Heavy metals were assessed in four species of sea turtles from the Baja California Peninsula, Mexico, representing the first report of heavy metal concentrations in tissues of post-yearling sea turtles from the Eastern Pacific. Concentrations of Cd measured in C. mydas kidney (653 microg/g dry wt) were the highest ever reported for any sea turtle species. Cd accumulated preferentially in kidney and the ratios of kidney to liver Cd in Baja California turtles were among the highest reported for sea turtles globally. Zn, Ni, and Mn concentrations were also significantly higher in kidney than other tissues, while Cu and Fe were greatest in liver, and all metals were lowest in muscle. With the exception of one value (69.9 microg/g in kidney of C. caretta), Pb was low in all tissues from Baja California. In comparisons across species, kidney of C. mydas had greater Zn and Ni concentrations as compared to other species, although there was no difference in liver metal levels among the species. Positive correlations were detected in the concentrations of Cd, Cu and Ni with the straight carapace length of C. caretta.

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Oxidative damage to proteins related to metals and antioxidant defenses in breastmilk AbstractIntroduction: Breast milk contains molecules needed for the development of children; the integrity and function of these molecules is affected by the presence of pro-oxidants. Protein carbonyls are mainly produced as a result of the interaction of metals with reactive oxygen species (ROS), which may initiate a chain reaction that promotes molecular oxidation.

The mining activity in the San Antonio-El Triunfo district, located in a mountainous region at 60 km southeast of La Paz, occured for more than 250 years and left behind severe contamination of soils and riverbed sediments which led to elevated concentrations of arsenic and other trace elements in the surface- and groundwater of the region. Although the main mining activity ended around 1911, contamination is still beeing distributed, especially from left behind tailings and mine waste piles. The contamination levels in the groundwater have been reported in several studies, but there is little information available on the surface water quality, and especially the temporal variation. In this study, we analyzed the surface water of the La Junta creek, in the southern part of the San Antonio-El Triunfo mining district. The working hypothesis was that by means of a spatial analysis of surface water and shallow groundwater, in combination with the temporal observation of the concentrations in runoff water, the effects of different sources of arsenic (natural geogene anomalies, due to historic mining activity, and hydrothermal related impact) in the La Junta creek can be recognized. This present study revealed that historic mining activity caused a mojor impact of arsenic but less contamination was observed than in the northern part of the district and elevated arsenic concentrations in stream water generally occurred during times of low streamflow.

La diferenciación de la calidad de agua en un acuífero puede ser útil como herramienta para el manejo del agua subterránea. En este trabajo, se aplicó el análisis de funciones empíricas ortogonales (EOF, por sus siglas en inglés) con rotación de ejes por el método varimax a 135 pozos, empleando para este propósito 12 parámetros de calidad de agua muestreada en la Reserva de la Biosfera del Vizcaíno, México. Los datos se obtuvieron del Instituto Nacional de Estadística, Geografía e Informática (INEGI). A partir del análisis EOF se retuvieron tres factores que juntos explican el 99% de la varianza en las series originales. La distribución de los coeficientes (factor loadings) con valores ai≥0.7 asociados a cada factor se agruparon en áreas geográficas específicas indicando la diferenciación del acuífero en tres áreas. Se discuten las diferencias de la calidad de agua entre las áreas. Una interpretación posterior de nuestros resultados empleando información sobre influencias naturales y antropogénicas, e información independiente de 28 pozos restantes monitoreados en 2003, otorgaron evidencia adicional para tal diferenciación, concluyendo que, aunque puramente estadístico el análisis EOF demostró ser útil en la diferenciación del acuífero. El enfoque empleado en este trabajo puede ser aplicado a otras áreas donde exista información química disponible del agua subterránea.