长岛附近海域夏秋季贝类毒素污染特征及潜在来源解析

Pollution characteristics and potential sources of shellfish toxins in summer and autumn in the sea area near Changdao Island Pollution characteristics and potential sources of shellfish toxins in summer and autumn in the sea area near Changdao Island

中文关键词: 贝类毒素  长岛  污染特征  潜在来源

英文关键词: shellfish toxins  Changdao Island  pollution characteristics  potential source

中文摘要:

      黄渤海海域的有害赤潮是研究者与监管部门持续关注的环境问题,长岛县地处黄渤海交汇海域,有潜在的海洋毒素污染风险。本研究以6-10月长岛附近海域贝类、浮游植物、沉积物为研究对象,通过分析不同样品中麻痹性贝类毒素(paralytic shellfish toxins, PSTs)、脂溶性贝类毒素(lipophilic shellfish toxins, LSTs)、软骨藻酸贝类毒素(domoic acid, DA)的残留及污染特征,探究长岛附近海域贝类毒素污染情况及潜在风险来源。结果显示,LSTs与DA检出率、含量较低。PSTs在不同月份、样品中均有检出,其中9月贝类与浮游植物PSTs含量最高,但所有样品均未超出安全限量。在浮游植物高通量测序结果中发现6-10月均有Alexandrium属藻类检出,9月丰度最高,且在沉积物中也发现Alexandrium属藻包囊,推测本研究中PSTs产毒藻可能为Alexandrium属藻类。虽然长岛附近海域PSTs含量相较黄渤海其它海域较低,但仍存在PSTs污染潜在风险。应加强对贝类毒素污染监测,可为该海域水产养殖区毒素污染的早期预警提供基础数据。

英文摘要:

      From 1990 to 2020, the red tide of Alexandrium tamarense, which produces paralytic shellfish toxins (PSTs), was monitored in the waters of the Nanhuangcheng Island sea area in Changdao County, with a cumulative affected area of 2.37 km2. The PSTs-producing Gymnodinium spp. was also detected in Yantai Sishili Bay and Weihai coastal waters, with a cumulative affected area of 48.88 km2. In 2020, the lipophilic shellfish toxins (LSTs)-producing Dinophysis spp. was detected in the waters of the North Yellow Sea. In 2021, the amnesic shellfish toxins (ASTs)-producing Pseudo-nitzschia was detected in small quantities in the typical Patinopecten yessoensis culture area of Zhangzi Island and Yantai Sishili Bay in the North Yellow Sea. PSTs, LSTs, ASTs and their toxin-producing algae have been widely found in the Yellow Sea and Bohai Sea. Shellfish samples and phytoplankton samples were collected in the waters off Changdao Island from June to October 2023 screened for a total of 29 shellfish toxins, including 14 PSTs, 14 LSTs, and domoic acid (DA). PSTs and LSTs were detected throughout the survey period, and DA was not detected. The main detected components of PSTs were GTX1, GTX2/3, C1, and C2, while LSTs were detected less frequently and at low concentration, and PTX2 was detected only in the Chlamys farreri sample of June (2.46 μg PTX2eq./kg SM) , which is much lower than the current EU safety limit of 160 μg PTX2eq./kg SM. Because the risk of DA and LSTs in the sea area around Changdao Island was low in this study, the analysis of the pollution characteristics and potential sources of PSTs would be focused on. None of the detected PSTs in shellfish samples from June to October exceeded the EFSA safety limits. The GTX2, GTX5, C1 and C2 of PST components were detected, with GTX2 being the highest detection rate of 53.3%, and C1 being the maximum concentration of 179 μg/kg. Among the shellfish samples collected during the whole survey period, PSTs were not detected in Mytilus galloprovincialis and Crassostrea gigas in June and August, and in all the shellfish samples collected in July. PSTs were detected in Chlamys farreri in September at 478 μg/kg, which was the highest concentration among all the months, followed by Chlamys farreri in October at 221 μg/kg. Among the phytoplankton samples, PSTs were detected collected from the stations S2, S3, and S4 in September, and stations S1 and S2 in October, with a relatively low concentration of PSTs. PSTs were not detected in other months and stations. The highest level of PSTs in phytoplankton was 23.92 μg/L at station S2 in September, and the average level was 20.7 μg/L. The average level of PSTs in October was 2.67 μg/L. In October, only two components were detected at stations S1 and S2, consist of dcGTX3 and GTX4. In September, the PSTs were more abundant, with a total of seven components, including GTX1/4, GTX2, dcGTX3, GTX5, C1/2. Further high-throughput analysis of phytoplankton revealed the presence of eight species of Alexandrium spp. with the highest abundance of Alexandrium spp. in September, and Alexandrium spp. cysts were found in the sediments in September, which suggests that the toxicity-producing algae of PSTs in the Changdao Island waters in the present study may be Alexandrium spp. Although the concentration of PSTs in the samples off Changdao Island was relatively low compared with other regions in the Yellow Sea and Bohai Sea, there is still a potential risk of PSTs contamination. To guarantee the quality and safety of aquatic products, the monitoring of shellfish toxins should be strengthened, which can provide basic data for early warning of toxins contamination in aquaculture areas.