海水和海洋沉积物中总磷的测定

系统介绍了海水和海洋沉积物中总磷的测定方法，选用Ｋ２Ｓ２Ｏ８为氧化剂将有关形式的Ｐ转化成ＰＯ＾３－４，连同样品中原有的ＰＯ＾３－４－起用以抗坏到为还原剂的磷钼蓝法测定。方法的精密度６％，回收率为９１％－１０７％。     

河流沉积物重金属污染质量控制基准的研究 Ⅰ.C-B-T质量三合一方法(Triad)

在综合数据库ＣＥＲＰ－ＤＢＭＳ支持下，利用水体沉积物质量三合一工具，初步建立江西乐安江表层沉积物中重金属污染的质量控制基准。通过将化学分析、毒性鉴定２和底栖群落结构变化三基元集成为一体的三轴图和相应的响应信息判断矩阵，基于现场生物响应的重金属污染的剂量－响应关系。     

Trace metals distribution and their dependence on some physico-chemical parameters in creek sediment

The concentrations of the trace metals Mn, Zn, Cr, V, Co, Ni, Ba, Pb, Cu, Cd, As and Hg, their spatial distribution, and their correlation as a function of physico-chemical parameters were investigated for grab sediment samples collected from different locations across the Thane Creek, Mumbai, India. Hydride generation atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, and differential pulse anodic stripping voltammetry were adopted for chemical analyses. Various geochemical indices were evaluated. The studied metal/metalloids were compared with sediment quality guideline values. Besides, the role of different physico-chemical parameters of the sediments such as pH, CaCO₃, cation exchange capacity, total carbon, and of the relative composition in respect to very coarse, coarse and medium sand, fine sand and very fine sand, silt and clay fraction were also critically investigated. Positive one-to-one correlations between fine sand and very fine sand, silt and clay, and total carbon with sediment metal concentrations have been noticed. Multiple regression analysis reveals strong positive correlations between sediment metal concentrations and total carbon content only.     

Trait space of rare plants in a fire‐dependent ecosystem

The causes of species rarity are of critical concern because of the high extinction risk associated with rarity. Studies examining individual rare species have limited generality, whereas trait‐based approaches offer a means to identify functional causes of rarity that can be applied to communities with disparate species pools. Differences in functional traits between rare and common species may be indicative of the functional causes of species rarity and may therefore be useful in crafting species conservation strategies. However, there is a conspicuous lack of studies comparing the functional traits of rare species and co‐occurring common species. We measured 18 important functional traits for 19 rare and 134 common understory plant species from North Carolina's Sandhills region and compared their trait distributions to determine whether there are significant functional differences that may explain species rarity. Flowering, fire, and tissue‐chemistry traits differed significantly between rare and common, co‐occurring species. Differences in specific traits suggest that fire suppression has driven rarity in this system and that changes to the timing and severity of prescribed fire may improve conservation success. Our method provides a useful tool to prioritize conservation efforts in other systems based on the likelihood that rare species are functionally capable of persisting.     

水系沉积物中铅含量的快速荧光测定方法的研究

建立了简单、快速测定Ｐｂ＾２＋的荧光测定方法。在ｐＨ＜６．８的酸度条件下,Ｐｂ＾２＋与浓度为１．４－２．０ｍｏｌ／Ｌ的Ｃｌ＾－形成的铅氯配合物在２６２．５ｎｍ的紫外光激光下发射出４８５．０ｎｍ可用于痕量铅离子测定的荧光,在选定激发单色器通带１０．０ｎｍ,发射单色器通带２０．０ｎｍ的仪器条件下,荧光强度与１．０×１０＾－７－１．０×１０＾－５ｍｏｌ／Ｌ范围的Ｐｂ＾２＋的线性关系可用△Ｆ＝１．０１×１     

水系沉积物中痕量铈、铅快速同时测定的荧光分析法研究

在研究氯化钾介质中铈(Ⅲ)、铅(Ⅱ)的荧光性质基础上,提出了快速测定铈、铅的荧光分析法。在实验条件下,用262．5nm紫外光激发,以120nm／min扫描300～520nm的发射光谱。其在352．4nm处峰高与2．0×10－8～2．0×10－6mol／LCe3－,在485．0nm处峰高与4．0×10－7～1．0×10－5mol／LPb2－,存在线性关系。该法用于标准水系沉积物分析,结果与标准值无显著性差异。Ce￣(3＋)和Pb￣(2＋)的检出限分别为1．5×10－8和2．0×10－7mol／L。      

玉米对受污染河道复合沉积物的修复

为减轻城市河道沉积物的受污染程度,利用温室盆栽玉米对其中的污染物进行了修复研究试验.结果表明,玉米体内累积最多的重金属是zn,占沉积物中Zn总量的56.69%,其中地上部分为1 985.56 mg·kg-1,占沉积物中Zn总量的30.16%,其余重金属(Pb、Cu、Ni、Cd)均为地上部分小于地下部分;Cd在玉米地上部分的累积量为2.33 mg·kg-1,为沉积物中Cd总量的40.10%;地上部累积的Zn、Pb、Cu和Ni等重金属数量与其离子交换态量显著相关,与重金属总量相关性不明显.种植玉米后沉积物中大分子有机物逐渐向小分子过渡,有效降低了有机物的污染.玉米的根际作用增加了沉积物中的微生物和酶活性.种植玉米较好地修复了受污染河道复合沉积物.     

红枫湖沉积物中重金属污染特征与生态危害风险评价

调查了红枫湖沉积物中重金属的含量、分布特征与富集情况. 分别以现代工业化前正常颗粒沉积物中重金属含量的最高背景值和红枫湖周边环境土壤的背景值为参比值,对红枫湖沉积物中重金属的富集系数和生态危害系数以及各采样点的生态危害指数进行了探讨,并结合瑞典学者Lars Hkanson潜在生态危害指数法对红枫湖沉积物中重金属的生态危害进行了评价. 结果表明:该湖泊沉积物中重金属含量分布呈现一定的区域特征,北湖湖区重金属平均含量高于南湖湖区;以现代工业化前正常颗粒沉积物中重金属含量的最高背景值为参比值,重金属的富集顺序为Cd＞Hg＞As＞Cu＞Zn＞Pb,污染水平顺序为Cd＞Hg＞As＞Cu＞Pb＞Zn;以红枫湖周边环境土壤平均值为参比值,重金属的富集顺序为Cu＞Cd＞Zn＞As＞Pb＞Hg,污染水平顺序为Cd＞Hg＞As＞Cu＞Pb＞Zn.       

沉积物中有机氯农药超声提取分析方法研究

应用超声提取沉积物中的有机氯农药(OCPs),GC-ECD进行定量分析. 研究了不同提取溶剂、提取时间、提取次数以及不同极性的毛细管色谱柱对沉积物中11种OCPs(六氯苯,α-HCH,γ-HCH,七氯,艾氏剂,δ-HCH,β-HCH,p,p′-DDE,o,p′-DDT,p,p′-DDD和p,p′-DDT)提取效率的影响,确定了沉积物中OCPs超声提取的最优条件:用正己烷/二氯甲烷(体积比为1∶1)作提取溶剂,提取60 min,提取1次,采用DB-1701毛细管色谱柱,GC-ECD定量测定可以得到较好的效果,提取效率均高于70%,满足美国环境保护局(USEPA)的要求. 利用最优条件分析了辽东湾沉积物中的OCPs含量. 结果表明,辽东湾沉积物中六氯苯,α-HCH,γ-HCH,七氯,δ-HCH,β-HCH,p,p′-DDE,o,p′-DDT,p,p′-DDD和p,p′-DDT均被检出;DDTs类以p,p′-DDT含量最高,且以DDE为主要的降解产物;HCHs以δ-HCH含量最高. 与其他湖泊河流沉积物相比,辽东湾HCHs,DDTs及六氯苯含量相对较高.      

南四湖及主要入湖河流表层沉积物对磷酸盐的吸附特征

研究了南四湖及其主要河流人湖口18个表层沉积物对磷的吸附能力、吸附动力学及其吸附等温线,并对湖区沉积物对磷吸附特征及其理化特征之间的关系进行了探讨.结果表明,对于处于不同营养水平的沉积物,对磷酸盐的吸附具有一致的特征.在前10h沉积物对磷酸盐的吸附量基本达到或超过平衡吸附量的80%,并且在0～1.0 h内吸附反应迅速.在本研究条件下,表层沉积物的cEPC的变化范围为0.010～0.157mg·L-1, Qmax的变化范围是86.74～118.32 mg·kg-1, TQmax的变化范围是99.97～281.11 mg·kg-1·cEPC、NAP、m、Qmax和TQmax与Ads-P都具有显著的正相关关系,沉积物Ads-P含量可以作为指导南四湖水体污染程度的一项指标. m与TQmax之间具有显著的正相关性,吸附效率不仅体现的是对外来磷的吸附效率,还应当包含对本身释放磷的再吸附的效率.对于南四湖沉积物TQmax、NAP和Qmax起到同样的贡献.沉积物的NAP与cEPC之间呈显著正相关性,总的趋势就是,当上覆水中磷含量相等时,具有高的NAP的沉积物易于向上覆水体释磷,反之具有较低NAP的沉积物易从水中吸附磷.