Suchergebnisse

Abstract
A planer equipped with a rotating cutting drum is used to remove about ten cm thick of road surfaces. This process generates dust likely to contain crystalline silica. The machine operator and people around may be particularly exposed. It is therefore essential to promote effective preventive solutions, in particular from dust collection and filtration systems, to reduce dust exposure. Tests were realized to evaluate the performance of technical devices designed to capture and filter dust emitted by road planers. The measurements were carried out on a road planer equipped with an air collection device located next to the milling drum, supplemented by an electrostatic separator to trap collected dust. The dust collection efficiency of the venting system was determined by gas tracing. The efficiency of the electrostatic separator was both evaluated in laboratory conditions (static machine) from a reference dust generated upstream of the system, and in the field during road surface planing. The tests conducted on the planer showed the effectiveness of the dust collection and filtration devices implanted on the machine and tested both in static and in the field. The capture efficiency determined by gas tracing is about 90 % and the separation efficiency of the electrostatic precipitator, determined on the static machine from test dust, is respectively 60 and 90% at aerodynamic diameters 1 and 4 μm. The average separation efficiency obtained from the measurements with the machine in real operation is 91% for respirable dust and 95% for respirable crystalline silica.

Abstract
Welding fumes (WF) are a complex mixture of ultrafine polymetallic particles, which can deposit in all regions of the respiratory tract. They contain high levels of transition metals (Cr, Cu, Mn …) known to catalyze the production of reactive oxygen species which are related to numerous adverse health effects. In industrial hygiene, collected WF are analyzed several days later, following usual standard techniques. However, during storage WF samples may undergo several physico-chemical modifications that may lead to an underestimation of their oxidative potential (OP) and metal bioaccessibility. In this work, we determined the influence of several usual storage conditions on the OP (dithiothreitol method OPDTT) and metal bioaccessibility of WF. Fresh WF were generated using a controlled welding bench and the collected particles were subsequently stored following various conservation conditions (temperature, atmosphere composition and durations) before analysis. OPDTT of WF significantly decrease with increasing storage duration when stored in ambient air, either at +20°C or -20°C, while there are no significant variations for storage under N2(g). Furthermore, the metal bioaccessibilities show similar trends to that of the OPDTT of WF for the tested conservation conditions. This work confirms that storage conditions of WF have an undeniable influence on their metal bioaccessibility and OPDTT. On-line analysis could offer an alternative to WF filter sampling, using OPDTT as a probe of health monitoring for exposed professionals

Exposure to hexavalent chromium [Cr(VI)] may occur in several occupational activities, e.g., welding, Cr(VI) electroplating and other surface treatment processes. The aim of this study was to provide EU relevant data on occupational Cr(VI) exposure to support the regulatory risk assessment and decision-making. In addition, the capability and validity of different biomarkers for the assessment of Cr(VI) exposure were evaluated. The study involved nine European countries and involved 399 workers in different industry sectors with exposures to Cr(VI) such as welding, bath plating, applying or removing paint and other tasks. We also studied 203 controls to establish a background in workers with no direct exposure to Cr(VI). We applied a cross-sectional study design and used chromium in urine as the primary biomonitoring method for Cr(VI) exposure. Additionally, we studied the use of red blood cells (RBC) and exhaled breath condensate (EBC) for biomonitoring of exposure to Cr(VI). Personal measurements were used to study exposure to inhalable and respirable Cr(VI) by personal air sampling. Dermal exposure was studied by taking hand wipe samples. The highest internal exposures were observed in the use of Cr(VI) in electrolytic bath plating. In stainless steel welding the internal Cr exposure was clearly lower when compared to plating activities. We observed a high correlation between chromium urinary levels and air Cr(VI) or dermal total Cr exposure. Urinary chromium showed its value as a first approach for the assessment of total, internal exposure. Correlations between urinary chromium and Cr(VI) in EBC and Cr in RBC were low, probably due to differences in kinetics and indicating that these biomonitoring approaches may not be interchangeable but rather complementary. This study showed that occupational biomonitoring studies can be conducted successfully by multi-national collaboration and provide relevant information to support policy actions aiming to reduce occupational exposure to chemicals. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. ; info:eu-repo/semantics/publishedVersion