Influence of the secondary motions on pollutant mixing in a meandering open channel flow

This paper presents large eddy simulation of turbulent flow in a meandering open channel with smooth wall and rectangular cross-section. The Reynolds number based on the channel height is 40,000 and the aspect ratio of the cross-section is 4.48. The depth-averaged mean stream-wise velocity agree well to experimental measurements. In this specific case, two interacting cells are formed that swap from one bend to the other. Transport and mixing of a pollutant is analysed using three different positions of release, e.g. on the inner bank, on the outer bank and on the centre of the cross section. The obtained depth-average mean concentration profiles are reasonably consistent with available experimental data. The role of the secondary motions in the mixing processes is the main focus of the discussion. It is found that the mixing when the scalar is released on the centre of the cross-section is stronger and faster than the mixing of the scalar released on the sides. When the position of release is close to a bank side, the mixing is weaker and a clear concentration of scalar close to the corresponding side-wall can be observed in both cases.     

Inferring chemical effects on carbon flows in aquatic food webs: Methodology and case study

The majority of ecotoxicological enclosure experiments monitor species abundances at different chemical concentrations. Here, we present a new modelling approach that estimates changes in food web flows from such data and show that population- and food web level effects are revealed that are not apparent from abundance data alone. For the case of cypermethrin in freshwater enclosures, photosynthesis and excretion (d⁻¹) of phytoplankton at 3.643 μg L⁻¹ cypermethrin were 30% lower and 100% higher than in the control, respectively. The ingestion rate of mesozooplankton (d⁻¹) was 6 times higher in the treated enclosures than in the control as food concentration increased with insecticide exposure. With increasing cypermethrin concentrations, nanoflagellates progressively relied on phytoplankton as their main food source, which rendered the food web less stable. We conclude that this tool has excellent potential to analyse the wealth of enclosure data as it only needs species abundance and general constraints.     

Integration of noninvasive prenatal prediction of fetal blood group into clinical prenatal care

Incompatibility of red blood cell blood group antigens between a pregnant woman and her fetus can cause maternal immunization and, consequently, hemolytic disease of the fetus and newborn. Noninvasive prenatal testing of cell-free fetal DNA can be used to assess the risk of hemolytic disease of the fetus and newborn to fetuses of immunized women. Prediction of the fetal RhD type has been very successful and is now integrated into clinical practice to assist in the management of the pregnancies of RhD immunized women. In addition, noninvasive prediction of the fetal RhD type can be applied to guide targeted prenatal prophylaxis, thus avoiding unnecessary exposure to anti-D in pregnant women. The analytical aspect of noninvasive fetal RHD typing is very robust and accurate, and its routine utilization has demonstrated high sensitivities for fetal RHD detection. A high compliance with administering anti-D is essential for obtaining a clinical effect. Noninvasive fetal typing of RHC/c, RHE/e, and KEL may become more widely used in the future. © 2014 John Wiley & Sons, Ltd.     

The importance of biological factors affecting trace metal concentration as revealed from accumulation patterns in co-occurring terrestrial invertebrates

As physicochemical properties of the soil highly influence the bioavailable fraction of a particular trace metal, measured metal body burdens in a particular species are often assumed to be more reliable estimators of the contamination of the biota. To test this we compared the Cd, Cu and Zn content of three spiders (generalist predators) and two amphipods (detritivores), co-occurring in seven tidal marshes along the river Schelde, between each other and with the total metal concentrations and the concentrations of four sequential extractions of the soils. Correlations were significant in only one case and significant site x species interactions for all metals demonstrate that factors affecting metal concentration were species and site specific and not solely determined by site specific characteristics. These results emphasize that site and species specific biological factors might be of the utmost importance in determining the contamination of the biota, at least for higher trophic levels. A hypothetical example clarifies these findings.     

A rule-based screening environmental risk assessment tool derived from EUSES

Within the context and scope of the forthcoming European Union chemical regulations (REACH), there is a need to be able to prioritise the chemicals for evaluation. Therefore, a simple, pragmatic and adequately conservative approach for the identification of substances of very low or no immediate concern at an early stage is presented. The fundamental principles and basic concepts are derived from the EU Technical Guidance Document and EUSES, and are translated into an easy-to-use rule-based system. For this development, the effect on risk characterisation ratios (RCRs) of the key environmental parameters in EUSES was quantified (taking into account several standardised chemical release scenarios). Using statistical analysis, ranges were identified for each key parameter, within which the end result of the assessment was not significantly affected. This information was then translated into a lookup table from which environmental risk characterisation ratios can be directly read as a function of a few parameters.     

Isotopes for improved management of nitrate pollution in aqueous resources: review of surface water field studies

Background  

Environmental agencies have to take measures to either reduce discharges and emissions of nitrate or to remediate nitrate-polluted water bodies where the nitrate concentrations exceed threshold values. Isotope data can support the identification of nitrate pollution sources and natural attenuation processes of nitrate.     

Sustained Yield Forestry in Sweden and Russia: How Does it Correspond to Sustainable Forest Management Policy?

This paper analyzes how sustained yield (SY) forestry is defined and implemented in Sweden and Russia, two countries with different forest-industrial regimes. We first compare definitions of SY forestry in national legislation and policies. Then we study forest management planning in two large forest management units with respect to: delivered forest products and values, how the harvest level of timber is defined, where the harvest takes place, and what treatments are used to sustain desired forest products and values. In Sweden SY forestry is maximum yield based on high-input forest management, and in Russia it is forestry based on natural regeneration with minimum investments in silviculture. We conclude that how SY forestry contributes to SFM depends on the context. Finally, we discuss the consequences of SY forestry as performed in Sweden and Russia related to its ability to support diverse forest functions, as envisioned in sustainable forest management policy.     

Ensemble Modeling of the Baltic Sea Ecosystem to Provide Scenarios for Management

We present a multi-model ensemble study for the Baltic Sea, and investigate the combined impact of changing climate, external nutrient supply, and fisheries on the marine ecosystem. The applied regional climate system model contains state-of-the-art component models for the atmosphere, sea ice, ocean, land surface, terrestrial and marine biogeochemistry, and marine food-web. Time-dependent scenario simulations for the period 1960–2100 are performed and uncertainties of future projections are estimated. In addition, reconstructions since 1850 are carried out to evaluate the models sensitivity to external stressors on long time scales. Information from scenario simulations are used to support decision-makers and stakeholders and to raise awareness of climate change, environmental problems, and possible abatement strategies among the general public using geovisualization. It is concluded that the study results are relevant for the Baltic Sea Action Plan of the Helsinki Commission.