Isolation and Identification of Toxic Chemicals in Wood Bark and its Correlation to Pulp Mill Effluent, 2002 Environmental Conference Proceedings

X. Zhang and M. Sain 

A research program has been initiated to identify the toxicity of unknown trace chemicals in the untreated and biologically treated paper mill effluents by isolating and identifying the micro- and nano-components from wood barks extracts and determining their acute and chronic toxicity values. Samples of spruce bark, spruce heartwood birch bark, and thermomechanical pulping (TMP) wastewater obtained after refining of spruce were isolated. All the extracts were derivated and analyzed by a HP GC-mass spectrometry system, and the constituents were identified by comparison of their MS spectra with those in NIST spectra library. The isolated components in spruce bark were compared with those in spruce heartwood, birch bark, and TMP wastewater. The main components of hexane-acetone extraction of spruce bark are fatty acids, resin acids, tannins monomers, saccharides and their derivatives, and some complex steroids. The hexane-acetone extract of TMP wastewater has similar components of fatty acids resin acids with that of spruce bark. Several phenolic materials identified when the wastewater was further extracted with more polar organic solvents: dichloromethane and diethyl ether are possibly derived from lignin and lignan and are difficult to be biodegraded with biological wastewater treatment processes, thus may have chronic toxic effects to aqua-life and aqua-ecosystem. Several micro-components are detected in GC-MS spectra of spruce extracts and are found to be absent in the untreated- and biologically treated-pulp effluents within the detectable limit. Attempt to find a correlation between wood bark toxicity and pulp mill effluent with the best available technology (BAT) will remain unsolved until further technological development to isolate and identify nano- and pico- quantity organic components from waste water being developed.