Phytoextraction potential of two Rumex acetosa L. accessions collected from metalliferous and non-metalliferous sites: effect of fertilization

Metal tolerance and phytoextraction potential of two common sorrel (Rumex acetosa L.) accessions, collected from a Pb/Zn contaminated site (CS, Lanestosa) and an uncontaminated site (UCS, Larrauri), were studied in fertilized and non-fertilized pots prepared by combining soil samples from both sites in different proportions (i.e., 0%, 33%, 66% and 100% of Lanestosa contaminated soil). The original metalliferous mine soil contained 20480, 4950 and 14 mg kg(-1) of Zn, Pb and Cd, respectively. The microcosm experiment was carried out for two months under greenhouse controlled conditions. It was found that fertilization increased mean plant biomass of both accessions as well as their tolerance. However, only the CS accession survived all treatments even though its biomass decreased proportionally according to the percentage of contaminated mine soil present in the pots. This metallicolous accession would be useful for the revegetation and phytostabilization of mine soils. Due to its high concentration and bioavailability in the contaminated soil, the highest values of metal phytoextracted corresponded to Zn. The CS accession was capable of efficiently phytoextracting metal from the 100% mine soil, indeed reaching very promising phytoextraction rates in the fertilized pots (6.8 mg plant(-1) month(-1)), similar to the ones obtained with hyperaccumulator plants. It was concluded that fertilization is certainly worth being considered for phytoextraction and revegetation with native plants from metalliferous soils.     

Long-term effects of lead poisoning on bone mineralization in vultures exposed to ammunition sources

Long-lived species are particularly susceptible to bioaccumulation of lead in bone tissues. In this paper we gain insights into the sublethal effects of lead contamination on Egyptian vultures (Neophron percnopterus). Our approach was done on the comparison of two populations (Canary Islands and Iberian Peninsula) differing in exposures to the ingestion of lead ammunition. Blood lead levels were higher in the island population (Canary Islands range: 5.10-1780 μg L⁻¹n = 137; Iberian Peninsula range: 5.60-217.30 μg L⁻¹n = 32) showing clear seasonal trends, peaking during the hunting season. Moreover, males were more susceptible to lead accumulation than females. Bone lead concentration increased with age, reflecting a bioaccumulation effect. The bone composition was significatively altered by this contaminant: the mineralization degree decreased as lead concentration levels increased. These results demonstrate the existence of long-term effects of lead poisoning, which may be of importance in the declines of threatened populations of long-lived species exposed to this contaminant.     

Increasing interannual and altitudinal ozone mixing ratios in the Catalan Pyrenees

Interannual, seasonal, daily and altitudinal patterns of tropospheric ozone mixing ratios, as well as ozone phytotoxicity and the relationship with NO_x precursors and meteorological variables were monitored in the Central Catalan Pyrenees (Meranges valley and Forest of Guils) over a period of 5 years (2004–2008). Biweekly measurements using Radiello passive samplers were taken along two altitudinal transects comprised of thirteen stations ranging from 1040 to 2300 m a.s.l. Visual symptoms of ozone damage in Bel-W3 tobacco cultivars were evaluated biweekly for the first three years (2004–2006). High ozone mixing ratios, always above forest and vegetation protection AOT40 thresholds, were monitored every year. In the last 14 years, the AOT40 (Apr–Sept.) has increased significantly by 1047 μg m^?3 h per year. Annual means of ozone mixing ratios ranged between 38 and 67 ppb_v (38 and 74 ppb_v during the warm period) at the highest site (2300 m) and increased at a rate of 5.1 ppb_v year^?1. The ozone mixing ratios were also on average 35–38% greater during the warm period and had a characteristic daily pattern with minimum values in the early morning, a rise during the morning and a decline overnight, that was less marked the higher the altitude. Whereas ozone mixing ratios increased significantly with altitude from 35 ppb_v at 1040 m–56 ppb_v at 2300 m (on average for 2004–2007 period), NO₂ mixing ratios decreased with altitude from 5.5 ppb_v at 1040 m–1 ppb_v at 2300 m. The analysis of meteorological variables and NO_x values suggests that the ozone mainly originated from urban areas and was transported to high-mountain sites, remaining aloft in absence of NO. Ozone damage rates increased with altitude in response to increasing O₃ mixing ratios and a possible increase in O₃ uptake due to more favorable microclimatic conditions found at higher altitude, which confirms Bel-W3 as a suitable biomonitor for ozone concentrations during summer time. Compared to the valley-bottom site the annual means of ozone mixing ratios are 37% larger in the higher sites. Thus the AOT40 for the forest and vegetation protection threshold is greatly exceeded at higher sites. This could have substantial effects on plant life at high altitudes in the Pyrenees.     

Simultaneous measurements of formaldehyde and nitrous acid in dews and gas phase in the atmosphere of Santiago,Chile

The amounts of formaldehyde and nitrous acid (HONO) in gas phase and dews of Santiago de Chile were simultaneously measured. Formaldehyde concentrations values in the liquid phase (dews) correlate fairly well with those in the gaseous phase and are even higher than those expected from gas–dew equilibrium. On the other hand, nitrite concentrations in dews were considerably smaller (ca. 15 times) than those expected from the gas-phase concentrations. This under-saturation is attributed to diffusion limitations due to the relatively large HONO solubility. In agreement with this, under-saturation increases with the rate of dew formation and the pH of the collected waters, factors that should increase the rate of gas to liquid HONO transfer required to reach equilibrium.     

Seasonal distribution and modeling of diesel particulate matter in the Southeast US

The fine and ultra fine size of diesel particulate mater (DPM) are of great health concern and significantly contribute to the overall cancer risk. In addition, diesel particles may contribute a warming effect on the planet's climate. The composition of these particles is composed principally of elemental carbon (EC) with adsorbed organic compounds, sulfate, nitrate, ammonia, metals, and other trace elements. The purpose of this study was to depict the seasonality and modeling of particulate matter in the Southeastern US produced by the diesel fueled sources (DFSs). The modeling results came from four one-month cases including March, June, September, and December to represent different seasons in 2003 by linking Models-3/CMAQ and SMOKE. The 1999 National Emissions Inventory Version 3 (NEI99) was used in this analysis for point, area, and non-road sources, whereas the National Mobile Inventory Model (NMIM) was used to create the on-road emissions. Three urban areas, Atlanta, Birmingham, and Nashville were selected to analyze the DPM emissions and concentrations. Even though the model performance was not very strong, it could be considered satisfactory to conduct seasonal distribution analysis for DPM. Important hourly DPM seasonality was observed in each city, of which higher values occurred at the morning traffic rush hours. The EC contributions of primary DPM were similar for all three sites (~ 74%). The results showed that there is no significant daily seasonality of DPM contribution to PM_2.5 for any of these three cities in 2003. The annual DPM contribution to total PM_2.5 for Atlanta, Nashville, and Birmingham were 3.7%, 2.5%, and 2.2%, respectively.     

Biodegradation potential of the genus Rhodococcus

A large number of aromatic compounds and organic nitriles, the two groups of compounds covered in this review, are intermediates, products, by-products or waste products of the chemical and pharmaceutical industries, agriculture and the processing of fossil fuels. The majority of these synthetic substances (xenobiotics) are toxic and their release and accumulation in the environment pose a serious threat to living organisms. Bioremediation using various bacterial strains of the genus Rhodococcus has proved to be a promising option for the clean-up of polluted sites. The large genomes of rhodococci, their redundant and versatile catabolic pathways, their ability to uptake and metabolize hydrophobic compounds, to form biofilms, to persist in adverse conditions and the availability of recently developed tools for genetic engineering in rhodococci make them suitable industrial microorganisms for biotransformations and the biodegradation of many organic compounds. The peripheral and central catabolic pathways in rhodococci are characterized for each type of aromatics (hydrocarbons, phenols, halogenated, nitroaromatic, and heterocyclic compounds) in this review. Pathways involved in the hydrolysis of nitrile pollutants (aliphatic nitriles, benzonitrile analogues) and the corresponding enzymes (nitrilase, nitrile hydratase) are described in detail. Examples of regulatory mechanisms for the expression of the catabolic genes are given. The strains that efficiently degrade the compounds in question are highlighted and examples of their use in biodegradation processes are presented.     

Multi-causal and integrated assessment of sustainability: the case of agriculturization in the Argentine Pampas

Assessing the sustainability of complex development processes requires multi-causal and integrated analyses. We develop a system-based methodology, rooted in interdisciplinary discussion and consensus building between 15 experts, to construct a multi-causal diagram which examines the sustainability of the Argentine Pampas′ process of agriculturization. The resulting diagram includes 25 factors and provides a big-picture of the multiple dimensions and interrelations affecting sustainability. According to this examination, the increasing concentration of production and the incorporation of technological innovations, triggered by economic and institutional factors, are the cause of environmental distresses and social changes, whose consequences for sustainability are still highly disputed. Nevertheless, the symptoms of both environmental and social unsustainability are more evident in the case of the extra-Pampean regions than in the Pampas. This suggests that the Pampean agriculture model should not be transferred to these regions without substantial modifications. The experts did not reach consensus on whether the agriculturization process is overall sustainable or unsustainable. Lack of consensus revolved mainly around opposing perspectives regarding the significance of the threats to environmental sustainability. The magnitude of socio-distributive unbalance and loss of rural jobs were also contentious. Yet, the paper shows how the exercise of building a joint causal diagram was undoubtedly helpful for linking piece-meal disciplinary facts, brought in from all fronts, into a comprehensive and coherent picture. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Treatment of IGCC power station effluents by physico-chemical and advanced oxidation processes

The aim of this work was to improve the quality of aqueous effluents coming from the Gasification Unit in an Integrated Gasification Combined Cycle (IGCC) Thermoelectric Power Station, with the purpose of fulfilling the future more demanding normative. To this end, an integral wastewater treatment including coagulation, flocculation, neutralization, photocatalytic oxidation, and ion-exchange has been studied. A final scheme has been proposed to remove pollutants. All the parameters of the treated wastewater are below pouring specifications. In the first stage, the wastewater was treated with CaCl2 (optimal dose=11 g CaCl2/g F-) as coagulant and a commercial anionic polyelectrolyte (optimal dose=0.02 g/g F-) as flocculant to remove fluoride ions (99%) and suspended solids (92%). The water was then neutralized, improving the degree of transmission of ultraviolet light, allowing the faster photo-degradation of pollutants. The photochemical study included different systems (H2O2, UV/H2O2, Fenton, Fenton-like, UV/Fenton, UV/Fenton-like and UV/H2O2/O2). In the Fenton-like system, the influence of two parameters (initial concentration of H2O2 and amount of Cu(II)) on the degradation of cyanide and formate (taken as the reference of the process) was studied. Experimental results were fit using neural networks (NNs). Results showed that the photocatalytic process was effective for total cyanide destruction after 60 min, while 180 min was needed to remove 80% of formates. However, a more simple system with UV/H2O2/O2 yields similar results and is preferred for industrial application due to fewer complications. Finally, an ion-exchange process with Amberlite IRA-420 was proposed to remove the excess of chlorides added as a consequence of the initial coagulation process.     

Multi-Destination and Multi-Purpose Trip Effects in the Analysis of the Demand for Trips to a Remote Recreational Site

One of the basic assumptions of the travel cost method for recreational demand analysis is that the travel cost is always incurred for a single purpose recreational trip. Several studies have skirted around the issue with simplifying assumptions and dropping observations considered as nonconventional holiday-makers or as nontraditional visitors from the sample. The effect of such simplifications on the benefit estimates remains conjectural. Given the remoteness of notable recreational parks, multi-destination or multi-purpose trips are not uncommon. This article examines the consequences of allocating travel costs to a recreational site when some trips were taken for purposes other than recreation and/or included visits to other recreational sites. Using a multi-purpose weighting approach on data from Gros Morne National Park, Canada, we conclude that a proper correction for multi-destination or multi-purpose trip is more of what is needed to avoid potential biases in the estimated effects of the price (travel-cost) variable and of the income variable in the trip generation equation.     

On the Use of MRF/AVN Global Information to Improve the Operational Air Quality Model OPANA

Operational air quality models have become an important tool to assist the decision makers in European Environmental Offices at different levels: cities, regional and state. Because of the important advance on computing capabilities during the last few years the possibility of incorporating the complex research and academic mesoscale air quality models under routine operational basis has become a reality. OPANA model is the operational version of the research model ANA (Atmospheric mesoscale Numerical pollution model for regional and urban Areas). This model is a limited area model (mesoscale beta) and the capability to extend the prediction horizon is limited unless proper boundary conditions are provided during long simulations. In this contribution we show how AVN/MRF (NOAA) vertical numerical meteorological soundings are incorporated to the OPANA system by using JAVA technology. This new feature helps to keep the air quality model into medium power workstations and the performance is improved accordingly. This technology avoids running mesoscale models over larger areas (continental scale) to accordingly increase the forecasting temporal horizon.