PCB mass transfer coefficients determined by application of a water surface sampler

A water surface sampler (WSS) was employed in combination with greased surface deposition plates (GSDPs) to measure the particulate dry deposition and gas exchange of polychlorinated biphenyls (PCBs) in Chicago, IL. Vapor phase PCB fluxes were calculated by subtracting the particulate fluxes obtained from GSDPs from total (particulate+gas) fluxes obtained from the WSS. Vapor phase PCB fluxes were divided by ambient air concentrations measured with a high volume sampler to calculate overall gas phase PCB mass transfer coefficients (K(G)). The calculated average PCB MTC was 0.54+/-0.47 cm s(-1). This experimentally determined average gas phase overall mass transfer coefficient, K(G), agreed well with the ones reported from studies using similar techniques and agreed well with modeled values obtained using MTC correlations developed for the WSS.     

Determination of hypoxia and dietary copper mediated sub-lethal toxicity in carp, Cyprinus carpio, at different levels of biological organisation

Hypoxic events frequently occur in the aquatic environment in association with micro pollutants, including heavy metals. Only a few studies are however available on the uptake and biological responses of heavy metals under hypoxic conditions. To elucidate the phenomenon, mirror carp Cyprinus carpio L. (16.13-16.22 g) were exposed chronically to dietary copper (Cu; 250 and 500 mg kg dry wt.⁻¹) for 30 d under normoxic (8.25 mg O₂ L⁻¹) and hypoxic (∼3 mg O₂ L⁻¹) conditions and adopting an integrated approach, sub-lethal biomarker responses were determined at different levels of biological organisation. Level of oxidative DNA damage (as determined by modified Comet assay) showed strong significant difference following exposure to dietary Cu level under normoxic (1.6-fold) as well as under hypoxic condition at both Cu levels (2.1 and 2.5-folds respectively). Significant difference was also observed for haematological parameters (i.e. increased red and white blood cells, haematocrit value and haemoglobin concentration). Quantitative histology revealed alterations in tissues (i.e. liver and gills) for hypoxic and all dietary Cu treatment groups under both normoxic and hypoxic conditions suggesting a compensatory response to these organs (p < 0.05). The order of Cu accumulation in tissues (as determined by ICP-OES) was liver > intestine > kidney > gill. Interestingly, SGR under both normoxic and hypoxic conditions reduced with elevating Cu levels (p = 0.019). Overall, the results provide evidence for enhanced toxicological responses in fish following exposure to Cu either alone or in combination with hypoxic condition and lends support to the evolving viewpoint that many water quality guidelines should be revisited in terms of new ecotoxicological criteria.     

Fixed-bed column sorption of borate onto pomegranate seed powder-PVA beads: a response surface methodology approach

Pomegranate seed powder (PS) was functionalized with polyvinyl alcohol (PVA) and utilized for boron removal from the aqueous system. Results of Brunauer--Emmett--Teller (BET) surface area analysis and Boehm titration indicated notable decrease in total surface area and increase in acidic surface functional groups of PS after PVA modification. Enhanced sorption is indicative of complex formation between diol groups of the pomegranate seed powder--polyvinyl alcohol (PS–PVA) and borate ions. Under column test, the saturated sorption capacity of boron was noted to be dependent on flow rate and bed height. The developed central composite design (CCD) was adequate to elucidate the sorption mechanism. Mathematical modeling of the column data was conducted, and a modified-dose-response model was the most suitable to describe the breakthrough curve and observed to be consistent with CCD analysis. This is further supported by extensive error analyses conducted between the model predicted and experimental data.     

A GIS-based model for rating natural protection areas according to natural protection priorities

There has been a major urban shift of population in Turkey over the last century. Most people lived in rural areas until 1960, but now more than half live in urban areas. This trend has continued over the last 20 years, as families moved further away from city centres to find houses in the country, and this has caused land use to change rapidly. In decision-making studies to protect nature areas, rating and assessment of ecological data by scientific verification is difficult due to the huge volume and diversity of data. Therefore, the search for the most suitable and applicable method to achieve physical planning based on ecological understanding has been sought. The necessity for numerous parameters to be taken into account has stimulated the use of geographic information systems (GIS). This study assesses the usefulness of a GIS-based model in the protected area of Kaynaklar County, to the south of the city of Izmir. Existing cultural and natural land-use types, as well as soil, hydrologic, geologic and geomorphologic data layers (future classes) were gathered from field observation and using Landsat and IKONOS satellite images, and transferred to a database according to GIS rules. Index values were determined by taking impact on attributes of natural protection as a priority and these were attached to each feature class. Layers of data were merged by spatial intersection methods and new polygons were created for both cultural and natural features. A three-grade final map of the study area was generated using total index values of each new polygon.     

Production of Fe2O3 from FeSO4·xH2O formed in galvanizing works

FeSO₄·xH₂O is generated in large amounts in galvanizing workshops. It can be reutilized by conversion to Fe₂O₃. In this study, the recovery of Fe₂O₃ from FeSO₄·xH₂O formed in the galvanizing process has been examined. The experimental work was carried out at various temperatures and times in the oxidizing medium. The reaction temperatures and times were selected as 450, 500, 550, 600, 650, 700, 800 and 900°C, and 15, 30, 45, 60, 90 and 120 minutes, respectively. In order to determine the amount of Fe₂O₃, a titrimetric method was applied. The reaction products were characterized by means of IR and XRD techniques.The extent of conversion is low at temperatures below 650°C. Almost all of the iron (II) sulfate in the original sample was converted to iron(III) oxide at 650°C (120 min), 700°C (90 min), 800°C (60 min) and 900°C (45 min).     

The association between prenatal exposure to polycyclic aromatic hydrocarbons and childhood intelligence: a systematic review of observational studies

Environmental Science and Pollution Research - Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy has been associated with many adverse child health. However, the evidence on such...