Assessment of heavy metals in Lake Uluabat, Turkey

The accumulation of heavy metals (Cu, Ni, Zn, Cd, Pb, Cr, B, As) was measured in water, plankton and sediment samples taken from different areas of Lake Uluabat during January 2003 to February 2004.The sequential extraction used in this study is useful to assess the potential mobility of heavy metals in the sediment indirectly. In this study, Cu, Pb, Cr, Cd, Ni and Zn concentrations were detected at higherlevels at Lake Uluabat for selected stations, especially in plankton samples. The magnitude of heavy metal concentrations in water and plankton samples was determined as B>Zn>As>Cd>Pb>Ni>Cr andZn>Ni>Cu>Cr>Cd>Pb, respectively. The mobile heavy metals in sediment samples were sequences as Pb>Cu>Cr>Ni>Cd>Zn, whereas the magnitude of easily mobilizable metal concentration was determinedas Pb>Ni>Cr>Cu>Cd>Zn. Concentration of Cu and Cr in mobile fraction is detected higher than in easily mobilizable fraction. Concentration of Pb, Cd, Zn and Ni in mobile fraction is detected in lower levels than in easily mobilizable fraction

Potentiometric titrations of some azo dyes containing a hydroxy group with tetrabutylammonium hydroxide in acetonitrile

Fifteen azo dyes containing a hydroxy group, phenol, 1-naphthol and 2-naphthol were titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) at room temperature. Potentiometric titration curves of these compounds in acetonitrile with TBAH propan-2-ol-methanol are similar to those of weak acids obtained in aqueous media with strong bases. Acetonitrile is a suitable medium for the weakly acidic compounds titrated in this work