The relation between salinity and copper complexing capacity of natural estuarine waters and the uptake of dissolved 64Cu by Macoma balthica

The radiotracer 64Cu was used to assess the influence of natural organic ligands on the bioavailability of copper. Biological availability of the 64Cu-complexes was measured by accumulation in the bivalve Macoma balthica. The experiments were carried out in April as well as in February with water from the relatively clean Oosterschelde Sea arm and the relatively polluted Westerschelde estuary. Adsorption onto shells, as well as uptake in tissues was assessed at salinities of 10‰ and 30‰. Simultaneously with the exposure experiments, ligand characteristics of the natural waters were assessed. High ligand concentrations, as occurring in the Westerschelde around February, reduced 64Cu (320 nM) uptake by more than 50%, in spite of the much lower salinity in the Westerschelde water. At the low salinity, uptake was increased slightly in Westerschelde water, but considerably in Oosterschelde water. This implies that at low ambient ligand concentrations (during the whole year in Oosterschelde water and in the summer period also in Westerschelde water) the influence of salinity on 64Cu uptake is more pronounced

Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimization

In occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust–exposed workers and a group of nonexposed individuals working in offices. Only metal dust–exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals

Local and regional sources as given by aerosol measurements and biomonitoring at Sado estuary area, Portugal

Gent air samplers were used for air particulate matter sampling in Sado estuary area, separating fine and coarse fractions. Three sampling sites were chosen (Palmela, Faralhão and Tróia), inside a 15 km × 25 km area at Setúba region, 50 km south of Lisbon, Portugal. Transplants of Parmelia sulcata Taylor were suspended in nylon bags within the same area following a 2.5 km × 2.5 km grid, during the same period as the aerosol collection. Both lichen transplants and filters were analysed by k 0-INAA. This work compares MCTTFA results given by the two air pollution monitoring procedures. The main differences concern a physiological factor in biomonitors and a better definition of traffic and re-suspension by aerosolsRadiation, Radionuclides and ReactorsApplied Science

Problems related to lichen transplants to monitor trace element deposition in repeated surveys: a case study from central Italy

The results of a transplant experiment with the fruticose lichen Evernia prunastri aimed at monitoring the trends of trace elements deposition in a repeated biomonitoring study are reported. Data comparability between the two surveys and interpretation of the results were addressed in this study. The ratio between the concentration of each element after the exposure and in control samples prior to exposure (exposed-to-control ratio, EC ratio), as well as an appropriate interpretative scale, were adopted as a means of determining the temporal trends of element accumulation by lichen transplants. The results showed that the method adopted is indeed a reliable tool, pinpointing a Zn smelting plant and an oil refinery as principal pollution sources in the area, which indicate that elements associated with the former were similarly accumulated in both 2002 and 2003, while elements associated with the latter tended to decrease in 2003

Rationalization and the "Engineer-Economists" in the Netherlands, 1920-1940

During the interwar period the Netherlands experienced a phase of rapid industrialisation and mechanisation and saw the introduction of many new labour-saving techniques on the work floor. This process, which went under the name ‘rationalisation of production’, caused great concern in the labour movement and sparked an intensive debate over the existence and extent of technological (or permanent) unemployment. Although the problem of technological unemployment was denied by the mainstream economists of the day, the problem was addressed by left-wing, mathematically trained economists, such as Theo van der Waerden and Jan Tinbergen. They sought for rigorous, ‘scientific’ arguments that would convince policy makers, colleagues and the public of socialist employment policies. This paper shows that Van der Waerden and Tinbergen used ever-increasing formal methods to face an issue, rationalisation, which became politically relevant and controversial in the specific context of the interwar period. Their new scientific tools gave them esteem and influence. In their role as advisers to the government they gained influence and were able to recommend policies that were in accordance with their political beliefs

Elemental composition of air masses under different altitudes in Azores, central north Atlantic

Radiation, Radionuclides and ReactorsApplied Science