The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion ...The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.展开更多
A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that inclu...A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that include coarse, fine and ultrafine particles, carbon monoxide (CO), oxides of nitrogen and sulphur, transitional metals, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds and bioaerosols. Lipid peroxidation level (LPX) and protein carbonyl content (PCC) help to evaluate oxidized protein content and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were evaluated in blood samples of study participants. The group of occupationally exposed (OE) workers consisted of 30 individuals ranging in age from 25 to 55 years, with a mean of 15 years in a brick production-related job. The control group included 30 volunteers who were neither environmentally nor occupationally exposed to brick production activities and whose sociodemo-graphic characteristics were similar to the OE group. Results indicate that none of workers used any type of protective equipment (respirator or face mask, gloves, coveralls) during brick manufacturing. LPX and PCC significantly increased (p < 0.5) in the OE group compared to the control group. SOD, CAT and GPx activity was significantly increased (p < 0.5) in the OE group compared to the control group. Therefore, evaluation of stress oxidative biomarkers is advisable in order to assay chronic exposure to workers in brick manufacturing.展开更多
文摘The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.
文摘A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that include coarse, fine and ultrafine particles, carbon monoxide (CO), oxides of nitrogen and sulphur, transitional metals, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds and bioaerosols. Lipid peroxidation level (LPX) and protein carbonyl content (PCC) help to evaluate oxidized protein content and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were evaluated in blood samples of study participants. The group of occupationally exposed (OE) workers consisted of 30 individuals ranging in age from 25 to 55 years, with a mean of 15 years in a brick production-related job. The control group included 30 volunteers who were neither environmentally nor occupationally exposed to brick production activities and whose sociodemo-graphic characteristics were similar to the OE group. Results indicate that none of workers used any type of protective equipment (respirator or face mask, gloves, coveralls) during brick manufacturing. LPX and PCC significantly increased (p < 0.5) in the OE group compared to the control group. SOD, CAT and GPx activity was significantly increased (p < 0.5) in the OE group compared to the control group. Therefore, evaluation of stress oxidative biomarkers is advisable in order to assay chronic exposure to workers in brick manufacturing.
