Multiorgan accelerated silicosis misdiagnosed as sarcoidosis in two workers exposed to quartz conglomerate dust

IntroductionClusters of silicosis cases have been reported in the fabrication of quartz conglomerate, a new high-silica-content artificial stone for kitchen and bathroom benchtops (countertops).AimWe describe two cases of accelerated-type silicosis with hepatic granulomas arising in workers exposed to artificial quartz conglomerates.MethodsA confident diagnosis of multiorgan silicosis was based on high level of respirable silica in the workplace, typical radiological alterations in chest high-resolution CT, histological findings in the lung and liver, and detection of silica crystals in both tissues by phase-contrast polarising light microscopy and scanning electron microscopy and energy dispersive spectroscopy.ResultsThe development of the disease <10 years after the first exposure is consistent with an accelerated-type of silicosis. Compared with other studies related to quartz conglomerate exposure, we determined that the levels of airborne crystalline silica during activity in the finishing area were between 0.260 and 0.744 mg/m3, that is, much higher than the threshold limit value according to American Conference of Governmental Industrial Hygienists (0.025 mg/m3). Moreover, liver granulomas were associated with accumulation of crystalline silica particles in the hepatic tissue.ConclusionsQuartz conglomerate fabrication is a potentially dangerous occupation. General practitioners and physicians should have awareness of this newly described occupational hazard. Accurate occupational history is critical in avoiding misdiagnosis, as silicosis caused by inhalation of dust from artificial quartz conglomerates may exhibit atypical presentation. These features seem to be related to the extremely high level of silica exposure and, possibly, to an increased toxicity of the dust generated in this process.

Characterization of Ambient Particulate Matter Sampled at an Active Sand Mine Facility in Northwestern Wisconsin

Concern has arisen about levels of silica in ambient particles near sand mines in Northwestern Wisconsin. Airborne particles released from mining and processing activity may release respirable silica into the air, which can have adverse health effects on individuals exposed to significant quantities. In order to assess these levels of silica, this study developed a parallel analysis using an X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS) analysis to test particles in real air samples. Calibrations were constructed for the XRD analysis (following NIOSH Method 7500) with silica standards containing 10 μg – 500 μg respirable silica on filter media with detection limits of 19-28 μg. SEM-EDS methods incorporated identifying the geologic composition of particles using the elemental analysis. Real air samples were collected at a sand mining site using a cascade impactor. Filter substrates were pre-weighed and post-weighed to determine the total dry mass of particles sampled and XRD results show at maximum 16 % of the mass can be attributed to crystalline silica in the samples. An SEM-EDS analysis to categorize the particles geologic classification using ratios of elements shows more than 70% of sampled particles are classified as potassium feldspars. KEYWORDS: Particulate Matter; Sand Mining; Silica; Atmospheric Characterization; XRD; SEM-EDS; Fugitive Dust

Respirable Silica: An Analysis of Recent Advances

Prevention and reduction of anthropogenically released greenhouse gasses and respirable particulate matter has enhanced health with environmental monitoring. It has shown exposure to carcinogens. Air quality analysis showed silica, polycyclic aromatic hydrocarbons, sulfuroxides, nitroxides, and ozone were associated with respiratory diseases in urban, residential, street level areas near windows. Moreover, validation with measurements of temperature, humidity, climate change, or energy production and consumption may show more silica associated with public health.