Browsing by Issue Date, starting with "2011-06-27"
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- Occupational Exposure to Formaldehyde: Genotoxic Risk Evaluation By Comet Assay And Micronucleus Test Using Human Peripheral LymphocytesPublication . Costa, S.; Pina, C.; Coelho, P.; Costa, C.; Silva, S.; Porto, B.; Laffon, B.; Teixeira, João PauloFormaldehyde (FA) is a world high-production compound with numerous applications ranging from production of resins to medicines. Due to its sensitizing properties, irritating effects and potential cancer hazard FA is of great environmental health concern. Numerous studies in humans and experimental animals demonstrated that inhaled FA produced toxicity, genotoxicity, and cancer at distal sites. IARC, based on sufficient data, reclassified FA as a human carcinogen. The highest level of human exposure to this aldehyde occurs in occupational settings, namely, in pathology and anatomy laboratories, where FA is commonly used as a fixative and tissue preservative. Several studies consistently showed that the levels of airborne FA in anatomy laboratories exceeded recommended exposure criteria. In order to assess the genotoxic effects of chronic occupational exposure to FA, a group of pathology/anatomy workers was assessed using a micronucleus (MN) test and comet assay. The level of exposure to FA was also determined and the time-weighted average (TWA) of exposure was calculated for each subject. The TWA mean value for FA exposed workers was 0.43 ± 0.06 ppm, exceeding national and international recommended limit levels of 0.3 ppm. Both MN frequency and comet assay parameters were significantly higher in exposed subjects. Data obtained confirm a correlation between genetic damage and occupational exposure to FA. These data, along with recent implications of human carcinogenicity, point out the need for close monitoring of occupational exposure to FA. Implementation of security and hygiene measures as well as good practices campaigns may be crucial to decrease risk.
- Micronucleus Frequencies in Lymphocytes and Reticulocytes in a Pesticide-Exposed Population in PortugalPublication . Costa, C.; Silva, S.; Neves, J.; Coelho, P.; Costa, S.; Laffon, B.; Snawder, J.; Teixeira, João PauloA wide range of chemical products known to be acutely toxic is currently used in the agricultural sector, including numerous pesticides with different compositions. Nevertheless, the effects in human health as result of chronic exposure to low levels are not yet completely understood. The methodology for determination of micronuclei (MN) in lymphocytes (CBMN) is well established, and accumulating data demonstrated a correlation to enhanced risk of cancer development. However, analysis of MN in reticulocytes (MN-RET) in humans is a recent tool on human biomonitoring. The aim of this study was to examine the influence of pesticide exposure on MN-RET and CBMN frequencies. In total, 177 individuals were studied (93 controls and 84 exposed). All individuals included in the exposed group were exposed regularly to various chemicals. Both MN-RET and CBMN were significantly higher in the exposed subjects compared to controls. The CBMN frequencies were quantitatively higher in females than males, especially within the exposed group. Smoking habits exerted no marked influence on the frequency of the biomarkers studied. A significant and positive correlation was found between both indicators. Within the exposed group, data showed that there was a significant correlation between MN-RET and recent exposure (exposure in the previous 10 d) that is not found when considering CBMN. It is conceivable that due to the short life span of reticulocytes, MN-RET were found to be more reliable to characterize recent genetic damage as opposed to CBMN.
- Geno- and Immunotoxic Effects on Populations Living Near a Mine: A Case Study of Panasqueira Mine in PortugalPublication . Coelho, P.; García-Lestón, J.; Silva, S.; Costa, C.; Costa, S.; Coelho, M.; Laffon, S.; Pásaro Mendez, E.; Teixeira, João PauloMining industry is a vital economic sector for many countries but it is also one of the most hazardous activities, both occupationally and environmentally. Existing studies point to several adverse effects on communities' health living near mines, effects such as mesothelioma and respiratory illnesses. Results achieved in a geochemical sampling campaign undertaken in the vicinity of São Francisco de Assis village showed an anomalous distribution of some heavy metals in soils and waters. To evaluate the effects of mining activities on human health produced by these conditions, a group of 28 individuals from São Francisco de Assis village was examined for some biological endpoints. A nonexposed group (30 individuals) with the same demographic characteristics without exposure to genotoxic compounds was also studied and data obtained from both groups compared. Results of the T-cell receptor mutation assay and micronucleus (MN) test showed significant increases in the frequencies of both mutations and MN in exposed subjects compared to controls. Data obtained in the analysis of the different lymphocyte subsets demonstrated significant decreases in percentages of CD3+ and CD4+ cells, and a significant increase in percentage of CD16/56+ cells, in exposed individuals. The results of the present study indicate an elevated risk of human environmental contamination resulting from mining activities, emphasizing the need to implement preventive measures, remediation, and rehabilitation plans. This would lead to a reduction in cancer risk not only for this particular population but for all populations exposed under similar conditions.
- Chemical Exposure and Occupational Symptoms Among Portuguese HairdressersPublication . Mendes, A.; Madureira, J.; Neves, P.; Carvalhais, C.; Laffon, B.; Teixeira, João PauloHairdressing is predominantly a female activity, in which several chemicals are handled, some of which are known to be allergenic and potentially carcinogenic. Several epidemiological studies showed an association between occupational exposure to chemicals in hairdressing salons and skin and respiratory-tract conditions. The aim of this study were to characterize the occupational exposure to total volatile organic compounds (VOC) and ammonia (NH3) in 50 Portuguese hairdressers' salons and to analyze the prevalence of respiratory and skin symptoms in 134 hairdressing professionals. Data indicated that internal sources of total VOC are mainly due to indoor sources, with average concentrations (1.4 mg/m3) above the Portuguese reference levels (0.6 mg/m3). Of the hairdressers' salons studied, 4% had a mean NH3 concentration higher than Portuguese (20 ppm) and American Conference of Industrial Hygienists (ACGIH) (25 ppm) reference levels. Hand dermatitis was the occupational symptom most reported by hairdressers (50%), followed by eye irritation (43%). The results of this study suggest that hairdressers' occupational activities are linked with higher risk of developing hand and wrist/arm dermatitis and symptoms in the upper respiratory tract. The proper use of disposable gloves, hands, wrists, and arms skin monitoring, and the frequent use of moisturizers in the workplace are effective measures to prevent the occurrence of dermatitis in these professionals. Displacement ventilation and/or local exhaust with adequate air exchange rate are recommended particularly in technical areas where hairdressing chemicals are mixed.