土壤-蔬菜系统中微囊藻毒素的环境归宿及生物累积研究

The frequent occurrence of microcystins (MCs) pollution induced by cyanobacterial blooms have lead to great ecological disasters and consequently threaten human health. Acute and chronic toxic effects from exposure through drinking water or aquatic food containing trace amount of MCs have been identified. MCs have defined as the potent hepatotoxins and tumor promoter. The effects of microcystins on water bodies and aquatic organisms have been concerned worldwide and studied deeply. Microcystins can be transferred to the soil-plant system via irragations of the contaminated surface water or direct discharge of cyanobacterial blooms to the farm as organic fertilizer. Soil plays an important role in the processes of microcystins transfer from aquatic environment to terrestrial environment and organisms.However, there is very little information on the fate of MCs in soil-plant system. Therefore, in order to evaluate the health risk of microcystins, researches on the contamination characteristics , environmental fate , ecological effects of MCs in soil especially soil-plant（vegetable）system are absolutely critical. The major objectives of the project are 1) to examine content levels, distribution characteristics ,bioaccumulation and influencing factors of common microcystins(i.e. MC-RR, -YR, and -LR) in the agricultural soils and plants around the high incidence of cyanobacterial blooming water areas through field sampling and using high-performance liquid chromatography - tandem mass spectrometry, 2) to explore the desorption , degradation and leaching characteristics in the different types of soil by indoor simulation experiments,3) to investigate the bioaccumulation biological degradation , migration and distribution characteristics of the common MCs in the soil-plant(vegetable) system by pot-culture experiments and evaluate the potential threat of the MCs-contaminated vegetable to human health.

由蓝藻水华产生的微囊藻毒素(MCs)造成水体污染及其危害越来越严重，在水环境和水生态毒理学领域已有大量研究，但其进入土壤-作物系统中的污染特征、环境归宿和生物累积等科学问题还鲜有研究。本项目拟采用液相色谱-串联质谱(HPLC- MS/MS)分析技术，通过田间采样分析，查明典型地区以蓝藻水华污染水体灌溉的农田土壤、作物(蔬菜)中微囊藻毒素的种类与含量、时空分布、生物富集、品种差异、健康风险及其影响因素；通过室内模拟实验（吸附实验、土柱实验、降解实验），探讨土壤中微囊藻毒素的环境行为（吸附、迁移、降解等）及其影响因素；通过盆栽实验，揭示不同土壤-蔬菜系统中微囊藻毒素的生物降解、生物有效性（生物富集、剂量效应、品种差异等）及其影响因素。研究结果将促进农业环保领域微囊藻毒素研究的发展，为农产品质量安全提供科学依据。

水体富营养化蓝藻水华引发的微囊藻毒素水体污染及其危害已越来越严重，一直以来在水环境和水生生物学研究领域已被广泛关注和大量研究。而微囊藻毒素通过灌溉水、施用藻肥等途径进入土壤-作物系统的污染及其危害问题，目前尚未被人们充分认识到并鲜见研究报道。鉴于微囊藻毒素对人体健康的严重危害，关于土壤-作物中微囊藻毒素的污染特征、生物有效性及其环境行为等科学问题已成为当前亟待研究的重要课题。.项目以微囊藻毒素为研究对象，建立了蔬菜、土壤基质中多种痕量微囊藻毒素的液相色谱串联质谱分析方法，采用这些方法对典型蓝藻水华污染水域周边农田-蔬菜系统进行调查分析，发现由于灌溉、施用藻肥等原因，典型蓝藻水华污染水域周边蔬菜、土壤中存在微囊藻毒素污染，食用蔬菜是人类对微囊藻毒素的重要暴露途径之一。盆栽试验发现微囊藻毒素通过蔬菜根部吸收累积并向可食用的茎叶部分转运，在亚细胞分布上微囊藻毒素主要存在于细胞壁上，其次是胞液中；微囊藻毒素对植物幼苗、植株有毒害作用，产生氧化胁迫效应，微囊藻毒素浓度与之间存在良好的剂量-效应关系。此外，项目对土壤中微囊藻毒素的降解、吸附、迁移等环境行为进行了研究。项目发表了5篇研究论文，其中2篇SCI收录，培养毕业了4名研究生，取得了关于微囊藻毒素在土壤-陆生作物系统中生物有效性和环境行为的相关数据。研究结果填补了土壤-蔬菜中微囊藻毒素的研究不足，为农产品质量安全提供了科学依据。