Trace metals and metalloids in Andean flamingos (Phoenicoparrus andinus) and Puna flamingos (P. jamesi) at two wetlands with different risk of exposure in the Bolivian Altiplano.

Birds are widely used as bioindicators in monitoring programs in wetlands. We compare concentrations of seven trace metals and metalloids (TMM) As, Cd, Cu, Fe, Hg, Pb, Znin both feathers and blood in two flamingo species in two high-altitude wetlands in Bolivia, with different levels of anthropogenic point source pollution. Lake Uru Uru (LUU) receives discharges from mining operations, and also effluents from the nearby city of Oruro, while Laguna Colorada (LCo) does not receive contaminants from anthropogenic sources. We sampled water and sediments at each site, as well as flamingos in three age classes in an effort to establish a benchmark for long-term monitoring. Metal concentrations in water did not differ between sites, whereas Zn and Pb concentrations of TMM in sediments were higher at LUU, and Hg higher at LCo. TMM concentrations were highly specific for all separate elements, but results point to differences between Andean flamingo (Phoenicoparrus andinus) chicks and the rest of the classes considered. As flamingo chicks did not molt before sampling, we pose that TMM concentrations in their blood and feathers may respond mainly to local conditions. Eggshells provide additional information, since adults transfer some TMM during egg development. Long-term monitoring in these species should include different age classes and sample both feathers and eggshells to monitor the environmental conditions and bioaccumulation of TMM in these species. Future studies should include sites devoid of natural sources of TMM to help distinguish sources of contamination, since some TMM (As and Pb) may be naturally in high concentrations in remote areas, like Laguna Colorada.

Low total mercury in Caiman yacare (Alligatoridae) as compared to carnivorous, and non-carnivorous fish consumed by Amazonian indigenous communities.

Mercury contamination in the River Beni basin is an important health risk factor, primarily for indigenous communities that live along the river. Among them are the Tacana, living in their original territory with sustainable use of their natural resources, consuming fish, Caiman yacare, and other riverine resources as their main source of protein. To assess mercury exposure to Tacana people, total mercury (THg) was evaluated in the muscle of seven commercial fish, and Caiman yacare (yacare caiman) during 2007 and 2008. THg was extracted by acid digestion and concentrations were determined by atomic absorption spectrometry. Mean mercury concentrations in C. yacare was 0.21 ± 0.22 µg g-1Hg w.w. (wet weight), which is lower than expected given its high trophic level, and its long life-span. It is possible that mercury in C. yacare is accumulated in other organs, not included in this study; but it is also possible that physiological mechanisms are involved that help caimans get rid of ingested mercury, or simply that C. yacare's diverse diet reduces THg accumulation. Carnivorous fishes (Pygocentrus nattereri, Pseudoplatystoma tigrinum, Zungaro zungaro, Plagioscion squamosissimus, and Leiarius marmoratus) had the highest total mercury concentrations, ranging from 0.35 to 1.27 µg g-1Hg w.w. moreover, most were above the limit recommended by WHO (0.5 µg g-1Hg w.w.); except for Leiarius marmuratus, which presented a mean of 0.353 ± 0.322 µg g-1Hg w.w. The two non-carnivorous fish species (Prochilodus nigricans, and Piaractus brachypomus) present mean concentrations of 0.099 ± 0.027, and 0.041 ± 0.019 µg g-1Hg w.w., respectively. Finally, recommendations on the consumption habits of Tacana communities are discussed.

The histopathology of corneal neovascularization. Inhibitor effects.

With the use of a previously described model of corneal neovascularization induced by thermal cautery, we examined the effects of inhibitors on both the incidence of corneal neovascularization and the degree of inflammatory cell response. Three known inhibitors of corneal neovascularization, 1% prednisolone acetate, indomethacin, and 0.3% flurbiprofen, were studied and the results were compared with those in saline-treated controls. As expected, corneal neovascularization, preceded by conjunctival and corneal polymorphonuclear leukocyte (PMNL) infiltration, occurred in all control animals. Corneal neovascularization did not occur in any of the inhibitor-treated eyes. Histopathologically, both conjunctival and corneal PMNL counts in the treated eyes were markedly reduced compared with controls. These findings are consistent with the hypothesis that inflammatory cells, particularly PMNLs, are closely associated with the initiation of corneal neovascularization.