Radiation-induced adaptive response in fish cell lines

There is considerable interest at present in low-dose radiation effects in non-human species. In this study gamma radiation-induced adaptive response, a low-dose radiation effect, was examined in three fish cell lines, (CHSE-214 (Chinook salmon), RTG-2 (rainbow trout) and ZEB-2J (zebrafish)). Cell survival after exposure to direct radiation with or without a 0.1 Gy priming dose, was determined using the colony forming assay for each cell line. Additionally, the occurrence of a bystander effect was examined by measuring the effect of irradiated cell culture medium from the fish cell lines on unexposed reporter cells. A non-linear dose response was observed for all cell lines. ZEB-2J cells were very sensitive to low doses and a hyper-radiosensitive (HRS) response was observed for doses <0.5 Gy. A typical protective adaptive response was not detected in any of the three fish cell lines tested. Rather, it was found that pre-exposure of these cells to 0.1 Gy radiation sensitized the cells to subsequent high doses. In CHSE-214 cells, increased sensitivity to subsequent high doses of radiation was observed when the priming and challenge doses were separated by 4 h; however, this sensitizing effect was no longer present when the interval between doses was greater than 8 h. Additionally, a "protective" bystander response was observed in these cell lines; exposure to irradiated medium from fish cells caused increased cloning efficiency in unirradiated reporter cells. The data confirm previous conclusions for mammalian cells that the adaptive response and bystander effect are inversely correlated and contrary to expectations probably have different underlying mechanisms.     

Radon concentration measurements in mofettes from Harghita and Covasna counties, Romania

In the Harghita volcanic range (Romania) there are many occurrences of dry CO(2) emanations, called mofettes. The emanating gas with high carbon dioxide content has a proved curative effect. The gas also contains important quantities of radon. Since the mofettes are used in curative purposes in several illnesses, in most of the cases without medical supervising, has been proposed to determine the radon activity concentration in some of the most frequented mofettes from Romania. The seasonal variations have also been monitored and were calculated the effective doses received by the patients during a cure. The radon activity concentrations' levels above the mofettes indoor air range between 548 and 10 717Bq/m(3) while within the gas pools' values between 3210 and 32 781Bq/m(3) have been measured. The effective dose received by the patients during a cure is between 0.0086 and 0.16mSv. No major seasonal variations of the radon activity concentrations levels have been pointed out so far in the studied mofettes.     

Land use history of a floodplain area during the last 200 years in the Upper-Tisza region (Hungary)

Research into landscape history makes it possible to follow landscape changes in the past and support landscape management, conservation and restoration programs. Floodplain habitats are lost, isolated and fragmented on account of land use. Nowadays, these habitats are threatened by modifications in the natural water regime, as well as agricultural and forestry practices. Floodplains have great importance because they provide a transition between aquatic habitats and terrestrial biotopes. Our analysis of aerial photographs and topographical maps revealed that the major predicted changes in the study area are related to agricultural abandonment and afforestation. The comparison of land cover maps from 1784 to 2005 showed intensification of agriculture with land cover conversions from arable land and orchards to grasslands, marshes and woodlands. The land use types that are mostly responsible for the fragmentation of the landscape are arable land, economic plantations and orchards. We found that fragmentation was greater after 1956. This was caused by socioeconomic changes and showed that the habitats of floodplains have changed intensively during the last 200 years. Knowledge of this last 200 years of history contributes to a more careful and wiser management of the region through biodiversity protection and environmental development.     

Controlling urban air pollution caused by households: uncertainty, prices, and income

We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households.     

Peroxidase-catalyzed stabilization of 2,4-dichlorophenol in alkali-extracted soils

Horseradish peroxidase- (HRP) mediated stabilization of phenolic contaminants is a topic of interest due to its potential for remediation of contaminated soils. This study evaluated the sorption of 2,4-dichlorophenol (DCP) and its HRP-mediated stabilization in two alkali-extracted soils. Alkali extraction reduced the soil organic matter (SOM) contents of the geomaterials and enriched the residual SOM with humin C. Sorption of DCP on these sorbents was complete within 1 d. However, most of the sorbed DCP was removed from the geomaterials by water and methanol, suggesting weak solute-sorbent interactions. The addition of HRP resulted in the generation of DCP polymerization products (DPP), which partitioned between the aqueous and solid phases. The DPP phase distribution was rapid and complete within 24 h. Between 70 and 90% of the added DCP was converted to DPP and up to 43% of the initial aqueous phase contaminant was transformed into a residue that was resistant to extraction with methanol. Bound residues of DPP increased with initial aqueous phase solute concentration and remained fairly constant after 7 d of contact. Contaminant stabilization was noted to be high in the humin-mineral geomaterial. Results illustrate that HRP may be effective in stabilizing phenolic contaminants in subsoils that are likely to contain SOM enriched in humin C.     

Efficiency of a protected-area network in a Mediterranean region: a multispecies assessment with raptors

Three different systems of designating protected areas in a Mediterranean region in southeastern Spain were studied, referring to their effectiveness and efficiency for protecting both the breeding territories and the suitable habitat of a set of ten raptor species. Taking into consideration the varying degrees of endangerment of these species, a map of multispecies conservation values was also drawn up and superimposed on the three protected-area systems studied. In order to compare the levels of protection afforded by the three systems, we considered two indices that measured their relative effectiveness and efficiency. The effectiveness estimated the proportion of territories or optimal habitat protected by the networks while efficiency implicitly considered the area of each system (percentage of breeding territories or optimal habitat protected per 1% of land protected). Overall, our results showed that the most efficient system was that formed by the set of regional parks and reserves (17 protected breeding territories per 100 km²), although, given its small total area, it was by far the least effective (only protecting the 21% of the breeding territories of all species and 17% of the area of high conservation value). The systems formed by the Special Protection Areas (designated under the EU “Birds Directive”) and by the Special Conservation Areas (designated under the EU “Habitats Directive”) notably increased the percentages of protected territories of all species (61%) and area of high conservation value (57%), but their efficiency was not as high as expected in most cases. The overall level of protection was high for all species except for the Lesser Kestrel (Falco naumanni), an endangered falcon that inhabits pseudo-steppe and traditional agricultural habitats, which are clearly underrepresented in the protected-area network of the study region.     

Using Mediterranean shrubs for the phytoremediation of a soil impacted by pyritic wastes in Southern Spain: a field experiment

Re-vegetation is the main aim of ecological restoration projects, and in Mediterranean environments native plants are desirable to achieve successful restoration. In 1998, the burst of a tailings dam flooded the Guadiamar river valley downstream from Aznalcóllar (Southern Spain) with sludges that contained elevated concentrations of metals and metalloids, polluting soils and waters. A phytoremediation experiment to assess the potential use of native shrub species for the restoration of soils affected by the spillage was performed from 2005 to 2007, with soils divided into two groups: pH < 5 and pH > 5. Four native shrubs (Myrtus communis, Retama sphaerocarpa, Rosmarinus officinalis and Tamarix gallica) were planted and left to grow without intervention. Trace element concentrations in soils and plants, their extractability in soils, transfer factors and plant survival were used to identify the most-interesting species for phytoremediation. Total As was higher in soils with pH < 5. Ammonium sulphate-extractable zinc, copper, cadmium and aluminium concentrations were higher in very-acid soils, but arsenic was extracted more efficiently when soil pH was >5. Unlike As, which was either fixed by Fe oxides or retained as sulphide, the extractable metals showed significant relationships with the corresponding total soil metal concentration and inverse relationships with soil pH. T. gallica, R. officinalis and R. sphaerocarpa survived better in soils with pH > 5, while M. communis had better survival at pH < 5. R. sphaerocarpa showed the highest survival (30%) in all soils. Trace element transfer from soil to harvestable parts was low for all species and elements, and some species may have been able to decrease trace element availability in the soil. Our results suggest that R. sphaerocarpa is an adequate plant species for phytostabilising these soils, although more research is needed to address the self-sustainability of this remediation technique and the associated environmental changes.     

Analyzing the Social Factors That Influence Willingness to Pay for Invasive Alien Species Management Under Two Different Strategies: Eradication and Prevention

Biological invasions occur worldwide, and have been the object of ecological and socio-economic research for decades. However, the manner in which different stakeholder groups identify the problems associated with invasive species and confront invasive species management under different policies remains poorly understood. In this study, we conducted an econometric analysis of the social factors influencing willingness to pay for invasive alien species management under two different regimes: eradication and prevention in the Doñana Natural Protected Area (SW Spain). Controlling for the participation of local residents, tourists and conservationists, email and face-to-face questionnaires were conducted. Results indicated that respondents were more willing to pay for eradication than prevention; and public support for invasive alien species management was influenced by an individual’s knowledge and perception of invasive alien species, active interest in nature, and socio-demographic attributes. We concluded that invasive alien species management research should confront the challenges to engage stakeholders and accept any tradeoffs necessary to modify different conservation policies to ensure effective management is implemented. Finally, our willingness to pay estimates suggest the Department of Environment of Andalusian Government has suitable social support to meet the budgetary expenditures required for invasive alien species plans and adequate resources to justify an increase in the invasive alien species management budget.     

Stakeholder Analysis and Social-Biophysical Interdependencies for Common Pool Resource Management: La Brava Wetland (Argentina) as a Case Study

This article gives an account of the implementation of a stakeholder analysis framework at La Brava Wetland Basin, Argentina, in a common-pool resource (CPR) management context. Firstly, the context in which the stakeholder framework was implemented is described. Secondly, a four-step methodology is applied: (1) stakeholder identification, (2) stakeholder differentiation-categorization, (3) investigation of stakeholders' relationships, and (4) analysis of social-biophysical interdependencies. This methodology classifies stakeholders according to their level of influence on the system and their potential in the conservation of natural resources. The main influential stakeholders are La Brava Village residents and tourism-related entrepreneurs who are empowered to make the more important decisions within the planning process of the ecosystem. While these key players are seen as facilitators of change, there are other groups (residents of the inner basin and fishermen) which are seen mainly as key blockers. The applied methodology for the Stakeholder Analysis and the evaluation of social-biophysical interdependencies carried out in this article can be seen as an encouraging example for other experts in natural sciences to learn and use these methods developed in social sciences. Major difficulties and some recommendations of applying this method in the practice by non-experts are discussed.     

Production and fate of copepod fecal pellets across the Southern Indian Ocean

The vertical distribution of copepods, fecal pellets and the fecal pellet production of copepods were measured at seven stations across the Southern Indian Ocean from productive areas off South Africa to oligotrophic waters off Northern Australia during October/November 2006. We quantified export of copepod fecal pellet from surface waters and how much was retained. Furthermore, the potential impact of Oncaea spp. and harpacticoid copepods on fecal pellets degradation was evaluated and found to be regional substantial. The highest copepod abundance and fecal pellet production was found in the western nutrient-rich stations close to South Africa and the lowest at the central oligotrophic stations. The in situ copepod fecal pellet production varied between 1 and 1,000 μg C m⁻³ day⁻¹. At all stations, the retention of fecal pellets in the upper 400 m of the water column was more than 99% and the vertical export of fecal pellets was low (<0.02 mg m⁻² day⁻¹).