Recent and historical pollution legacy in high altitude Lake Marboré (Central Pyrenees): A record of mining and smelting since pre-Roman times in the Iberian Peninsula.

We have analyzed potential harmful trace elements (PHTE; Pb, Hg, Zn, As and Cu) on sediment cores retrieved from lake Marboré (LM) (2612 m a.s.l, 42°41'N; 0° 2'E). PHTE variability allowed us to reconstruct the timing and magnitude of trace metal pollutants fluxes over the last 3000 years in the Central Pyrenees. A statistical treatment of the dataset (PCA) enabled us to discern the depositional processes of PHTE, that reach the lake via direct atmospheric deposition. Indeed, the location of LM above the atmospheric boundary layer makes this lake an exceptional site to record the long-range transport of atmospheric pollutants in the free troposphere. Air masses back-trajectories analyses enabled us to understand the transport pathways of atmospheric pollutants while lead isotopic analyses contributed to evaluate the source areas of metal pollution in SW Europe during the Late Holocene. PHTE variability, shows a clear agreement with the main exploitation phases of metal resources in Southern Europe during the Pre-Industrial Period. We observed an abrupt lead enrichment from 20 to 375 yrs CE mostly associated to silver and lead mining and smelting practices in Southern Iberia during the Roman Empire. This geochemical data suggests that regional atmospheric metal pollution during the Roman times rivalled the Industrial Period. PHTE also increased during the High and Late Middle Ages (10-15th centuries) associated to a reactivation of mining and metallurgy activities in high altitude Pyrenean mining sites during climate amelioration phases. Atmospheric mercury deposition in the Lake Marboré record mostly reflects global emissions, particularly from Almadén mines (central Spain) and slightly fluctuates during the last three millennia with a significant increase during the last five centuries. Our findings reveal a strong mining-related pollution legacy in alpine lakes and watersheds that needs to be considered in management plans for mountain ecosystems as global warming and human pressure effects may contribute to their future degradation.

Variation in ribosomal DNA intergenic spacers among populations of Anopheles albimanus in South and Central America.

Variation in the length and copy number of intergenic spacers (IGS) of nuclear ribosomal DNA were examined to test for genetic differentiation among Anopheles albimanus populations. Extensive collections were made in Guatemala but populations were also sampled over a large range of its distribution in Central and South America. Discriminant analysis of IGS patterns in individual mosquitoes indicated that populations generally had unique sets of IGS length variants. The IGS patterns from populations on the Pacific side of Central America were distinct from those on the Atlantic side or from South America. Cluster analysis indicated a similar trend. The IGS diversity in Central America was 50% greater than in South America. These results suggest that barriers to gene flow exist among Atlantic and Pacific coast populations of An. albimanus. No gene flow barriers were detected among populations from Colombia, Ecuador, Peru, and Venezuela.

Iron, vitamin B-12 and folate status in Mexico: associated factors in men and women and during pregnancy and lactation.

To determine the prevalence and causes of anemia in rural Mexico, blood samples and longitudinal dietary data were collected from 187 women, some pregnant and then lactating, and from 72 men. Blood was used to measure anemia, mean cell volume, and plasma ferritin, folate and vitamin B-12. Anemia was found in 33% of the men, 54% of nonpregnant, nonlactating women, 35% of pregnant women and 41% of lactating women, and varied by season. Low iron stores (ferritin) accompanied anemia in only 8% of men compared with 38-67% of women. Low meat intake and poor dietary iron bioavailability were associated with anemia in women. There were no cases of low plasma folate. Low plasma vitamin B-12 was common in all groups, and the incidence increased from 15% at 7 mo of pregnancy to 30% at 7 mo of lactation. Vitamin B-12 was lower in the plasma and milk of anemic lactating women than in plasma and milk of non-anemic lactating women and was classified as deficient in 62% of breast milk samples.