Galena weathering under simulated calcareous soil conditions.

Exploitation of polymetallic deposits from calcareous mining sites exposes galena and others sulfides to weathering factors. Galena weathering leads to the formation of lead phases (e.g., PbSO(4), PbCO(3)) with a higher bioaccessibility than galena, thus increasing the mobility and toxicity of lead. Despite the environmental impacts of these lead phases, the mechanisms of galena oxidation and the transformation of lead secondary phases, under neutral-alkaline carbonated conditions, have rarely been studied. In this work, an experimental approach, combining electrochemical and spectroscopic techniques, was developed to examine the interfacial processes involved in the galena weathering under simulated calcareous conditions. The results showed an initial oxidation stage with the formation of an anglesite-like phase leading to the partial mineral passivation. Under neutral-alkaline carbonated conditions, the stability of this phase was limited as it transformed into a cerussite-like one. Based on the surface characterization and the formation of secondary species, the weathering mechanisms of galena in calcareous soil and its environmental implications were suggested.

An integrated health risk assessment approach to the study of mining sites contaminated with arsenic and lead.

In order to test the value of an integrated approach for the analysis of health risks at contaminated sites, an integrated health risk assessment in a mining area was performed following 3 steps: 1) Environmental monitoring of surface soil, 2) assessment of exposure to metals in children and native rodents, and 3) DNA damage evaluation (comet assay) in children and rodents. These aspects also were studied in less exposed populations. Our results in humans showed that children living in the most polluted area (Villa de la Paz, Mexico) had higher lead blood concentrations (geometric mean of 13.8 microg/dL) and urinary arsenic levels (geometric mean of 52.1 microg/g creatinine) compared to children living in a control area (Matehuala, Mexico; blood lead of 7.3 microg/dL; urinary arsenic of 16.8 microg/g creatinine). Furthermore, the exposed children also had increased DNA damage (tail moment mean in Villa de la Paz of 4.8 vs 3.9 in Matehuala; p < 0.05). Results in rodents were identical. Animals captured in the polluted area had higher levels of arsenic (geometric mean of 1.3 microg/g in liver and 1.8 microg/g in kidney), lead (0.2 microg/g in liver and 0.9 microg/g in kidney), and cadmium (0.8 microg/g in liver and 2.2 microg/g in kidney), and increased DNA damage (tail moment mean of 18.2) when compared to control animals (arsenic in liver of 0.08 microg/g and kidney of 0.1 microg/g; lead in liver of 0.06 microg/g and kidney of 0.3 microg/g; cadmium in liver of 0.06 microg/g and kidney of 0.6 microg/g; and tail moment of 14.2). With the data in children and rodents, the weight-of-evidence for health risks (in this case DNA damage) associated with metal exposure in Villa de la Paz was strengthened. Therefore, a remediation program was easier to justify, and a feasibility study at this site is under way.

Un centro joven para jóvenes / A young center for young people

Desde el primero de marzo de 1978, año en el que se fundó CORA (Centro de Orientación para Adolescentes), dicha institución brinda apoyo a los jóvenes en materia de salud sexual y reproductiva, con el propósito de evitar el embarazo y enfermedades venéreas mediante campañas de profesionales de la salud y educación en escuelas, áreas de trabajo, comunidades y hospitales, tanto urbanos como rurales. El documento contiene: 1. Consejo Directivo 2. Introducción 3. Objetivos 4. Actividades 5. Proyectos de CORA 6. Resultados 7. Estrategias desarrolladas 1978-1991 8. Area de investigación y evaluación 9. Publicaciones y materiales didácticos 10. Area de enseñanza 11. Capacitación internacional 12. Organización de Reuniones Internacionales 13. Servicios/Actividades afectivo-participativas/Servicios de Anticoncepción 14. Indicadores del Impacto de CORA 15. Aportaciones principales de CORA 16. Distinciones 17. Membresías de CORA