太湖における非ステロイド性抗炎症薬（NSAIDs）の時間的・空間的な発生と関連リスク評価

[Temporal and Spatial Occurrence of NSAIDs in Taihu Lake and Relevant Risk Assessment].

• Jie Lian
• Yi-Fei Li
• Xiao-Xuan Wang
• Bin Ye
• Hua Zou
• Hong-Xing Shi

抄録

非ステロイド性抗炎症薬（NSAIDs）は、太湖で高頻度に検出される薬物残留物の一種である。しかし、太湖全体としての典型的な NSAID 混合物の四季にわたる発生については、ほとんど情報が得られていない。そこで、ジクロフェナク、イブプロフェン、インドメタシン、ナプロキセン、ケトプロフェンを含む5種類の代表的な非ステロイド性抗炎症薬（NSAIDs）の太湖水中濃度を高速液体クロマトグラフィー質量分析法（HPLC-MS/MS）を用いて、太湖全体を網羅する19本の横断幕で各季節ごとにモニターした。太湖水中におけるNSAID混合物の時間的・空間的発生と環境要因との相関を分析し、混合物リスク商（MRQ）モデルを用いてNSAID混合物の生態学的リスクを評価した。太湖の北部、西部、東部海域のNSAIDs濃度は、中部海域と比較して高いレベルにある。太湖のNSAIDs濃度は、夏季（15.9-134.3 ng-L）と秋季（16.4-144.6 ng-L）に高いが、春季（25.3-72.5 ng-L）に低い。MRQ モデルによる評価では、太湖では年間を通じて非ステロイド系抗炎症薬の混合物による生態リスク（MRQ>1）が高い区間が 9 区間あることがわかった。中・高レベル（MRQ>0.1）のNSAID混合物の生態リスクは、春、夏、秋の季節に渡って長く続き、その中でも秋に最もリスクが高いことがわかった。全体として、太湖水中のNSAID混合物による汚染を無視することはできず、特に秋の汚染には細心の注意を払う必要がある。

Non-steroidal anti-inflammatory drugs (NSAIDs) are a class of drug residues with a high frequency of detection in Taihu Lake. However, little information is available about the occurrence of typical NSAID mixtures in Taihu Lake as a whole across the four seasons. Therefore, for each season, the concentrations of five typical NSAIDs including diclofenac, ibuprofen, indomethacin, naproxen, and ketoprofen were monitored in the water of Taihu Lake by the method of high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) at 19 transects covering the entire lake. The temporal and spatial occurrence of NSAID mixtures in the water of Taihu Lake and their correlation with environmental factors were analyzed, and the mixture risk quotient (MRQ) model was also used to assess the ecological risk of the NSAID mixtures. The research results are as follows:① The concentrations of NSAIDs in the northern, western, and eastern waters of Taihu Lake are at a higher level compared to those in the central waters. Ketoprofen is the main contributor to the contamination of NSAID mixtures in all regions of Taihu Lake. ② The concentrations of NSAIDs in Taihu Lake are higher in summer (15.9-134.3 ng·L) and autumn (16.4-144.6 ng·L) but lower in spring (25.3-72.5 ng·L) and winter (14.6-57.4 ng·L), being significantly correlated with water conductivity and pH, respectively. ③ The MRQ model evaluation reveals that there are nine sections in Taihu Lake showing a high ecological risk (MRQ>1) from NSAID mixtures throughout the year. The ecological risk of the NSAID mixtures at a medium or high level (MRQ>0.1) lasts for a long time spanning the spring, summer, and autumn seasons, of which the risk is greatest in autumn. Overall, the pollution caused by the NSAID mixtures in the water of Taihu Lake should not be ignored, and especially great attention should be paid to the pollution in autumn.