Determining algal-available phosphorus in pulp and paper mill effluents:: Algal assays vs routine phosphorus analyses

We determined the potentially algal-available P (P-aa) in pulp and paper mill effluents by two bioassay techniques (a dual-culture assay and a batch approach) and compared it with chemically analysed P (total P, total dissolved P, reactive P, dissolved reactive P and dissolved hydrolysable P). The mean P-aa given by the dual-culture assay was within a 40% range of that given by the batch approach. The P-aa obtained by both bioassays differed from total P. Dissolved reactive P appeared to be the most readily available chemical P fraction, but other P fractions also contributed to P-aa. The analysis of reactive P, which involves direct staining of an unfiltered sample, best approximated the P-aa given by the dual-culture assay (relative error 9%). The results suggest that assessment of eutrophying effluent P can be improved by analysing simple chemical P fractions in wastewater. The fractions to be analysed, however, may be site specific. (c) 2006 Elsevier Ltd. All rights reserved.