渤海渔业生物重金属污染及风险评价

Heavy metal pollution and risk assessment in different species of fish from the Bohai Sea

关键词:  重金属  渤海  渔业生物  污染指数  人体健康

Key words:  Heavy metal  Bohai Sea  Fisheries organisms  Pollution index  Human health

摘要:

重金属污染是渤海长期面临的环境问题之一，同时对渤海海产品安全和人体健康构成潜在风险。为了解渤海海域鱼类重金属污染状况，在该海域采集的渔业生物中随机选取了10种144条鱼类样本，运用电感耦合等离子体质谱法测定了鱼类肌肉组织中重金属Cu、Zn、Pb、Cd、Cr和As的含量；采用单因子污染指数法、内梅罗综合污染指数法和金属污染指数法评价了单一重金属和综合重金属污染情况；采用每日摄入量和目标危害系数评估了渤海鱼类重金属污染对人体的食用安全风险。研究结果显示，渤海鱼类肌肉中重金属Cu、Zn、Pb、Cd、Cr和As的平均含量分别为(0.702±0.680)、(9.697±5.279)、(0.035±0.059)、(0.029±0.035)、(0.093±0.091)和(0.959±0.813) mg/kg。与我国其他海域相比，渤海鱼类重金属含量处于较高水平。鱼类重金属污染评价结果显示，Cd和无机As (iAs)为渤海鱼类重金属污染的主要元素，细纹狮子鱼(Liparis tanakae)受到重金属综合污染的程度最大。食用风险评估结果表明，摄食渤海鱼类带来的重金属每日摄入量处于较低水平，所有鱼类样本单一重金属和综合重金属目标危害系数值均<1，表明正常摄食渤海鱼类不会对消费者构成健康风险。本研究结果有助于加深理解渤海渔业生物的重金属污染状况，同时为保障渤海水产品的食用安全提供科学依据。

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.