Physico-chemical characterization and leaching of tannery wastes

The toxicity of tannery wastes was examined and discussed using several analytical methods and tests: X-ray fluorescence (XRF), Scanning electron microscopy X-ray spectrometer dispersive energy microanalysis (SEM-EDX); gas chromatog raphy + mass spectrometry (GC-MS); acid nitric digestion; EP toxicity test; inductively coupled plasma atomic emission spectrometry (ICP-AES); biotoxicity tests with Photobacte rium phosphoreum, Daphnia magna and Sprague-Dawley (rats); and other conventional tests. A comparison between the ele ments detected by X-ray fluorescence, scanning electron microscopy + X-ray spectrometer dispersive energy microanalysis and inductively coupled plasma atomic emis sion spectrometry after nitric acid digestion was carried out. A valoration of toxicity, considering the elements and com pounds detected and the biotoxicity tests was done for each type of waste. Twenty-four samples of semi-processed leather trimmings and shavings, crust or finished chrome-tanned leather trim scraps and sludges from settling in the effluent streams were analyzed.