Morphological and functional responses of a metal-tolerant sunflower mutant line to a copper-contaminated soil series

Environmental Science and Pollution Research - The potential use of a metal-tolerant sunflower mutant line for biomonitoring Cu phytoavailability, Cu-induced soil phytotoxicity, and Cu...     

Exploiting plant metabolism for the phytoremediation of persistent herbicides

Weed control by herbicides has helped us to create the green revolution and to provide food for at least the majority of human beings living today. However, some herbicides remain in the environment and pose an ecological problem. The present review describes the properties and fate of four representative herbicides known to be presistent in ecosystems. Metabolic networks are depicted and it is concluded that removal of these compounds by the ecologically friendly technique of phytoremediation is possible. The largest problem is seen in the uptake of the compounds into suitable plants and the time needed for such an approach.     

Debromination of hexabromobenzene by its co-grinding with CaO

A hexabromobenzene (HBB, C6Br6) powder was subjected to co-grinding with excess CaO powder in air using a planetary ball mill to investigate mechanochemical debromination of the HBB sample. The reaction proceeds smoothly with an increase in both grinding time and molar ratio of CaO addition. The co-grinding enables us to debrominate HBB, forming CaBr2, C and CaCO3 besides excess CaO in the product. CaBr2 in the product tends to absorb moisture from the atmosphere to form CaBr2 x nH2O. The reaction yield is quantitatively evaluated by measuring the amount of water-soluble bromide through water washing and the amount of unreacted HBB through toluene washing. It is found that almost 100% of debromination is achieved by 6 h grinding with the molar ratio kept constant at 2:1. Radicals are detected in the ground products, possibly due to rupture in the covalent bonds of C-C and C-Br in HBB.     

Use of the aquatic lichen Dermatocarpon luridum as bioindicator of copper pollution: accumulation and cellular distribution tests

Laboratory experiments were conducted to investigate the potential use of the aquatic lichen Dermatocarpon luridum as bioindicator of copper pollution. Lichen thalli were exposed to 0.00, 0.25, 0.50, 0.75 and 1.00 mM copper in synthetic freshwater to solve the problems of metal bioavailability. The mineral composition of this media was prepared so that it corresponded to the ion composition of natural waters in D. luridum ecosystems. Sequential elution procedures using NiCl2 or Na2-EDTA (20 mM) were used to determine the distribution of metals at different cellular sites. The copper concentration extracted from thalli was correlated with pollution intensity, the greater correlation being with the Na2-EDTA extractant. The malondialdehyde concentration in thalli can be used as indicator of copper pollution; however, similar membrane degradation was observed for 0.25 and 0.50 mM copper and for 0.75 and 1.00 mM copper.     

Radon, helium and CO2 measurements in soils overlying a former exploited oilfield, Pechelbronn district, Bas-Rhin, France

The Pechelbronn oilfield (Rhine Graben, France), where mining activity ended in the 1960s, has been used for waste disposal for twenty years. Since the wastes are varied, work is underway to identify the discharged materials and their derivatives, as well as to locate and quantify potential discharge sites. Two major goals were assigned to the present work. The first was to identify or refine the location of hidden structures that could facilitate gas emanation up to the surface, by studying soil gas concentrations (mainly ²²²Rn, CO₂, CH₄ and helium) and carbon isotope ratios in the CO₂ phase. The second was devoted to examining, from a health and safety viewpoint, if the use of the oilfield as a waste disposal site might have led to enhanced or modified gas emanation throughout the area.It appeared that CO₂ and ²²²Rn evolution in the whole area were similar, except near some of the faults and fractures that are known through surface mapping and underground observations. These ²²²Rn and CO₂ anomalies made it possible to highlight more emissive zones that are either related to main faults or to secondary fractures acting as migration pathways. In that sense, the CO₂ phase can be used to evaluate ²²²Rn activities distant from tectonic structures but can lead to erroneous evaluations near to gas migration pathways. Dumping of wastes, as well as oil residues, did not appear to have a strong influence on soil gaseous species and emanation. Similarly, enhanced gas migration due to underground galleries and exploitation wells has not been established. Carbon isotope ratios suggested a balance of biological phenomena, despite the high CO₂ contents reached. Other monitored gaseous species (N₂, Ar, H₂ and alkanes), when detected, always showed amounts close to those found subsurface and/or in atmospheric gases.     

Academic expertise in assisting private companies in the fields of environment and environmental toxicology: the role of individual expertise

Environmental Science and Pollution Research - The scientific knowledge produced by academic research can be valued in all sectors of human activity, including private sector. The ROVALTAIN...     

Air pollutant concentrations near three Texas roadways,Part I: Ultrafine particles

Vehicular emitted air pollutant concentrations were studied near three types of roadways in Austin, Texas: (1) State Highway 71 (SH-71), a heavily traveled arterial highway dominated by passenger vehicles; (2) Interstate 35 (I-35), a limited access highway north of Austin in Georgetown; and (3) Farm to Market Road 973 (FM-973), a heavily traveled surface roadway dominated by truck traffic. Air pollutants examined include carbon monoxide (CO), oxides of nitrogen (NO_x), and carbonyl species in the gas-phase. In the particle phase, ultrafine particle (UFP) concentrations (diameter < 100 nm), fine particulate matter (PM_2.5, diameter < 2.5 μm) mass and carbon content and several particle-bound organics were examined. All roadways had an upwind stationary sampling location, one or two fixed downwind sample locations and a mobile monitoring platform that characterized pollutant concentrations fall-off with increased distance from the roadways. Data reported in this paper focus on UFP while other pollutants and near-roadway chemical processes are examined in a companion paper. Traffic volume, especially heavy-duty traffic, wind speed, and proximity to the road were found to be the most important factors determining UFP concentrations near the roadways. Since wind directions were not consistent during the sampling periods, distances along wind trajectories from the roadway to the sampling points were used to study the decay characteristics of UFPs. Under perpendicular wind conditions, for all studied roadway types, particle number concentrations increased dramatically moving from the upwind side to the downwind side. The elevated particle number concentrations decay exponentially with increasing distances from the roadway with sharp concentration gradients observed within 100–150 m, similar to previously reported studies. A single exponential decay curve was found to fit the data collected from all three roadways very well under perpendicular wind conditions. No consistent pattern was observed for UFPs under parallel wind conditions. However, regardless of wind conditions, particle concentrations returned to background levels within a few hundred meters of the roadway. Within measured UFP size ranges, smaller particles (6–25 nm) decayed faster than larger ones (100–300 nm). Similar decay rates were observed among UFP number, surface, and volume.     

Potential of <Emphasis Type="Italic">Ranunculus acris</Emphasis> L. for biomonitoring trace element contamination of riverbank soils: photosystem II activity and phenotypic responses for two soil series

Foliar ionome, photosystem II activity, and leaf growth parameters of Ranunculus acris L., a potential biomonitor of trace element (TE) contamination and phytoavailability, were assessed using two riverbank soil series. R. acris was cultivated on two potted soil series obtained by mixing a TE (Cd, Cu, Pb, and Zn)-contaminated technosol with either an uncontaminated sandy riverbank soil (A) or a silty clay one slightly contaminated by TE (B). Trace elements concentrations in the soil-pore water and the leaves, leaf dry weight (DW) yield, total leaf area (TLA), specific leaf area (SLA), and photosystem II activity were measured for both soil series after a 50-day growth period. As soil contamination increased, changes in soluble TE concentrations depended on soil texture. Increase in total soil TE did not affect the leaf DW yield, the TLA, the SLA, and the photosystem II activity of R. acris over the 50-day exposure. The foliar ionome did not reflect the total and soluble TE concentrations in both soil series. Foliar ionome of R. acris was only effective to biomonitor total and soluble soil Na concentrations in both soil series and total and soluble soil Mo concentrations in the soil series B.     

Heavy metal recovery from the fine fraction of solid waste incineration bottom ash by wet density separation

Journal of Material Cycles and Waste Management - This work is aimed at exploring the recovery of heavy metals from the fine fraction of solid waste incineration bottom ash. For this study,...