Determination of Optimal Sampling Transects for Heavy Metal Contaminated Dagu River Sediments

Determination of optimal sampling transects and pollutants for river sediments are essential and valuable. To determine if the concentration of some metals were highly correlated, correlations between heavy metals (As, Pb, Cd, Cr, Hg, Cu, Ni and Zn) were analyzed using statistic analysis software (SAS) based on monitoring data of heavy metals along the whole watercourse sediments of Dagu River. To allow a reduction in the number of monitoring transects analyzed in the future monitoring of watercourse, a co-threshold method was developed based on correlations between metals and corrected with the first three extremum single thresholds. Results show that all investigated metals except Zn and Ni in Dagu River sediments are positively correlated with at least other three metals. Among the monitored 28 sampling transects, 11 sampling transects are found to be the more informative sampling transects. To determine the metal contents in Dagu River sediments in the future, only the detection of the preferred metals in each informative sampling transect are required.