascertain the perception of people in the country regarding bottled and tap water quality. The survey form was formulated based on the stated preference approach and was furnished in both Arabic and English languages. Some questions in the survey form require rating the quality of tap water and identifying the type of water the respondent drinks. For respondents who usually drink bottled water, they were asked to choose the reason(s) why they usually drink bottled water. Those who drink tap water more often were similarly asked to choose the reason(s) why they prefer tap water to bottled water. The study revealed that a large fraction of the UAE residents classify the quality of tap water as either good or excellent, yet many of them drink bottled water. This could be attributed in part to the high standard of living where the cost of bottled water is considered by the majority of the respondents as affordable. Other influential factors include the belief that bottled water has a better taste and concerns about tap water contamination. The latter may stem from the perception that water is not sufficiently treated or contamination is induced into the water from the distribution system or the in-house storage tanks. The study shows that more people in the UAE will drink tap water if relevant authorities provide information about tap water quality and if regular inspections and cleaning of the in-house storage tanks is conducted.

Adsorption of Cu (II) ions by untreated sugarcane bagasse (USCB) and treated sugarcane bagasse (TSCB) was investigated. Sugarcane bagasse was treated with 0.1M oxalic acid prior to TSCB adsorption studies. Dependence of Cu (II) adsorption on pH, contact time, temperature and initial concentration of adsorbate solution were also investigated. Optimum pH 2 and contact time of 100 minutes were observed for both USCB and TSCB, while Cu II sorption increased with temperature. Under optimum condition, TSCB adsorbed Cu (II) ions better than USCB (1.854mgg^-1and 0.556mgg^-1respectively). Thermodynamic investigations showed that Cu (II) adsorption was feasible, spontaneous and endothermic. Kinetic data was adequately described by Ho’s pseudo-second-order kinetic model while intra-particle diffusion model described a slow adsorption affinity. It was concluded that Cu (II) adsorption by sugarcane bagasse is a favourable chemisorption process and was well explained by both Langmuir and Freundlich isotherms.

The cytotoxic effect was evaluated by the Cytokinesis Block Proliferation Index. Regarding this index, the precursor (1) is not cytotoxic at all tested concentrations. Complexes (3), (4) and (5) induced cytotoxicity at the concentrations of 20, 50 and 75 μM, while complexes (6) and (8) were cytotoxic at all tested concentrations. Complex (7) was cytotoxic at 5, 10 and 20 μM but extremely toxic at 50 and 75 μM. Finally complex (2) was extremely toxic at all tested concentrations except at 1 μM. 

Antioxidant defense mechanisms are crucial for plants to survive under stress conditions. We investigated the capacity of a wild fern species, Nephrolepis biserrata, growing in the vicinity of industrial land to accumulate heavy metals, and assessed its antioxidative response under metal stress. The soils in this particular area were highly contaminated with zinc followed by lead and copper. As control, N. biserrata located 10 km away from the industrial area were collected and assessed. N. biserrata from the contaminated sites accumulated metals in their tissues in similar descending order of zinc>lead>copper. The values of bioaccumulation factor between 0 to 0.1 indicate N. biserrata as a moderate accumulator for the tested metals. For the enzymatic antioxidant assays, the activities of catalase and ascorbate peroxidase were significantly higher in N. biserrata from contaminated soil compared to control, while the activity of superoxide dismutase was not differ significantly in plants from both sites. We also detected higher contents of total phenolics and total flavonoids in N. biserrata collected from contaminated site compared to control. Our HPLC analysis revealed higher levels of myricetin and kaempferol in plant samples from the contaminated area. Our study verified the capacity of N. biserrata to scavenge oxygen radicals when exposed to heavy metal stress. Such ability to tolerate stressful condition suggests that the plant is a potential metal phytoremediator.