Anthropogenic pollution and oxygen depletion in the lower Yangtze River as revealed by sedimentary biomarkers

The Yangtze River receives 37.5% of the municipal sewage of China, whose fate constitutes a major environmental and health concern. This study applied phytosterols, 5β(H)-stanols, tetrahymanol and 17α,21β(H)-C30-hopane to examine sewage and petroleum-derived organic pollutants, and assess their impact on the biogeochemistry of the lower river benthic environment. The results showed that significant contributions from sewage and petroleum pollutants were preserved in the riverbed. These potentially contributed to O2 depletion and apparently an anoxic environment in the riverbed, either directly or via an impact on primary productivity.