Incorporating soil structure and root distribution into plant uptake models for radionuclides: toward a more physically based transfer model

Most biosphere and contamination assessment models are based on uniform soil conditions, since single coefficients are used to describe the transfer of contaminants to the plant. Indeed, physical and chemical characteristics and root distribution are highly variable in the soil profile. These parameters have to be considered in the formulation of a more realistic soil-plant transfer model for naturally structured soils. The impact of monolith soil structure (repacked and structured) on Zn and Mn uptake by wheat was studied in a controlled tracer application (dye and radioactive) experiment. We used Brilliant Blue and Sulforhodamine B to dye flow lines and 65Zn and 54Mn to trace soil distribution and plant uptake of surface-applied particle-reactive contaminants. Spatial variation of the soil water content during irrigation and plant growth informs indirectly about tracer and root location in the soil profile. In the structured monolith, a till pan at a depth of 30 cm limited vertical water flow and root penetration into deeper soil layers and restricted tracers to the upper third of the monolith. In the repacked monolith, roots were observed at all depths and fingering flow allowed for the fast appearance of all tracers in the outflow. These differences between the two monoliths are reflected by significantly higher 54Mn and 65Zn uptake in wheat grown on the structured monolith. The higher uptake of Mn can be modelled on the basis of radionuclide and root distribution as a function of depth and using a combination of preferential flow and rooting. The considerably higher uptake of Zn requires transfer factors which account for variable biochemical uptake as a function of location.     

Sharing developed countries’ post-2012 greenhouse gas emission reductions based on comparable efforts

The Bali Action Plan as adopted under the United Nations Framework Convention on Climate Change (UNFCCC) in 2007, states that Annex I (developed) countries should reduce their greenhouse gas emissions, based on comparable efforts. Within this context, we have explored various comparable effort approaches (for example, equal marginal abatement costs for all countries) for reducing emissions by the year 2020 for individual countries and regions. In all calculations, the total reduction for Annex I countries as a group is assumed to be 30% below 1990 levels. In the analysis, we compare the reduction targets as calculated from the different approaches with the emission reductions as pledged by these countries as part of the Copenhagen Accord, as drafted under the UNFCCC in 2009. Our analysis indicates that the different elements in these calculations may cause a diversity in outcomes and that, therefore, individual countries may favour certain elements over others. These elements include (a) the choice of the approach itself (the same approach may produce very different outcomes for countries with diverging national circumstances, such as Canada and Russia); (b) the reference year (such as 1990 or 2006 emissions, is very important for countries with an increase in emissions since 1990 (e.g. the United States, Canada) or for those that have lower emission levels (e.g. Russia, the Ukraine)); and (c) rules on land use (these are important for countries with large forest areas). It should be noted that the stringency of the individual countries’ reductions as pledged, differs substantially from the stringency of the reduction targets calculated from the effort-sharing approaches. The current pledges by both the European Union and the United States, are lower than the reductions that would be obtained in the effort-sharing approaches for a 30% overall reduction in Annex I countries.     

The water footprint of hydroelectricity: a methodological comparison from a case study in New Zealand

Hydroelectricity has been rated to have a large water footprint (WF) on global average. We assessed the WF of hydroelectricity by three different methods using New Zealand as a case study. The first (WF-1) and second (WF-2) methods only consider the consumptive water use of the hydroelectricity generation system, while our third method (WF-3) accounts for the net water balance. Irrespective of the method, the WF of New Zealand’s hydroelectricity was found much smaller than the commonly cited international value of 22 m³ GJ⁻¹. Depending on the method, the national WF ranged from 1.55 m³ GJ⁻¹ (WF-3) to 6.05 m³ GJ⁻¹ (WF-1). The WF- 3 considers the net water balance including rainfall, which is the key driver for replenishing water resources. It provides meaningful information that helps our understanding of the differences of the WF in locations, which are diverse in terms of water resource availability. We highlight the effects of local climatic differences and the structural specifics of a hydroelectricity scheme on the WF. The large variation in the WF of hydropower across New Zealand illustrates the inappropriateness of using global average values. Local values, calculated using our hydrologically rational method, must be used.     

Combined application of QEM-SEM and hard X-ray microscopy to determine mineralogical associations and chemical speciation of trace metals

We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.     

Who Cares about Farmed Fish? Citizen Perceptions of the Welfare and the Mental Abilities of Fish

This paper explores citizens’ views about the welfare of farmed fish and the mental abilities of fish with a large survey data sample from Finland (n = 1,890). Although studies on attitudes towards animal welfare have been increasing, fish welfare has received only limited empirical attention, despite the rapid expansion of aquaculture sector. The results show that the welfare of farmed fish is not any great concern in the Finnish society. The analysis confirms the distinct character given to farmed fish compared to traditional farmed animals. Salmon are rated low in their mental abilities, including the capacity to feel pain, which may weaken ethical concerns for fish welfare. When analyzing the social determinants surrounding the rating of the welfare of farmed fish, it was shown that fish welfare attitudes follow general animal welfare attitudes regarding age and place of residence as fish welfare tends to be rated more negatively among younger age groups and among urban residents. However, no clear connection could be identified between gender and the rating of fish welfare, which may suggest that the distinct cultural categorization of fish diminishes the typical gender difference identified in animal attitudes. It is concluded that in order to improve awareness about fish welfare, there is a need to increase dissemination of scientific knowledge about fish and their welfare. Moreover, further research should be directed toward studying the moral positioning of fish and the distinct moral categorization they receive.     

How conservation and humanitarian groups respond to production of border security on the Arizona–Sonora border

US policies for securing the border with Mexico are driven by multiple political concerns, including the desire to control illegal trade and immigration in a way that conveys “border security” to a national audience. Highly visible border enforcement near urban centres and via the border fence has pushed migrants into far less visible and remote wilderness areas, driving both ecological degradation and a humanitarian crisis. This study employed ethnographic methods to explore how natural resource agency employees and humanitarian volunteers in Altar Valley Arizona perceived and responded to the production of border security. We found that both groups recognised human rights and environmental concerns, although they assigned different priorities and addressed them through conflicting means. As in other cases where consumers are separated from production practices, there was a general consensus among informants that it was important to raise the consciousness of the national audience about the negative externalities of producing border security.     

Multi-criteria decision analysis in adaptation decision-making: a flood case study in Finland

Decision-making for the purpose of adaptation to climate change typically involves multiple stakeholders, regions and sectors as well as multiple objectives related to the use of resources and perceived benefits. Standard cost–benefit analysis can be argued to take into account easily monetised effects only. Multi-criteria decision analysis (MCDA) embedded in participatory processes can therefore play an important role in defining the decision context and exploring stakeholders’ preferences. In this paper, a case study on flood protection of the Kokemäki river running through the city of Pori in West Finland was conducted. The study was realised as a MCDA workshop involving the key stakeholders of the region. The analysis produced a robust ranking of the considered flood protection alternatives. According to the stakeholders, the approach was useful as an exploratory way of gaining a deeper and shared understanding of the flood protection. It was shown that MCDA is well suited for decision-making in adaptation to climate change–enhanced extreme events.     

Parasitismus und ‘Endokrine Disruption’ in Fischen

Background

Since the 1960s the scientific community has become increasingly aware of the need for integrative and holistic approaches to solve environmental issues. It has not only been recognized that changing environmental conditions can alter toxicological properties of pollutants but also that susceptibility of organisms to man-made chemicals strongly depends on environmental factors. This is especially true with respect to the endocrine control of reproductive processes in many aquatic species including fish, which are mainly influenced by changes in the surrounding environment such as day length, temperature, water flow, etc. Thus, it is astounding that the use of integrative approaches to address the question of the ecotoxicological relevance of the disruption of endocrine and related reproductive functions is rate. As a consequence of this shortcoming, there is increasing demand both among scientists and politicians regarding more holistic approaches in the endocrine disruptor research.

Aim

This contribution aims to critically discuss current strategies and approaches as well as to identify alternative strategies in context with the environmental risk assessment of endocrine disruptors. This will be exemplified using an ecotoxicological study with bream (Abramis brama) that was conducted along a major European river, the Elbe.

Results and Discussion

Local bream (Abramis brama) populations collected along the river Elbe were characterized by different magnitudes and/or types of endocrine alterations. Although there is a relatively extensive data set available regarding its contamination with wide range of chemicals in the Elbe, it has not been possible to conclusively relate the observed endocrine effects to the exposure to individual compounds or mixtures of chemicals. However, during the gross morphological evaluations of the fish it was observed that at some locations a great number of the individuals caught were parasitized with the tapeworm Ligula intestinalis. Furthermore, statistical analysis revealed that a relatively great percentage of the variation of the biological endpoints observed both among individuals and sampling sites could be explained by the occurrence of this parasite. Overall, the findings of these studies indicate that there is a complex interaction not only among the exposure to chemicals and parasitism but also of both of these aspects with the occurrence of biological effects in fish.

Conclusions

The gaps in our current knowledge as well as the findings from the few studies available indicate, the there is a need to revise our current approaches to characterize and evaluate exposure scenarios regarding their potential to cause endocrine disruption in wild organisms. Given the complexity of most environmental exposure scenarios, involving multiple factors including anthropogenic and natural influences and their interactions, I therefore see the urgent need to initiate a discussion on more integrative approaches in this field in favor of true ‘ecotoxicological studies’ that integrate both ecology and toxicology.     

Alteration of steroidogenesis in H295R cells by organic sediment contaminants and relationships to other endocrine disrupting effects

A novel bioassay with the human adrenocortical carcinoma cell line H295R can be used to screen for endocrine disrupting chemicals that affect the expression of genes important in steroidogenesis. This assay was employed to study the effects of organic contaminants associated with the freshwater pond sediments collected in the Ostrava-Karvina region, Czech Republic. The modulation of ten major genes involved in the synthesis of steroid hormones (CYP11A, CYP11B2, CYP17, CYP19, 17betaHSD1, 17betaHSD4, CYP21, 3betaHSD2, HMGR, StAR) after exposure of H295R cells to sediment extracts was investigated using quantitative real-time polymerase chain reaction (PCR). Crude sediment extracts, containing high concentrations of polycyclic aromatic hydrocarbons (PAHs) and moderate amounts of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) significantly stimulated expression of the CYP11B2 gene (up to 10-fold induction), and suppressed expression of 3betaHSD2 and CYP21 genes. A similar pattern was observed with the extracts after treatment with concentrated sulfuric acid to remove labile chemicals (including PAHs) leaving only persistent PCBs, OCPs and potentially PCDD/Fs. Comparison of the results with other mechanistically based bioassays (arylhydrocarbon receptor, AhR, mediated responses in H4IIE-luc cells, and estrogen receptor mediated effects in MVLN cells) revealed significant endocrine disrupting potencies of organic contaminants present in the sediments (most likely antiestrogenicity). Pronounced effects were observed particularly in sediment extracts from the Pilnok Pond which harbors an unusual intersexual population of the narrow-cawed crayfish Pontastacus leptodactylus (Decapoda, Crustacea). This pilot study provided the first experimental evidence of the wider application of the H295R bioassay for screening complex environmental samples, and the results support the hypothesis of chemical-induced endocrine disruption in intersexual crayfish.     

Environmental risk,toxicity, and biodegradation of polyethylene: a review

Environmental Science and Pollution Research - Polyethylene is the second-most-commonly-used commercial polymer. It is used in various industries, including agricultural mulches, composite...