Occurrence of microcystins in 22 representative reservoirs in eastern Kagawa
| Autor: | Tabuchi, Yumi, Kawamura, Osamu |
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| Jazyk: | japonština |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | 香川大学農学部学術報告. 72(125):51-55 |
| ISSN: | 0368-5128 |
| Popis: | application/pdf マイクロシスチン（MCs）は，アオコを構成する藍藻が生産する強い肝臓毒性と発がんプロモーター活性を有する。MCsは，富栄養化した淡水を汚染し，家畜やヒトへの健康被害を起こしている。2014年に香川大学農学部近郊の男井間池が高濃度のMCs汚染していることが明確なったので，香川の溜井のMCs汚染実態を明らかにすることを目的として，香川東讃の代表的な22の溜池の汚染調査を行った。その結果，検体の40%が飲料水中のMCsの基準値を1ng/mLを超えており，20%がオーストラリアなどで設定しているレクリエーション水の規制値を10ng/mLを超えていた。また，5%の検体が10,000ng/mL以上の極めた高いMCsに汚染されていた。最高濃度MCsは88,498ng/mLでこの検体のわずか0.027mLで耐容一日摂取量に相当しするほどの高濃度汚染であった。周囲が農地や住宅地に囲まれている船岡池，男井間池や平池の平均MCs濃度は1,000ng/mLを超えていた。一方，周囲が森などの木々に囲まれている公渕池，石神池や川股池での平均MCs濃度は0.1ng/mL以下でかなり低濃度であった。また，MCs濃度の対数と溶存態総窒素の相関係数はr2=0.417であり，MCs濃度の対数と溶存態総リンの相関係数はr2=0.575といずれも高い正の相関性を示した。以上の結果から，これらの溜池では，周囲から流れ込む窒素やリンが引き起こした富栄養化がMCsの高濃度汚染を引き起こした可能性が強く示唆された。 Microcystins (MCs) are one of toxic cyanotoxins, which are contaminated in eutrophicated lakes and ponds. MCs have the strong liver toxicity and carcinogenetic promoter activity, and causes healthy damage to livestock animals and humans. In 2014, we clarified that Oimai Pond, near the Faculty of Agriculture, Kagawa University, was contaminated with high concentrations of MCs. In order to clarify the MCs contamination in reservoir of Kagawa, we measured MCs, dissolved total nitrogen and dissolved total phosphorus in 22 representative reservoirs in eastern Kagawa. In the results, 40% of the samples exceeded the standard value of MCs in drinking water (1 ng/mL), and 20% exceeded the regulation value of recreational water (10 ng/mL) set in Australia. In addition, 5% of the samples were contaminated with extremely high MCs of over 10,000 ng/mL. The highest concentration of MCs was 88,498 ng/mL, and only 0.027 mL of this sample was corresponding to the tolerable daily intake of MC-LR. The average of MCs concentrations of Funaoka, Oima and Hira ponds surrounded by farmland and residential area exceeded 1,000 ng/mL. On the other hand, the average of MCs concentrations in Kinbuchi, Ishigami, and Kawamuta ponds surrounded by trees such as forests was less than 0.1 ng/mL. The correlation coefficient between the logarithm of MCs concentration and dissolved total nitrogen was r2=0.417, and the correlation coefficient between the logarithm of MCs concentration and dissolved total phosphorus was r2=0.575, both showing a high positive correlation. These results suggest that eutrophication caused by nitrogen and phosphorus flowing from the surrounding area may cause highly contamination with MCs in these reservoirs. |
| Databáze: | OpenAIRE |
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