Distribution and assessment of surface water contamination by application of chemometric and deterministic models

SummaryChemometrics and deterministic modelling is proposed to extract useful information from data sets obtained in environmental monitoring studies. Contamination from organic compounds in the Llobregat River basin (Catalunya, NE Spain) was investigated for the period 2003–2006. From the application of Multivariate Curve Resolution using Alternating Least Squares (MCR-ALS), five different patterns of organic compound contamination are identified, explaining nearly 65% of the total variance of data. While pollution from chlorinated pesticides and alkylphenols shows lower levels in recent years, contamination resulting from PAHs has a rather constant distribution in space as well as in time. On the other hand, diffuse pollution from an agricultural pattern with terbutryn and chlorpyrifos increases in the year 2006 as compared to 2005. Dynamics of the products describing this last agricultural pattern are modeled using the modelling system GIBSI. Existing cultures in the studied area as well as possible pesticide usages and application loads are considered for the simulation of pesticide concentrations in water. In this way, the transfer of pesticides applied on soils to the water system is assessed and compared with other possible scenarios involving alternative practices. A new modelling approach based on considering different contamination patterns instead of using individual variables and chemicals is proposed at the end of this work.