采矿业污染河流底泥及河漫滩沉积物的粒径组成与砷形态分布特征

采用连续提取法分析了刁江底泥和河漫滩沉积物中砷的形态变化规律及其与沉积物粒径组成的关系.结果表明,刁江流域底泥和河漫滩沉积物中As含量分布存在差异,底泥中As主要赋存在63～170μm粒级颗粒中,河漫滩沉积物中As主要赋存在63μm粒级颗粒中.底泥和河漫滩沉积物中砷主要以铁合态、钙合态和残渣态的形式存在,且残渣态比例相对较高,表现出典型的尾砂污染特征.底泥中残渣态砷(Res-As)组成比例总体较高,主要赋存在63～170μm粒级颗粒中,而洪水水位河漫滩沉积物中Res-As组成比例相对较低,这与不同沉积物中硫化态砷的氧化反应差异有关.对于中下游河段,底泥和中水水位河漫滩沉积物中Res-As总体上呈逐渐降低的趋势,铁合态砷(Fe-As)组成比例的分布与Res-As呈相反的趋势.     

污水厂出水DOM的分级及三卤甲烷生成势研究

研究目的在于调查寒冷季节城市污水处理厂出水中天然有机物化学组分分级,探讨各分级组分与消毒副产物生成潜能间之关系。采集污水厂二级出水,以三种不同树脂把污水厂出水中有机物分离成六类不同组分,其中A水厂含量最高的物质为亲水酸性物质(33%)而B水厂的疏水性中性物质含量最多约占总有机物的64%。从总体来看两水厂的疏水性物质含量大于亲水性物质含量,疏水性物质的三卤甲烷生成势也较大,是水体中消毒副产物的主要前驱物质。疏水性有机物质较多,代表受生活污水污染严重,得知该城市污水主要受民生污染较多。     

外源硫酸盐对武汉南湖表层沉积物磷形态的作用

采用室内模拟实验,选取武汉市南湖表层沉积物及相应上覆水,研究了硫酸盐的输入对沉积物磷形态的影响.结果表明,硫酸盐输入水体后提高了沉积物磷的迁移活性,导致上覆水中总磷(TP)、溶解性正磷酸盐(SRP)含量升高,上升幅度随硫酸盐输入量的增加而增加.硫酸盐扩散到沉积物后,先是生成酸可挥发性硫(AVS),进而转变成铬还原硫.硫酸盐输入提高了沉积物pH值,而使Eh降低.沉积物不同磷形态对外源硫酸盐的响应有所差异,二钙磷(Ca2-P)含量随输入硫酸盐浓度的增加而增加,含量最高的铁磷(Fe-P)为800mg/kg左右,占总磷的51.4%~56.6%,受硫酸盐的影响极显著(P<0.01),在沉积物中含量降低而向上覆水中释放.上覆水中溶解性铁和TP、SRP均呈显著正相关.硫酸盐对沉积物中闭蓄态铁磷(O-Fe-P)也产生显著影响(P < 0.05),总体而言是促进其释放.     

Lead redistribution in a mine soil treated with three manures and incubated at two different temperatures

The study of heavy metals’ redistribution between different fractions allows to know their bioavailability and mobility in soils. Soil samples were collected from a lead mine in Hamadan provinces, NW Iran. In a factorial experiment soil was treated with cow, sheep and poultry manures (20?g?kg^?1 soil) separately and incubated near field capacity at 10°C and 37°C. An untreated soil (as control) was also incubated at the same temperatures. After 0 and 120 days, a sequential extraction scheme was used to fractionate Pb of incubated samples into soluble-exchangeable (Sol-Exch), organic matter associated (AOM), carbonates associated (ACar), and residual (Res) forms. Soil Pb in Sol-Exch and AOM fractions were increased by manure application significantly. The AOM and ACar forms of Pb were higher in soils treated with the manures and incubated in lower temperature. In contrast, the Sol-Exch and Res chemical forms of Pb were higher in the soils incubated at 37°C. These results may be related to the higher calcium carbonate dissolution and organic matter decomposition because of better biological activity in the soils incubated in higher temperature. The increase of the Res fraction (stable form) in this condition may resulted in lower toxicity and mobility in soil environment.     

Characterization of phosphorus species and modeling for its organic forms in eutrophic shallow lake sediments,North China

Variations of phosphorus （P） and its species in surface sediment of Baiyangdian Lake, a eutrophic shallow lake located in North China, were investigated through combination of field survey and numerical calculation based on cluster analysis. P fractionation was performed by a sequential extraction scheme, categorized as loosely bound P （NH4Cl-P）, reductant soluble P （BD-P）, metallic oxide bound P （NaOH-P）, calcium bound P （HCl-P） and organic P （Org-P）. P concentrations exhibited regional similarities and a total of four sub-areas were identified in which the same rank was HCl-P 〉 Org-P 〉 BD-P ,=NaOH-P 〉NH4Cl-E NH4Cl-P, BD-P and Org-P were found to contribute to P enrichment in overlying water column. Specifically, labile Org-P acted as a potential pool with a greater contribution in aerobic layer compared to anaerobic layer. A hysteresis （lag = 4 months） existed when labile Org-P concentration was negatively correlated with aerobic layer thickness. In view of magnitude of identified P contributors in sub-areas, higher potential of P release was present in Fuhe River and Tang River estuary areas. On the basis of calibration and verification, the mathematical model with parameter settings applied in this study was improved to serve as a tool for limnology management and eutrophic control.     

Characterization studies of a semi‐automated separation method for analysis of non‐ortho substituted polychlorinated biphenyl (PCB) congeners in environmental samples

Non‐ortho substituted polychlorinated biphenyl (PCB) congeners can account for the majority of the dioxin‐like toxicity in environmental samples, yet analysis for these congeners is difficult because other PCB congeners co‐elute with them in most Chromatographic methods. An automated method was developed which incorporates a porous graphitic carbon (PGC) column which is commercially available. Non‐ortho substituted congeners were successfully separated from interfering PCB congeners. Recoveries of non‐ortho substituted congeners were consistently reproducible (CV < 9%) when chicken eggs were fortified with individual congeners.     

Effect of acid rain on the fractionation of heavy metals and major elements in contaminated soils

Acid rain is a serious environmental problem worldwide. In the present study, we investigated the effect of acid rain (1:1 equivalent basis H₂SO₄:HNO₃) at pH values of 2.0, 4.0 and 7.0 on the fractionation of heavy metals (Cd, Cu, Fe, Mn, Ni, Pb and Zn) and major elements (K, Na, Ca, and Mg) in contaminated calcareous soils over a 2084 h period. Heavy metals and major elements in soil samples were fractionated before and after 2084 h kinetic release using a sequential extraction procedure. Before kinetic studies the predominant fractions of K, Na, Ca, Mg, Cd and Ni were mainly associated with carbonate fraction (CARB), whereas Fe, Mn and Zn were associated with the Fe–Mn oxide fraction (Fe–Mn oxide). The highest percentage of Pb and Cu were found in the exchangeable (EXC) and organic matter (OM) fractions, respectively. After kinetic study using different simulated acid rain solutions, the major fractions of heavy metals (expect of Cu) and Na was the same as before release. Upon the application of different acid rain solutions, K and Mg were found dominantly in Fe–Mn oxide fraction, whereas Ca was in the EXC fraction. The results provide valuable information regarding metal mobility and indicated that speciation of metals (Cu and Zn) and major elements in contaminated calcareous soils can be affected by acid rain.     

湖泊底泥土地利用对土壤中重金属铅、铜形态影响

采用田区试验研究了田间种植冬小麦条件下,底泥土地利用前后土壤中重金属铅、铜的形态演变及小麦各器官中铅、铜的富集。结果表明,随着底泥施用量的增加,土壤中重金属铅、铜的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态均有不同程度的增加,本试验所有处理中,可交换态铅的质量分数范围为0.02~0.10 mg·kg-1,碳酸盐结合态铅的质量分数范围为0.04~0.24 mg·kg-1,铁锰氧化物结合态铅质量分数为0.41~1.88 mg·kg-1,有机物结合态铅质量分数范围为1.23~4.92 mg·kg-1,残渣态铅质量分数范围为4.82~23.66 mg·kg-1;各处理与对照相比,可交换态铜质量分数增加了40.00%~200.00%,碳酸盐结合态铜质量分数增加了36.84%~363.16%,铁锰氧化物结合态铜质量分数增加了7.17~45.15%,有机结合态铜质量分数增加了7.98%~62.61%,残渣态铜质量分数增加了0.12%~9.69%,各处理的残渣态铅、铜质量分数均较高。随着底泥用量增加,小麦根系、茎叶、籽粒中铅、铜质量分数均呈增加趋势,植株对重金属铅、铜的富集顺序为根系>茎叶>籽粒,铜的富集系数均大于铅。小麦籽粒产量、茎叶生物量及地上部生物量随着底泥施用量的增加,均出现了先增加后减少的现象,当小麦籽粒产量达到最大值时,籽粒中铅、铜质量分数未超出我国相应标准,依此确定底泥环境安全施用量为3051.29 t·hm-2。     

PO43-和柠檬酸对稀土元素在小麦体内积累和分异的影响

基于营养液培养,添加外源稀土和ICP-MS分析技术,研究了无机配体PO₄^3-(Pi)及有机配体柠檬酸(Cit)对小麦器官中稀土元素积累和分异的影响.结果表明,不同Pi水平对小麦根中的稀土总含量(∑REE)影响较小,但显著降低叶中∑REE含量;而不同Cit水平对小麦根、叶中∑REE含量都有明显降低作用.对照植物(无Pi、Cit添加)中,稀土元素在小麦根中具有中稀土(MREE)富集及M-型四重效应分布特征,叶中有重稀土(HREE)富集及W-型四重效应分布特征.不同Pi处理对四重效应无明显作用,但进一步加强HREE在小麦叶片中的富集.添加柠檬酸使对照植物根和叶中的分异有逐渐减弱的趋势,在高浓度处理时(Cit≥150μmol·L^-),小麦根和叶中出现轻稀土(LREE)富集.     

天然水体溶解性有机物(DOM)分级组分对典型城市源污染的荧光响应

运用化学(树脂)分级方法和三维荧光光谱技术,从总体溶解性有机物(DOM)到DOM各分级组分,逐步深入考察其总体分级特征及各组分三维荧光特征对典型城市生活源污染的响应特征和机理. 总体DOM分级特征对污染的产生和变化响应较弱,而DOM的分级组分对生活源污染具有较好的响应特性. DOM的总体分级特征表明,无污染的源头水DOM中以憎水酸(HoA)为主(相对含量最高),其次为亲水性物质(HiM),而受污染水体DOM中的憎水性碱和中性物质(HoBN)及弱憎水酸(WHoA)的绝对含量和相对含量均明显增高,表明用HoBN和WHoA组分相对含量的增加指示污染的增加具有一定的可行性. 研究各分级组分的三维荧光光谱结构特征表明,HoA,HoBN及HiM均对城市源污染具有良好的响应特性,受污染水体的HoA和HoBN组分荧光特征信息更为突出和丰富,且主要为具有紫外吸收的生物代谢类蛋白物质;最为特异的是WHoA组分,其在源头水中主要为含共轭结构的富里酸类物质,而在受污染水体中该类物质几乎消失且荧光响应也急剧降低. 分析式分级法获得的水体DOM主要分级组分对城市源污染具有较好的响应特性.