Phytoremediation potential of vetiver grass irrigated with wastewater for treatment of metal contaminated soil.

A field experiment was conducted to understand the potential of vetiver grass (Vetiveria zizanioides) in heavy metal uptake from the soil and wastewater. Four main irrigation treatments including T1 (treated industrial wastewater), T2 (1:1 ratio of municipal:industrial wastewater), T3 (treated municipal wastewater) and T4 (fresh water) were applied. Moreover, the effect of arbuscular mycorrhizal fungus (AMF), Glomus mosseae, on plant growth and heavy metal concentration was evaluated. Three main criteria including bioconcentration factor (BCF), translocation factor (TF) and heavy metal uptake were applied to assess the potential of vetiver grass in accumulation and translocation of heavy metals to aerial parts. The highest concentration of heavy metals was found in plant and soil irrigated with T1 treatment followed by T2, T3 and the lowest concentrations were found in T4 treatment. Irrigation with treated municipal wastewater led to a significant increase in plant biomass and heavy metal uptake compared to other treatments. In T1 treatment (industrial wastewater), vetiver grass caused a significant decrease in Zn, Fe, Cu, Cd and Pb concentrations in soil as compared to no-plant treatment (without planting vetiver grass). Therefore, vetiver grass, irrigated with treated industrial wastewater, is a promising method for the development of urban and industrial green space.

Life cycle assessment for municipal solid waste management: a case study from Ahvaz, Iran.

This study assessed the available status of waste management system in Ahvaz and its impact on the environment, as well as seven other scenarios in order to quantitatively calculate potential environmental impacts by utilizing the life cycle assessment (LCA) method. These scenarios were as follows: scenario 1: landfilling without biogas collection; scenario 2: landfilling with biogas collection; scenario 3: composting and landfilling without biogas collection; scenario 4: recycling and composting; scenario 5: composting and incineration; scenario 6: anaerobic digestion, recycling, and landfilling; scenario 7: anaerobic digestion and incineration. Emissions were calculated by the integrated waste management (IWM) model and classified into five impact categories: resource consumption, global warming, acidification potential, photochemical oxidation, and eco-toxicity. In terms of resource consumption and the depletion of non-renewable resources, the third scenario showed the worst performance due to its lack of any recycling, energy recovery, and conversion to energy. In terms of greenhouse gas emissions and the effect on global warming, scenario 1 and scenario 2 showed that disposing the whole amount of waste resulted in the most amount of greenhouse gases produced. Moreover, 50% gas and energy recovery from landfills, in comparison with the non-recovery method, reduced the index of global warming by 12%. Finally, scenarios which were based on producing energy from waste showed a reasonably positive performance in terms of greenhouse gases emissions and the influence on global warming.

The impact of meteorological parameters on PM10 and visibility during the Middle Eastern dust storms.

Air pollution is one of the most pressing issues in populated Middle Eastern cities, in particular for the city of Ahvaz, Iran, imposing deleterious effects on the environment, public health, economy, culture, and other sectors. In this study, we investigate the relationship between meteorological parameters, PM10, AOD, air mass source origin, and visibility during severe desert dust storms (Average3h PM10 > 3200 µg m-3) between 2009 and 2012. Six of seven such events occurred between February and March. Interestingly, for the seven cases there was always an alarming PM10 mass concentration peak (137-553 µg m-3) between 12:00-18:00 (local time) that was 18-24 h before the dominant peak of the storm (3279-4899 µg m-3). The maximum wind speed over the multi-day periods examined for the dust storms is usually observed 6 h before the alarming PM10 peak. The minimum relative humidity, dew point temperature and air pressure occurred ± 3 h around the time of the alarming PM10 peak. Wind speed was the meteorological parameter that was consistently higher around the time of the first peak as compared to the second peak, with the reverse being true for sea level pressure. Based on four years of daily data in Ahvaz, PM10 was positively correlated with wind speed and air temperature and inversely correlated with sea level pressure and RH. An empirically-derived equation with R2 = 0.95 is reported to estimate the maximum PM10 concentration for severe desert dust events in the study region based on meteorological parameters. Finally, AOD is shown to correlate strongly (R2 = 0.86) with PM10 during periods with severe desert dust storms in the region.