The high potential of Pelargonium roseum plant for phytoremediation of heavy metals

The major objective of this investigation was to evaluate the potential of scented geraniums, Pelargonium roseum, to uptake and accumulate heavy metals nickel (Ni), cadmium (Cd), or lead (Pb). For this, plants were grown in an artificial soil system and exposed to a range of metal concentrations over a 14-day treatment period. Then, metals from the entire biomass were extracted. The results showed that scented geranium plants accumulated in excess of 20,055 mg of Ni kg^?1 dry weight (DW) of root and 10,889 mg of Ni kg^?1 DW of shoot, and in excess of 86,566 mg of Pb kg^?1 DW for roots and 4,416 mg of Pb kg^?1 DW for shoots within 14 days. Also, the uptake and accumulation of cadmium in roots of scented geranium plants increased with the exposure at low (250, 500 mg?L^?1) and medium level (750 mg?L^?1) followed by a decline at the highest level (1,000 mg?L^?1). The highest accumulation in roots (31,267 mg?kg^?1 DW) was observed in 750 mg?L^?1 cadmium treatment. In the shoots of scented geraniums, the highest amount of metal accumulation (1,957 mg?kg^?1 DW) was detected at 750 and 1,000 mg?L^?1 of cadmium in the culture solution. Finally, since the high concentrations of Ni or Pb accumulated in shoots of scented geranium has far exceeded 0.1 % DW and for Cd has far exceeded 0.01 % DW, P. roseum is a new hyperaccumulator species for these metals and can be used in phytoremediation industry.     

Modelling categorical data to identify factors influencing concern for the natural environment in Iran

Loglinear modelling techniques were used to identify the interactions and interrelationships underlying categorical environmental concern data collected from 9062 respondents in Iran. After fitting various loglinear models to the data, the most parsimonious model highlighted that a combination of interacting factors, namely educational attainment, age, gender, and residential location were responsible for influencing personal concern for the environment. Although high educational attainment had a close correspondence with high concern for the environment the loglinear results, when visualized with a geographical information system, demonstrated wide spatial variations in educational attainment and concern for the environment. Nearly two-thirds of the respondents were not highly educated, and were therefore not highly concerned for the environment. The finding that both rural and urban male and female respondents in the 15-24 years age category, with 10-12 years of education, had the strongest interaction with personal concern for the environment could be beneficial for policy planners to utilize education as the primary instrument to enhance environmental governance and prospects for sustainable development.     

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production

The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3MWh, or 46kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.     

Chlorinated solvents: will the alternatives be safer?

Over the next decade, use of chlorinated solvents, a widely employed class of chemicals, will decline significantly because of increasingly stringent environmental regulations. These solvents pose certain health and environmental problems and they have been heavily scrutinized. The alternatives to the solvents are being adopted without controls. In some cases, these substances will pose other health and environmental problems that are likely to be as serious; in other cases, the alternatives have not been examined for their health and environmental effects at all. This case study demonstrates that regulations on chlorinated solvents and their potential alternatives are inconsistent with one another and conflicting.