Abstract
The concentration of the trace elements in river water, drainage, sediment, periphyton and the larvae of an aquatic insect, caddisfly, Stenopsyche marmorata, which were sampled four times in a year from the water area of the upstream and midstream parts of Tama River, where the drainage from factories flows in, were measured.
The concentrations of nickel, copper, lead and zinc in river water were highest at the downstream of the place where the drainage from factories flows in, and showed the tendency of rapid decrease toward downstream. The concentrations of these elements in sediment were high only at the place where the drainage from factories flows in. The concentrations of these elements in periphyton and the larvae were highest at the downstream of the place where drainage flows in anytime, and gradually decreased toward downstream.
These results suggested that periphyton and the larvae are useful monitors of the contamina-tion with the trace elements in low concentrations for rivers in water areas for city water source, and those make the detection of the contamination with cannot be detected with river water and sediment possible.
