The use of maize and poplar in chelant-enhanced phytoextraction of lead from contaminated agricultural soils

Chelant-enhanced phytoextraction of heavy metals is an emerging technological approach for a non-destructive remediation of contaminated soils. The main objectives of this study were (i) to assess the extraction efficiency of two different synthetic chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS)) for desorbing Pb from two contaminated agricultural soils originating from a mining and smelting district and (ii) to assess the phytoextraction efficiency of maize (Zea mays) and poplar (Populus sp.) after EDTA application. EDTA was more efficient than EDDS in desorbing and complexing Pb from both soils, removing as much as 60% of Pb. Maize exhibited better results than poplar when extracting Pb from the more acidic (pH approximately 4) and more contaminated (up to 1360 mg Pb kg(-1)) agricultural soil originating from the smelting area. On the other hand, poplars proved to be more efficient when grown on the near-neutral (pH approximately 6) and less contaminated (up to 200 mg Pb kg(-1)) agricultural soil originating from the mining area. Furthermore, the addition of EDTA led to a significant increase of Pb content especially in poplar leaves, proving a strong translocation rate within the poplar plants.     

Geochemical and Pb isotopic evidence for sources and dispersal of metal contamination in stream sediments from the mining and smelting district of Príbram, Czech Republic

Stream sediments from the mining and smelting district of Príbram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of bulk metal and mineralogical determinations, sequential extractions and Pb isotopic analyses. The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9800 mg Pb kg(-1), 26 039 mg Zn kg(-1), 316.4 mg Cd kg(-1), 256.9 mg Cu kg(-1)). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF>40). Lead, Zn and Cd are bound mainly to Fe oxides and hydroxides. In the most contaminated samples Pb is also present as Pb carbonates and litharge (PbO). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting (206Pb/207Pb=1.16), while the role of secondary smelting (car battery processing) is negligible.     

Mercury in fish tissues in the area of Malachov Hg-ore deposit (Slovakia)

Environmental Geochemistry and Health - The abandoned Malachov deposit belongs among the most important historic Hg deposits in the world. The soil, groundwater, surface water, plants, and animals...     

The role of sulphur in cadmium(II) ions detoxification demonstrated in in vitro model: Dionaea muscipula Ell.

Fertilization by phosphorus and also nitrogen fertilizers are the main source of cadmium soil contamination. Cadmium is relatively easily taken up by plants and then consequently enters their food chain. We investigated whether the cultivation medium with or without sulphates supplement affects the synthesis of protective low molecular mass thiols such as cysteine, reduced glutathione, oxidized glutathione and phytochelatins (PC2) in Dionaea muscipula treated with cadmium(II) ions at 0, 1, 5, 10, 25, 50, 100, 250, 500 and 1,000 μM for 6 weeks. The plants cultivated in the presence of sulphates showed higher cadmium tolerance due to faster growth and lesser number of necrosis hallmarks. Further, we utilized liquid chromatography with electrochemical detection for determination of the thiols in plant tissues. In the case of the plants cultivated on media supplemented with sulphates for 6 weeks the average PC2 level was 2,830 ng/g of fresh weight (FW). However, the plants cultivated on media without the presence of sulphates on average contained 1,160 ng PC2/g FW. Results obtained showed the positive effect of sulphur supplementation in cadmium detoxification processes in plants. In addition to thiol content, we also determined level of majority secondary metabolite of Venus flytrap, naphthoquinone plumbagin. Generally, the presence of sulphates in the media enhanced the protective mechanism and did not affect directly the synthesis of secondary metabolite plumbagin.     

Road safety performance indicators and their explanatory value: A critical view based on the experience of Central European countries

Counts of road crashes and their victims represent essential information for road safety practitioners allowing them to analyse their spatial and temporal aspects. However, they cannot provide details on the factors causing road crashes. As a result, various road safety performance indicators (RSPIs) were introduced, making it possible to gather information on the effectiveness of interventions on road safety in given areas. However, analysis of the trends in road casualties in several Central European countries based on safety performance (measured by RSPIs) suggest that not even these indicators can provide full understanding of road safety trends, and, if they are applied generally without the required background information, this could even lead to serious misinterpretation of the trends in road casualties. Sudden breaks in long-term trends seem to be linked to the transition process and to certain legislative reforms. The exposure and socio-economic climate appear to have had a major impact on road crash outcomes. Various additional indicators describing organisational and structural aspects may be helpful, therefore, in better understanding and predicting the development in road safety for individual countries.     

Separating habitat invasibility by alien plants from the actual level of invasion

Habitats vary considerably in the level of invasion (number or proportion of alien plant species they contain), which depends on local habitat properties, propagule pressure, and climate. To determine the invasibility (susceptibility to invasions) of different habitats, it is necessary to factor out the effects of any confounding variables such as propagule pressure and climate on the level of invasion. We used 20 468 vegetation plots from 32 habitats in the Czech Republic to compare the invasibility of different habitats. Using regression trees, the proportion of alien plants, including archaeophytes (prehistoric to medieval invaders) and neophytes (recent invaders), was related to variables representing habitat properties, propagule pressure, and climate. The propagule pressure was expressed as the proportion of surrounding urban and industrial or agricultural land, human population density, distance from a river, and history of human colonization in the region. Urban and industrial land use had a positive effect on the proportion of both archaeophytes and neophytes. Agricultural land use, higher population density, and longer history of human impact positively affected the proportion of archaeophytes. Disturbed human-made habitats with herbaceous vegetation were most invaded by both groups of aliens. Neophytes were also relatively common in disturbed woody vegetation, such as broad-leaved plantations, forest clearings, and riverine scrub. These habitats also had the highest proportion of aliens after removing the effect of propagule pressure and climate, indicating that they are not only the most invaded, but also most invasible. These habitats experience recurrent disturbances and are rich, at least temporarily, in available nutrients, which supports the hypothesis that fluctuating resources are the major cause of habitat invasibility. The least invaded habitats were mires and alpine-subalpine grasslands and scrub. After removing the effect of propagule pressure and climate, some habitats actually invaded at an intermediate level had very low proportions of aliens. This indicates that these habitats (e.g., dry, wet, and saline grasslands, base-rich fens, and broad-leaved deciduous woodlands) are resistant to invasion.     

Uncommon heavy metals,metalloids and their plant toxicity: a review

Heavy metals still represent a group of dangerous pollutants, to which close attention is paid. Many heavy metals are essential as important constituents of pigments and enzymes, mainly zinc, nickel and copper. However, all metals, especially cadmium, lead, mercury and copper, are toxic at high concentration because of disrupting enzyme functions, replacing essential metals in pigments or producing reactive oxygen species. The toxicity of less common heavy metals and metalloids, such as thallium, arsenic, chromium, antimony, selenium and bismuth, has been investigated. Here, we review the phytotoxicity of thallium, chromium, antimony, selenium, bismuth, and other rare heavy metals and metalloids such as tellurium, germanium, gallium, scandium, gold, platinum group metals (palladium, platinum and rhodium), technetium, tungsten, uranium, thorium, and rare earth elements yttrium and lanthanum, and the 14 lanthanides cerium, dysprosium, erbium, europium, gadolinium, holmium, lutetium, neodymium, promethium, praseodymium, samarium, terbium, thulium and ytterbium.