Abstract
Contents of heavy metals, ignition loss and clay were measured in sediment samples of the lower reach of the Nagara River and the data were subjected to multiple regression analysis. Heavy metal contents in sediments were correlated significantly with ignition loss and clay contents. Multiple regression coefficients were more than 0.92 among these three factors. Heavy metal concentration in sediments could be predicted with probability of over 85% by estimating ignition loss and clay using the multiple regression equations. The amounts of heavy metal accumulation on unit mass of ignition loss and clay were able to be separately calculated from the regression equations. Heavy metal accumulation on sediments was dependent more highly on ignition loss than clay. Constants in regression equations were good approximations to analytical results of heavy metals in sediments of unpolluted area in the river, therefore, they could be regarded as background values of heavy metals in sediments of the river.
