Comprehensive study of endocrine disrupting compounds using grab and passive sampling at selected wastewater treatment plants in South East Queensland, Australia

Chemical (gas chromatography-mass spectrometry, GC-MS) and biological (E-Screen assay) analyses were used to determine the concentrations of 15 endocrine disrupting compounds (EDCs) and estrogen equivalent (EEq) in grab and passive samples from five municipal wastewater treatment plants (WWTPs) in South East Queensland, Australia. EEq concentrations derived by E-Screen assays for the grab samples were between 108-356 ng/L for the influents and < 1-14.8 ng/L for the effluents with the exception of one effluent sample which was at 67.8 ng/L EEq. The EDC concentrations and EEq values for the passive samples were several times lower than those of the grab samples: a decrease probably caused by, but not limited to biofouling, low flow rate, biodegradation and temperature which can progressively reduce the uptake of compounds into the sampler. At this stage, grab sampling is the most reliable method for field monitoring; nevertheless, passive sampler is a useful sampling tool but the method requires more research to ensure that the information obtained can be interpreted appropriately. Although alkylphenols and phthalates were detected at higher concentrations in the wastewater samples as compared to natural hormones, the environmental risk may be negligible as their estrogenic potencies are several orders of magnitude lower than that of the natural estrogens. In most wastewater samples, the natural estrogens contributed to 60% or more of the EEq value. Removal efficacy of most estrogenic and xenoestrogenic compounds from the conventional activated sludge or biological nutrient removal (BNR) WWTPs monitored in this study was in the range of 80-> 99%. The efficiency of the WWTPs in removing estrogenic activity was > 95%. The EEqs of the E-Screen and those calculated from the results of extensive chemical analyses using the estradiol equivalency factors were comparable for most of the WWTPs samples.     

Seasonal variations of natural ventilation and radon-222 exhalation in a slightly rising dead-end tunnel

The concentration activity of radon-222 has been monitored, with some interruptions, from 1997 to 2005 in the end section of a slightly rising, dead-end, 38-m long tunnel located in the Phulchoki hill, near Kathmandu, Nepal. While a high concentration varying from 6 x 10(3) Bq m(-3) to 10 x 10(3) Bq m(-3) is observed from May to September (rainy summer season), the concentration remains at a low level of about 200 Bq m(-3) from October to March (dry winter season). This reduction of radon concentration is associated with natural ventilation of the tunnel, which, contrary to expectations for a rising tunnel, takes place mainly from October to March when the outside air temperature drops below the average tunnel temperature. This interpretation is supported by temperature measurements in the atmosphere of the tunnel, a few meters away from the entrance. The temporal variations of the diurnal amplitude of this temperature indeed follow the ventilation rate deduced from the radon measurements. In the absence of significant ventilation (summer season), the radon exhalation flux at the rock surface into the tunnel atmosphere can be inferred; it exhibits a yearly variation with additional transient reductions associated with heavy rainfall, likely to be due to water infiltration. No effect of atmospheric pressure variations on the radon concentration is observed in this tunnel. This experiment illustrates how small differences in the location and geometry of a tunnel can lead to vastly different behaviours of the radon concentration versus time. This observation has consequences for the estimation of the dose rate and the practicability of radon monitoring for tectonic purposes in underground environments.     

When attempts at robbing prey turn fatal

Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1?%) were captured in turn. The ant workers hunt in a group and use the “Velcro?” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases.     

Meta-ecosystem engineering: nutrient fluxes reveal intraspecific and interspecific feedbacks in fragmented mussel beds

Ecologists still have to elucidate the complex feedback interactions operating among biodiversity and ecosystem processes in engineered systems. To address this, a field experiment was conducted to mimic natural mussel bed meta-ecosystems (Mytilus spp.) of the lower St. Lawrence Estuary (Quebec, Canada) and partition the effects of their biotic and abiotic properties and spatial structure on ecosystem processes and community dynamics of associated macro-invertebrates. We found positive intraspecific feedbacks between mussels and their recruits, and negative interspecific feedbacks between mussels and their associated ecosystem. These feedbacks were associated with mussel bed ecosystem processes (fluxes of ammonium and oxygen). In addition, we showed that proximity between mussel patches increased within-patch nutrient fluxes. Our study revealed the potential for meta-ecosystem engineering to drive feedback interactions between community and ecosystem functioning in marine fragmented systems. It also shows the relevance of meta-ecosystem theories as a conceptual framework to elucidate biotic and abiotic processes controlling ecosystem and community structure. Such framework could contribute to ecosystem-based management of spatially structured systems such as reserve networks and fragmented ecosystems.     

Biophysical and monetary quantification of ecosystem services in a mountain region: the case of avoided soil erosion

Environment, Development and Sustainability - Even though ecosystem services have a significant contribution to human well-being, their value is not always recognized. Despite difficulties, the...     

Impacts of Decentralized Power Generation on Distribution Networks: a Statistical Typology of European Countries

The development of decentralized sources of power out of renewable sources of energies has been triggering far-reaching consequences for Distribution System Operators over the past decade in Europe. Our paper benchmarks across 23 European countries the impact of the development of renewables on the physical characteristics of power distribution networks and on their investments. It builds on a large spectrum of databases of quantitative indicators about the dynamics of installed capacity of renewable energy resources and the power generation out of them, electricity independence, quality of electricity distribution, smart grids investments, Network System Operators capital expenditures, length of the distribution networks, overall costs of power networks paid by private agents, and electricity losses, all in relation with the development of decentralized generation. The heterogeneity of these indicators across Europe appears to be wide notably because of physical constraints, historic legacies, or policy and regulatory choices. A cluster analysis allows for deriving six groups of countries that display statistically homogenous characteristics. Our results may provide decision makers and regulators with a tool helping them to concentrate on the main issues specific to their countries as compared to the European median, and to look for possible solutions in the experience of other clusters which are shown to perform better for some indicators.     

VARIABILITY CHARACTERISTICS OF MONTHLY PRECIPITATION IN CENTRAL OKLAHOMA1

ABSTRACT: To fully take advantage of regional climate forecast information for agricultural applications, the relationship between divisional and station scale precipitation characteristics must be quantified. The spatial variability of monthly precipitation is assumed to consist of two components: a systematic and a random component. The systematic component is defined by differences in long-term mean precipitation between stations within a climate division, and the random component by differences between station and divisional standardized values. For the Central Climate Division of Oklahoma, the systematic component has a positive precipitation gradient from west to east with a slope ranging between 3 to 16 mm of precipitation per 100 km depending on the month of the year. On the other hand, the random component ranges between 27 to 48 percent of the mean temporal variation of the monthly precipitation. This significant random spatial variability leads to large localized departures from divisional values, and clearly demonstrates the critical influence of the random component in the utilization of divisional climate forecasts for local agricultural applications. The results of this study also provide an uncertainty range for local monthly precipitation projections that are derived from divisional climate information.     

How contamination sources and soil properties can influence the Cd and Pb bioavailability to snails

To better understand the fate of metals in the environment, numerous parameters must be studied, such as the soil properties and the different sources of contamination for the organisms. Among bioindicators of soil quality, the garden snail (Cantareus aspersus) integrates multiple sources (e.g. soil, plant) and routes (e.g. digestive, cutaneous) of contamination. However, the contribution of each source on metal bioavailability and how soil properties influence these contributions have never been studied when considering the dynamic process of bioavailability. Using accumulation kinetics, this study showed that the main assimilation source of Cd was lettuce (68 %), whereas the main source of Pb was the soil (90 %). The plant contribution increased in response to a 2-unit soil pH decrease. Unexpectedly, an increase in the soil contribution to metal assimilation accompanied an increase in the organic matter (OM) content of the soil. For both metals, no significant excretion and influence of source on excretion have been modelled either during exposure or depuration. This study highlights how the contribution of different sources to metal bioavailability changes based on changes in soil parameters, such as pH and OM, and the complexity of the processes that modulate metal bioavailability.     

Nineteenth-century land-use legacies affect contemporary land abandonment in the Carpathians

Regional Environmental Change - Historical land use may shape landscapes for centuries into the future, but it remains unclear how much land-use legacies affect contemporary land use. Knowing for...