南黄海中部E2柱样沉积物来源的稀土元素及微量元素示踪

应用稀土元素地球化学示踪方法,分析了南黄海中部E2柱样的∑REE、∑LREE、∑HREE、∑LREE/∑HREE、δEu和δce的变化特征.结果表明,近200年来南黄海中部沉积物的稀土元素可能均受相同来源控制,稀土元素分布具上陆壳特征.南黄海中部E2柱样和中国东部上地壳的稀土分布模式一致,而与深海沉积物的稀土分布模式相差较大,反映了黄海沉积物和中国大陆壳的亲缘性.近200年来沉积物的δCe和δEu变化不大,且其平均值与上陆壳基本一致,说明近200年来源区的氧化-还原条件和酸碱性可能变化不大,稀土元素主要是由大陆岩石风化和搬运而来,而不是海水提供的.高场强元素丰度及其特征比值的变化幅度不大,与中国东部上地壳一致,指示中国大陆岩石的风化产物是黄海沉积物的主要源区.∑REE与TiO2具有良好的相关性,指示稀土元素与TiO2一样主要来自陆源碎屑物质.     

由硫酸亚铁(绿矾)制取还原铁粉的工艺研究

提出了一种新的绿矾综合利用的途径,即绿矾经碳酸盐转化,然后采用无烟煤作还原剂,CaCO3为添加剂,进行高温还原焙烧制取还原铁粉.先将绿矾用水溶解,用理论量1.2倍的(NH4)2CO3将FeSO4转化为FeCO3,FeCO3焙烧的最佳条件是FeCO3∶无烟煤∶CaCO3为100∶60∶8,焙烧温度为1000℃,焙烧时间为4.5 h.粗还原铁粉化学成分除C含量较高外,符合国家有关标准,900℃左右经氢气精还原1 h所得精还原铁粉化学成分的各项指标,均达到或优于国家有关标准的要求.     

武汉东湖沉积物氮磷形态垂向分布研究

以武汉东湖为研究对象,分析并比较了3个采样点柱状沉积物中各种形态氮、磷的垂向分布,并结合pH进行了研究.结果表明:东湖沉积物pH小于上覆水中pH并随沉积物深度增加呈下降趋势.总氮与总磷均为处于湖湾区的1号点最高,2号点湖心最低,3号点居中.氨氮和硝酸盐氮也表现为1号点远远大于2号点和3号点.随着近年治污力度的加大,1号点的氮磷水平呈下降趋势,但是3号点受面源污染影响,氮、磷水平上升很快,甚至在表层已经和1号点持平.磷虽然仍然是东湖最主要的限制性营养元素,但受硝化与反硝化作用及聚磷菌的影响,近20a来,东湖沉积物总氮含量下降很大,氮磷比仅为3左右.     

Arsenic species analysis in porewaters and sediments using hydride generation atomic fluorescence spectrometry

It was observed that the atomic fluorescence emission due to signal during the determination of As（Ⅲ） in the mixture of As（Ⅲ） and As（V） could has a 10% to 40% of fluorescence emission As（V）. Besides, interferes from heavy metals such as Pb（Ⅱ）, Cu（Ⅱ） can cause severe increase of the signals as compared to the insignificant effects caused by Cd（Ⅱ）, Zn（Ⅱ）, Mn（Ⅱ） and Fe（Ⅲ）. On the basis of further studies, the masking agent of 8-hydroxyquinoline was used as an efficient agent to eliminate interference of As（V） emission and the heavy metal of Cu^2＋ and Pb^2＋ in the measurements of arsenic species, After a series standard additions and CRM researches, a sensitive and interference-free analytical procedure was developed for the speciation of arsenic in samples of porewaters and sediments in Poyang Lake, China.     

粗粒沉积物对污水的净化能力试验研究

采用连续和间歇２种注入方式,对粗粒松散沉积物净化污水的能力进行了试验研究,结果表明,１．５ｍ厚的砂卵石层对污水中细菌,合成洗涤剂,总铬等污染物的净化率可达５０％以上,间歇注入试验对Ｍｎ（Ⅱ）的净化率可达７６．１５％,而连续注入试验２４．７％,污水在粗粒沉积物中的入渗属氧化条件,有利于硝化作用进行。     

Determination and Assessment of HCHs and DDTs Residues in Sediments from Lake Dongting, China

The contamination of organochlorine pesticides hexachlorocyclohexane (HCH) and Dichlorodiphenyltrichloroethane (DDT) and their eco-environmental assessment in surface sediments from Lake Dongting, the second-largest freshwater lake in China, were studied. Concentrations of ∑HCH (=α-HCH + β-HCH + γ-HCH +δ-HCH) were 0.21--9.59 ng/g dry weight and those of ∑ DDT = p,p'-DDD+p,p'-DDE+o,p'-DDT+p,p'-DDT) ranged from under detectable limit to 10.15 ng/g dry weight. The ratios of α-HCH to γ-HCH were above 7 at most sampling sites while no or a small amount of β-HCH were found at all sites, suggesting the degradation of HCH used in the history and possibly current use of HCH in the region. The low ratios (below 2.0 in most cases) of (p,p'-DDE+p,p'-DDD) to p,p'-DDT and high levels of individual isomers of DDT at some sites also suggested that there have still been fresh inputs of DDT into Lake Dongting. Through the comparison between concentrations of HCH and DDT residues in sediments of Lake Dongting and those from other places in China and also from the results of our eco-environmental assessment, it can be concluded that Lake Dongting is the water body with high contamination of both HCH and DDT in its sediments in comparison with other water bodies in China.     

Distribution, Enrichment and Accumulation of Heavy Metals in Coastal Sediments of Salina Cruz Bay, México

Surface sediment samples collected from the Salina Cruz Bay in the last twenty years, were analyzed for the total available trace elements (Cr, Cu, Fe, Pb, Ni, V, and Zn) to evaluate metal contamination due to possible anthropogenic inputs. Normalization of metals to iron and fine-grained fraction (< 63 μm) indicated relatively high enrichment factors for lead during the last two decades. Sediment Quality Guidelines suggest that lead must be considered as a chemical of potential concern in the marine and estuarine ecosystem. Concentration levels of lead ranged from 5–124 μg/g, while Ni and V below 70 and 30 μg/g, respectively. Geoaccumulation and enrichment factors for the rest of elements show comparable values to those reported for sites with similar activities in the world. Spatial distribution suggests that in addition to harbor activities, a transboundary source for Pb must account for the observed trends.     

ASsessment Of Alcohol Ethoxylate Surfactants And Fatty Alcohols Mixtures In River Sediments And Prospective Risk Assessment

A feasible and relatively readily available analytical method was adapted for the assessment of alcohol ethoxylates (AE) and fatty alcohols (FA) in sediments. This study illustrates the simultaneous measurement of 38 of 114 possible alcohol ethoxylate ethoxymers (AE) and fatty alcohols (FA) found in commercially important AE products. We predicted toxicity for all identified fractions, as well as the total mixture toxicity, relative to three exposure scenarios via sewage treatment plants (STP) for these widely used chemicals in consumer products and hence generate a preliminary environmental risk screening for AE and FA in sediments. The method is based on derivatization of solvent or solid-phase extracts with 2-fluoro-N-methylpyridinium p-toluenesulfonate (Pyr+). The derivatized extracts were analyzed with liquid chromatography/mass spectrometry (LC/MS) operating in the positive ion electrospray mode. The extraction efficiency of AE and FA in three different sediments of varying composition was evaluated with spike-recovery studies, ranging from 64% to 80%. The detection limits for individual ethoxymers typically ranged from 1 to 5ngg⁻¹on a dry weight basis. The mean limit of detection (LOD) was 6ngg⁻¹and the median LOD was 3ngg⁻¹. AE and FA in sediments were found to be stable for two weeks if preserved with 3% (v/v) formalin and stored at 4–6^∘C. Based on equilibrium partitioning, background concentrations of AE and FA were predicted to be below concentrations known to elicit chronically toxic effects. Total worst case mixture toxicities for all AE ethoxymers combined with FA were predicted to result in a risk quotient less than 0.6. Activated sludge treatment (STP) significantly reduced the release of total AE and FA by four-fold, suggesting that the total mixture risk quotient would be < 0.15 for sediment dependent organisms.     

Dynamics of Organic Carbon and Microbial Biomass in Alluvial Soil With Tillage and Amendments in Rice-wheat Systems

Rice-wheat cropping systems of the Indo-Gangetic plains (IGP) occupying 12 million ha of productive land are important for the food security of South Asia. There are, however, concerns that yield and factor productivity trends in these systems are declining/stagnating in recent years. Decrease in soil organic carbon is often suggested as a reason for such trends. A field experiment was conducted to study the soil organic carbon (SOC) and soil microbial biomass carbon (MBC) dynamics in the rice-wheat systems. Use of organic amendments and puddling of soil before rice transplanting increased SOC and MBC contents. Microbial biomass carbon showed a seasonal pattern. It was low initially, reached its peak during the flowering stages in both rice and wheat and declined thereafter. Microbial biomass carbon was linearly related to SOC in both rice and wheat indicating that SOC could be used as a proxy for MBC.     

基于风险分析的流域优先有机污染物筛查:研究与应用

应用高通量分析方法对大清河流域47个沉积物中的潜在风险有机污染物进行了分析,共筛查到104种有毒有机污染物。应用基于风险分析的筛查体系对检出率高于10%的54种污染物进行了概率风险评估,筛查出11种具有潜在风险的流域优先有机污染物,包括农药(特草克、氨磺磷、枯莠隆)、工业用品及副产物(二苯胺、9,10-蒽醌、萘、2-甲基萘)及家庭及个人护理品(咖啡因、苯乙酮、苯甲酮、联苯)等。结果表明,基于风险分析的流域污染物筛查方法体系可成功地对流域内优先污染物进行识别与筛查,为流域管理提供科学依据。