Analysis of dust and noise exposure levels in the mining industry from the national surveillance program in 2019 / 中华劳动卫生职业病杂志

Objective: To understand the exposure level of dust and noise in the mining industry and provide data support for revising policy for the prevention and control of occupational diseases. Methods: In May 2022, Data was collected through the National Surveillance Program for Occupational Hazards in the Workplace. Descriptive analysis was conducted for dust and noise levels by industry type and enterprise size from 7, 679 enterprises in the mining industry among 29 provincial regions nationwide. Results: The enterprises in the mining industry included in the National Surveillance Program for Occupational Hazards in the Workplace are mainly small and micro, accounting for 47.97% (3684/7679) and 30.00% (230/7679) respectively. The industry is mainly compred of employers in the non-metallic ming and beneficiation industry, accounting for 50.25% (3859/7679). Among the enterprises with silica dust, coal dust, and noise hazards, the proportion of enterprises where total dust concentration and noise intensity exceed the standard is higher than 50%. 30% of the posts are with an exposure level of silica dust, coal dust, and noise that exceeds the standard. The exceedance rate and the median of the time-weighted average concentration of total coal dust among large and medium-sized enterprises are higher than those among small and micro-sized enterprises (P<0.05) . Conclusion: The dust and noise hazards in the mining industry are lower than in the past in China, but more than 25% of workers are still at a high risk of occupational pneumoconiosis and noise deafness. Therefore, intervention and surveillance strategies should be strengthened in the future.

Silicon Dioxide Particles Deposited in Vessels and Cartilage of the Femoral Head

Silicosis had been considered for decades as an illness with manifestations of lung fibrosis due to inhalation of overconcentrated SiO2 dust. To the best of our knowledge, studies have yet to report SiO2 deposits in any other tissues and organs. In the present case, while performing bilateral artificial total hip arthroplasty for one patient, we found that the articular cartilage of the bilateral femoral head was black. Therefore, specimens thereof were sent for pathological examination. Pathological examination (immunohistochemistry) and polarized light microscopy revealed the presence of considerable brown, acicular, rhombic, and crumb-like crystals. The crystals were mainly composed of SiO2. SiO2 could deposit in vessels and femoral head cartilage via blood circulation.

Estimating radiation dose from building materials

Natural radioactivity in materials under certain conditions can reach the hazardous radiological levels. So, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The present study deals with the measurement of radioactivity using "gamma-ray spectrometry" from naturally occurring radionuclides in the soil, stone and sand samples used as building materials in North-Eastern Haryana state of India. The places are in the vicinity of Shivalik range of Himalayas. The activity concentrations for 226Ra, 232Th and 40K varied from 18 +/- 1.5 to 156 +/- 6Bqkg[-1], 23 +/- 1 to 300 +/- 5Bqkg[-1] and 32 +/- 0.5 to 1705 +/- 14 Bqkg[-1] respectively in various samples. The absorbed dose rate in soil, sand and stone samples is investigated at 1 m above ground level. Ra equivalents, Internal and external hazard indices have also been calculated. The natural radioactivity levels measured in the samples under present study are below the recommended limits except for black stone [SB] and red stone [SR]. However, these samples satisfy the universal standards

Characterization of biominerals in species of Canna (Cannaceae)

Plant biominerals are not always well characterized, although this information is important for plant physiology and can be useful for taxonomic purposes. In this work, fresh plant material of seven wild neotropical species of genus Canna, C. ascendens, C. coccinea, C. indica, C. glauca, C. plurituberosa, C. variegatifolia and C. fuchsina sp. ined., taken from different habitats, were studied to characterize the biominerals in their internal tissues. For the first time, samples from primary and secondary veins of leaves were investigated by means of infrared spectroscopy, complemented with X-ray powder diffractometry and scanning electron microscopy. The spectroscopic results, supported by X-ray powder diffractometry, suggest that the calcium oxalate is present in the form of whewellite (CaC2O4×H2O) in all the investigated samples. It is interesting to emphasize that all IR spectra obtained were strongly similar in all species studied, thus indicating an identical chemical composition in terms of the biominerals found. In this sense, the results suggest that the species of Canna show similar ability to produce biogenic silica and produce an identical type of calcium oxalate within their tissues. These results can be an additional trait to support the relationship among the families of Zingiberales. Rev. Biol. Trop. 58 (4): 1507-1515. Epub 2010 December 01.

Los biominerales de las plantas no siempre han sido bien caracterizados aunque esta información es importante en fisiología vegetal y puede ser de utilidad para fines taxonómicos. En este trabajo se estudió material vegetal fresco de siete especies silvestres neotropicales: Canna, C. ascendens, C. coccinea, C. indica, C. glauca, C. plurituberosa, C. variegatifolia and C. fuchsina sp. ined., provenientes de diferentes localidades, con el fin de caracterizar los biominerales presentes en sus tejidos foliares internos. Por vez primera, muestras de venas primarias (ejes foliares) y secundarias de hojas de estas especies se investigaron por medio de espectroscopia de infarrojo, complementada con estudios por difracción de rayos X de polvos y microscopía electrónica de barrido. Los resultados indicaron la presencia de ópalo (sílice biogénica) y oxalato de calcio en los tejidos vegetales analizados. Además, se determinó que el oxalato de calcio está presente en forma de whewellita (CaC2O4×H2O), información nueva para el género. Tanto el ópalo como la whewellita están presentes en todas las especies analizadas, que representan aproximadamente un tercio de las especies silvestres del género. La capacidad de biomineralizar SiO2 en forma de ópalo en especies de Canna de diversos ambientes resulta también un rasgo altamente sugerente para futuros estudios.

Características da exposição ocupacional a poeira sem marmorarias da cidade de São Paulo / Characteristics of occupational exposure to dust in the work environment of marble shops in the city of São Paulo

O estudo das características da exposição ocupacional a poeiras no beneficiamento de rochas ornamentais em marmorarias teve como base a aplicação das convenções adotadas pela American Conference of Governmental Industrial Hygienists (ACGIH), pela International Organization for Standardization (ISO) e pelo Comité Europeén de Normalisation (CEN) para a classificação de poeiras por faixa de tamanhos de partícula. Foram consideradas as relações entre as concentrações de poeira nos ambientes de trabalho, os tipos de rochas trabalhadas, as operações a úmido e a seco, as máquinas e as ferramentas utilizadas e os tamanhos das partículas suspensas no ar. Os ambientes de trabalho das marmorarias mostraram altas concentrações de poeira nas frações inalável, torácica e respirável, originadas pelas ferramentas utilizadas no setor de acabamento a seco. As concentrações de sílica chegaram a ser 16 vezes superiores ao valor do limite de exposição ocupacional de 0,05 mg/m3. A avaliação de uma marmoraria que adotou acabamento a úmido mostrou que a probabilidade das concentrações ambientais ultrapassarem os valores de referência ocupacionais pôde ser reduzida em até 99%.

This paper reports a study based on the application of conventions adopted by the American Conference of Governmental Industrial Hygienists (ACGIH), International Organization for Standardization (ISO) and Comité Europeén de Normalisation (CEN) for the classification of types of dust by particle size range. The occupational exposure characterization took into account the relations among dust concentrations at workplace, types of rocks worked on, wet and dry operations, machinery and tools used, and the size distribution of particles suspended in the air. The workplaces at the marble shops were characterized by high concentrations of dust in inhalable, thoracic and respirable fractions, produced by the tools used in the dry abrasive polishing sector. The silica concentrations were up to 16 times higher than the 0.05 mg/m3 occupational exposure limit recommended. The evaluation of a marble shop that made use of the wet abrasive polishing process showed that the probability of environmental concentrations exceeding the occupational reference values could be reduced by up to 99%.

Major ion and heavy metal chemistry of Pachin river (Itanagar) - levels and sources.

The Pachin river is an upland tributary of the Brahmaputra river, originating in the foot-hills of the lesser Himalayas. A systematic study of major ions and heavy metals in the surface water of the river was carried out at peak, intermediate and low flow conditions during an one-year interval to assess the relative contributions from weathering and pollution. The major ion chemistry indicates that silicate weathering and precipitation are the major contributing factors to the river's chemical composition. The Pachin river is characterized by a low overall conductivity, even during times of evaporative concentrations during low flow. This corresponds to the fact that the catchment area is still relatively pristine, i.e., well forested and without significant industry. However, heavy metal patterns clearly reflect source input from agricultural activity and urban development. The levels of Fe and Co were amongst the highest of any rivers of the Indian sub-continent, while these and Cr, Mn, Cu and Se each exceeded the world average value. These results clearly indicate that rivers draining pristine areas can be significantly modified by human activities, and consequently, these must be monitored to ensure that useable water supplies meet the prescribed safety standards.

Nutrient concentration in groundwater of Pondicherry region.

The surface and groundwater samples were collected from urban, rural areas, shallow and deep aquifers in Pondicherry region. The samples were analysed for various nutrients such as Nitrate Nitrogen, Nitrite Nitrogen, Ammonia Nitrogen, Phosphate and Dissolved silica.The elevated concentrations often fold increase against a background concentration of less than 2 mg/L of nitrates was observed in the study area. The maximum nitrate concentration (22 mg/L) in water is well within the limits of 45 mg/L prescribed by World Health Organization. The nutrients were observed about 2 to 3 times higher in groundwater of urban areas than in rural areas, indicating abundant leaching of nutrients from municipal waste and sewage effluent. The nutrients displayed a trend of higher concentration in shallow groundwater and lower in the water in deep aquifer and tank water. The higher concentrations of dissolved silica (13 mg/L to 100 mg/L) against an average concentration of 5 mg/L in the ground water of unreactive aquifers shows the presence of amorphous silica in the subsurface formations, slightly acidic to neutral nature of water in aquifers and also interaction between formation material and water.

Detection of Toxoplasma oocysts from soil by modified sucrose flotation and PCR methods.

A detection method of Toxoplasma gondii oocysts from soil was evaluated using the sucrose flotation technique with modification involving addition of 0.1% gelatin into washing and floating solutions. PCR was performed on untreated samples and after treatment with polyvinylpyrrolidone (PVP), heating and cooling, and NaCl. The addition of gelatin in the sucrose solution yielded a higher number of oocysts. A very thin band was observed when DNA extract was diluted to 1:1024, indicating the presence of PCR inhibitor in the soil. PCR performed on untreated DNA, on PVP-treated, and on PVP-treated with heating and cooling without added bovine serum albumin (BSA) showed a band only at higher dilutions (1:1024 and 1:512) but at a much lower dilution (1:8) with BSA. In contrast, DNA treated with all three agents showed a band at a much lower dilution (1:64), even without added BSA, and no dilution was required when BSA was added. The PCR inhibitors present in the soil were removed by employing various treatment procedures during DNA extraction, and BSA in PCR. Furthermore, the detection limit with the method was 1 oocyst/g of soil, indicating that this method is useful in epidemiological studies.

Longitudinal and seasonal variations of epilimnetic silica in a morphologically complex reservoir and the significance of flow regime and internal processes to their dynamics.

Spatial and temporal dynamics of silica (SiO2) were examined in a morphologically complex reservoir, based on data collected between high-flow year and low-flow year. SiO2 averaged 3.4 mg/L and varied from 0.1 to 9.7 mg/L depending on the year and the location. The paired sample test of SiO2 showed that in mainstem sites, SiO2 was significantly (t = 3.577, p < 0.01) greater in the high-flow year than in the low-flow year, and this pattern was similar to that of embayment sites, indicating an importance of flow regime on the silica loading. During the high-flow year, SiO2 was significantly (t = 3.577, p < 0.01) greater in the mainstems than in the embayments, but during the low-flow year, there was no statistical difference between the two reaches. SiO2 showed a distinct longitudinal decline from the headwaters to the dam in the high-flow year, and it was modified by the plunging of metalimnetic density current in the mid-lake reach. Seasonal fluctuation of SiO2 was influenced by internal nutrient cycling and diatom populations. Dominant phytoplankton abundance had an inverse relation between the two algal populations of bluegreens and diatoms during August-December of the low-flow year. In other words, bluegreen algae dominated at the low SiO2 (< 2.5 mg/L) during the summer period of the low-flow year, whereas diatoms dominated with the increase of SiO2 in fall overturn. Overall results suggest that increase of silica in this system is primarily regulated by interannual flow regime, but the internal loading during fall overturn and biological up-take by seasonal growth of diatom community were also considered as an important process controlling the input of silica.

A Histologic Demonstration of Siliceous Materials in Simian Lung Mite Infected Lung Tissues by Microincineration

Approximately 90% of freshly imported macaques and other Old World Monkeys are known to be infected with respiratory mites. The lung associated pigments are integral components of pulmonary acariasis in Old World Monkeys; at least three distinctive pigmental bodies are identified in association with lung mite infection. Two major components of pigments are recently identified as silica by using elemental analysis using a high voltage electron microscope and an energy-dispersive X-ray analysis technique. Since a limited number of infected monkey lung tissues and associated pigments can be examined by this tedious procedure, it was important for us to examine much greater number of specimens to verify our initial observation. Ten microincineration technique described provided a unique and practical way to identify the mineral elements in as many 27 histologic sections within a short span of time. Silica and silicates are heat resistant whereas majority of organic materials including lung mite parasites disintegrated under the extreme temperature. Mineral elements were exclusively located within the polarizable white ash. More than 90% of total pigmental bodies identified were found to be related to siliceous materials in 20 incinerated infected monkey lung tissues whereas five noninfected lungs similarly examined did not reveal any pigmental bodies. Other than a small of fine granular mucin substances which were PAS positive, the majority of lung mite associated pigments such as large granules of hemosiderin, needle-like crystals and other fine granules engulfed by macrophages were identified to be siliceous materials as they have persisted even after microincineration. Mite parasites and other organic materials were completely disintegrated. Similar pigmental bodies examined by microscope X-ray analysis were positive for silicate. This finding suggests that lung mite infection in Old Monkeys apparently predisposed silicosis. Therefore, until the link between lung mite infection and silicosis is clarified, expreimental inhalation toxicologic findings in mite-infected Old World monkeys should be interpreted cautiously.

Assessment of liver dysfunction in silica exposed workers

Seventy five silica exposed workers in sandbricks industry and twenty five controls were chosen for this study. Each individual was subjected to a questionnaire [for personal and medical histories] and clinical examination. Liver function tests, procollagen III peptide, alpha-I - antitrypsin, hepatitis markers [B and C], haematological tests for schistosomiasis, urine and stool analysis, abdominal sonography and chest X-ray were done for all chosen subjects. Environmental study was done for estimation of total and free crystalline silica. The results of environmental study showed higher concentration of total respirable dust and free crystalline silica than threshold limit values. Silica exposed workers had a significantly higher mean of gamma-glutamyl trans peptidase and procollagen III peptide than controls. These two parameters increased significantly in exposed workers [free from schistosomiasis and / or hepatitis markers] as chest grading of silicosis and time intensity factor increased. Gamma-glutamyl-trans peptidase and procollagen III peptide can be used for early detection of liver dysfunction in silica exposed workers. Also, in the pre-employment medical examination, individuals with previous liver affection [either due to schistosomiasis and / or hepatitis] should not be exposed to silica to avoid further deterioration of liver function

Role of macrophages in experimental malaria: IV--Bioassay of silica in immunity against Plasmodium berghei infection.

Silica treated mice when challenged with Plasmodium berghei showed increase in duration of prepatent(PP) and survival period (SP) and median survival day(MSD) as compared with controls. Daily parasite density curve during the course of infection was similar to control. Response to the parasite challenge, however, was dependent on the dose of silica. No increase in SP at 0.7 mg and in PP at 35 mg (cumulative doses) dose was observed. A dose upto 5 mg per mouse before challenge resulted in protection of the animal. No mortality was recorded in mice which received silica alone (35 mg; 5 mg/day x 7 days). Death due to lethal P.berghei infection could be delayed or prevented by altering/reducing the functional activities of macrophages during the course of infection.

Metals, silica and AHS content of equisetum bogotense HBK and equisetum giganteum L.(HORSETAIL) / Metales

Sio2, Li,Na,K,Ca,Mg,Cu,Zn,Fe,Pb, and ash content in equisetum bogotense HBK and equisetum giganteum L.(equisetaceae) in aerial parts were determined. These plants are used in natural and homoeopathic medice because of their therapeutic properties

Efeito dos tipos de espessantes usados nos géis condicionadores sobre a resistência de uniäo e morfologia da superfície do esmalte e dentina / Effect of the thickning agents kinds used in ettchant gels on enamel and dentin bond strength and surface morfology

O propósito deste estudo foi verificar, através da microscopia eletrônica de varredura, a morfologia da superfície do esmalte e dentina após o condicionamento com ácido na forma de gel contendo sílica e polímero como agente espessante. Além disso, determinar se o tipo de espessante usado para formar o gel afetou a resistência de uniäo entre o substrato (esmalte ou dentina) e a resina restauradoura. As fotomicrografias mostraram que o ácido fosfórico a 35 por cento, contendo sílica como espessante, deixou uma camada de resíduos sobre a dentina após a lavagem com água. Näo houve evidências de resíduos de sílica na superfície do esmalte. A superfície do esmalte e dentina tratada com ácido fosfórico a 10 por cento, contendo um agente polimérico como espessante, apresentou-se limpa e sem contaminantes. O condicionamento com os ácidos fosfórico a 35 por cento e fosfórico a 10 por cento apresentam padröes básicos topográficos semelhantes sobre o esmalte e dentina. O valor médio de resistência ao cisalhamento entre o esmalte tratado com ácido fosfórico a 10 por cento e a resina restauradora foi estatisticamente superior (p<0,05) em relaçäo ao procedimento feito com ácido fosfórico a 35 por cento. Na superfície da dentina, os valores näo apresentaram diferença estatisticamente entre os dois agentes condicionadores

Determinaçäo gravimétrica de aerodispersóides / Gravimetric determination of aerosols

O presente trabalho tem por objetivo estabelecer a metodologia correspondente a preparaçäo, determinaçäo gravimétrica e validade de amostras de aerodispresóides,, utilizando-se de filtros-membranas

Determinaçäo quantitativa de sílica livre cristalizada por difraçäo de raios / Qualitative determination of crystallized free silica by ray diffraction

O presente trabalho tem por objetivo apresentar metodologia padronizada para análise de sílica por difraçäo de raios X, desenvolvida pela FUNDACENTRO a partir da adaptaçäo de métodos internacionais modernos, aplicáveis a essa finalidade

Determinación espectrofotométrica de dióxido de silicio libre en los polvos industriales / Spectrophotometric determination of free silica in industrial dusts

Se comprueban algunas inconsistencias del método de Polezhaev, para la determinación de silicio libre en polvos industriales, se introduce el tratamiento de las muestras con ácido fluorbórico y se estiman las condiciones óptimas del análisis colorométrico con ácido molíbdico. El intervalo de pH que corresponde a las maxima absorbsancia oscila entre 2 y 6, y la longitud de onda crítica es de 815 nm. Se expresa que el método modificado es exacto, sensible, preciso, específico y rápido, y puede ser utilizado para la determinación de silicio libre en muestras de polvo en suspensión