Mercury toxicity induces oxidative stress in growing cucumber seedlings

In this study, the effects of exogenous mercury (HgCl(2)) on time-dependent changes in the activities of antioxidant enzymes (catalase and ascorbate peroxidase), lipid peroxidation, chlorophyll content and protein oxidation in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were exposed to from 0 to 500microM of HgCl(2) during 10 and 15 days. Hg was readily absorbed by growing seedlings, and its content was greater in the roots than the in shoot. Time and concentration-dependent reduction in root and shoot length was observed at all concentrations tested, equally in the roots and shoot, at both 10 and 15 days. At 50microM HgCl(2), root fresh weight of 15-day-old seedlings increased, and at other concentrations, it reduced. For 10-day-old seedlings, reduction in root and shoot fresh biomass was observed. At 15 days, only at 50microM HgCl(2) was there no observed reduction in shoot fresh biomass. Dry weight of roots increased at 500microM both at 10 and 15 days, though at 250microM HgCl(2) there was only an increase at 15 days. There was a significant effect on shoot dry weight at all concentrations tested. Hg-treated seedlings showed elevated levels of lipid peroxides with a concomitant increase in protein oxidation levels, and decreased chlorophyll content when exposed to between 250 and 500microM of HgCl(2). At 10 days, catalase activity increased in seedlings at a moderately toxic level of Hg, whereas at the higher concentration (500microM), there was a marked inhibition. Taken together, our results suggest that Hg induces oxidative stress in cucumber, resulting in plant injury.     

Road traffic deaths in Brazil: rising trends in pedestrian and motorcycle occupant deaths

Objective: According to the World Health Organization, the global burden of road traffic mortality exceeds 1.27 million people annually; over 90 percent occur in low- and middle-income countries. Brazil's road traffic mortality rate of ～20 per 100,000 is significantly higher than nearby Chile or Argentina. To date, there has been very little information published on road traffic fatalities among vulnerable road users (VRUs) in Brazil. Methods: Road traffic fatality data from 2000 to 2008 were extracted from Brazil's Mortality Information System (SIM). Road traffic deaths were extracted using the International Classification of Diseases (ICD-10) V-codes (V01-V89) and then subcategorized by VRU categories. Information was then disaggregated by gender, age, and region. Results: In 2008, 39,211 deaths due to road traffic injuries were recorded in Brazil, resulting in a crude mortality rate of 20.7 per 100,000 inhabitants. Pedestrian mortality averaged 5.46 deaths per 100,000 between 2000 and 2008. The mortality rate for elderly pedestrians (80+ years) is 20.1 per 100,000, over 10 times that of 0- to 9-year-olds. In the past decade, motorcycle occupant mortality has dramatically increased by over 300 percent from 1.5 per 100,000 in 2000 to 4.7 per 100,000 in 2008. The 20- to 29-year age group remains most affected by motorcycle deaths, with a peak fatality rate of 10.76 per 100,000 in 2008. The north and northeast regions, with the lower per capita gross domestic product (GDP), have higher proportions of VRU deaths compared with other regions. Conclusions: Vulnerable road users are contributing an increasing proportion of the road traffic fatalities in Brazil. Nationally, elderly pedestrians are at particularly high risk and motorcycle fatalities are increasing at a rapid rate. Less prosperous regions have higher proportions of VRU deaths. Understanding the epidemiology of road traffic mortality in vulnerable road user categories will better allow for targeted interventions to reduce these preventable deaths.     

Role of the fungal mycelium in the retention of radiocaesium in forest soils

The aim of this work was to study possible binding of 137Cs to various organic components in the soil and fungi, by using various sequential extraction procedures. The retention and binding of 137Cs has been studied in two horizons Of/Oh and Ah/B of a Ukrainian forest soil. The exchangeable fractions 137Cs from soil (sum of H2O and 1 M NH4OAc fraction) were found to be 12% in the organic-rich layer (range 11-14%) and 23% in the organic-poor (range 20-29%). The hydrolysis with 10% H2SO4 resulted in an additional release of 30% of 137Cs from the organic-rich soil (range 30-35%) and 38% from the organic-poor soil horizon (range 27-53%). Extraction with 30% H2O2 released 11 and 15% of the 137Cs activity from organic-rich and organic-poor soil horizons. The corresponding values for treatment with 98.8% NaOCl were about 27% in both types of soil. About 11% of the total 137Cs activity was found in the humic acid fraction, about 5% in the fulvic fraction and 46% in the residue fraction. Relatively high level of 137Cs activity in soil (ca. 50%) was thus still left unsolved in the residue fraction. About 29% of 137Cs activity concentration in fungal mycelia was found as water soluble with a range of 11 to 41%. Additionally 24% of the 137Cs activity from mycelia was released by 1 M ammonium acetate extraction. Together, water and 1 M ammonium acetate extraction released about 53% of the total 137Cs activity in the mycelia. In fruit bodies of mycorrhizal fungi, 68% of the total 137Cs inventory was found to be water soluble at room temperature and 93% at 80 degrees C.     

Algal cultures with effluents from biological treatment of urban wastewaters by anaerobiosis

Experiments have been carried out on cultures of native algae of Andalucía (Spain) with effluents from the biological treatment of urban wastewaters by anaerobiosis, using continuous and discontinuous systems.The influence of different hydraulic retention times of the wastewater on the algal cultures has been determined: on the level of algal biomass reached, and on the degree of purification achieved, measured from the evolution of various quality parameters.     

A tubular ceramic membrane coated with TiO2-P25 for radial addition of H2O2 towards AMX removal from synthetic solutions and secondary urban wastewater

Environmental Science and Pollution Research - This work aims to integrate several hydrogen peroxide (H2O2) activation mechanisms, photolysis (UVC irradiation), chemical electron transfer (TiO2-P25...     

Investigation of two new low-cost adsorbents functionalized with magnetic nanoparticles for the efficient removal of triclosan and a synthetic mixture

Environmental Science and Pollution Research - Triclosan (TCS) is widely used in the production of antibacterial products, being often found in wastewater. Therefore, this study developed new...