RESEARCH ARTICLE Changes in character of organics in the receiving environment of effluent from a sulphite pulp mill John A. van Leeuwen & Rosmala Lewis & Peter Goonan & Naomi Struve & Andrew Everson & Steven Nothrop & Ronald J. Smernik & Christopher W. K. Chow & Rolando Fabris & Madhawa Rupasinghe Received: 4 October 2011 / Accepted: 19 December 2011 / Published online: 7 January 2012 # Springer-Verlag 2012 Abstract Purpose The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent dis- charge were investigated to assess the basis for the persis- tence or attenuation of colour. Methods Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state 13 C cross polarization (CP) NMR. The characteristics of organics from mill waste- water before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14 years were studied in the context of changes in mill processing and climate impacts. Results High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations. Conclusions These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with divalent metals, as well as through dilution processes. Keywords Colour . Effluent . Pulp mills . Lake . Receiving environment . Characterization 1 Introduction The impacts of pulp and paper mill operations and discharge of wastewaters on receiving waters have been reported to be significant due to degradation of receiving water quality and reduction in the health of aquatic ecosystems (McLeay 1987; Larsson et al. 1988; Grimvall et al. 1991; Hynynen et al. 2004; Karrasch et al. 2006; Hall et al. 2009; Barrett et al. 2010). Degradation of receiving waters from pulp and paper mill effluents have been reported because of a wide Responsible editor: Hailong Wang J. A. van Leeuwen (*) : R. Lewis : A. Everson : S. Nothrop : C. W. K. Chow Centre for Water Management and Reuse, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia e-mail: john.vanleeuwen@unisa.edu.au P. Goonan : N. Struve Environment Protection Authority, Adelaide, SA, Australia R. J. Smernik School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SA 5064, Australia C. W. K. Chow : R. Fabris Australian Water Quality Centre, South Australian Water Corporation, Adelaide, SA 5000, Australia M. Rupasinghe District Council of Mt Barker, Mount Barker, SA 5251, Australia Environ Sci Pollut Res (2012) 19:2151–2158 DOI 10.1007/s11356-011-0714-y