AUTHOR=Lao Qibin , Cai Shangjun , Huang Peng , Chen Fajin , Su Qizhong , Lei Xuetie , Zhou Xin , Chen Chunqing , Zhu Qingmei , Lu Xuan , Liu Guoqiang 

TITLE=Contaminant Characteristics and Influencing Factors of Heavy Metals in Seawater and Sediments in a Typical Mariculture Bay in South China

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.923494

DOI=10.3389/fmars.2022.923494

ISSN=2296-7745

ABSTRACT=Heavy metal pollution in the mariculture areas is of considerable attention due to its potential ecological effects and public concern for seafood safety. Better understanding of the current contamination status and historical trend of heavy metals in the ecosystems of mariculture areas is important implications for the sustainable development of marine ecosystems, and public health concerns. To assess the impact of human activities on heavy metal pollution in the mariculture area, seven metals (Cu, Pb, Zn, Cd, Hg, As and Cr) and the environmental parameters were seasonally investigated in the surface seawater and sediments in Qinzhou Bay, a typical mariculture bay in South China. Seasonal variations in concentration of heavy metals was found in both seawater and sediment, which is mainly influenced by seasonal hydrological change, biological activity and human influence. The concentration of heavy metals in the seawater was at a relatively higher level than that of other mariculture areas in China, while the lower level was found in sediment. The concentration of Cu increased in both seawater and sediment for the past decades (increased by nearly 2 times), which mainly influenced by the mariculture and shipping activities. The concentration of Hg decreased significantly in the seawater for the past 40 years (decreased by 13 times) due to the decrease of production and usage of Hg. However, the concentrations of Pb, Zn and Cd in seawater showed an increasing trend in the mariculture bay, while the concentrations of Pb, Zn, As and Cr decreased in the sediment over the past decades. The decrease of pH value (decreasing by 4.7% for the past 20 years) was responsible for the different trend of those metals between seawater and sediment, because the decrease of pH could re-release metals from sediments into the water column. Hg and As is the main ecological risk factor in the mariculture bay. This study suggests that environmental changes, such as ocean acidification, affect the distribution of metals in seawater and sediments, which should be more vigilant and concerned under the global climate change.