Arsenic partitioning among particle-size fractions of mine wastes and stream sediments from cinnabar mining districts

Tailings from abandoned mercury mines represent an important pollution source by metals and metalloids. Mercury mining in Asturias (north-western Spain) has been carried out since Roman times until the 1970s. Specific and non-specific arsenic minerals are present in the paragenesis of the Hg ore deposit. As a result of intensive mining operations, waste materials contain high concentrations of As, which can be geochemically dispersed throughout surrounding areas. Arsenic accumulation, mobility and availability in soils and sediments are strongly affected by the association of As with solid phases and granular size composition. The objective of this study was to examine phase associations of As in the fine grain size subsamples of mine wastes (La Soterraña mine site) and stream sediments heavily affected by acid mine drainage (Los Rueldos mine site). An arsenic-selective sequential procedure, which categorizes As content into seven phase associations, was applied. In spite of a higher As accumulation in the finest particle-size subsamples, As fractionation did not seem to depend on grain size since similar distribution profiles were obtained for the studied granulometric fractions. The presence of As was relatively low in the most mobile forms in both sites. As was predominantly linked to short-range ordered Fe oxyhydroxides, coprecipitated with Fe and partially with Al oxyhydroxides and associated with structural material in mine waste samples. As incorporated into short-range ordered Fe oxyhydroxides was the predominant fraction at sediment samples, representing more than 80 % of total As.     

Matches and mismatches between conservation investments and biodiversity values in the European Union

Recently, the European Commission adopted a new strategy to halt the loss of biodiversity. Member states are expected to favor a more effective collection and redistribution of European Union (EU) funds under the current Multiannual Financial Framework for 2014–2020. Because of the large spatial variation in the distribution of biodiversity and conservation needs at the continental scale, EU instruments should ensure that countries with higher biodiversity values get more funds and resources for the conservation than other countries. Using linear regressions, we assessed the association between conservation investments and biodiversity values across member states, accounting for a variety of conservation investment indicators, taxonomic groups (including groups of plants, vertebrates, and invertebrates), and indicators of biodiversity value. In general, we found clear overall associations between conservation investments and biodiversity variables. However, some countries received more or less investment than would be expected based on biodiversity values in those countries. We also found that the extensive use of birds as unique indicators of conservation effectiveness may lead to biased decisions. Our results can inform future decisions regarding funding allocation and thus improve distribution of EU conservation funds.     

Effect of inoculation in composting processes: modifications in lignocellulosic fraction

Three microbial isolates, identified as Bacillus shackletonni, Streptomyces thermovulgaris and Ureibacillus thermosphaericus were tested as inoculants in composting processes in relation to their capacity to improve lignocellulose degradation. Different wastes from agricultural activities were used as raw material for the heaps: pepper plant waste (PPW) as the main component and olive-oil mill waste (OMW), almond shell (AS), pruning waste (PW) and rice straw (RS) as additives. Cellulose was more extensively degraded than hemicellulose and lignin, although the use of inoculants (B. shackletonni and S. thermovulgaris) improved the action of the autochthonous microbiota just in the AS heaps. A higher efficiency was observed for lignin, since lower concentrations of this polymer were detected in the inoculated heaps in relation to control heaps. U. thermosphaericus was the most efficient microorganism since inoculation with this strain decreased the final lignin content in a range between 17.23% and 24.34%. S. thermovulgaris and B. shackletonni led to a higher reduction of the lignin levels in the OMW and PW heaps (14.25% and 19.07% less lignin than control heaps) and OMW (13%), respectively. The composting process can therefore be improved by means of inoculation if the microorganisms used for this purpose are appropriate for the characteristics of the raw material.     

Eco-efficiency in the SMEs of Venezuela. Current status and future perspectives

This paper presents a comparison analysis of eco-efficiency in the small and medium sized enterprises (SMEs) of Venezuela. The research can be divided into three parts: the first part reviews similar studies in the literature on the level of eco-efficiency exhibited by the companies of Venezuela and other countries. In the second place, the findings of a survey conducted on Venezuelan SMEs allowed the definition of 54 eco-efficiency profiles. Thirdly, six national experts in cleaner production and eco-efficiency were interviewed. The interview was based on a questionnaire similar to that used in the survey of the Venezuelan SMEs. At a second meeting, the experts were asked to discuss on the similarities and differences between their answers and those of the company's managers.The findings of the survey allow us to conclude that Venezuelan SMEs understand the legal environmental regulations that affect them but they do not perceive the influence of external driving forces like customers demand for green products or institutional incentives. The adoption of eco-efficiency practices is not perceived as an incentive to improve competitiveness so that the environmental strategies adopted generally aim at reducing costs or avoiding non-compliance sanctions and negative effects on the company image. Materials recycling and reuse, especially packaging materials, are common practices; however, other environmental tools or practices have not been implemented yet, e.g. environmental management systems (EMS), process, product and services design tools based on the product life cycle, renewable energy resources or green marketing. There are also differences among the eight industrial sectors analyzed, food and chemical industries having the higher index of eco-efficiency practices, and plastic and wood industries the lower.     

First fossil evidence of an “interglacial refugium” in the Pyrenean region

A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.     

The role of wetlands in the chromophoric dissolved organic matter release and its relation to aquatic ecosystems optical properties. A case of study: Katonga and Bunjako Bays (Victoria Lake; Uganda)

Chromophoric Dissolved Organic Matter (CDOM) is an important component in freshwater and marine ecosystems and plays direct and indirect role in biogeochemical cycles. CDOM originates from the degradation process of organic materials, usually macrophytes and planktons. The present work examines the importance of wetland derived CDOM on the optical and bio-optical properties of two bays of Lake Victoria (Uganda, Africa). This was achieved by determining the attenuation and extinction coefficients of filtered and unfiltered water samples from two equatorial bays on the Ugandan coastline of Lake Victoria. Katonga Bay is a wetland lined bay that receives water from the Katonga river, while Bunjako Bay is an outer bay between Katonga Bay and Lake Victoria. The results showed that attenuation was highest in Katonga Bay and the role of CDOM is most dominant near the river inlet. The quantity and quality of CDOM is extremely different in the two bays: in Katonga Bay it is possible to hypothesize a terrestrial origin of CDOM (transported by the wetland river). On the contrary, in Bunjako Bay, spectral measurements of absorption indicate a modified CDOM and/or alternative CDOM source. The terrestrial CDOM in Katonga Bay is more capable of absorbing harmful UV radiation than the CDOM present in the Bunjako Bay. The resulting optical environment in the former bay presented a water column with a very limited penetration of harmful UV radiation, while a higher penetration was observed in the Bunjako Bay.     

Accumulation of As, Cd and selected trace elements in tubers of Scirpus maritimus L. from Doñana marshes (South Spain)

The collapse of a pyrite-mining, tailing dam on 1998 contaminated an area of 4286 ha along the Agrio and Guadiamar river valleys in southern Spain. Over 2700 ha of the Do?ana marshes, an important wintering area for wetland European birds, were contaminated. This study reports analyses of the tubers of Scirpus maritimus (an important food for greylag geese, Anser anser) collected in 2000 in the "Entremuros" (spill-affected area) and in nearby unaffected Do?ana marshes (control areas). In the spill-affected area mean tuber tissue concentrations of Cd (0.25 mg kg-1) and Zn (61 mg kg-1) were greater than in those tubers from the control area (0.02 mg kg-1 for Cd, and 22 mg kg-1 for Zn); values of Cd and Zn in "Entremuros" (samples collected two years after the mine spill) were much smaller than those reported only a few months after the accident. Trace elements (As, Fe, Mn and Tl, and to a lesser extent Cd and Pb) showed a preferential accumulation in the outer skin of tubers. Surprisingly, concentrations of As and Fe were greater in tubers from some marsh sites not affected by the mine-spill than in tubers from the "Entremuros". We suggest that relic river channels within the Do?ana marshes may be contaminated by trace elements from historic mining activities. An exhaustive study of macrophytes and other plant species in this area is recommended to identify potential risks to wildlife.