Records of trace metals since the Holocene in sediments of Laizhou Bay, Bohai Sea, China

Trace metal (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, Li, and Co) concentration profiles along a sediment core were investigated to obtain background values, assess depositional trends and contamination levels in the Laizhou Bay, China. The enrichment factors of the metals indicated no anthropogenic enrichment, except for Pb, Cd, and Hg, which have been influenced by human activities since 7 ka. The mean concentrations of trace metals in the 10-7 ka phase can be considered as the background values in the study area. Principal component analysis indicated that the metals were mainly naturally sourced throughout the observed depositional period. Their geoaccumulation indices indicated that the sediments were not contaminated by Cu, Zn, Cr, Ni, and Co, but were contaminated by Pb, Cd, and Hg during the 7-0 ka period.

Automated summary

The concentrations of trace metals (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, Li, and Co) in sediment cores were studied to determine background levels, assess deposition patterns, and examine contamination in Laizhou Bay, China. Anthropogenic enrichment was observed for Pb, Cd, and Hg, which can be traced back to human activities since 7 thousand years ago. Trace metal concentrations during the 10-7 thousand years ago phase were considered as background levels. Analysis showed that the metals were mainly from natural sources, and contamination was observed for Pb, Cd, and Hg during the 7-0 thousand years ago period.