Centennial records of cadmium and lead in NE China lake sediments

Abstract

Cores (15 to 40 cm of depth) were collected from 11 lakes of the Songnen Plain in northeastern China to reconstruct changes in potentially harmful trace element (PHTE) inputs as tracers of human activities. In each profile, most PHTE enrichment factors do not differ significantly from the pre-industrial values (EF < 1.5), except for Cd (EF = 2–5.5). This shows that detrital material accounts for a large part of the PHTE supply to the Songnen Plain lakes. Radiometric dating of the cores (210Pb, 137Cs) showed that Cd contamination started from the mid-20th century and sharply increased in the 1980s', a pattern that matches the rapid economic and industrial growth of China. Comparison with other records in China suggests that a large part of the anthropogenic Cd in these lakes is likely local in origin. Although the Cd inputs, controlled by carbonate minerals, probably originated from a combination of sources, an intensification in agricultural practices, through the use of chemical fertilizers, manure and wastewater would explain these discrepancies between records. These findings highlight the importance of local factors on the Cd geochemical cycle in China. The large anthropogenic component of the Cd inventory compared to other PHTEs (Cu, Ni, Pb, Sb, V, Zn) and its high toxicity indicate that it should be prioritized in future environmental management.