蓝藻在国外评述 Review of cyanobacteria in a foreign country
Cyanobacteria is the scientific name for blue-green algae(蓝藻学名为蓝毒素)Cyanobacterial toxins are the naturally produced poisons stored in the cells of certain species of cyanobacteria. (在蓝藻内部的特定区域存有蓝毒素)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.(蓝毒素内的毒素分为很多种,其中一个分类为肝毒素和神经毒素,它们是已知的会侵袭肝脏和神经的毒素,另一个分类的毒素对皮肤有刺激作用,当蓝毒素细胞破裂或死亡时,以上分类的毒素就会被释放到水中)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.(当暴露在含有蓝藻毒素的湖水中,虽然一部门人会生病,但是饮用含有受污染藻类的水却未必会导致死亡。长期地暴露在含有蓝藻肝毒素的水中,即使含量较低,也有可能对人体产生长期的或慢性的不利影响)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.(如果你不断的摄入含有蓝藻的水,鱼或者其他水产品,就可能会产生头痛,发烧,腹泻,腹痛,反胃或者呕吐。如果你在受污染的水中游泳,也有可能会产生皮肤发痒或者眼睛皮肤受到刺激,如果你怀疑直接接触到了污染水源并且身体发生了不良反应,用干净水冲洗身体并立即联系医生)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.(煮沸的水不会去除蓝藻中的毒素,因为你不可能凭借水的外表,气味或者味道去检测毒素的存在,只有化学测试才可以)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.(如果条件允许,不要使用受污染水洗衣服和餐具,如果实在没有其他水源,做家务要用水时必须戴上橡胶手套,使用受污染水洗澡应该避免,因为皮肤直接接触水会造成皮肤刺激和皮疹)
藻毒素具有水溶性和耐热性。易溶于水,甲醇或丙酮,不挥发,抗pH变化。MC-LR的分子式为C49H74N10O12,分子量为995.2(计算时往往按1000计)。
其在水中的溶解性大于1g/L,化学性质相当稳定。在水中藻毒素自然降解过程是十分缓慢的,当水中的含量为5ug/L时,三天后,仅10%被水体中微粒吸收,7%随沙沉淀。藻毒素有很高的耐热性,加热煮沸都不能将毒素破坏,也不能将其去除;自来水处理工艺的混凝沉淀、过滤、加氯也不能将其去除。有调查试验研究表明在某湖周围3个自来水厂的出厂水中检出低浓度的藻毒素(128~1400ng/L),结果提示采用常规的饮水消毒处理不能完全消除水体中的藻毒素。
它是一种肝毒素,这种毒素是肝癌的强烈促癌剂。
家畜及野生动物饮用了含藻毒素的水后,会出现腹泻、乏力、厌食、呕吐、嗜睡、口眼分泌物增多等症状,甚至死亡。病理病变有肝脏肿大、充血或坏死,肠炎出血、肺水肿等。
对于人类健康,微囊藻毒素也具有很大危害性。其中MC-LR的半致死剂量(LD50)约为50~100 ug/kg。人们在洗澡、游泳及其他水上休闲和运动时,皮肤接触含藻毒素水体可引起敏感部位(如眼睛)和皮肤过敏;少量喝入可引起急性肠胃炎;长期饮用则可能引发肝癌。医学部门已发现饮水中微量微囊藻毒素与人群中原发性肝癌的发病率有很大相关性。1996年在巴西造成100多名急性肝功能故障,7个月内至少50人死于藻毒素产生的急性效应,引起举世瞩目的关注。淡水水体中的蓝藻毒素已成为全球性的环境问题,世界各地经常发生蓝藻毒素中毒事件。