Assessment of potentially toxic element contamination in commercially harvested invertebrates from the Beibu Gulf, China.

Marine pollutants, especially potentially toxic elements (PTEs), increasingly threaten the ecological environment and fishery resources of the Beibu Gulf due to their bioaccumulative nature, toxicity, and persistence. However, the occurrences of multiple PTEs in marine invertebrates within this region remains unclear. Hence, a total of 18 species of commercially harvested invertebrates (shrimp, crab, cephalopod, shellfish, and sea cucumber) were collected from the Beibu Gulf, and the concentrations of nine important PTEs (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) were examined. Subsequent stable isotope analysis for δ13C and δ15N facilitated investigations into biomagnification and human health risk assessment. The results showed that, except for As, the concentrations of the PTEs in the invertebrates were below the national safety limits. Furthermore, significant positive correlations were found between trophic levels (TLs) and log-transformed concentrations of As (P < 0.001, R2 = 0.20) and Cr (P < 0.001, R2 = 0.13), indicating biomagnification of these two metals across trophic positions among species. Finally, the human health risk assessment revealed that the consumption of cephalopod, shellfish, and sea cucumber poses a higher risk of adverse effects compared to shrimp and crab.

Phylogeography and population structure of Lagocephalus spadiceus (Richardson, 1845) (Tetraodontiformes, Tetraodontidae) in the South China Sea.

The climate fluctuations during the Late Pleistocene significantly influenced the phylogeographic structure and historical dynamics of marine fishes in the marginal seas of the western Pacific Ocean. The puffer fish, Lagocephalus spadiceus, holds substantial nutritional and economic value in the South China Sea. To investigate the demographic history and population structure of the L. spadiceus, the mitochondrial DNA COI and Cyt b gene datasets from 300 individuals across eight populations in the South China Sea were sequenced. Our findings revealed high haplotype diversity (0.874 ± 0.013) and low nucleotide diversity (0.00075 ± 0.00058). The phylogenetic tree and haplotype networks revealed no significant genetic differentiation along the northern coast of South China Sea. Neutrality tests, mismatch distribution analyses, and Bayesian skyline plots suggested that L. spadiceus underwent population expansion during the Late Pleistocene. Both ocean currents and climate change significantly influenced the geographical distribution and genetic population structure of L. spadiceus.

Heavy Metals in Surface Sediment of Plateau Lakes in Tibet, China: Occurrence, Risk Assessment, and Potential Sources.

Tibetan Plateau lakes have high ecological value and play a crucial role in maintaining ecological balance. This research aimed to study the pollution characteristics, ecological risk, and potential sources of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the surface sediments of 12 Tibetan Plateau lakes. The results of the toxicity risk index (TRI) showed that only Gongzhu Tso (28.09) and La' ang Tso (20.25) had heavy metals that could pose a very high risk of toxicity to aquatic organisms. Hg posed the highest potential ecological risk to aquatic organisms. Based on the results of multiple analyses, we inferred that the contents of Cr, Cu, Hg, and Ni in sediments of Tibetan lakes were influenced by industrial and agricultural development; Cd, Pb, and Zn were influenced by transport and atmospheric transport; and As was derived from geothermal activity and rock weathering.

Levels and health risk assessment of potential toxic elements in three dominant fish species from the Beibu Gulf, South China Sea.

In this study, eight potential toxic elements (PTEs) and stable isotope ratios (δ13C and δ15N) were analyzed in three dominant fish species of the Beibu Gulf, namely Saurida tumbil, Pennahia macrocephalus and Upeneus sulphureus. The mean contents (mg/kg, dry weight) of As, Cd, Cr, Cu, Mn, Ni, Pb and Zn in the three species of fish were 10.94, 0.11, 0.55, 2.00, 5.80, 0.47, 0.39, 41.70, respectively. Cr, Mn and Pb showed potential biomagnification effects in fish bodies while Cu and Zn were biodiluted through the food chain. The results of the health risk assessment showed that the total hazard quotient (THQ) ranged from 0.11 to 0.32 and 1.34 to 1.70 and the total carcinogenic risk (TCR) ranged from 5.44 × 10-4 to 1.35 × 10-3 and 6.35 × 10-3 to 1.57 × 10-2 for adults and children, respectively. These results suggest that consumption of the three fish species by adults lead to carcinogenic health risks and consumption of the three fish species by children would result in significant adverse health effects.