Determination of polychlorinated biphenyl and polycyclic aromatic hydrocarbon marine regional Sediment Quality Guidelines within the European Water Framework Directive

Marine regional Sediment Quality Guidelines (SQG) for polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) from the Basque coast (SE Bay of Biscay) were determined, on the basis of sediment chemistry, toxicity and benthic community disturbance from analysis of 756 estuarine and coastal samples. The SQG were calculated using a percentile approach (based upon effect and non-effect data), using non-normalised and normalised concentration, by total organic carbon. However, normalisation by total organic carbon did not result in any improvement in accuracy compared with non-normalised values. Hence, this study proposes non-normalised SQG values for assessment of the chemical and physicochemical status in marine waters in the Basque Country, within the Water Framework Directive: 24.6–29 μg kg^?1 for total PCBs; 164–285 μg kg^?1 for low molecular weight PAH; 922–1537 μg kg^?1 for high molecular weight PAH; and 1607–2617 μg kg^?1 for total PAH.     

Background metal levels determination in bivalves – quality assessment of the European Water Framework Directive

Background levels of metals (Ag, Cd, Cu, Cr, Hg, Ni, Pb and Zn) in biomonitors (Mytilus galloprovincialis mussels and Crassostrea gigas oysters), in estuarine waters within the Basque Country (south-east Bay of Biscay) are estimated using non-parametric statistical tools and data are presented graphically, with the aim of being used in assessing the ecological status, within the European Water Framework Directive (WFD). The basis for this study was the statistical analysis of data compiled from monitoring programmes undertaken along the Basque coast, between 1990 and 2008. For this analysis, a heuristic method was adapted and used. Results showed different metal background ranges throughout the year for both mussels and oysters. Values corresponding to the upper limit of the background range (i.e. value of the upper whisker of the box-plot) are proposed as the ‘high/good’ status boundary, according to the WFD.     

Evaluation of the use of bioaccumulation and biological effects tools in caged mussels,within the European Water Framework Directive

Bioaccumulation and biological effects of pollution were assessed in mussels (Mytilus galloprovincialis) caged for one month at three sites in the Oiartzun estuary (south-eastern Bay of Biscay, Spain) with the aim of evaluating their usefulness within the investigative monitoring defined in the European Union Water Framework Directive (WFD). The highest concentrations of organic contaminants determined in mussels' tissue were detected towards the inner part of the estuary but no gradient pattern was found for metal bioaccumulation. Population fitness responses measured as condition index, stress on stress and gonad index were similar in all caged mussels and did not follow the organic pollution gradient. However, biomarkers determined at tissue, cell and protein level (histopathology, micronuclei frequency, malondialdehyde levels and vitellogenin-like protein levels) revealed a higher stress syndrome at the inner part of the estuary showing signs of genotoxicity, oxidative stress and endocrine disruption. Overall, the integrated chemical–biological approach in connection with mussel caging technique proved to be a useful tool to assess environmental pollution, allowing a better understanding of the cause–effect relationship within the investigative monitoring defined in the WFD.     

The three-dimensional prey field of the northern krill, Meganyctiphanes norvegica, and the escape responses of their copepod prey

In the north Atlantic, Meganyctiphanes norvegica feeds predominantly on copepods, including Calanus spp. To quantify its perceptual field for prey, and the sensory systems underlying prey detection, the responses of tethered krill to free-swimming Calanus spp. were observed in 3D using silhouette video imaging. An attack–which occurred despite the krill’s being tethered—was characterized by a pronounced movement of the krill’s antennae towards the target, followed by a propulsion and opening of the feeding basket. Frequency distributions of prey detection distances were significantly different in the light vs. the dark, with median values of 26.5 mm and 19.5 mm, respectively. There were no significant differences in the angles at which prey were detected by krill (relative to the predator’s longitudinal body axis) in the light vs. the dark. Prey detections were symmetrically distributed on either side of the predator, in both light and dark. However, significant asymmetry was found in the dorsal–ventral direction with 80% of the prey detections located below the midline of the krill’s body axis and, given the placement and orientation of the compound eyes, presumably outside its visual field of view. This indicates that, at least under these conditions, vision was not the main sensory modality involved in the detection of active prey by M. norvegica. However, under some circumstances, vision may provide supplemental information. Avoidance responses of copepod prey were nearly twice the velocity of their nominal background swimming speed (153 ± 48 and 85 ± 75 mm s⁻¹, respectively), on average taking them 43 ± 16 mm away from the predator. This is far beyond the krill’s perceptual range, suggesting that the escape reaction provides an effective deterrent to predation (although perhaps less so for free-swimming krill). This information can be used to parameterize models that assess the role of krill as predators in marine ecosystems.     

Investment Evaluation of an Integrated Steel Mill using Multiple Criteria

A conventional steel manufacturing process generates considerable amounts of reject streams and secondary raw material. These streams are either recycled back to the process or treated as waste. Recycling affects negatively on the production yield and on the controllability of unit operations. Waste represents considerable cost unless utilized in another production process as raw material. In these streams, there exists a potential to use the chemical elements more effectively. Therefore, it might be interesting to find an economical technical solution to collect the streams and increase steel production.

Investments on process equipment are typically evaluated using conventional economic figures, like payback time, Net Present Value (NPV) etc. The problem with these practices is, that they consider only numerical aspects. Non-numerical and non-economical criteria are hard to cater to the evaluation. Still, they may affect on the investment profitability in the long run. Such criteria include environmental friendliness or the aspects of process integration.

The article presents a comparison of a conventional steel manufacturing process with one reject stream processing alternative. A target in the process modification is to optimize the use of material and energy within the site. The comparison is based on a balanced set of criteria that affect on the efficiency of an investment. The use of these criteria is a part of the new methodology that has been developed to evaluate investments on integrated process sites. In addition to the criteria, the complete methodology includes: 1) connection of company’s strategic issues into technical design and decision making, 2) optimization of the process and calculation of process potentials (differences in the performance values between the existing process and the modified process) through the use of process integration methodologies and 3) use of decision-making aids. The research is a part of Finnish National Technology Program, “Process-Integration 2000–2004”.     

Properties of a Poly(3-hydroxybutyrate) Depolymerase from Penicillium funiculosum

A poly(3-hydroxybutyrate) (PHB) depolymerase was purified from a fungus, Penicillium funiculosum (IFO6345), with phenyl-Toyopearl and its properties were compared with those of other PHB depolymerases. The molecular mass of the purified enzyme was estimated at about 33 kDa by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The pH optimum and pI were 6.5 and 6.5, respectively. The purified protein showed affinity to Con A-Sepharose, indicating that it is a glycoprotein. Diisopropylfluorophosphate and dithiothreitol inhibited the depolymerase activity completely. The N-terminal amino acid sequence of the purified enzyme was TALPAFNVNPNSVSVSGLSSGGYMAAQL, which contained a lipase box sequence. This purified enzyme is one of the extracellular PHB depolymerase which belong to serine esterase. The purified enzyme showed relatively strong hydrolytic activity against 3-hydroxybutyrate oligomers compared with its PHB-degrading activity. PHB-binding experiments showed that P. funiculosum depolymerase has the weakest affinity for PHB of all the depolymerases examined.     

Anaerobic PAH degradation in soil by a mixed bacterial consortium under denitrifying conditions

Polycyclic aromatic hydrocarbons (PAHs) are one of the main classes of contaminants in the terrestrial environment. Concentrations of biphenyl, fluorene, phenanthrene and pyrene were added to soil samples in order to investigate the anaerobic degradation potential of PAHs under denitrifying conditions. A mixed population of microorganisms obtained from a paddy soil was incubated for 20 days in anaerobic conditions in the presence of soil alone or with nitrate, adding, as electron donors, PAHs and, in some samples, glucose or acetate. At regular time intervals oxidation-reduction potential, PAHs concentration, microbial ATP and nitrate concentration into the solution were measured. Degradation trends for each hydrocarbon are similar under all conditions, indicating that the molecular conformation prevails over other parameters in controlling the degradation. Poor degradation results were obtained when PAHs were the only organic matter available for the inoculum, thus confirming the recalcitrance to degradation of these compounds. Biodegradation was influenced by the addition of other carbon sources. As better degradation results were generally obtained when acetate or glucose were added, the hypothesis of a co-metabolic enhancement of PAH biodegradation seems likely. Thus, anaerobic biodegradation of PAHs studied, biphenyl, fluorene, phenanthrene and pyrene, seems to be possible both through fermentative and respiratory metabolism, provided that low molecular weight co-metabolites and suitable electron acceptors (nitrate) are present.     

Woody residues of the grape production chain as an alternative precursor of high porous activated carbon with remarkable performance for naproxen uptake from water

Environmental Science and Pollution Research - Activated carbon prepared from grape branches was used as a remarkable adsorbent to uptake naproxen and treat a synthetic mixture from aqueous...     

Neutral modelling of agricultural landscapes by tessellation methods—Application for gene flow simulation

Neutral landscape models are not frequently used in the agronomical domain, whereas they would be very useful for studying given agro-ecological or physical processes. Contrary to ecological neutral landscape models, agricultural models have to represent and manage geometrical patches and thus should rely on tessellation methods. We present a three steps approach that aimed at simulating such landscapes. Firstly, we characterized the geometry of three real field patterns; secondly, we generated simulated field patterns with two tessellation methods attempting to control the value of some of the observed characteristics and, thirdly, we evaluated the simulated field patterns. For this evaluation, we considered that good simulated field patterns should capture characteristics of real landscapes that are important for the targeted agro-ecological process. Real landscapes and landscapes simulated using either a Voronoi or a rectangular tessellation were thus compared when used as input data within a gene flow model. The results showed that neither tessellation method captured field shapes correctly, thus leading to over or (small) under estimation of gene flow. The Voronoi tessellation, though, performed better than the rectangular tessellation. Possible research directions are proposed to improve the simulated patterns, including the use of post-processing, the control of cell orientation or the implementation of other tessellation techniques.