Total, chemical, and biological oxygen consumption of the sediments in the Ziya River watershed, China

Abstract

Sediment oxygen demand (SOD) is a critical dissolved oxygen (DO) sink in many rivers. Understanding the relative contributions of the biological and chemical components of SOD would improve our knowledge of the potential environmental harm SOD could cause and allow appropriate management systems to be developed. A various inhibitors addition technique was conducted to measure the total, chemical, and biological SOD of sediment samples from 13 sites in the Ziya River watershed, a severely polluted and anoxic river system in the north of China. The results showed that the major component of SOD was chemical SOD due to iron predominate. The ferrous SOD accounted for 21.6-78.9 % of the total SOD and 33.26-96.79 % of the chemical SOD. Biological SOD represented 41.13 % of the overall SOD averagely. Sulfide SOD accounted for 1.78-45.71 % of the total SOD and it was the secondary predominate of the chemical SOD. Manganous SOD accounted for 1.2-16.6 % of the total SOD and it was insignificant at many sites. Only four kinds of benthos were collected in the Ziya River watershed, resulting from the low DO concentration in the sediment surface due to SOD. This study would be helpful for understanding and preventing the potential sediment oxygen depletion during river restoration.

Assessment of the sediment quality of freshwater ecosystems in eastern China based on spatial and temporal variation of nutrients

“…In these areas, rapid population growth, industrial development, and increased agricultural production have led to an increasing flow of untreated sewage and rubbish to the environment. The resulting N, P, and organic matter loads in the watershed greatly increase the risk of eutrophication (Pernet-Coudrier et al 2012;Rong and Shan 2016), and cause changes to the benthonic fauna and affect the benthic metabolism. Thus, scientific and comprehensive assessments of sediment quality are in urgent need.…”