Temporal changes in elemental composition in decomposing filamentous algae (Cladophora glomerata and Pilayella littoralis) determined with PIXE and PIGE.

Particle-induced X-ray emission and particle-induced gamma-ray emission spectrometry were successfully applied in a study of the elemental composition of decomposing filamentous algae. Fresh brown (Pilayella littoralis) and green (Cladophora glomerata) algal materials were placed in cages at 4m depth in a water column of 8m in the Archipelago Sea, northern Baltic Sea. Every second week decaying algae were sampled from the cages to allow measurements of changes in the elemental compositions. In the study of the elemental losses the concentrations were compensated for the mass reduction. The results show that sulphur, chlorine and partly potassium were lost during decomposition of P. littoralis and C. glomerata. Most of the other elements studied were recovered in the remaining algal mass. Special attention was paid to sorption and desorption of elements, including metal binding capacity, in the decaying algal materials. The affinity order of different cations to the two algal species was established by calculation of conditional distribution coefficients, D'(M). For instance for P. littoralis the following series of binding strength (affinity) of cations were obtained: Al>Ti>Fe >> Mn>Ni, Cu>Ba, Cr, Zn>>Rb>K, Sr>Pb>>Ca>>Na>Mg. Notably is that the binding strength of strontium was more than 10 times higher for P. littoralis than for C. glomerata. Due to their high binding capacity and good affinity and selectivity for heavy metal ions these algae have great potential as biological sorbents. Large variations in elemental content during decomposition complicate the use of algae for environmental monitoring.

Comparison of VOC and ammonia emissions from individual PVC materials, adhesives and from complete structures.

Emission rates of volatile organic compounds (VOCs) and ammonia measured from six PVC materials and four adhesives in the laboratory were compared to the emission rates measured on site from complete structures. Significantly higher specific emission rates (SERs) were generally measured from the complete structures than from individual materials. There were large differences between different PVC materials in their permeability for VOCs originating from the underlying structure. Glycol ethers and esters from adhesives used in the installation contributed to the emissions from the PVC covered structure. Emissions of 2-ethylhexanol and TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) were common. High ammonia SERs were measured from single adhesives but their contribution to the emissions from the complete structure did not appear as obvious as for VOCs. The results indicate that three factors affected the VOC emissions from the PVC flooring on a structure: 1) the permeability of the PVC product for VOCs, 2) the VOC emission from the adhesive used, and 3) the VOC emission from the backside of the PVC product.

Elemental analyses of pine bark and wood in an environmental study.

Bark and wood samples were taken from the same individuals of Scots pine (Pinus sylvestris L.) from a polluted area close to a Cu-Ni smelter in Harjavalta and from some relatively unpolluted areas in western Finland. The samples were analysed by thick-target particle induced X-ray emission (PIXE) after preconcentration by dry ashing at 550 degrees C. The elemental contents of pine bark and wood were compared to study the impact of heavy metal pollution on pine trees. By comparison of the elemental contents in ashes of bark and wood, a normalisation was obtained. For the relatively clean areas, the ratios of the concentration in bark ash to the concentration in wood ash for different elements were close to 1. This means that the ashes of Scots Pine wood and bark have quite similar elemental composition. For the samples from the polluted area the mean concentration ratios for some heavy metals were elevated (13-28), reflecting the effect of direct atmospheric contamination. The metal contents in the ashes of pine bark and wood were also compared to recommendations for ashes to be recycled back to the forest environment. Bark from areas close to emission sources of heavy metal pollution should be considered with caution if aiming at recycling the ash. Burning of bark fuel of pine grown within 6 km of the Cu-Ni smelter is shown to generate ashes with high levels of Cu, Ni as well as Cd, As and Pb.

Evaluation of VOC measurments in the EXPOLIS study. Air Pollution Exposure Distributions within Adult Urban Urban Populations in Europe.

Personal exposures and microenvironment concentrations of 30 target VOCs were measured for 401 participants living in five European cities as a part of the EXPOLIS (Air Pollution Exposure Distributions within Adult Urban Populations in Europe) study. Measurements in Basel used an active charcoal (Carbotech) adsorbent as opposed to the Tenax TA used in the other study centres. In addition, within each centre, personal and microenvironment VOC sampling required different sampling pumps and, because of different sampling durations, different sampling flow rates. Thus, careful testing of the sampling and analysis procedures was required to ensure accuracy and comparability of collected data. Monitor comparison tests using Tenax TA showed a mean VOC concentration ratio of 0.95 between the personal and microenvironment monitors. The LODs for the target VOCs using Tenax TA ranged from 0.7 to 5.2 microg m(-3). The LODs for the 14 target compounds quantifiable using Carbotech ranged from 0.9 to 3.2 microg m(-3). Tenax TA field blanks showed no remarkable contamination with the target VOCs, except benzaldehyde, a known artefact with this adsorbent. Thus, the diffusion barrier system used prevented contamination of Tenax TA samples by passive diffusion during non-sampling periods. Duplicate and parallel evaluations of the Tenax TA and Carbotech showed an average difference of < 17% in VOC concentrations within the sampling methods, but a systematic difference between the methods (Tenax TA: Carbotech concentration ratio = 1.18-2.36). These field evaluations and quality assurance tests showed that interpretation and comparison of the results in any VOC monitoring exercise should be done on a compound by compound basis. It is also apparent that carefully planned and realised QA and QC (QA/QC) procedures are needed in multi-centre studies, where a common sampling method and laboratory analysis technique are not used, to strengthen and simplify the interpretation of observed VOC levels between participating centres.

Thick-target PIGE analysis of plant materials preconcentrated by dry ashing.

Plant materials were dry ashed at 550 degrees C and analysed using particle-induced prompt gamma-ray emission (PIGE). The analyses were performed with an external beam of 3 MeV protons incident on the target. Seven biological certified reference materials were analysed and used for the evaluation of the method for Na, Mg, Al, P and Mn. The elemental concentration to detection limit ratios were greatly enhanced by dry ashing of the biological materials. The concentrations of the elements in ashes were clearly above the values at which reliable analyses can be made. The method was applied to samples of spruce and pine. Due to the low ash content of the wood samples, the sensitivity of the method was radically improved. The detection limits for the five elements studied in spruce wood were in the range 0.014-2.5 mug g(-1). The set-up and the beam current used enabled simultaneous particle-induced X-ray emission spectrometry (PIXE) analyses, with the sensitivity optimised for heavier trace elements.

Organizational factors influencing serious occupational accidents.

The aim of this article is to examine organizational factors influencing serious occupational accidents. The study was part of a larger project investigating 99 serious occupational accidents in southern Finland. A workplace analysis and an accident analysis were done at accident sites. In connection with this investigation, 73 victims, 91 foremen, and 83 co-workers were interviewed with a structured questionnaire. The results showed that the need to save time, tight schedules, and a lack of caution had a greater influence on accidents than did the foremen, co-workers, customers, professional pride, curiosity, or the wage system. Big companies had the lowest risk of serious occupational accidents. Accident risk was significantly greater for subcontractors than for main contractors.

Zinc compounds in urethral catheters. A possible source of toxicity?

The cytotoxicity of latex urinary catheters has been earlier documented. During the manufacturing process tens of chemicals are added to the natural rubber base. Several of the accelerators and other chemicals used have carcinogenic and acute toxic effects. Some of the accelerators are zinc compounds. In the present study, the cytotoxicity and zinc concentration of 68 latex catheter extracts were analysed. The siliconized latex catheters were the most toxic, and a correlation was seen between the IC50 values and the zinc concentration. The good manufacturing practice (GMP) has to some extent resolved the cytotoxicity problem of latex urinary catheters. There is, however, still a need to reformulate the manufacturing process and to find new catheter materials to meet the new EN standards concerning the biological safety of urinary catheters.

Methods of hazard analysis applied in the light metal industry.

There is a present a wide variety of methods to be used for the identification and evaluation of hazards. The information resulting from a hazard analysis can be used to develop measures for either the elimination or the control of hazards. Hazard analysis has not yet been used very widely in industry. More information is needed, eg, about the applicability of methods to different types of systems. A joint project, where hazard analysis was applied to various fields, was carried out in the Nordic countries. One part of this project concentrated on the light metal industry. A trial was carried out on a production line for which man-machine tasks play an important role. Job analysis was selected as the means of revealing possible accidents. On the production line this procedure turned out to be a good point for systematic investigation. The selection of the methods to be applied within a system should be done carefully. It is important that sufficient knowledge is available both about the characteristics of the system and about the existing methods. The rapid increase of information in this area makes it possible to put hazard analysis to better use in industry.