Anthropogenic impacts on the temporal variation of heavy metals in Daya Bay (South China)

A detailed study of a sediment core from Daya Bay (South China) has revealed three stages of heavy metal deposition over the past century. Prior to the 1980s, heavy metal concentrations were low with limited influence by human activities. From the 1980s to 2000, metal pollution intensified, and anthropogenic activities, such as oil and petrochemical industries, and fuel combustion, had the greatest direct influence on Hg, Ni, Pb, and Zn concentrations, whereas atmospheric deposition and mariculture were also contributors to the continued in-crease in Cr, Cu, Pb, Zn, and Ni. Since the year 2000, heavy metal concentration has declined and stabilized. It is noteworthy that anthropogenic input of Cu and Pb is ongoing and may result in a moderate pollution risk. Both modified pollution index (MPI) and modified ecological risk (MRI) consistently indicate that the ecological risk in terms of heavy metals in Daya Bay has remained moderate over the past 70 years.

Automated summary

A detailed study of a sediment core from Daya Bay in South China has shown three stages of heavy metal deposition over the past century. Prior to the 1980s, heavy metal concentrations were low with limited influence from human activities. From the 1980s to 2000, metal pollution increased, primarily due to anthropogenic activities such as oil and petrochemical industries and fuel combustion. Atmospheric deposition and mariculture also contributed to the increase in certain heavy metals. Since 2000, heavy metal concentrations have declined and stabilized. However, ongoing anthropogenic input of copper and lead poses a moderate pollution risk. The modified pollution index and modified ecological risk consistently indicate a moderate ecological risk from heavy metals in Daya Bay over the past 70 years.