PCA and PLS methods applied to ecotoxicological data: Ecobalance project

Abstract

Within a case study ‘Ecobalance’, the fate and effects of various chlorinated and non-chlorinated organic compounds and some heavy metals discharged from pulp and paper mills into water, sediment and aquatic animals were studied in a recipient area of southern Lake Saimaa, SE Finland. The main aim of the project was to find an empirical link between chemical emission parameters and ecotoxicological effects expressed in the ecosystem. As part of the \‘Ecobalance’ project, principal component analysis (PCA) and partial least squares (PLS) methods were used to interpret the data of the lake area. The PLS method was used to estimate the lake area affected by mill effluents and to calculate the fraction of wastewater in sampling sites. The study area is mainly affected by one pollution source. There is, however, also another pollution source, another pulp mill located near the research area. The effect of this source can be seen in the sites near the outer margin of the area. The effect of the major source effluents can be clearly seen in the data of exposed animals and sediment samples. © 1996 by John Wiley & Sons, Ltd.