Modeling sediment oxygen demand in a highly productive lake under various trophic scenarios.

Hypolimnetic oxygen depletion in lakes is a widespread problem and is mainly controlled by the sediment oxygen uptake (SOU) and flux of reduced substances out of the sediments (Fred). Especially in eutrophic lakes, Fred may constitute a major fraction of the areal hypolimnetic mineralization rate, but its size and source is often poorly understood. Using a diagenetic reaction-transport model supported by a large data set of sediment porewater concentrations, bulk sediment core data and lake monitoring data, the behavior of Fred was simulated in eutrophic Lake Baldegg.

Benthic nitrite exchanges in the Seine River (France): An early diagenetic modeling analysis.

Nitrite is a toxic intermediate compound in the nitrogen (N) cycle. Elevated concentrations of nitrite have been observed in the Seine River, raising questions about its sources and fate. Here, we assess the role of bottom sediments as potential sources or sinks of nitrite along the river continuum.

Chromosome aberrations after high-dose 131I and 99mTc-MIBI administration using a micronucleus assay.

Objective: We evaluated the potential detrimental cytogenetic effects of Tc-methoxyisobutyl isonitrile (MIBI) and I on patients who were exposed to the radiopharmaceutics for cardiac imaging or thyroid cancer therapy, respectively.

Methods: Mononuclear leukocytes were isolated both before and after radiopharmaceutical administration and subsequently cultured. Micronuclei frequency was then assessed and microscopic evaluation of apoptosis was conducted.

Non-steady state modeling of arsenic diagenesis in lake sediments.

A one-dimensional reactive transport model describing the coupled biogeochemical cycling of As, C, O, Fe, and S was used to interpret an extensive geochemical sediment (As, Fe, S, (210)Pb, (137)Cs, C(org)) and pore water (As, Fe, SO(4)(2-), SigmaS(-II) and pH) data set collected in the perennially oxygenated basin of an oligotrophic lake. Historical variations in atmospheric deposition of As and SO(4)(2-) were explicitly included as upper boundary conditions in the model calculations. The results show that the depth profile of sediment-bound As reflects both the past changes in As deposition and the diagenetic redistribution of As among the Fe(III) oxyhydroxide and Fe(II) sulfide pools.