Organic contaminants in western pond turtles in remote habitat in California

Remote aquatic ecosystems are exposed to an assortment of semivolatile organic compounds (SOCs) originating from current and historic uses, of local and global origin. Here, a representative suite of 57 current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons were surveyed in the plasma of the western pond turtle (Emys marmorata) and their potential prey items and habitat. California study sites included Sequoia National Park, Whiskeytown National Recreation Area, and Six Rivers National Forest. Each was downstream of undeveloped watersheds and varied in distance from agricultural and urban pollution sources. SOCs were detected frequently in all sites with more found in turtle plasma and aquatic macroinvertebrates in the two sites closest to agricultural and urban sources. Summed PCBs were highest in Whiskeytown National Recreation Area turtle plasma (mean; 1.56 ng/g ww) compared to plasma from Sequoia National Park (0.16 ng/g ww; p = 0.002) and Six Rivers National Forest (0.07 ng/g ww; p = 0.001). While no current-use pesticides were detected in turtle plasma at any site, both current- and historic-use pesticides were found prominently in sediment and macroinvertebrates at the Sequoia National Park site, which is immediately downwind of Central Valley agriculture. SOC classes associated with urban and industrial pollution were found more often and at higher concentrations at Whiskeytown National Recreation Area. These findings demonstrate a range of SOC exposure in a turtle species with current and proposed conservation status and shed additional light on the fate of environmental contaminants in remote watersheds

Seasonal dynamics of PCBs in the plankton of Lake Erie

L’importante masse des données et documents disponibles pour les cher- cheurs dans les corpus de lettres et sciences humaines implique aujourd’hui de créer de nouveaux dispositifs de visualisation de l’information et d’aide à l’édition critique. La nécessité pour les chercheurs de devoir critiquer les sources qui seront au cœur de leurs travaux induit de pouvoir rechercher, visualiser, annoter, et constituer des corpus de références bibliographiques dans des processus de recherche de plus en plus collectif et collaboratifs. C'est la proposition faite avec ISIDORE Table (ou ISIDORE tactile)

Quantitative biomonitoring of PAHs using the barnes mussel (Elliptio complanata)

The elimination rate constants (k2) of nine polycyclic aromatic hydrocarbons (PAHs) were examined for the freshwater mussel Elliptio complanata. The concentrations of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and indeno[1,2,3-c,d]-pyrene revealed a significant inverse relationship with time and their k2 values ranged from 0.10 to 0.22 day-1. The k2 values of these significantly cleared PAHs were similar to k2 values observed for nonmetabolized organochlorines in mussels previously reported in the literature. The inverse relationship between k2 and Kow provides evidence that the nine PAHs were being passively eliminated from the mussels and that they can be used to calibrate the mussel as a quantitative biomonitor. A general expression relating elimination rate constants and chemical Kow is derived for hydrophobic contaminants in E. complanata. The k2 versus log Kow regression equation for mussels developed herein was similar to other studies documenting the elimination of PCBs and PAHs in a number of bivalve species