CHARACTERIZATION OF PLANT STEROLS FROM 22 US PULP AND PAPER-MILLS

Recent concerns regarding the possible biological effects of plant ste rols, especially beta-sitosterol and its metabolites, prompted the dev elopment of a method for the determination of campesterol, beta-sitost erol, stigmastanol, and stigmasterol in pulp and paper industry wastew aters. The method utilizes a liquid/liquid extraction with methyl-t-bu tyl ether followed by trimethylsilylation derivatization with GC/FID a nalysis. The method has been applied to wastewater samples from biolog ical treatment systems at 22 US mills. Estimated treatment system remo val efficiencies and mass discharge rates are reported. Estimated trea tment system removal efficiencies ranged from 64-79% for most analytes . However, the concentration of stigmasterol was observed to increase across aerated stabilization basins. The estimated mass discharge rate s for total plant sterols ranged from a low of 0.2 g/T to a high of 25 .2 g/T, depending on the specific mill sampled. (C) 1997 IAWQ.