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Bogadi-Are, Ana ;Turk, Rajka ;Karacic, Visnja ;Zavalic, Marija ;Trutin-Ostovic, Karmen
doi: 10.1177/074823379701300402pmid: 9249930
Forty-nine female workers in the shoemaking industry, exposed to a solvent mixture containing benzene and twenty-seven non-exposed controls, were investigated. Concentrations of benzene and toluene in the working atmosphere, as well as benzene and toluene in blood and phenols in pre- and post-shift urine as parameters of biological monitoring, were determined. In order to assess hematotoxic risk, a complete blood cell count with differential, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, reticulocytes, serum iron, alkaline phosphatase in neutrophils and red blood cell glycerol lysis time were determined in all subjects. Benzene concentrations in the workplace atmosphere at the shoemaking factory ranged from 1.9 to 14.8 ppm (median=5.9). Significant difference in benzene in blood (p = 0.005) and phenol in post-shift urine (p = 0.003) between exposed workers and controls confirmed exposure to benzene. Hemoglobin level (p = 0.02) and mean corpuscular hemoglobin concentration (p = 0.0002) in the shoe workers were lower, and band neutrophils (p = 0.005) and mean corpuscular volume (p = 0.03) higher, than in controls. Red blood cell glycerol lysis time was significantly higher (p = 0.000001) in shoe workers (X ± SD = 41.6 ± 8.9) than in controls (X ± SD = 31.1 ± 6.5) and showed a significant correlation with exposure biomarkers. The results confirm that benzene exposure below 15 ppm may produce qualitative abnormalities, particularly macroerythrocytosis and increased red cell glycerol resistance, in the absence of an overt quantitative decrease in circulating blood cells. Increased resistance to the hemolytic action of glycerol is a potentially useful biological monitoring procedure in medical surveillance of benzene exposed workers. The results of this study suggest that potential threshold concentration for hematologic effects of benzene is lower than 15 ppm.
Abadin, Henry G. ;Hibbs, Beth F. ;Pohl, Hana R.
doi: 10.1177/074823379701300403pmid: 9249931
The purpose of this report is to provide an overview of the public health implications of exposure via breast milk to cadmium, lead, and mercury for nursing infants and to provide health-based guidance. Daily intakes were calculated and compared with guidance values used for public health assessments at hazardous waste sites. Cadmium, lead, and mercury under normal conditions are found in breast milk at concentration ranges of < 1 μg/L, 2-5 μg/L, and 1.4-1.7 μg/L, respectively. Women exposed environmentally or occupationally can have higher levels in their breast milk. Concentrations of about 5 μg/L (cadmium), 20 μg/L (lead), and 3.5 μg/L (mercury) appear to be adequate screening levels. Many factors affect both the distribution of cadmium, lead, and mercury in breast milk and the health consequences to an infant. It is not clear what additional impact low-level exposure via breast milk may have on an infant born with a body burden to one of these metals. There is sufficient evidence to make the case that contaminated breast milk is a source of potential risk to infants in certain populations. Prevention strategies that include behavior modification and proper nutrition should be communicated to women at risk. Identification and elimination of exposure pathways and a critical analysis of the benefits of breast feeding versus heavy metal exposure are needed on a site-specific or individual basis. Research is required to better understand the impact of low-level exposure to heavy metals via breast milk. Breastfeeding should be encouraged under most circumstances.
Rodriguez-Zaragoza, Salvador ;Magana-Becerra, Alejandro
doi: 10.1177/074823379701300404pmid: 9249932
Several species of pathogenic Acanthamoeba cause infections to humans, but amoebic keratitis is more frequently found than any other due to the increasing number of contact lens wearers in the world. Cysts and trophozoites of these amebas are airborne and may pollute water from the air. We investigated the proportion of pathogenic Acanthamoeba from the atmosphere of the city of San Luis Potosi. Samples were taken by the impinger method, every month during one year. We isolated 23 strains of Acanthamoeba, 61% of them were non-pathogenic, 31% were non-pathogenic with invasive capacity and 8% were pathogenic to mice. Almost 40% of these strains represent danger of infections to humans. The isolations were more abundant during the dry season in the south (urban) and west (suburban) stations, which means that the sanitary conditions around stands may enhance the proportion of pathogenic strains in the surroundings.
doi: 10.1177/074823379701300405pmid: 9249933
An environmental hazard ranking model (benchmark ranking model) has been developed and used for the ranking of organic compounds likely to be found in petroleum refinery effluents. The hazardfunction is essentially a multiplication of variables for toxicity (as LC50), octanol-water ratio (Kow), soil adsorption (Koc), solubility (S), and half-life (T1/2). The final score is obtained by taking the logarithm of the hazard and normalizing the values from 1-10. It is a benchmark ranking (BR) approach in the sense that the hazard for chemicals with essentially unknown environmental behaviors may be compared with the hazard for chemicals with well-known behaviors. In general, debates on water pollution have focused on non-polar (hydrophobic) compounds whereas polar (water soluble) compounds have attracted much less attention and regulation. This study focuses on a number of the polar compounds (methyl-tertiary butyl-ether [MTBE], morpholine, metanolamine and others) since there are indications that some of these may cause environmental damage. While non-polar compounds receive the highest score in the study, the combination of frequently large volumes, low biodegradability, low treatability, and analytical detection problems suggest caution when neglecting polar compounds in waste minimization pursuits and in the assessment of environmental hazard and damage. The ranking results are compared to those obtained by using three regulatory systems for the screening and classification of chemicals from the USA and Western Europe. Only the environmental dimension, not the human health dimension, is incorporated in the comparisons and final scores. Although there is good agreement, the number of compounds that get a low score (1-3 on the 1-10 scale) are fewer in the BR system than in the other systems, partly due to the weight of degradation as T½ in the function. The lack of accurate input data, in particular for biodegradation, is a major problem in the ranking. Data for biological oxygen demand (BOD), or from major biodegradation models such as BIODEG and AERUD, give little or no distinction between compounds that biodegrade in four months or forty years.
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