Assessment of the vertical characteristics and contamination levels of toxic metals in sediment cores from typical Chinese intertidal zones.

The heavy metal (As, Cd, Cr, Cu, Hg, Pb, and Zn) contents of 24 sediment cores were obtained and analyzed from 12 typical Chinese intertidal zones. The results revealed a gradual improvement in the environmental quality of the intertidal zone. Enrichment factor and geoaccumulation index analyses demonstrated a generally good environmental quality of intertidal sediment, with some areas of serious contamination, such as the Xiamen Jiulong Estuary, the Yangtze River Estuary, and the Pearl River Delta. Relative to the guidelines for sediment quality, the studied intertidal zones were moderately impacted, with a risk of biotoxic impacts. This research reveals the status of toxic metal pollution in the intertidal zone of China and provides a reference for coastal area development.

Vertical profiles and contamination assessments of heavy metals in sediment cores from typical intertidal zones in northern China.

The concentrations of 7 heavy metals (Cu, Pb, Zn, Cr, Cd, As and Hg) were analysed in 12 sediment cores collected from 6 typical intertidal zones in northern China. The data reveal that the environmental quality of the northern Chinese intertidal environment has gradually improved and that the concentrations of Cu, Pb, Zn, Cr, Cd, As and Hg averaged over all sediments were 29.2, 25.8, 78.5, 72.2, 0.168, 10.7 and 0.044 mg/kg, respectively. The results of the geoaccumulation index and enrichment factor methods demonstrate that most of the sediments in the intertidal zone in northern China have good environmental quality, although some areas are contaminanted, including the Yangtze River Estuary, which is seriously contaminanted. According to sediment quality guidelines, the heavy metal concentrations in the sediments in the 6 typical intertidal zones in this survey are categorized as having moderate impacts with potential adverse biotoxic effects.

Heavy Metal Pollution Characteristics in the Modern Sedimentary Environment of Northern Jiaozhou Bay, China.

The particle size distribution characteristics of sediments and the concentrations of heavy metals in Jiaozhou Bay were investigated in this study. The average concentrations of Cu, Pb, Zn, Cr, Cd, Hg and As were 36.88, 29.60, 82.08, 77.48, 0.083, 0.048 and 11.00 mg/kg, respectively. The heavy metal concentrations were highest in the eastern sediments, followed by those at the top of the bay, and the lowest concentrations were observed in the central region. Overall, a decreasing trend from the center of the bay to the periphery was observed. Additionally, the distribution of heavy metals in sediments was not completely controlled by sediment particle size. The degree of heavy metal contamination was evaluated using the geoaccumulation index and Hakanson's method. The results revealed that the level of heavy metal pollution in the sediments was relatively low and that the main pollution elements were Cu and Hg. In addition, the sediments are associated with various levels of potential ecological risk due to the high pollution levels of Hg and Cd.