Determining of risk areas due to exposure to heavy metals in the Toluca Valley using epiphytic mosses as a biomonitor.

The work aim is to identify the risk areas by exposure to Cr, Cu, Pb and Zn in the Metropolitan Zone of Toluca Valley (MZTV) using the mosses Fabriona cilaris and Leskea angustata as a biomonitors, geostatistical interpolation and multi-criteria evaluation by analytical hierarchy process. The results from the estimation of the enrichment factors (EF) showed that Pb is the heavy metal with the highest values, followed by the Zn, Cu and Cr. The EF obtained for all heavy metals show that there is a moderate to high anthropogenic enrichment. The above indicates that in the MZTV there are emission sources that contribute (significantly) in the amount of Cr, Cu, Pb and Zn accumulated in the biomonitor. Combustion processes, vehicle emissions, biomass burning, brick kiln emissions, agricultural and livestock activities, manufacturing industry and re-deposition by the action of the wind, were identified as the main heavy metals sources in the MZTV. Risk maps showed the high and medium risk areas are located in sites with poor urban vegetation coverage and close to highways and industrial parks. Low risk areas are located in sites with high urban vegetation coverage. The method used for identifying risk areas is a rapid and low-cost evaluation tool can allow local government environmental agencies to define public policies on air pollution control.

[Neonatal hemochromatosis. Report of 3 autopsy cases]. / Hemocromatosis neonatal. Informe de tres casos de autopsia.

INTRODUCTION: Neonatal hemochromatosis is a disease that starts in utero, characterized by severe fibrosis or cirrhosis and siderosis of the liver and other organs without affecting the mononuclear fagocytic system. The most important clinical features are severe hepatic failure at birth and hypoglycemia. The diagnosis is made excluding other diseases more frequently seen in the neonatal period and with at least two of the clinicopathologic criteria delineated by Knisely. METHODS: A retrospective analysis of the autopsies of newborn done at the Department of Pathology of the Hospital de Pediatría, C.M.N. SXXI, IMSS, a tertiary care facility in the period 1989 from 1997. Those cases with primarily hepatic disease as the main diagnosis were chosen. The degree of siderosis was determined cualitatively. The amount of Fe and copper in the liver and spleen in samples fixed in formalin was obtained using X ray fluorescence in the Instituto Nacional de Investigaciones Nucleares, two control cases were also tested. RESULTS: Only four out of 210 autopsies of newborn babies were found to have hepatic disease as a main diagnosis but without an etiology determined. In three of such cases the diagnosis of neonatal hemochromatosis was made. All patients were male with ages six, 29 and 36 days, one with Down's syndrome. The ratio of iron deposits in liver/spleen in hemochromatosis' cases was higher to 1.5 in the liver in contrast to the two control cases. CONCLUSIONS: These cases showed the utility of the autopsy in establishing the adequate diagnosis in three cases of neonatal hemochromatosis. The importance of establishing an accurate diagnosis is to recognize it as an entity with a lethal course, that can be potentially managed with liver transplant as well as genetic counseling to the family. A remarkable finding in the study of these cases was the ratio of iron concentration in the liver and spleen that allowed to discard other causes of siderosis. To our knowledge this finding has never been recorded.