Abstract
In June 2023, surface seawater samples from 30 stations were collected in Laizhou Bay, and the degree, distribution, and potential ecological risks of heavy metal pollution in surface seawater in Laizhou Bay were evaluated by single factor index method, potential ecological risk method, and principal component analysis method. Results show that the average values of Cu, Pb, Zn, Cr, Cd, Hg, and As in the surface seawater of Laizhou Bay sea area were 9.33, 1.68, 15.11, 6.76, 0.47, 0.11, 4.28 μg /L, and the average values of the single-factor pollution indices were 1.38, 1.68, 0.76, 0.14, 0.39, 1.50, 0.21, the average value of potential ecological risk index was 6.92, 8.16, 0.76, 0.27, 11.77, 60.15, 2.11, respectively; and the average value of the comprehensive ecological risk index was 89.84. The quality of seawater in the sea area of Laizhou Bay did not exceed the national standard for Type Ⅲ seawater quality. Except for some stations, the potential ecological risk of seawater is slight; the distribution of heavy metal elements is affected by the hydrodynamic factors in the sea area. Cu, Pb, Zn, Hg, Cd elements are constantly enriched in the center of the sea area under the influence of the circulation in the eastern part of the Laizhou Bay, and Cr, As elements are distributed in a ring band under the influence of the clockwise circulation in the western part of the Laizhou Bay and the northeasterly flow in the central part of the bay. The principal component and correlation analyses showed that the correlation coefficients among Cu, Pb, Zn, Cr, Cd, Hg, and As were small, and none of them had similar pollution levels or common pollution sources. The concentration of heavy metals is at a medium level compared with those of other sea areas in China. Compared with the concentration of seawater in Laizhou Bay in 2020, the overall trend shows a certain increase, and they migrate and accumulate from the coast to the center of the sea.
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