The States of pH, Eh in Surface Sediments of the Yangtze River Estuary  and Its Adjacent Areas and Their Controlling Factors

Key words: 
• Yangtze River estuary /
• East China Sea /
• surface sediment /
• pH /
• Eh /
• influence factor

Abstract: 00)
〖WT5HZ〗Abstract〓〖WTBZ〗The values of pH and Eh (OxidationReduction Potential) of the surface sediments in the Yangtze River estuary and its adjacent areas were determined with a precision acidimeter (pH meter) and a ORP meter. The space distributions of pH and Eh of the sediments in these areas are figured out and their influence factors are systematically discussed. The results indicate that the surface sedimentary environment in the study areas is neutral or weak alkaline with pH value ranging from 7.1 to 7.8. The distribution of pH value in the area is zonal and heterogeneous. The redox in the area is reductive with Eh ranging from 300mv to 100mV and mostly ranging around 250mV. Distribution of Eh in the area also seems zonal and heterogeneous. The value of pH in these areas is mainly dominated by the natures of water masses as well as grained size of sediment and patterns of bioturbation. While the natures water masses, water stratification, and patterns of bioturbation are the controlling factors of Eh in these areas. 