Impact of mining activities on soils in a semi-arid environment: Sierra Almagrera district, SE Spain

Field and laboratory-column studies were undertaken in order to investigate soil contamination derived from past mining activity in the Sierra Almagrera (SA) district in southeast Spain. The tailings, soil and sediment samples that were collected showed high concentrations of Ag, As, Ba, Cu, Pb, Sb and Zn when analyzed. The mean concentrations of these elements in the tailings were 29.8, 285.4, 54000, 57.7, 2687.5, 179.0 and 2269.0 ppm, respectively. In the soil samples these decreased to 14.3, 96.9, 24700, 37.5, 1859.1, 168.5 and 815.7 ppm, respectively. Geochemical analyses demonstrated high levels of As, Pb and Zn which were above the intervention values set forth in the Andalusian Regulations for Contaminated Soils for As (>50 ppm), Pb (>500 ppm) and Zn (>2000 ppm). Column experiments and mineralogical studies suggest that the dissolution of sulfates and other secondary phases, accumulated in soils and waste-sites during the dry season, acts to control the mobility of metals. The elution curves obtained from column experiments showed a mobilization of Ba, Cu, Pb and Zn, while a low mobility was seen for Ag, As and Sb.     

Plant genes link forests and streams

Although it is understood that the composition of riparian trees can affect stream function through leaf litter fall, the potential effects of genetic variation within species are less understood. Using a naturally hybridizing cottonwood system, we examined the hypothesis that genetic differences among two parental species (Populus fremontii and P. angustifolia) and two groups of their hybrids (F1 and backcrosses to P. angustifolia) would affect litter decomposition rates and the composition of the aquatic invertebrate community that colonizes leaves. Three major findings emerged: (1) parental and hybrid types differ in litter quality, (2) decomposition differs between two groups, a fast group (P. fremontii and F1 hybrid), and a slow group (P. angustifolia and backcross hybrids), and (3) aquatic invertebrate communities colonizing P. fremontii litter differed significantly in composition from all other cross types, even though P. fremontii and the F1 hybrid decomposed at similar rates. These findings are in agreement with terrestrial arthropod studies in the same cottonwood system. However, the effects are less pronounced aquatically than those observed in the adjacent terrestrial community, which supports a genetic diffusion hypothesis. Importantly, these findings argue that genetic interactions link terrestrial and aquatic communities and may have significant evolutionary and conservation implications.     

Emergent conservation outcomes of shared risk perception in human-wildlife systems

Human perception of risks related to economic damages caused by nearby wildlife can be transmitted through social networks. Understanding how sharing risk information within a human community alters the spatial dynamics of human-wildlife interactions has important implications for the design and implementation of effective conservation actions. We developed an agent-based model that simulates farmer livelihood decisions and activities in an agricultural landscape shared with a population of a generic wildlife species (wildlife-human interactions in shared landscapes [WHISL]). In the model, based on risk perception and economic information, farmers decide how much labor to allocate to farming and whether and where to exclude wildlife from their farms (e.g., through fencing, trenches, or vegetation thinning). In scenarios where the risk perception of farmers was strongly influenced by other farmers, exclusion of wildlife was widespread, resulting in decreased quality of wildlife habitat and frequency of wildlife damages across the landscape. When economic losses from encounters with wildlife were high, perception of risk increased and led to highly synchronous behaviors by farmers in space and time. Interactions between wildlife and farmers sometimes led to a spillover effect of wildlife damage displaced from socially and spatially connected communities to less connected neighboring farms. The WHISL model is a useful conservation-planning tool because it provides a test bed for theories and predictions about human-wildlife dynamics across a range of different agricultural landscapes.     

Flammability of heat transfer fluid aerosols produced by electrospray measured by laser diffraction analysis

Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration.     

Air-water PCB fluxes from southwestern Lake Michigan revisited

From simultaneous air and water polychlorinated biphenyl (PCB) measurements collected in September 2010, we re-evaluated the direction and magnitude of net air-water exchange of PCBs in southwest Lake Michigan and compared them with estimations made using similar approaches 15 years prior. Air and water samples were collected during a research expedition on Lake Michigan at 5 km off the coast of Chicago, with prevailing winds from the southwest of our location. Gas-phase ΣPCB concentrations ranged from 190 to 1100 pg m^?3 with a median of 770 pg m^?3, which is similar to the concentrations measured in the City of Chicago at the same time and similar to concentrations measured in this part of the lake over the last 20 years. Water dissolved-phase ΣPCB concentrations ranged from 150 to 170 pg L^?1 with a median of 160 pg L^?1, which is one-tenth of that measured in the 1990s. ?PCB net fluxes showed a slightly absorptive behavior, with a median of (?) 21 ng m^?2 day^?1 and an interquartile range of (?) 47 to (+) 5 ng m^?2 day^?1, where (?) and (+) fluxes indicate absorption and volatilization, respectively. Airborne PCB concentrations were higher when the winds were coming from Chicago and drive the deposition. Our fluxes are not significantly different from estimations from 1994 and 1995 and suggest that absorption of PCBs into the waters is slightly more prevalent than 15 years ago. It was confirmed that Chicago remains an important atmospheric source of PCBs to Lake Michigan.

     

Non-immunological hydrops fetalis and intrapericardial teratoma: Case report and review

A large intrapericardial teratoma was found at necropsy in a 38−week stillborn fetus, in which prenatal diagnosis of hydrops fetalis and an ehogenic cardiac mass had been made. Clinical and pathological data are reported. In utero intrapericardial teratomata lead to different outcomes depending on whether fetal hydrops is associated. When generalized fetal hydrops is not present, the outcome is good, even in cases with large pericardial effusions. When generalized fetal hydrops occurs, it often results in a poor outcome. In our literature review, we have found eight perinatal deaths in nine similar cases reported.     

An Environmental Kuznets Curve for N2O emissions in Germany: an ARDL approach

This paper analyses the relationship between nitrous oxide (N₂O) emissions, economic growth, agricultural land used and exports in Germany. We use time‐series data between 1970 and 2012 and the Autoregressive Distributed Lag (ARDL) methodology to test for cointegration in the long run. Results show that there is a quadratic long run relationship between N₂O emissions and economic growth, confirming the existence of an Environmental Kuznets Curve (EKC) for Germany. Agricultural land area affects N₂O emissions positively, whereas exports affect emissions negatively. The turning point is $27,880, which is within the sample and implies that Germany is in the decreasing part of the curve of environmental degradation. The paper shows that, contrary to testing the EKC in less developed countries, mitigation of N₂O emissions does not negatively affect growth in Germany. As such, it is feasible to undertake any conservative policy in order to reduce emissions without major consequences on economic sectors.