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(79-03) Comparison of empirical and statistical /chemical analysis techniques as tools for source control. Bailey, Howard1, Laginestra, Edwina2, Thomas, Colette*,3, Tang, Armando1, Hunt, Peta3, Mulhall, Ann-Maree3, Tang, Cheryl3, Burgess, Scott3, Krassoi, Frederick3, 1 195 Pemberton Ave, North Vancouver, BC2 B6 RANAD, Jamieson St, Silverwater, NSW3 100 Christie St, St Leonards, NSW ABSTRACT- The toxicity of complex leachate from capped contaminated waste mounds within the Homebush Bay Olympic Park site was assessed as part of an ongoing study. A number of approaches were used, including empirical methods, statistical and associative methods. The empirical methods generally consisted of toxicity tests, followed by TIEs to determine the cause of toxicity. The statistical methods involved Principle Components Analysis and Spearman correlations to evaluate relationships between various contaminants and the toxicity endpoints. Finally, chemical concentrations found at each site were compared with trigger guidelines to identify constituents that might be present at toxic concentrations. Direct empirical methods (ie. toxicity tests followed by TIEs) provided the greatest ability to identify causes of toxicity in the samples. The statistical analyses often identified relationships but provided no means of determining which of the identified constituents were likely to be the actual cause of toxicity. Comparisons of measured concentrations of selected constituents against trigger values often identified a number of contaminants present at concentrations potentially associated with adverse effects. The results of this study suggested that direct empirical methods provide the best option in terms of identifying the actual level and cause of toxicity of complex wastes. Such results are also likely to be more meaningful in terms of developing source control or treatment options to reduce toxicity. Similarly, empirical results provide a substantive basis for formulating and evaluating risk assessment and management options, and is also quite likely to be the most cost-effective approach to studies of this type. Key words: TIE, WET, leachate, monitoring |
