Preparation of a reference mussel tissue material for polycyclic aromatic hydrocarbons and trace metals determination.

Due to high cost of certified reference materials (CRMs), reference materials (RMs) are preferred to check the method performance in environmental analysis. In this work, a laboratory reference material (LRM) was prepared and characterised to carry out the quality control in monitoring analysis of eight polycyclic aromatic hydrocarbons (PAHs) and nine trace metals in mussel tissue. Mussels were collected in a naturally polluted area. Before the reference material was bottled, the mussel tissue was stabilised by freeze-drying, ground and sieved. For the material characterisation, several statistical tests were applied to check the homogeneity of the analytes in the tissue, and a stability test was performed to study the effect of the storage temperature in the analyte concentration. Other characteristics such as specific density, moisture and lipid contents as well as particle size distribution of the material were determined. Although the LRM had a homogeneous distribution for all PAHs and almost all metals, the stability study showed different results at both storage temperatures studied. For both PAHs and trace metals, the material was suitable to assure the quality control of the analysis.

Distribution of organic microcontaminants, butyltins, and metals in mussels from the Estuary of Bilbao.

Mussels are used as bioindicators of chemical pollution in coastal and estuarine waters. We measured the concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalate esters (PEs), butyltins, and metals (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn) in mussel tissues collected from the lower Bilbao estuary (Arriluze, north of Spain) every 2 months from November 2002 to March 2004. The concentration (microg g(-1) dry weight) of PAHs, PCBs, and PEs ranged from 5.1 to 18.3, from 0.04 to 0.2, and from 1.5 to 27.6, respectively. Temporal pattern variations, including maximum and minimum values, were determined for metals and BTs from their concentration profiles during a period of 1 year. The main feature of organic microcontaminants was relatively high concentration values, reflecting the overall industrial and harbour activities of the site. Moreover, the ratios of methylated species and certain other diagnostic ratios suggested a petrogenic origin for PAHs. Finally, the relations among the concentrations found in mussel tissues and the levels of several cell biomarkers were established by a partial least squares model.

On-line separation for the speciation of mercury in natural waters by flow injection-cold vapour-atomic absorption spectrometry.

Inorganic mercury and methylmercury are determined in natural waters by injecting the filtered samples onto a low cost commercial flow injection system in which an anion exchange microcolumn is inserted after the injection loop (FIA-IE). If hydrochloric acid is used as the carrier solution, the HgCl4(2-) species (inorganic mercury) will be retained by the anion exchanger while the CH3HgCI species (methylmercury) will flow through the resin with negligible retention. Four anion exchangers and seven elution agents were checked, in a batch mode, to search for the best conditions for optimal separation and elution of both species. Dowex M-41 and L-cysteine were finally selected. Mercury detection was performed by cold vapour-electrothermal atomic adsorption spectrometry (HG-ETAAS). Both systems were coupled to perform the continuous on-line separation/detection of both inorganic mercury and methylmercury species. Separation and detection conditions were optimized by two chemometric approaches: full factorial design and central composite design. A limit of detection of 0.4 microg L(-1) was obtained for both mercury species (RSD < 3.0% for 20 microg L(-1) inorganic and methylmercury solutions). The method was applied to mercury speciation in natural waters of the Nerbioi-lbaizabal estuary (Bilbao, North of Spain) and recoveries of more than 95% were obtained.