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

► The Distributions of sedimentary biomarkers in the lower Yangtze River were investigated. ► Sewage and petroleum-derived pollutants were significant contributors to sedimentary organic matter in the lower river. ► Algal production was low in the lower river. ► Reducing, probably anoxic, conditions exist in parts of the riverbed, likely resulting from organic pollution.