渭河陕西段潜流带沉积物重金属变化初步分析

为厘清潜流带沉积物重金属时空变化及与水量交换、沉积物颗粒结构间的关系,于2013年春夏两季对渭河陕西段5个研究断面66个测试点位沉积物的野外原位渗透系数、颗粒粒径、重金属含量进行分析.结果表明:影响渭河沉积物渗透系数的主要因素是沉积物粒径,同时沉积物垂向分层、排列组合也影响其渗透性能;沉积物重金属Cu、Zn、Pb、Cd质量分数在垂向上不同深度其含量大小不同,在时间上总体呈现春季夏季,富集系数(EF指数)分析结果显示春季Cu、Zn(除华县)、Pb(除眉县)、Cd富集严重且主要受人为输入源影响,夏季除Cd元素外,Cu、Zn、Pb的EF值均1.5,说明其含量主要来源于地壳和岩石圈的自然风化过程;Pearson相关分析发现粘土与粉砂(粒径0.075 mm)百分比与沉积物重金属质量分数呈弱相关,重金属粒径效应不显著,粒径不是控制重金属含量的主要环境影子;对单一重金属垂向不同深度含量进行相关性研究发现除Cd外,其余3种重金属在垂向上的相关系数均0.5(p0.01),说明单一重金属在垂向上具有同源性且存在相互迁移与转化.     

闽江河口短叶茳芏沼泽湿地沉积物磷的赋存形态和空间分布

对闽江河口区不同盐度短叶茳芏沼泽湿地沉积物中磷的赋存形态和分布特征进行了研究,探讨了河口沉积物中磷的来源及其影响因子.结果表明:1闽江河口湿地沉积物全磷(TP)含量介于607.91~807.60 mg·kg-1,平均值为726.29 mg·kg-1;有机磷(OP)含量介于120.44~166.63 mg·kg-1,平均值为139.43 mg·kg-1,约占TP的18.93%;无机磷(IP)含量介于479.65~647.56 mg·kg-1,平均值为586.86 mg·kg-1,约占TP的81.07%,IP是磷的主要赋存形态.2IP中,赋存形态以闭蓄态磷(O-P)和铁结合态磷(Fe-P)为主,分别占IP的39.97%和32.92%;其次是钙结合态磷(Ca-P)和铝结合态磷(Al-P),分别占IP的17.89%、9.22%.3在空间分布上,TP、OP、IP含量在由海向陆方向整体呈先降低后递增趋势;IP不同赋存形态在空间上也整体上呈现出以上趋势;垂直方向上,总体都表现为随土层深度波动降低,这在一定程度上反映了近年来河口湿地环境污染的加剧.4磷的赋存形态和空间分布特征是电导率、pH、容重、含水率和粒度等多因子综合作用的结果.     

滇池表层沉积物对磷的吸附特征

在室内模拟条件下,从滇池表层沉积物对磷的吸附动力学与热力学两个角度出发,研究了滇池沉积物对磷的吸附特征,同时探讨了不同磷形态对磷吸附特性的影响,结果表明:1滇池不同形态磷含量顺序为:有机磷钙(O-P)钙结合态磷(Ca-P)金属氧化物结合态磷(Al-P)残渣态磷(Res-P)可还原态磷(Fe-P)弱吸附态磷(NH4Cl-P);2沉积物对磷的吸附动力学过程分为2个阶段,即快吸附和慢吸附阶段.快吸附阶段主要发生在0~0.5 h内,而慢吸附阶段主要发生在0.5~4 h.滇池沉积物对磷的吸附过程主要在4 h内完成.3外海北部上覆水磷酸盐(SRP)浓度低于沉积物中磷的吸附/解吸平衡浓度(EPC0),可初步判断该区域沉积物有向上覆水体释放磷的风险.4不同区域沉积物磷的最大吸附量(Qmax)和总最大吸附量(TQmax)均以外海南部最大.5沉积物本底吸附态磷含量(NAP)与钙结合态磷(Ca-P)呈显著正相关关系(R2=0.5139,p0.05),而其他吸附特征参数与磷形态之间相关性均不显著.6与洱海、太湖等湖泊相比,滇池沉积物磷的本底吸附态磷(NAP)和最大吸附量(Qmax)均处于较高水平,磷污染较为严重.     

Application of fish index of biological integrity (FIBI) in the Sanmenxia Wetland with water quality implications

Long-term changes of fish biotic integrity in the Sanmenxia Wetland,North China,since the 1950 s were assessed using the fish index of biological integrity（FIBI）. The water and sediment quality was evaluated by the water quality index（WQI） and sediment pollution index（SPI）. The results showed that FIBI continuously decreased from 46 to 20 during the past 5 decades,which indicated that the fish community state shifted from fair to very poor conditions,and damming by itself did not affect the fish biotic integrity. At the same time,WQI fell from 83 to 44.1,and SPI increased from 0.99 to 2.14 since the 1960 s,resulting from fast regional socio-economic development and insufficient wastewater treatment. Correlation analysis suggested that water quality significantly affected biotic integrity（r = 0.867,p 〈 0.05） through direct effects on the fish community. As a representative example of many wetlands in North China,our study clearly demonstrated that the biological integrity was degraded,induced both by water quality deterioration and sediment pollution,further driven by the contradiction between rapid development of regional economy and lagging development of sewage treatment facilities,which were thought to be the main factor responsible for the degradation of biological integrity.     

全氟化合物对表层沉积物中细菌群落结构的影响

选择集中分布氟化工相关企业的山东省小清河水系,自上游至莱州湾入海口采集10个表层沉积物样点(XQ1~XQ10),采用高效液相色谱/质谱联用(HPLC/MS-MS)监测全氟化合物(perfluoroalkyl substances,PFASs),分析影响细菌群落结构的基础环境因子,提取细菌DNA并运用第二代Illumina Mi Seq测序技术分析其细菌群落结构.结果表明,在小清河流域沉积物中12种PFASs均有不同程度检出,并以全氟辛酸(PFOA)为主,生产企业集中区下游样点XQ5的PFOA浓度在4、7月分别高达456.2 ng·g-1和748.7 ng·g-1.PFOA是小清河4月影响微生物群落结构的关键因子,与群落丰富度和均匀度呈显著负相关;硫杆菌属(Thiobacillus)在低浓度PFOA条件下数量较少,但在高浓度PFOA下数量较高且成为优势菌种,初步证明硫杆菌属是PFOA污染响应的敏感物种,有作为指示微生物的潜质;PFOA在浓度较低时(100 ng·g-1)对微生物群落结构的影响不显著.     

影响粪固醇在大连近海沉积物上吸附的环境因素研究

试验采用大连海湾近海表层沉积物为吸附剂,以粪固醇为吸附质,通过正交实验法,研究了吸附质的初始浓度、反应温度、溶液盐度、pH以及沉积物粒度等因素对近海沉积物吸附粪固醇的影响。结果表明:不同环境因素对吸附的影响程度不同,影响程度依次为吸附质初始浓度>温度>盐度>沉积物粒度>pH。吸附质初始浓度、盐度、温度对粪固醇在沉积物上的吸附作用有一定的影响;沉积物粒度、溶液pH对吸附影响不显著。     

上海市小城镇河流沉积物重金属污染特征研究

以3个典型小城镇河流为例,研究上海市小城镇河流沉积物重金属污染特征.结果显示,沉积物Zn的浓度在3.11～3.74g/kg之间,是农用污泥Zn使用允许最高值0.5g/kg的6～8倍,沉积物Zn的极度污染已经成为上海市小城镇河流沉积物区域性环境问题;沉积物Pb和Cu的浓度分别在0.03～1.00g/kg和0.07～0.20g/kg之间,小城镇河流沉积物也明显受到Pb和Cu污染且污染区域差异性大,沉积物中铁、锰、铬等重金属污染相对较轻;毒性弱的Fe,Mn,Zn沉积物区域污染差异性相对小,而毒性强的Pb,Cu,Cr区域差异性相对较大;沉积物重金属污染一般中型河流污染相对稍突出,小城镇河流沉积物由于Zn的严重污染不能用作施用污泥;利用重金属与TP,重金属与Fe之间的相关性探源结果显示:小城镇生活污水的地表排放使得街道灰尘成为河流沉积物Pb的一个重要来源.     

渗滤液污染羽中沉积物氧化还原缓冲能力研究

通过土柱模拟实验研究含水层沉积物的氧化还原缓冲能力及其在不同氧化还原带中的变化.结果表明,随着污染的加重,沉积物的氧化容量(OXC)减小,而还原容量(RDC)升高.在未受污染的沉积物中,Fe³⁺是OXC的主要组成,约占OXC的70.5%;TOC是RDC的主要组成,约占RDC的98.7%.在厌氧环境中大部分无定型态和部分晶体态Fe³⁺被还原,还原产物主要以FeCO₃和FeS形式沉淀;在产甲烷带/硫酸盐还原带和铁还原带中,Fe²⁺的沉积使得可离子交换态Fe²⁺含量由原样中的0.5%分别升高至3%和1.84%.因此Fe³⁺是含水层中主要的氧化还原缓冲剂,Fe³⁺还原、Fe²⁺沉淀和Fe2+的离子交换等作用大大减小了厌氧渗滤液污染羽的扩展,对进入含水层的还原性污染物有重要的缓冲作用.     

Phosphorus sorption capacities in a headstream landscape The pond chain structure

Understanding phosphorus sorption phenomena in different wetland sediments is important in controlling the P output in headstream watersheds. The pond chain structure （PCS） is widespread in the headstream agricultural watersheds in the southeast of China. Phosphorus sorption characteristics were determined for pond surface sediments （0-12 cm） along a pond chain structure in Liuchahe watershed of Chaohu Lake. Results showed that P sorption capacities （expressed by P sorption index （PSI）） varied both with the landscape position of the ponds and sediment depth. From foothill ponds to riverside ponds the P sorption capacities indicated a significant gradient variability. The higher elevation ponds showed greater sorption capacities, and with the pond elevation decline, P sorption capacities gradually decreased. Some physico-chemical properties, such as pH, oxalate-extractable Fe （Feox）, organic matter （TOC） and Mehlich l-extractable Ca, Mg of pond sediments also indicated significant gradient variability from high elevation ponds to low elevation ponds. Feox was the sediment parameters most highly positively correlated with PSI and was the key factor in controlling P sorption capacity in the pond chain structure （r=0.92, p〈0.001）. Long-term hydrologic and sediment inputs can affect the distribution of sediment constituents and further affect the P sorption capacity. Making the best of the spatial difference of sorption capacities of ponds in watersheds to control nonpoint source P pollutant is necessary.