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题名: 典型湖库微囊藻毒素的归趋及其对主要水生生物的影响
作者: 贾军梅
学位类别: 博士
答辩日期: 2016-11
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 陈求稳
关键词: 湖库,微囊藻毒素,影响因素,归趋,影响 ; lakes, microcystins, factors, environmental fate, influences
其他题名: The environmental fate and influences of microcystins on aquatic organisms in typical lakes across China
学位专业: 环境工程
中文摘要:     大量的营养盐排入水体,导致世界范围内的湖泊等淡水系统均存在不同程度的富营养化问题。富营养化的湖泊,在适宜的温度、光照等环境条件下,浮游植物大量繁殖,产生的微囊藻毒素(MCs)危害人体和其他生物体的健康。因此,MCs产生的影响因子、生物体内MCs累积传递以及MCs对生物体产生的危害一直是科学家们关注的热点。
    本研究首先以太湖和洋河水库作为研究区域,采集了太湖和洋河水库不同季节的水样和浮游植物样品,分析对比了太湖和洋河水库2013-2014年不同季节MCs在水中的含量、藻细胞的含量和藻细胞的产毒能力,对照太湖和洋河水库各季节的水质参数,确定影响MCs产生和释放的环境因子。其次,通过太湖常规监测的浮游植物和浮游动物的数据,结合搜集的MCs历史数据,研究蓝藻和MCs对最初级的消费者浮游动物可能产生的影响。最后,采集太湖水生植物和水生动物样品,研究MCs在水生生物的分布累积情况,同时分析MCs对高等水生生物可能造成的影响,评价摄入MCs对人体健康造成的风险。研究主要取得了如下成果:
    (1) 洋河水库夏季藻细胞中的MC-LR、MC-YR和MCs以及总的MCs含量明显高于太湖中的含量;洋河水库夏季水中溶解的MC-LR和MCs显著地高于太湖。与洋河相比,太湖夏季较大比例的MCs释放到水体中。2013年秋季太湖单位细胞产毒量较高,而2014年春季洋河水库单位细胞产毒量较高。MC-LR是太湖和洋河水体中溶解的MCs最主要的变体,也是洋河藻细胞内的MCs最主要的变体。MC-RR 是太湖藻细胞内MCs的最主要变体。与太湖相比,洋河水库水中和藻细胞中MC-LR/MCs 均较高。洋河水库较高的MCs是由于其较高的蓝藻数量决定的,而洋河水库水中溶解的MCs 较高是由于蓝藻藻细胞中MCs较高所致。MCs的释放并不是只由细胞自身裂解决定的,存在其他的因素促进MCs释放到水体中。太湖的水生植物可能会刺激MCs释放。温度是太湖2013年秋季具有更高的单位细胞产毒量的原因。氮和光强是洋河水库2014年春季具有较高单位细胞产毒能力的原因。氮也是洋河水库MC-LR/MCs 较高的原因。
(2) 太湖和洋河水库水中MCs最主要变体可以很好的预测水中MCs含量,细胞中MCs最主要变体也可以很好的预测细胞中MCs含量。洋河水库的叶绿素a的含量可以预测藻细胞中的MC-LR,MC-YR和 MCs以及总的MCs,这对于简化MCs检测的步骤,更及时的预测MCs的含量具有重要的实际意义。洋河水库总体的MC-LR当量比太湖高,且含量可能会对洋河水库周边人群的健康造成风险。此外,MCs含量季节变化明显,某些季节湖库中的水饮用风险非常高,例如太湖和洋河水库秋季MC-LR当量均超过1.0 μg/L。
    (3) 太湖年度平均的浮游植物数量,尤其是蓝藻数量,在1998-2007年十年中呈上升趋势,MCs含量也呈上升趋势。太湖年度平均的浮游动物数量呈下降趋势,而年度平均的浮游动物生物量保持不变。太湖枝角类浮游动物在十年间呈上升趋势,原生动物保持稳定,而桡足类和轮虫数量下降。浮游植物和浮游动物的多样性指数均呈下降趋势。随着蓝藻数量从低丰度组增加到中丰度组,枝角类、桡足类和轮虫数量均增加,而原生动物数量保持平稳。随着蓝藻数量从中丰度组增加到高丰度组,枝角类、桡足类、轮虫和原生动物变化很少,然而枝角类、桡足类和轮虫的生物量却明显减少。太湖的研究表明:蓝藻数量的增加促使枝角类数量增加,桡足类和轮虫数量减少,总体上使得浮游动物数量减少;MCs含量增加促进了桡足类和浮游动物总体数量的减少,可能同时降低了浮游动物的生物多样性。
    (4) MCs广泛的存在于太湖的水、蓝藻细胞、水生植物、虾和鱼体中,在所有这些样品中都100%检测到了MCs。MCs在不同生物体中累积程度的顺序大体上为初级生产者(水生植物)>三级消费者(肉食鱼)>次级消费者(鱼、虾)>初级消费者(草食鱼)。水生植物、虾和鱼类中最高含量的MCs分别在微齿眼子菜、秀丽白虾和箴鱼体内发现。虾和三种鱼类(太湖新银鱼、湖鲚和白鲢)体内的MCs与他们的食物暴露的含量紧密相关。金鱼藻由于其吸收营养盐,累积大量的MCs同时对MCs有很强的耐受性,可以作为理想的植物引入湖泊中,以减少微囊藻水华的发生和MCs的污染。根据太湖中MCs含量,MCs可能会对某些水生植物的生理行为产生显著地影响,甚至会造成一些水生植物的死亡。基于秀丽白虾、鲚鱼、箴鱼和鲫鱼中MCs含量进行计算,它们每日摄入量均超过世界卫生组织的推荐值,因此会对人体健康造成潜在威胁。
英文摘要:     Large amount of nitrogen and phosphorus was discharged into waterbody, resulting in the eutrophication of freshwater systems worldwide. In an entrophication system, cyanobacterial blooms occur frequently due to rising temperature and appropriate light condition. Many cyanobacteria could produce secondary metabolites known as microcystins (MCs) which had adverse effect on both animal and human health. Therefore, the influencing factor, environmental fate and the adverse effect of MCs had caught attentions of scientists around the world.
    Lake Taihu and Yanghe Reservoir were chosen as study areas. Samples of water and phytoplankton were taken in Lake Taihu and Yanghe Reservoir in different seasons during 2013-2014. The MCs concentrations in water, MCs in phytoplankton and MCs quota as well as water parameters were analyzed and compared between Lake Taihu and Yanghe Reservoir to identify the influencing factor of MCs in the two lakes. Besides, based on the monthly data of phytoplankton and zooplankton in Lake Taihu during 1998-2007, together with the MCs collected in literatures, the effect of cyanobacteria and MCs on the zooplankton community was evaluated in Lake Taihu. Finally, samples of hydrophytes and aquatic animals in Lake Taihu were taken to identify the environmental fate, ecological influences and human health risk of MCs in Lake Taihu. The major contribution of the study as follows:
    (1) We identified the environmental factors influencing MCs abundance by monitoring Lake Taihu and Yanghe Reservoir in 2013 and 2014. The MC-LR, MC-YR and MCs in algal cells and total MCs of Yanghe Reservoir were significantly higher than in Lake Taihu in summer. The dissolved MC-LR and MCs of Yanghe Reservoir were significantly higher than in Lake Taihu in summer. More proportion of MCs was released in Lake Taihu than in Yanghe Reservoir in summer. Lake Taihu had higher MCs quota in autumn of 2013 and Yanghe Reservoir had higher MCs quota in spring of 2014. MC-LR was the main congener of dissolved MCs in Lake Taihu and Yanghe, and also the main congener of MCs in algal cells in Yanghe Reservoir. MC-RR was the main congener of MCs in algal cells in Lake Taihu. Yanghe Reservoir had higher MC-LR/MCs both in water and algal cells. The higher MC in Yanghe Reservoir was determined by higher cyanobactria biomass,and the higher dissolved MC in Yanghe Reservoir was decided by distinct higher MCs in algal cells. The release of MCs was not only decided by cell lysis but also other factors in the two lakes. The present of microphytes in Lake Taihu may induce more MCs release into water as an allelopathic infochemical. Temperature mainly contributed to the higher MCs quota in autumn of 2013 in Lake Taihu. N availability and light contributed to the higher MCs quota in spring of 2014 in Yanghe Reservoir. The higher MC-LR/MCs in Yanghe Reservoir was owing to abundant nitrogen in Yanghe Reservoir.
(2) The main congeners of MCs can be used as a simpler index to predict the MCs concentration in water and algal cell in the two lakes. The chla could predict MC-LR in algal cell, MC-YR in algal cell, MCs in algal cell and total MCs in Yanghe Reservoir. Yanghe Reservoir present higher MC-LR equivalent (MC-LR eq) than Lake Taihu and the MC-LR eq value in Yanghe Reservoir could pose potential health risk to local people. Both Lake Taihu and Yanghe present high MC-LR eq exceeded 1.0 μg/L in autumn.
    (3) The annual average phytoplankton abundance especially that of cyanobacteria, and total MCs increased during the 10-year study. Annual average zooplankton abundance decreased, whereas annual average zooplankton biomass was unchanged. Cladoceran abundance showed an increasing trend and protozoan abundance remained stable, while copepod and rotifer abundance displayed a decreasing trend. Both annual average H-phytoplankton and H-zooplankton exhibited generally decreasing trends. Along with the increase in cyanobacterial abundance from the low to medium level, abundance of cladocerans, copepods and rotifers were all increased, but the protozoan abundance remained stable. Along with the increase in cyanobacterial abundance from the medium to high level, variations in cladoceran, copepod, rotifer, and protozoan abundances were low, but there was a clear decrease in cladoceran, copepod, and rotifer biomass. This Lake Taihu study revealed that: the increase in cyanobacterial abundance contributed to the increase in cladoceran abundance, decrease in copepod and rotifer abundance, and decrease in zooplankton abundance during the 10 years of study; and the increase in total MCs concentration may contribute to the decrease in copepod abundance and zooplankton abundance and its biodiversity.
    (4) Widespread MC contamination in water, algal cells, macrophytes, shrimps and fish was found in Lake Taihu. The ubiquitous presence of MCs in water, algal cells and biota was found in 100% of samples. MC accumulation was in the order of primary producer > tertiary consumer > secondary consumer > primary consumer. The highest levels of MCs in macrophytes, shrimps and fish tissue were found in Potamogeton maackianus, Exopalaemon modestus, and Hyporhamphus intermedius, respectively. The MCs level in shrimps and the tissues of three fish species, Neosalanx tangkahkeii taihuensis, Coilia ectenes and silver carp, was closely linked to their dietary exposure. Ceratophyllum demersum L. was an ideal plant for introduction into lakes to protect against Microcystis blooms and MCs, due to its ability to absorb nutrients, accumulate large amounts of MCs and tolerate these toxins compared to other macrophytes. According to the MC levels in this study, MCs could cause significant effects on physiological or behavioural processes, or even death to some macrophytes in Lake Taihu. The average daily intakes (ADIs) of MCs for Exopalaemon modestus and three fish species, Coilia ectenes, Hyporhamphus intermedius and Carassius carassius, were all above the tolerable daily intakes (TDI) set by the World Health Organization (WHO), implying there existed potential threats to human health.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/36867
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
贾军梅. 典型湖库微囊藻毒素的归趋及其对主要水生生物的影响[D]. 北京. 中国科学院研究生院. 2016.
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