藍藻在國外評述 Review of cyanobacteria in a foreign country
Cyanobacteria is the scientific name for blue-green algae(藍藻學名為藍毒素)Cyanobacterial toxins are the naturally produced poisons stored in the cells of certain species of cyanobacteria. (在藍藻內部的特定區域存有藍毒素)These toxins fall into various categories. Some are known to attack the liver (hepatotoxins) or the nervous system (neurotoxins); others simply irritate the skin. These toxins are usually released into water when the cells rupture or die.(Although many people have become ill from exposure to freshwater cyanobacterial toxins, death from algal-contaminated drinking water is unlikely to occur given that water resources are usually effectively managed to control taste, odour and other algae-related problems. It's possible that extended exposure to low levels of cyanobacterial hepatotoxins could have long-term or chronic effects in humans.(藍毒素內的毒素分為很多種,其中一個分類為肝毒素和神經毒素,它們是已知的會侵襲肝髒和神經的毒素,另一個分類的毒素對皮膚有刺激作用,當藍毒素細胞破裂或死亡時,以上分類的毒素就會被釋放到水中)Although many people have become ill from exposure to freshwater cyanobacterial toxins, death from algal-contaminated drinking water is unlikely to occur given that water resources are usually effectively managed to control taste, odour and other algae-related problems. It's possible that extended exposure to low levels of cyanobacterial hepatotoxins could have long-term or chronic effects in humans.(當暴露在含有藍藻毒素的湖水中,雖然一部門人會生病,但是飲用含有受污染藻類的水卻未必會導致死亡。長期地暴露在含有藍藻肝毒素的水中,即使含量較低,也有可能對人體産生長期的或慢性的不利影響)If you ingest water, fish or blue-green algal products containing elevated levels of toxins, you may experience headaches, fever, diarrhoea, abdominal pain, nausea and vomiting. If you swim in contaminated water, you may get itchy and irritated eyes and skin, as well as other hay fever-like allergic reactions. If you suspect you might have come into contact with cyanobacterial toxins and are experiencing any of these symptoms, rinse any scum off your body and consult your physician immediately.(如果你不斷的攝入含有藍藻的水,魚或者其他水産品,就可能會産生頭痛,發燒,腹瀉,腹痛,反胃或者嘔吐。如果你在受污染的水中遊泳,也有可能會産生皮膚發癢或者眼睛皮膚受到刺激,如果你懷疑直接接觸到了污染水源並且身體發生了不良反應,用幹淨水衝洗身體並立即聯繫醫生)Boiling water does not remove toxins from the water. As it is impossible to detect the presence of toxins in the water by taste, odour or appearance, you must assume that they are present until testing is completed.(煮沸的水不會去除藍藻中的毒素,因為你不可能憑藉水的外表,氣味或者味道去檢測毒素的存在,衹有化學測試纔可以)If there is a safe source of water available, don't use contaminated water for washing clothes or dishes. If no alternative supply is available, use rubber gloves to avoid direct contact with the water. Bathing or showering in contaminated water should be avoided, as skin contact with the algae can lead to skin irritation and rashes.(如果條件允許,不要使用受污染水洗衣服和餐具,如果實在沒有其他水源,做傢務要用水時必須戴上橡膠手套,使用受污染水洗澡應該避免,因為皮膚直接接觸水會造成皮膚刺激和皮疹)
藻毒素具有水溶性和耐熱性。易溶於水,甲醇或丙酮,不揮發,抗pH變化。MC-LR的分子式為C49H74N10O12,分子量為995.2(計算時往往按1000計)。
其在水中的溶解性大於1g/L,化學性質相當穩定。在水中藻毒素自然降解過程是十分緩慢的,當水中的含量為5ug/L時,三天後,僅10%被水體中微粒吸收,7%隨沙沉澱。藻毒素有很高的耐熱性,加熱煮沸都不能將毒素破壞,也不能將其去除;自來水處理工藝的混凝沉澱、過濾、加氯也不能將其去除。有調查試驗研究表明在某湖周圍3個自來水廠的出廠水中檢出低濃度的藻毒素(128~1400ng/L),結果提示采用常規的飲水消毒處理不能完全消除水體中的藻毒素。
它是一種肝毒素,這種毒素是肝癌的強烈促癌劑。
傢畜及野生動物飲用了含藻毒素的水後,會出現腹瀉、乏力、厭食、嘔吐、嗜睡、口眼分泌物增多等癥狀,甚至死亡。病理病變有肝髒腫大、充血或壞死,腸炎出血、肺水腫等。
對於人類健康,微囊藻毒素也具有很大危害性。其中MC-LR的半致死劑量(LD50)約為50~100 ug/kg。人們在洗澡、遊泳及其他水上休閑和運動時,皮膚接觸含藻毒素水體可引起敏感部位(如眼睛)和皮膚過敏;少量喝入可引起急性腸胃炎;長期飲用則可能引發肝癌。醫學部門已發現飲水中微量微囊藻毒素與人群中原發性肝癌的發病率有很大相關性。1996年在巴西造成100多名急性肝功能故障,7個月內至少50人死於藻毒素産生的急性效應,引起舉世矚目的關註。淡水水體中的藍藻毒素已成為全球性的環境問題,世界各地經常發生藍藻毒素中毒事件。