Progress in Fishery Sciences (Apr 2024)
Heavy Metal Pollution and Risk Assessment in Different Species of Fish from the Bohai Sea
Abstract
The Bohai Sea, which is China's only semi-enclosed inland sea, has received significant inputs of heavy metals from the rapidly industrializing and urbanizing Bohai Sea Economic Rim. Because of the limited water exchange and self-purification capacity, heavy metal pollution in the Bohai Sea has been intensifying, making it a focal area of heavy metal pollution research. Furthermore, the Bohai Sea serves as one of China's traditional fishing grounds, acting as both a spawning area and foraging ground for various economically significant fishery species, thereby providing abundant seafood for urban and rural communities in the Bohai Sea region. Heavy metals are considered one of the principal pollutants in the marine environment of the Bohai Sea due to their high accumulation and resistance to degradation. They accumulate within organisms and are subsequently transferred through the food chain, resulting in pollution of marine biological resources. The issue of heavy metal pollution in the Bohai Sea has raised concerns among researchers regarding food product safety and human health risks.To assess the status of heavy metal pollution in fish species from the Bohai Sea, we randomly selected 144 samples from 10 different fish species collected during a fisheries resource survey in the Bohai Sea region. All fish samples were stored frozen at –20℃ until further analysis. The collected samples were thawed at room temperature, dissected to obtain muscle tissues, freeze-dried, and subsequently ground into a fine powder using agate mortar. Approximately 0.2 to 0.5 g of the homogenized samples were digested using a microwave digestion system with 2.5 mL of concentrated H2SO4, 4.0 mL of concentrated HNO3, and 1.5 mL of H2O2. The concentrations of heavy metals, i.e., Cu, Zn, Pb, Cr, Cd, and As, were determined using inductively coupled plasma mass spectrometry (ICP-MS). To estimate inorganic As (iAs) in fish muscle from the Bohai Sea, we used the highest reported percentage of iAs in the total As, which was 6.88%, as observed in the literature. The study assessed the single-element pollution and comprehensive heavy metal pollution in Bohai Sea fish using the single factor pollution index, Nemerow comprehensive pollution index (PN), and metal pollution index (MPI). To evaluate the dietary risk posed by heavy metal-contaminated fish, we introduced daily intake (DI) and target hazard quotient (THQ) as assessment indicators. DI represents the daily intake of heavy metals from fish consumption, whereas THQ indicates the potential health risk of ingesting heavy metals.The fish samples collected for this study belonged to 10 different species: Setipinna taty, Scomberomorus niphonius, Pampus argenteus, Trichiurus lepturus, Eupleurogrammus muticus, Engraulis japonicus, Cynoglossus joyneri, Thryssa kammalensis, Liparis tanakae, and Enedrias fangi. The mean values of heavy metal concentrations in the muscle tissues of Bohai Sea fish were as follows: Cu (0.702±0.680) mg/kg, Zn (9.697±5.279) mg/kg, Pb (0.035±0.059) mg/kg, Cr (0.029±0.035) mg/kg, Cd (0.093±0.091) mg/kg, and As (0.959±0.813) mg/kg. When we compared the heavy metal content in fish from the Bohai Sea with those from other sea regions, our findings indicated that there are notable differences in heavy metal levels among fish species in various sea areas of China. Fish from the Bohai Sea exhibit relatively higher levels of Cu, Zn, and As. The single-element pollution index for Cu, Pb, Cd, Cr, and iAs ranged from 0.003 to 0.056, 0.003 to 0.165, 0.021 to 0.767, 0.017 to 0.085, and 0.059 to 0.373, respectively. Some fish samples displayed Cd or iAs contamination, indicating that Cd and iAs were the major contributors to heavy metal pollution in Bohai Sea fish. The PN for the 10 fish species in the Bohai Sea ranged from 0.185 to 1.210, with lionfish exhibiting the highest PN value, signifying severe contamination. The MPI ranged from 0.022 to 0.097, with bluefin trevally, lionfish, and tongue sole having similar and higher MPI values compared to other species. The results of the dietary risk assessment showed that the daily intake of heavy metals (Cu, Zn, Pb, Cd, Cr, and iAs) from consuming Bohai Sea fish was relatively low, and it was below the maximum allowable intake levels established by the Food and Agriculture Organization (FAO) of the United Nations, the World Health Organization (WHO), and the National Research Council (NRC) for Zn, Cu, Pb, Cd, iAs, or Cr. The THQ values for single heavy metals and THQS for multiple heavy metals were all less than 1.0, indicating that consuming Bohai Sea fish is unlikely to pose health risks to consumers. Different heavy metals had varying contributions to THQs, with the average THQ values for Bohai Sea fish species ranking as follows: Pb (0.0029) < Cu (0.0059) < Cd (0.0098) < Cr (0.0105) < Zn (0.0113) < iAs (0.0733).Our findings contribute to a deeper understanding of the heavy metal pollution status in Bohai Sea fishery biota. Additionally, they provide a crucial scientific foundation for ensuring the safety of seafood products from the Bohai Sea. Furthermore, this study offers valuable insights for consumers, enabling the provision of more informed dietary recommendations.
Keywords
