The mechanisms of stabilization by silicon-rich amendments of cadmium, zinc, copper and lead in a multi-metal contaminated acidic soil and the mitigation of metal accumulation in rice were investigated in this study. The results from a pot experiment indicated that the application of fly ash (20 and 40 g kg−1) and steel slag (3 and 6 g kg−1) increased soil pH from 4.0 to 5.0-6.4, decreased the phytoavailability of heavy metals by at least 60%, and further suppressed metal uptake by rice. Diffusion gradient in thin-film measurement showed the heavy metal diffusion fluxes from soil to solution decreased by greater than 84% after remediation. X-ray diffraction analysis indicated the mobile metals were mainly deposited as their silicates, phosphates and hydroxides in amended treatments. Moreover, it was found metal translocation from stem to leaf was dramatically restrained by adding amendments, which might be due to the increase of silicon concentration and co-precipitation with heavy metals in stem. Finally, a field experiment showed the trace element concentrations in polished rice treated with amendments complied with the food safety standards of China. These results demonstrated fly ash and steel slag could be effective in mitigating heavy metal accumulation in rice grown on multi-metal contaminated acidic soils. 相似文献
The activity of xanthine oxidoreductases (xanthine oxidase, XO, EC 1.2.3.2 and xanthine dehydrogenase, XDH, EC 1.1.1.204) in partially purified extracts of Gonyaulax polyedra was measured over 24 h both in a light:dark cycle and in constant light. This is the first demonstration of xanthine oxidoreductase in a unicellular alga. The activity of the O2-dependent form (XO) was found to be 15 times higher in light than in darkness. The same time-of-day specific differences persisted in constant light, demonstrating a control of XO by the circadian clock. In contrast, the activity of the NAD-dependent form (XDH) is not under circadian control. Because pharmacological inhibition of XO also blocks the effect of blue light on the Gonyaulax circadian clock, the possible relationship between XO and light reception in this unicellular alga will be discussed. 相似文献
Objective: We examined the prevalence of and characteristics associated with drink-driving in China. We compared this study's drink-driving findings with those from the United States to explore how effective traffic safety interventions from Western cultures might be adapted for use in China.
Methods: Data from the 2010 China Chronic Disease and Risk Factor Survey were analyzed to describe the prevalence and characteristics associated with drink-driving in China.
Results: Overall, 1.5% of Chinese adults reported drink-driving in the past 30 days—3% of males and 0.1% of females. However, among males who had driven a vehicle in the past 30 days and consumed at least one alcoholic beverage in the past 30 days, 19% reported drink-driving during the 30-day period. Excessive drinking, binge drinking, nonuse of seat belts, and having been injured in a road traffic crash in the past year were most strongly associated with drink-driving among males.
Conclusions: Drink-driving is prevalent among male drivers in China. Although large differences exist between China and the United States in the proportion of adults who drive, the proportion who consume alcohol, and some of the personal characteristics of those who drink and drive, similarities between the 2 countries are present in patterns of risk behaviors among drink-driving. To reduce injuries and deaths from drink-driving, effective interventions from Western cultures need to be tailored for adoption in China. 相似文献