Distribution of heavy metals in coastal sediments under the influence of multiple factors: A case study from the south coast of an industrialized harbor city (Tangshan, China)

This research investigated the spatial distribution of heavy metals,
including mercury (Hg), cadmium (Cd), copper (Cu), arsenic (As), nickel
(Ni), lead (Pb), chromium (Cr), and zinc (Zn), in surface sediments from
the coastal area near to an industrial harbor (the Tangshan Harbor, China)
with 161 sediment samples. The results showed that the distribution
patterns of Cr, Cu, Zn, Ni, and Pb were similar to each other, high in the
northwest, southeast, and southwest regions of the study area and low in
the northeast region, which corresponded well with components of
sedimental sizes. The uncontaminated specimen proportions for Hg, Cd, Cu,
As, Ni, Pb, Cr, and Zn were 6.8%, 4.3%, 31.1%, 28.6%, 42.9%, 64.6%, 44.7%,
and 50.3%, respectively. Based on principal component analysis (PCA) and
positive matrix factorization (PMF), four distinct sources of pollution
were quantitatively attributed, including agricultural activities
(22.08%), fossil fuel consumption (24.14%), steel production (29.78%), and
natural sources (24.00%). Hg (80.29%), Cd (82.31%) and As (65.33%) in the
region’s coastal sediments were predominantly contributed by fossil fuel,
steel production and agricultural sources, respectively. Cr (40.00%), Cu
(43.63%), Ni (47.54%), and Zn (38.98%) were primarily of natural
lithogenic origin, while Pb mainly came from the mixed sources of
agricultural activities (36.63%), fossil fuel (36.86%), and steel
production (34.35%). Multiple factors played important roles in the
selective transportation of sedimentary heavy metals, especially sediment
properties, and hydrodynamic sorting processes in the study area.