Chemical modeling of groundwater in the Banat Plain, southwestern Romania, with elevated As content and co-occurring species by combining diagrams and unsupervised multivariate statistical approaches.

The study proposes a combined model based on diagrams (Gibbs, Piper, Stuyfzand Hydrogeochemical Classification System) and unsupervised statistical approaches (Cluster Analysis, Principal Component Analysis, Fuzzy Principal Component Analysis, Fuzzy Hierarchical Cross-Clustering) to describe natural enrichment of inorganic arsenic and co-occurring species in groundwater in the Banat Plain, southwestern Romania. Speciation of inorganic As (arsenite, arsenate), ion concentrations (Na, K, Ca, Mg, HCO, Cl, F, SO, PO, NO), pH, redox potential, conductivity and total dissolved substances were performed. Classical diagrams provided the hydrochemical characterization, while statistical approaches were helpful to establish (i) the mechanism of naturally occurring of As and F species and the anthropogenic one for NO, SO, PO and K and (ii) classification of groundwater based on content of arsenic species.

A miniaturized capacitively coupled plasma microtorch optical emission spectrometer and a Rh coiled-filament as small-sized electrothermal vaporization device for simultaneous determination of volatile elements from liquid microsamples: spectral and analytical characterization.

A low power and low argon consumption (13.56 MHz, 15 W, 150 ml min(-1)) capacitively coupled plasma microtorch interfaced with a low-resolution microspectrometer and a small-sized electrothermal vaporization Rh coiled-filament as liquid microsample introduction device into the plasma was investigated for the simultaneous determination of several volatile elements of interest for environment. Constructive details, spectral and analytical characteristics, and optimum operating conditions of the laboratory equipment for the simultaneous determination of Ag, Cd, Cu, Pb and Zn requiring low vaporization power are provided.