INTER-LABORATORY STUDY OF THE DETERMINATION OF POLYCHLORINATED BIPHENYLS IN A PAPER-MILL EFFLUENT

Six laboratories collaboratively studied a method for determining polychlorinated biphenyls (PCB) in paper mill effluent. The recovery and relative standard deviation (RSD) for the PCB Aroclor 1242 added to and extracted from distilled water were 95.6 and 14.7%, respectively. Because the RSD of data from direct injection of Aroclor 1242 solutions into the gas chromatograph was of similar magnitude (15.6%), gas chromatographic analysis provided the principal source of variation in the overall determination. Participating laboratories achieved an average 93.7% recovery of Aroclor 1242 added to a paper mill effluent; data had a RSD of 16.0%. The method is satisfactory for use with paper mill effluents having PCB concentrations above 2 .mu.g/l; it compares favorably with findings from studies in other environmental matrices. Greater variation might be expected from effluents containing significant interferences.