太湖沉积物重金属污染及生态风险性评价

对1993年～1999年所采集的太湖表层沉积物中重金属含量进行了统计分析和生态风险性评价.结果表明,太湖沉积物的pH值呈中性至弱碱性,较适合于沉积物中粘土矿物及腐殖质对重金属的吸附;太湖大部分地区沉积物未受到重金属污染,且沉积物中重金属处于安全状态.沉积物生态风险性指数评价结果也表明,太湖大部分地区目前无重金属生态危害.     

Multivariate Analysis of Interactions Between Phytoplankton Biomass and Environmental Variables in Taihu Lake, China

Phytoplankton variation in large shallow eutrophic lakes is characterized by high spatial and temporal heterogenity. Understanding the pattern of phytoplankton variation and the relationships between it and environmental variables can contribute to eutrophic lakes management. In this study Taihu Lake, one of the largest eutrophic fresh water lake in China, was taken as study area. The water body of Taihu Lake was divided into five regions viz. Wuli bay (WB), Meilian Bay (MB), West Taihu Lake (WTL), Main Body of Taihu Lake (MBTL) and East Taihu Lake (ETL). Concentrations of chlorophyll-a and the related environmental variables were determined in each region in the period 2000–2003. Factor analysis and multivariate analysis were applied to evaluate the interactions between phytoplankton variation and environmental variables. Results showed that the highest average concentrations of TN, TP and Chl-a were observed in WB, followed in a descending order by MB and WTL, and the lowest concentrations of TN, TP and Chl-a were observed in MBTL and ETL. Chl-a and TP concentrations in most regions (except ETL) declined during the study period. It suggested that to some extent the lake was recovering from eutrophication. However, persistent ascending of TN and NH₄–N in all five regions indicated the deteriorating of water quality in the study period. Results of multivariate showed that the relationships between phytoplankton biomass and environmental variables varied among regions. TP illustrated itself a controlling role on phytoplankton in WB, MB, WTL and MBTL according to the significant positive relations to phytoplankton biomass in these regions. Nitrogen could be identified as a limiting factor to phytoplankton biomass in ETL in view of the positive correlations between TN and phytoplankton and between NH₄–N and phytoplankton. Spatial variation of interactions between phytoplankton and environmental parameters suggested proper eutrophication control measures were needed to restore ecological system in each region of Taihu Lake.     

太湖湖风指数阈值的计算

根据2012年8月17—23日的太湖湖风加密观测实验结果,将湖岸3个常规气象站和湖面2个浮标站观测的风速和气温资料代入经典的湖风指数公式,通过Fisher二级判别法和历史拟合率最大法确定了太湖湖风指数的阈值为3.0。该结论为研究太湖湖风的发生频率及其对蓝藻水华全湖输移的影响提供了理论依据。     

Eutrophication conditions and ecological status in typical bays of Lake Taihu in China

Sampling was conducted at three site groups, group E (in East Taihu Bay), G (in Gonghu Bay) and M (in Meiliang Bay) in Lake Taihu. TN and TP concentrations among site groups was in the increasing order of E < G < M. TP level at G sites is at the critical threshold for loss of submersed macrophytes. Mean values of DO and Transparence showed different trend, i.e., E > G > M. The mean phytoplankton fresh-weight biomass at M sites was 5.81 mg/l, higher than that at E sites (4.96 mg/l) and G sites (5.18 mg/l). Mean zooplankton fresh-weight biomass was in the decreasing order of M (6.4 mg/l) > G (4.9 mg/l) > E (2.7 mg/l). However, Rotifera density was in the sequence of E > G > M. Both zooplankton biomass and phytoplankton biomass increased with the rise of TN and TP concentrations. Relationships between zooplankton biomass and phytoplankton biomass showed that zooplankton played a limited role in the control of algae in eutrophic lakes. Nutrient availability is much more important than zooplankton grazing pressure in controlling phytoplankton growth in lakes. For most sites in Lake Taihu, reduction of nutrient loading, as well as macrophyte conservation, zappears to be especially important in maintaining high water quality and regulating lake biological structure, but for M sites, it’s urgent to control nutrient inputs rather than to restore macrophyte community.     

太湖蓝藻水华暴发主要特征初析

太湖水体富营养化加剧引起了多方面的关注,针对近年实际监测结果,结合历年流域水环境质量的变化,初步归纳了当前太湖蓝藻水华暴发的地域特征、时间周期特点及主要水质指标的变化规律,总结了太湖蓝藻水华的暴发呈多峰形状态.2007年太湖沙渚水源地藻类生物量的两峰三阶段的特征进一步表明,太湖蓝藻水华的暴发进入了高频期.     

太湖微囊藻毒素与湖泊物理因素之间的关系

应用酶联免疫吸附法(ELISA)监测了太湖2001年的微囊藻毒素的周年变化,探讨了微囊藻毒素浓度(Microcystin-LR,MCLR)和水温、光照、悬浮质、溶解氧、风浪等湖泊物理因素之间的关系,显示微囊藻毒素在夏秋季节较高,但各采样点微囊藻毒素浓度的最高值及其变化趋势与各采样点所处地理位置,水动力学变化及样点周围水域藻类生长情况等有密切关系,从湖泊物理因素来看,微囊藻毒素浓度受风浪和水温的影响较大。     

太湖水体溶解态磷的时空变化特征

对2010年太湖西岸区北段、湖心北区、贡湖、梅梁湾、竺山湾、西岸区南段、湖心南区、南岸区和湖心区9个研究点位水体中的溶解态总磷(TSP)、溶解态反应磷(SRP)和叶绿素a(Chl-a)进行了长达1年的动态监测,全面分析了太湖不同月份、不同区域水体溶解态磷含量的时空动态变化特征及其与藻类生长的相关性。全湖月平均TSP变化范围为(0.027±0.019)~(0.054±0.042)mg/L,SRP变化范围为(0.009 ± 0.006)~(0.035 ± 0.020) mg/L,夏秋季SRP含量高于春冬季。北太湖区溶解态磷含量普遍高于南太湖区,近岸溶解态磷含量高于离岸。各点位年均TSP变化范围为(0.019±0.011)~(0.104±0.038) mg/L,SRP变化范围为(0.009±0.006)~(0.041±0.022)mg/L。全年SRP变异(53.2%)高于TSP(23.4%)、近岸变异高于离岸、表层高于底层。溶解态磷含量日变化特征不明显,外源磷输入影响太湖水体溶解态磷分布。全年中太湖水体TSP、SRP与Chl-a呈显著正相关,相关系数分别为0.313(P<0.01)、0.284(P<0.01)。     

太湖梅梁湾水源水中微囊藻毒素浓度的变化

对太湖梅梁湾水源水中的总藻毒素TMC[(TMC-LR) (TMC-RR)]和胞外藻毒素EMC[(EMC-LR) (EMC-RR)]进行了跟踪检测.结果表明,水体中TMC-RR、TMC-LR、EMC-RR、EMC-LR质量浓度平均分别为1.819 μg/L、1.090 μg/L、0.491 μg/L和0.077 μg/L,无锡市的主要水源地水质已受到微囊藻毒素的污染.提出,应加强水源地水体中微囊藻毒素浓度的监测,确保饮用水的安全.     

The Status of Pesticide Residues in the Drinking Water Sources in Meiliangwan Bay, Taihu Lake of China

The study was carried out to assess the levels of pesticide residues in the water of Meiliangwan Bay, Taihu Lake of China. The most commonly employed organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs) and herbicide atrazine were analyzed. The water samples were collected seasonally from Meiliangwan Bay within a period of one year. The pesticides were analyzed by gas chromatography (GC) with μECD or NPD after solid-phase extraction (SPE), which was confirmed by GC with an ion trap mass spectrometry (MS). The mean concentrations were 1.98 ng/l for lindane, 0.378 ng/l for heptachlor epoxide, 0.367 ng/l for p,p′-DDE, 0.496 ng/l for p,p′-DDD, 1.06 ng/l for p,p′-DDT and 51.6 ng/l for dichlorvos, 39.0 ng/l for demeton, 346 ng/l for dimethoate, 4.12 ng/l for methyl parathion, 11.6 ng/l for malathion, 2.17 ng/l for parathion and 217 ng/l for atrazine. Generally, low concentrations of OCP were found, whereas the concentrations of the OPPs and atrazine in the water of Taihu Lake were relatively high. Heptachlor epoxide and lindane were the two most commonly encountered OCPs while dichlorvos, demeton and dimethoate were found to have much higher concentrations and occurrences than other OPPs.     

改进的模糊综合评价法在太湖水质类别判定中的应用

水质判别是一个多参数多级别的模糊概念,基础的模糊综合评价法存在局限性,对基础模糊数学法中隶属度函数及最大隶属度原则进行改进,建立一种改进的模糊综合评价法。以太湖流域水质判别为实例验证了此方法比传统的方法更有效,且适合在太湖流域应用。     

夏季太湖梅梁湾水体中细菌的群落结构

利用高通量测序技术,选择16S rRNA V6区作为目标片段,对夏季太湖梅梁湾水体中的细菌群落结构进行了分析,结果表明,共产生了101 427条优质序列,细菌为100 935条,占99.5%;在蓝藻暴发期间,共检测到14门,55属,610个操作分类单位。优势门类为蓝藻门(39.7%),放线菌门(27.2%)和变形菌门(23.4%),微囊藻属(21.0%)和聚球藻属(15.9%)为主要优势种。     

太湖流域景观生态风险评估

在GIS和RS技术支持下,以遥感数据和土地利用数据为基础,以行政区划为评价单元,构建景观生态风险评价模型,定量评价了研究区内景观生态风险的时空动态变化特征。结果表明,较低风险区主要分布于以苕溪为主的山地丘陵区,中等风险区主要分布于农业发达的平原区,较高风险区及高风险区主要集中于沿湖经济发达区。     

太湖蓝藻水华暴发程度年度预测

近年来,尽管太湖主要水质指标有所改善,但蓝藻水华暴发的频次和面积并未明显减少。为了探讨太湖蓝藻水华暴发的环境驱动因子,统计了2012—2020年历年4—10月预警期间的太湖蓝藻水华发生规模与频次,结合同步浮标自动监测数据和实验室分析数据,构建了蓝藻水华预测模型。以太湖蓝藻水华综合指数(I_c)表征蓝藻水华强度,并通过I_c与环境因子的相关性分析,筛选出1月水温、1月电导率、1月生化需氧量和3月总氮浓度4项环境指标,最终构建了以该4项环境指标为自变量、I_c为因变量的太湖年度蓝藻水华强度多元线性回归预测模型。该预测模型的决定系数达到了0.908,平均相对误差为10.35%,预测精度总体表现较好。     

太湖浮游植物种类组成时空变化规律

从2010年的3月到2010年的10月,通过春、夏、秋3个季度的采样,对太湖东部的浮游植物种类组成及其变化进行渊查,发现浮游植物92属279种,太湖东部五个采样点位的浮游植物常见种季节变化明显,而各湖区浮游植物种类绀成空间变化较小。通过对太湖东部浮游植物种类组成的时空变化的规律的初步探索,为预警监测及水环境保护提供技术支持。     

氮、磷等环境因子对太湖微囊藻与水华鱼腥藻生长的影响

为探索太湖主要水华藻类（微囊藻与水华鱼腥藻）在多种环境因子作用下的生长变化机理,在实验室内对部分水华藻类（微囊藻、鱼腥藻）进行分离培养,研究氮、磷、温度等环境因子对水华藻类生长增殖的影响。研究表明,高水温（30℃）是微囊藻的最适生长温度;随着氮、磷浓度的提高,微囊藻的生长速率加快;低磷是鱼腥藻生长的限制因子。同时,通过野外测定的各项指标发现,当藻类密度较低时,其与总氮、总磷呈正相关。     

夏季太湖蓝藻水华暴发与臭氧污染的关联性

夏季受东南季风、湖流等因素影响,太湖蓝藻向西北部水域集聚,该区域平均藻密度可高达1×109个/L以上,其中蓝藻集中堆积的近湖岸区域藻类密度更高,蓝藻在不同生命阶段释放的藻源性VOCs的成分谱和产生量有较大差异,其中烯烃和有机胺反应活性较强。蓝藻水华高发期太湖西岸非甲烷总烃的浓度约为常州市区的3.3倍,日变化趋势符合蓝藻代谢规律。太湖西部蓝藻水华、湖西区的非甲烷总烃浓度和臭氧污染程度时空变化规律表明:太湖西部(宜兴)是整个流域臭氧污染最严重的区域,其臭氧污染的形成与太湖蓝藻水华暴发有关联性。     

自动监测预警太湖蓝藻爆发规律研究

以太湖湖体中沙渚、兰山嘴两个自动站的监测数据为基础,分析了太湖蓝藻爆发过程中主要水质指标变化情况。研究结果表明,蓝藻引发灾害性湖泛现象的主要过程分为生长期、平稳期、死亡期、高危前期、灾害期和恢复期,在高危前期和灾害期,溶解氧(DO)快速下降,而总氮(TN)等参数的变化正好与DO变化相反,这一显著特征可作为预警的重要信息。     

江苏省太湖流域水环境自动监控系统技术框架构建研究

为全面提升江苏省水环境的监控预警能力,我省在太湖流域相关市县建立了覆盖省市交界断面、出入湖口门、饮用水源地的全方位自动监控网络,为相关自动监控系统的技术框架构建提供了重要参考依据,弥补了现行环境监测体系的不足,为太湖流域的监控预警、生态补偿、流域考核等工作提供了重要参考。     

太湖蓝藻水华预警监测综合系统的构建

近年来随着浅水型湖泊的富营养化进程不断加快,蓝藻水华暴发现象也频繁出现,采用科学、全面的手段对太湖蓝藻暴发进行预警十分必要。根据太湖蓝藻预警监测中使用的现场巡视、卫星遥感、实验室分析、自动监测等监测技术手段,分别建立各自监测系统,结合各监测系统特点和相互关系,对太湖蓝藻水华预警监测综合系统的构建进行了探讨,以期能够更好地开展太湖蓝藻水华预警监测工作,为确保太湖地区饮用水安全,提高环保部门应对太湖蓝藻水华暴发的能力,为政府决策提供技术支持和保障。     

基于无人机高光谱遥感在太湖蓝藻水华监测中的一次应用

采用机载高光谱视频相机,在4个季节对太湖蓝藻进行7次、18个架次的有效拍摄。对拍摄到的高光谱影像进行辐射定标、几何拼接等预处理后,提取不同浓度蓝藻和水草等其他物体的高光谱数据,发现不同浓度的蓝藻光谱在680 nm后表现出较大差异。采用主成分分析（PCA）对高光谱数据降维后,结合k-近邻（kNN）分类算法,可实现对蓝藻的精准定位。定性识别结果经光谱预处理后,采用连续投影算法（SPA）进行特征波段提取,发现蓝藻光谱的季节差异主要表现在450 nm~570 nm和760 nm~910 nm波段。