The hydrological cycle of Lake Ipê and the principal parameters that could affect its abiotic parameters and its metal (Fe, Mn, and Cd) concentrations were investigated. A detailed study of seasonal variations using Principal Components Analysis (PCA) for the most relevant metals (Fe, Mn and Cd) was performed, assisted by the MINTEQA2 geochemical equilibrium program using 15 water abiotic param...

We welcome the opportunity to respond to the Comment of Bence et al. (2000) regarding the suitability of the new geochemical parameter we have introduced. Part of their comment, however, addresses issues either not directly related to our paper, or issues published elsewhere. The lengthy comment seems a disproportionate reaction to what was a paper of limited scope, simply introducing one new g...

Paper focuses on the analysis of geochemical data with values below the limit of detection (LOD). Such values are treated as text and are difficult to use in further calculations of mean, standard deviation and other statistical parameters. To estimate several methods for substitution of values below the LOD with fractions of LOD (zero, LOD/2, LOD/√2, LOD and no data values), a large dataset of...

Predicting and controlling the concentrations of redox-sensitive elements are primary concerns for environmental remediation of contaminated sites. These predictions are complicated by dynamic flow processes as hydrologic variability is a governing control on conservative and reactive chemical concentrations. Subsurface heterogeneity in the form of layers and lenses further complicates the flow...

Geophysical and geochemical investigations concerning deformation events of tectonic interest at the underground laboratory of Gran Sasso have been carried out and possible correlations with local seismicity are also investigated. We have planned and realized an automatic multiparametric equipment (water temperature, electrical conductivity, pH, Rn) and from the May 1996 we performs automatic m...

We present global and regional correlations between whole-rock values of Sr/Y and La/Yb and crustal thickness for intermediate rocks from modern subduction-related magmatic arcs formed around the Pacific. These correlations bolster earlier ideas that various geochemical parameters can be used to track changes of crustal thickness through time in ancient subduction systems. Inferred crustal thic...

The application of several magnetic parameters to ochre samples has found that they can be used to characterize samples from known ochre quarries. This technique also allows the sourcing of ochre found in archaeological contexts and provides an alternative to geochemical methods of provenancing ochres. Simple magnetic parameters (susceptibility and isothermal remanence) are effective in discrim...

Few studies have demonstrated changes in community structure along a contaminant plume in terms of phylogenetic, functional, and geochemical changes, and such studies are essential to understand how a microbial ecosystem responds to perturbations. Clonal libraries of multiple genes (SSU rDNA, nirK, nirS, amoA, pmoA, and dsrAB) were analyzed from groundwater samples (n = 6) that varied in contam...