Cadmium uptake and translocation in tumbleweed (Salsola kali), a potential Cd-hyperaccumulator desert plant species: ICP/OES and XAS studies

Cadmium is a heavy metal, which, even at low concentrations, can be highly toxic to the growth and development of both plants and animals. Plant species vary extensively in their tolerance to excess cadmium in a growth medium and very few cadmium-tolerant species have been identified. In this study, tumbleweed plants (Salsola kali) grown in an agar-based medium with 20 mgl(-1) of Cd(II) did not show phytotoxicity, and their roots had the most biomass (4.5 mg) (P < 0.05) compared to the control plants (2.7 mg) as well as other treated plants. These plants accumulated 2696, 2075, and 2016 mg Cd kg(-1) of dry roots, stems, and leaves, respectively. The results suggest that there is no restricted cadmium movement in tumbleweed plants. In addition, the amount of Cd found in the dry leaf tissue suggests that tumbleweed could be considered as potential cadmium hyperaccumulating species. X-ray absorption spectroscopy studies demonstrated that in roots, cadmium was bound to oxygen while in stems and leaves, the metal was attached to oxygen and sulfur groups. This might imply that some small organic acids are responsible for Cd transport from roots to stems and leaves. In addition, it might be possible that the plant synthesizes phytochelatins in the stems, later coordinating the absorbed cadmium for transport and storage in cell structures. Thus, it is possible that in the leaves, Cd either exists as a Cd-phytochelatin complex or bound to cell wall structures. Current studies are being performed in order to elucidate the proposed hypothesis.     

Precipitation of aragonite by calcitic bivalves in Mg-enriched marine waters

To understand the relative importance of biological versus physicochemical control over biomineralization, we have tested if the chemical composition of the medium (i.e., the Mg/Ca ratio) can change the mineralogy of mollusk shells. The shells of mollusks are made of calcite and/or aragonite, which are by far the most common CaCO₃ polymorphs. Several species of bivalves with predominantly calcitic shells have been cultivated in artificial seawater with a Mg/Ca molar ratio within the range of 8.3–9.2, well above the present value for seawater (5.2). Four out of six species used (the scallop Chlamys varia, the oyster Ostrea edulis, the saddle oyster Anomia ephippium and the mussel Mytilus edulis) survived long enough to secrete significant amounts of calcium carbonate. The deposits (sometimes extensive) formed on the interior shell surfaces were predominantly aragonitic. Three individuals of C. varia also increased their length by adding new shell at the margin. Contrary to the internal shell deposits, these margins were high-Mg calcite. This implies that the marginal mantle is able to exert a more strict control on the secreted mineral phase than the mantle facing the internal shell surface. This is the first report on an in vivo experimentally forced switch in bivalve shell mineralogy, from calcite to aragonite due to a change in water chemistry.     

Spondyloarthropathy in vertebrae of the aquatic Cretaceous snake <Emphasis Type="Italic">Lunaophis aquaticus</Emphasis>, and its first recognition in modern snakes

Inflammatory arthritis is documented for the first time in snakes. Ossification of the intervertebral capsule and zygapophyseal joints resulting in segmental vertebral fusion was observed in the aquatic Cretaceous snake Lunaophis aquaticus. Such pathologic alterations are pathognomonic for the spondyloarthropathy form of inflammatory arthritis. A survey of 2144 snakes in recent collections, performed to identify Holocene prevalence, revealed only two occurrences in extant snakes. The findings in Bitis gabonica and Elaphe taeniura were indistinguishable from those noted in Lunaophis aquaticus and identical to those previously recognized in modern varanids. The pathology likely represents a form of reactive arthritis related to enteropathic infection. While the disease probably did not affect general locomotion, its vertebral column position may have compromised mating.     

Application of Poly(styrene-co-divinylbenzene) Macroporous Microparticles as a Catalyst Support in the Enzymatic Synthesis of Biodiesel

Macroporous poly(styrene-co-divinylbenzene) microparticles, with three different structural characteristics, have been synthesized and used as supports in the immobilization of lipase from Burkholderia cepacia. The best immobilization yield was found upon using microparticles with 35 % of divinylbenzene and the immobilized lipase on this type of particles was used as a catalyst to obtain biodiesel from soybean oil and ethanol. From the experimental results of the transesterification reaction, an empirical model quantitatively relating the temperature, the concentration of the enzyme and the transesterification yield was obtained. Statistical analysis of this model indicated that within the range of values of the variables studied (35–47 °C and 231–788 U/mg respectively) only the enzyme concentration exerted a significant influence on the reaction yield. Additionally, the good fit of a Michaelis–Menten-type model to the experimental results suggests that the limiting step of the reaction was the formation of the enzyme-substrate complex.     

Monitoring of sources and atmospheric processes controlling air quality in an urban Mediterranean environment

Different monitoring parameters (PM mass concentrations, number–size distribution, black carbon, gaseous pollutants, and chemical composition, among others) are currently used in air quality studies. Urban aerosols are the result of several sources and atmospheric processes, which suggests that a single monitoring technique is insufficient to quantitatively evaluate all of them.This study assesses the suitability of a number of monitoring techniques (PM mass concentrations, number and size distribution of ultra-fine particles, levels of gaseous pollutants, and a complete chemical characterization of PM₁₀ and PM_2.5) by examining the response of those techniques to the different emission sources and/or atmospheric processes affecting an urban Mediterranean area (Barcelona, NE Spain).The results of this work reveal that the PM mass, the number concentration and the chemical composition give different, but complementary, information. Whereas the mineral matter, a key atmospheric aerosol component across the Mediterranean, is not properly quantitatively assessed by measuring sub-micrometric particles, the monitoring of the number concentration is indispensable to interpret the origin of specific aerosol episodes. Furthermore, the chemical composition yields very relevant information to deduce the causes of specific pollution episodes.The number concentration of ultra-fine particles in urban areas is strongly dependent upon vehicle exhaust emissions, which may cause adverse health impacts. Moreover, urban Mediterranean environments are favourable to produce nucleation-mode particles (<20 nm) with photochemical origin. In those cases, these particles are expected to be of high solubility and consequently their toxicity may differ from that of traffic-generated ultra-fine particles. Thus, the use of a single monitoring parameter to evaluate the health effects seems to be not enough.     

Lead isotope ratios in lichen samples evaluated by ICP-ToF-MS to assess possible atmospheric pollution sources in Havana,Cuba

Epiphytic lichens, collected from 119 sampling sites grown over “Roistonea Royal Palm” trees, were used to assess the spatial distribution pattern of lead (Pb) and identify possible pollution sources in Havana (Cuba). Lead concentrations in lichens and topsoils were determined by flame atomic absorption spectrophotometry and inductively coupled plasma (ICP) atomic emission spectrometry, respectively, while Pb in crude oils and gasoline samples were measured by ICP-time of flight mass spectrometry (ICP-ToF-MS). Lead isotopic ratios measurements for lichens, soils, and crude oils were obtained by ICP-ToF-MS. We found that enrichment factors (EF) reflected a moderate contamination for 71% of the samples (EF > 10). The ²⁰⁶Pb/²⁰⁷Pb ratio values for lichens ranged from 1.17 to 1.20 and were a mixture of natural radiogenic and industrial activities (e.g., crude oils and fire plants). The low concentration of Pb found in gasoline (<7.0 μg L^?1) confirms the official statement that leaded gasoline is no longer used in Cuba.     

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.     

Monitoring of firefighters exposure to smoke during fire experiments in Portugal

Forest fires represent a serious threat to public security in Europe due to the large burned area. Moreover, smoke pollution due to forest fire events is an important public health issue for the communities directly affected, and particularly for the personnel involved in firefighting operations. Aiming to contribute to the scientific knowledge concerning firefighters exposure to forest fires smoke, data of individual exposure to carbon monoxide, nitrogen dioxide, volatile organic compounds, and particulate matter were obtained during experimental field fires for a group of 10 firefighters equipped with portable “in continuum” measuring devices. Measured values are very high exceeding the Occupational Exposure Standard limits, in particular for peak limit thresholds. These are the first measurements and analysis of firefighter's individual exposure to toxic gases and particles in fire smoke experiments in Europe. However, they already indicate that urgent measures to avoid these levels of exposure are needed.     

Multilingual education of students on a global scale and perspective—international networking on the example of bioindication and biomonitoring (B&B technologies)

Living or formerly living organisms are being used to obtain information on the quality of the general health status of our environment by bioindication and biomonitoring methods for many decades. Thus, different roads toward this common scientific goal were developed by a lot of different international research groups. Global cooperation in between various scientific teams throughout the world has produced common ideas, scientific definitions, and highly innovative results of this extremely attractive working field. The transdisciplinary approach of different and multifaceted scientific areas—starting from biology, analytical chemistry, via health physics, up to social and economic issues—have surpassed mental barriers of individual scientists, so that “production” of straightforward common results related to the influence of material and immaterial environmental factors to the well-being of organisms and human life has now reached the forefront of international thinking. For the further sustainable development of our common scientific “hobby” of bioindication and biomonitoring, highest personal energy has to be given by us, being teachers to our students and to convince strategically decision makers as politicians to invest (financially) into the development of education and research of this innovative technique. Young people have to be intensively convinced on the “meaning” of our scientific doing, e.g., by extended forms of education. One example of multilingual education of students on a global scale and perspective is given here, which we started about 3 years ago.