Occurrence of nonylphenol ethoxylates and their metabolites in Canadian pulp and paper mill effluents and sludge

A survey of the concentrations of nonylphenol ethoxylates (NPnEO) and their metabolites in the primary and secondary treated effluent and sludge samples collected from pulp and paper mills was conducted. Through the coordination of the Pulp and Paper Research Institute of Canada (PAPRICAN), 19 Canadian and one U.S. mill of various process types and waste treatment methods supplied samples in this study. Previously developed solid-phase extraction, supercritical fluid extraction, high performance liquid chromatography and gas chromatography/mass spectrometry methods were used for the determination of NPnEO and their metabolites, nonylphenol (NP) and the carboxylates (NPEC), in effluent and sludge samples. The levels of NPnEO ranged from <2 to 129 (median 4.5) mu g/L and from <2 to 71.3 (median 5.8) mu g/L for the primary and secondary effluents, respectively. The concentrations of NP varied from <0.1 to 1.32 (median 0.35) mu g/L. in the primary effluent and from <0.1 to 4.32 (median <0.1) mu g/L in the secondary effluent. NPECs were found in only one primary and four secondary effluent samples, with an overall concentration range from <1 to 32 mu g/L. These results are lower than those reported: for paper mill effluents discharged into the lower Fox River, WI,USA. For the pulp and paper mill sludge, the levels of NPnEO and NP, on a dry weight basis, varied from <1 to 90.8 (median 21) mu g/g and from <0.05 to 121 (median 1.3) mu g/g, respectively. While NPnEO and NP were detected in nearly all sludge, their concentrations were lower than those observed for digested sewage sludge. Again, NPEC were found in only four samples, with an overall range from <1 to 18.5 mu g/g. No relationship between the nonylphenolic levels in the effluent samples and the process and waste treatment types of the mill was found.