Determination of lead in waters and sediments from the wetland Tablas de Daimiel National Park (Spain)

Electrothermal atomic absorption spectrometry (ETAAS) has been used for lea d control in waters and sediments of the wetland Tablas de Daimiel National Park. The lead determination in the wetland water is hindered by an enhanc ed salt content, so matrix interference was evaluated. The use of stabilize d temperature platform atomization technique, Zeeman background correction and palladium nitrate as matrix modifier were found advisable. For the sedi ments a closed-vessel microwave dissolution method has been proposed using a mixture of HCl-HNO3-HF and a heating time of 90 s. With subsequent ETAAS using platform atomization and Zeeman background correction, no chemical mo dification was necessary. Using these conditions, the interferences were co mpletely removed for both waters and sediments and the calibration curve in ultrapure water (1% nitric acid) was linear up to 30 mu g/L. The detection limits for waters and sediments were 0.95 mu g/L and 0.78 mu g/g, respecti vely. The accuracy of the proposed method for sediments was validated by an alyzing certified reference materials (obtained values were within the cert ified ones) and spiked wetland sediments (mean recovery of 99.0%).