DETECTION OF CONTAMINATED SAMPLES USING A 2-WAY COMPOSITING SCHEME

Compositing of sediment or water samples provides an opportunity to sc reen numerous samples economically if contamination is a relatively ra re occurrence. However, standard compositing procedures simply identif y that contamination exists among one or more constituent samples of t he composite. Using a two-way compositing strategy, detected contamina tion in composited samples can be attributed directly to constituent s amples without further analyses. Procedure is illustrated using benthi c sediment samples contaminated with crude oil following an oil spill. The proposed compositing scheme has a relative efficiency of n/2 comp ared to the analysis of individual samples when n 2 is the number of s amples screened (e.g., n2 = 16 samples, relative efficiency is 4/2 = 2 ).