Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun 27;20(6):e0326701.
doi: 10.1371/journal.pone.0326701. eCollection 2025.

Heavy metal distribution and ecological risk in surface sediments of the Bohai Sea

Shilin Li  1   2   3 , Jianlei Chen  2   3 , Xuzhi Zhang  2   3 , Jianshe Zhang  1 , Yongjiang Xu  2   3 , Yong Xu  2   3
Affiliations

Heavy metal distribution and ecological risk in surface sediments of the Bohai Sea

Shilin Li et al. PLoS One. .

Abstract

Heavy metal contamination in marine sediments poses significant ecological risks, particularly in semi-enclosed seas like the Bohai Sea, where limited water exchange exacerbates pollution retention. Heavy metals are persistent, bioaccumulative, and toxic, making their assessment crucial for environmental management. This study investigated the spatial distribution, seasonal dynamics, and potential ecological risks of heavy metal contamination in the central Bohai Sea, with an emphasis on regulatory interventions and anthropogenic influences. The annual average concentrations of Cu, Zn, Pb, Cd, Hg and As in surface sediments were 15.951, 32.556, 15.234, 0.250, 0.028 and 2.628 mg/kg, respectively, all below China's Class I Marine Sediment Quality Standards. Seasonal variations revealed peak concentrations in August for Zn, Pb, Hg and As, likely driven by increased terrestrial inputs and hydrodynamic conditions. Cd exhibited the highest ecological risk, with a single-factor risk index exceeding 30 in May, followed by Hg, Pb, Cu, As and Zn. The comprehensive pollution index remained below 5 across all seasons, indicating overall low pollution levels. However, localized exceedances of Class I standards for Cu, Pb and Cd were observed, particularly in summer and autumn. Spatially, metal concentrations were higher near industrial and riverine discharge zones, with anthropogenic sources such as petrochemical industries, aquaculture, and urban runoff contributing significantly. This study highlighted seasonal and spatial heterogeneity in heavy metal contamination in the central Bohai Sea, emphasizing the influence of industrial activities and hydrodynamic processes. While overall pollution levels were low, the high ecological risk associated with Cd underscores the need for continued monitoring and targeted pollution control measures. Strengthening enforcement of industrial regulations, improving sediment management, and addressing seasonal fluctuations in pollutant inputs were critical for mitigating future risks. These findings provided a scientific foundation for sustainable marine environmental management and policy formulation in the Bohai Sea.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Surveyed area and sampling locations of surface sediments(The red star mark is the oil spill point of Penglai 19−3).
Fig 2
Fig 2. Seasonal extremes and averages for various metals.
Fig 3
Fig 3. Comprehensive pollution of heavy metals in surface sediments in the central Bohai Sea.
Fig 4
Fig 4. Single factor evaluation of heavy metal pollution in sediments.
Fig 5
Fig 5. The potential ecological risk factors and risk indices of heavy metals in surface sediments.
Fig 6
Fig 6. Seasonal variations of heavy metals in sediments.
Fig 7
Fig 7. Annual Variations in Heavy Metal Accumulation in Sediments.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Wang X, Fu R, Li H, Zhang Y, Lu M, Xiao K, et al. Heavy metal contamination in surface sediments: A comprehensive, large-scale evaluation for the Bohai Sea, China. Environ Pollut. 2020;260:113986. doi: 10.1016/j.envpol.2020.113986 - DOI - PubMed
    1. Liu B, Wang J, Xu M, Zhao L, Wang Z. Spatial distribution, source apportionment and ecological risk assessment of heavy metals in the sediments of Haizhou Bay national ocean park, China. Marine Pollution Bulletin. 2019;149:110651. doi: 10.1016/j.marpolbul.2019.110651 - DOI
    1. Mohsen M, Wang Q, Zhang L, Sun L, Lin C, Yang H. Heavy metals in sediment, microplastic and sea cucumber Apostichopus japonicus from farms in China. Mar Pollut Bull. 2019;143:42–9. doi: 10.1016/j.marpolbul.2019.04.025 - DOI - PubMed
    1. Liang J, Liu J, Xu G, Chen B. Distribution and transport of heavy metals in surface sediments of the Zhejiang nearshore area, East China Sea: Sedimentary environmental effects. Mar Pollut Bull. 2019;146:542–51. doi: 10.1016/j.marpolbul.2019.07.001 - DOI - PubMed
    1. Chen Q, Chen P. Changes in the heavy metals and petroleum hydrocarbon contents in seawater and surface sediment in the year following artificial reef construction in the Pearl River Estuary, China. Environ Sci Pollut Res Int. 2020;27(6):6009–21. doi: 10.1007/s11356-019-07406-x - DOI - PubMed

LinkOut - more resources