Historical trends of trace metals in muddy deposit along the Zhejiang coast, East China Sea: response to economic development and hypoxia.

One sediment core spanning approximately 138 years was taken from the muddy deposits along the Zhejiang coast of the East China Sea, which is located in a hypoxic zone south of the Yangtze River estuary. When the sources of the trace metals in the core were analyzed, the three geochemical sources were identified as lithogenic, anthropogenic, and reductive deposits based on both principal component analysis and the ratios of terrigenous elements. The temporal distribution of the enrichment factor of copper in the sediment core matches the timeline of economic development and national policy in China.

Distribution and source of organic matter in surface sediment from the muddy deposit along the Zhejiang coast, East China Sea.

To constrain organic matter compositions and origins, elemental (TOC, TN, C/N) and stable carbon (δC) and nitrogen isotope (δN) compositions are measured for surface sediments collected from muddy deposit along the Zhejiang coast, East China Sea. The results showed that the TOC, TN, C/N, δC, and δN were 0.19-0.