Wide-spread and systematic errors in the analysis of soils for polychlorinated biphenyls. Part 1. A review of inter-laboratory studies

Abstract

The determination of polychlorinated biphenyls in soils is one of the most widely performed tests among environmental laboratories. It is a very difficult test and is subject to a great deal of inter-laboratory variance and bias. A new inter-laboratory study, using five soils spiked at four different concentrations with Aroclor 1260, was conducted with two groups of laboratories numbering 20 and 129, respectively. The results of this study are compared with the results of the other studies but show that the bias is concentration dependent. A number of definite patterns of recovery are noted, indicating that the large variance and bias was not due to random errors but to wide-spread systematic errors.