Characteristics and Health Risk Assessment of Heavy Metal Pollution in Haikou Bay and Adjacent Seas

Anthropogenic activity shapes the assemble and co-occurrence pattern of microbial communities in fishing harbors around the Bohai economic circle

This study aimed to elucidate the effects of coastal environmental stress on the composition of sediment bacterial communities and their cooccurrence patterns in fishing harbors around the Bohai Economic Circle, China. Compared with the natural sea area, fishing harbors contained higher levels of organic pollution (organic pollution index = 0.12 ± 0.026) and considerably reduced bacterial richness and evenness. The distributions of sediment microbial communities clustered along the pollutant concentration gradients across fishing harbors. Betaproteobacteria dominated (76%) organically polluted fishing harbors, which were mostly disturbed by anthropogenic activities. However, the harbors also revealed the absence of numerous pathogenic (Coxiella and Legionella) and photosynthetic (Synechococcus and Leptolyngbya) bacteria. Abundant genera, including Thiobacillus and Arenimonas, exhibited a positive correlation with total phosphorus and a negative correlation with total nitrogen in sediments. Meanwhile, Sulfurovum, Psychrobacter, and Woeseia showed the opposite trend. Pollutant accumulation and anthropogenic activities caused the decrease in the sediment microbial diversity and dispersal ability and promoted convergent evolution. Severely polluted harbors with simplified cooccurrence networks revealed the presence of destabilized microbial communities. In addition, the modularity of bacterial networks decreased with organic pollution. Our results provide important insights into the adjustment mechanism of microbial communities to community organization and functions under environmental pollution stress. Overall, this study enhanced our understanding of how microbial communities in coastal sediments adapted and survived amidst anthropogenic activities like oily effluent discharges from large ships, wash water, domestic sewage, garbage, and fisheries wastes. It also examined their resilience to future contamination.

Risk assessment of As, Cd, Cr, and Pb via the consumption of seafood in Haikou

In order to mitigate the risk of excessive heavy metal intake, a study was conducted to assess the levels of arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) contamination in 23 edible seafood species obtained from markets in Haikou. The findings were analyzed to evaluate the potential health hazards posed to the local population through consumption. The metals were detected via inductively coupled plasma mass spectrometry (ICP-MS) for quantification. The non-carcinogenic and carcinogenic health risks in humans were assessed via target hazard quotient (THQ), combined target hazard quotient (CTHQ), and target cancer risk (TR). The results indicated that the rank order based on the median metal concentration was As > Cd > Cr > Pb. THQ and CTHQ showed that nine seafood species posed a non-carcinogenic risk regarding from As and Cd consumption separately, or the four targeted metals ingestion together. TR assessment indicated that the InAs in all the species presented a carcinogenic risk to coastal residents. The Cd content in bivalves, algae, and several crustacean (Mantis Shrimp, Orchid Crab, Red spot Swimming Crab) and fish species (Japanese Scad, Pacific Saury), and Cr levels in most bivalve species (Razor Clams, White Clams, Fan Shells, Oysters, Blood Clams) presented a carcinogenic risk. The As, Cd, Pb, and Cr levels of seafood in Haikou were assessed species presented a potential health risk. Necessitating stricter risk should be management and detection capability and monitoring will be improved.

Risk assessment of trace metals and polycyclic aromatic hydrocarbons in seawater of typical bays in the Bohai Sea

The ecological risks of trace metals (Cu, Zn, As, Cd, Pb, and Hg) and PAHs in seawater from three typical bays of the Bohai Sea (the Liaodong Bay, Bohai Bay, and Laizhou Bay) were comprehensively assessed by recompiling 637 sites. Results highlighted that scrutiny should be given to the ecological risks of Cu (3.80 μg/L) in the Bohai Bay and Hg (0.23 μg/L) in the Laizhou Bay. Conversely, the Liaodong Bay exhibited negligible ecological risks related to trace metals. The risks of ΣPAHs in the Liaodong Bay, Bohai Bay, and Laizhou Bay were moderate, with mean concentrations of 368.16 ng/L, 731.93 ng/L, and 187.58 ng/L, respectively. The source allocation of trace metals and PAHs required consideration of spatial variability and anthropogenic factors, which greatly affected the distribution and composition of these pollutants. The combined ecological risks in the Bohai Bay (6.80 %) and Laizhou Bay (5.43 %) deserved more attention.