Metal Extraction from Road Sediment using Different Strength Reagents: Impact on Anthropogenic Contaminant Signals

Washoff of road deposited sediment into storm drainsystems is one of the major contributors to nonpoint sourcepollution in urban fluvial networks. These sediments contain avariety of potentially toxic organic and inorganic contaminants.Road sediment from 13 locations in an urban (non-industrialized)drainage basin, and soil from 10 background (control) locationswere collected to assess total and labile fractions of Al, Co,Cu, Fe, Mn, Ni, Pb and Zn. Four digestions, of varying strength,were used to assess contaminant levels, these included: a totalfour-acid digestion, a microwave-assisted digestion withconcentrated nitric acid (USEPA Method 3051), a 0.5 M `cold' HCl,and a 0.05 M EDTA (pH 7). Road sediment data indicate that Al,Co, Fe, Mn and Ni were primarily lithogenic in origin, while Cu,Pb and Zn showed very significant anthropogenic signals, mostprobably from vehicle-related sources. Median Pb concentrationenrichment ratios for the EDTA extraction were about 42,indicating an extreme anthropogenic signal. The weak extractants(HCl and EDTA) are considered in this study to be superior intheir ability to characterize the degree of anthropogeniccontamination and should be utilized more widely in environmentalcontaminant studies.     

西南地区紫色水稻土活性碳库的季节动态

以西南大学农业部紫色土生态环境重点野外科学观测试验站试验田为研究对象,探讨了土壤有机碳(soil organiccarbon,SOC)、易氧化有机碳(readily oxidized carbon,ROC)、可溶性有机碳(dissolved organic carbon,DOC)和微生物生物量碳(microbial biomass carbon,MBC)的季节变化。结果表明,在油菜生长季,紫色水稻土SOC、ROC及MBC含量具有相似的季节变化特征,表现为在油菜生长初期和末期含量高,而在生长中期含量低;三者的含量均在生长末期达到最高,分别为16.20g.kg-1、3.58 g.kg-1及309.70 mg.kg-1.DOC含量的季节变化模态为单峰型,在植物生长中期达到最高值37.64 mg.kg-1.各活性有机碳组分的分配比例与其含量的季节变化趋势大致相同,ROC、DOC分配比例以及微生物商的季节变化范围分别为15.49%～23.93%、0.11%～0.32%和1.44%～2.06%.SOC及ROC含量主要取决于地下5 cm处温度、土壤N含量及pH值,MBC含量的主要影响因子为地下5 cm处温度、根系生物量及根系C、N含量,DOC含量主要受土壤水分含量的限制.     

多种方法识别青岛大沽河平原区地下水硝酸盐污染来源

硝酸盐是地下水中最常见的一种污染物,其来源的确定对于硝酸盐污染的治理非常重要.大沽河是山东半岛主要河流之一,其地下水含水层是重要的饮用水来源,但近年硝酸盐含量普遍很高,除了少数位置外,都超过了中华人民共和国国家标准,有必要对其污染来源进行研究.采用N同位素、N-O同位素和卤化物比率3种方法综合确定了硝酸盐污染来源.研究发现:该区地下水的N同位素比率值表明76%的取样点的硝酸盐来源与粪肥、污水、大气沉降、化肥和土壤N有关;氮氧同位素的结果显示80%的硝酸盐污染源为粪便或污水;卤化物比率也证明了这一来源.这和该区蔬菜生产大量施用粪肥和化肥进行农业种植是一致的,两者的混合施用使同位素比率和卤化物比率偏高,硝酸盐的主要污染来源是化肥和粪肥.多种方法相结合能够更准确地确定地下水硝酸盐的污染来源.     

VOC in an urban and industrial harbor on the French North Sea coast during two contrasted meteorological situations

Two measurement campaigns of volatile organic compounds (VOC) were carried out in the industrial city of Dunkerque, using Radiello passive samplers during winter (16–23 January) and summer (6–13 June) 2007. 174 compounds were identified belonging to six chemical families. Classifying sampling sites with similar chemical profiles by hierarchical ascending classification resulted in 4 groups that reflected the influence of the main industrial and urban sources of pollution. Also, the BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) quantification allowed us to map their levels of concentration. Benzene and toluene (BT) showed high concentrations in Northern Dunkerque reflecting the influence of two industrial plants. Differences among spatial distributions of the BT concentrations over contrasted meteorological conditions were also observed. An atypical ratio of T/B in the summer samples led us to investigate the BTEX origins shedding light on the contribution of pollutants transported across various zones of VOC emissions situated in Europe.     

MODELING THE EFFECTS OF URBANIZATION ON BASIN WATER YIELD AND RESERVOIR SEDIMENTATION1

ABSTRACT: The dam impounding White Rock Lake was completed in 1910 to provide water for the City of Dallas. Since then, land use on the watershed has changed from entirely rural to over 77 percent urban. A model called SWRRB (Simulator for Water Resources in Rural Basins) was utilized to determine the effect of urbanization on water and sediment entering the lake. The simulation results show that, if urbanization had not occurred, then the annual surface runoff would be 135 mm rather than 151 mm and the annual sediment yield would be 4.4 t/ha rather than 4.1 t/ha. Also, the effect of urbanization on delivery ratios was shown and a positive linear correlation was found. Finally, the weather generator in SWRRB was utilized to estimate the loss of reservoir capacity until 2050 for three different land use management scenarios.     

四种不同植物湿地对不同C/N比生活污水的净化效果与季节动态

进水浓度、C/N比、植物种类是影响垂直流型人工湿地对生活污水净化效果的重要因素.本文主要研究了菖蒲(Acorus calamus)、香蒲(Typha orientalis)、千屈菜(Lythrum salicaria)和水葱(Scirpus Validus)等4种植物湿地在不同碳添加及C/N比处理条件下对模拟生活污水的净化效果和季节动态.结果表明,4种湿地植物在不同C/N比(2.5∶1、5∶1和10∶1)进水条件下均能正常生长.在一个生长季内4种湿地植物对主要污染物的平均去除效率为:COD 63.41%~78.02%,TN 33.19%~52.86%,TP 52.64%~73.16%.当C/N为5∶1时,香蒲湿地的COD和TP去除效果最佳,而当C/N为2.5∶1时,菖蒲湿地的TN去除率最高.夏末秋初(7—9月)人工湿地的净化效果较好,而冬季(11月—翌年1月)去除效果明显下降.总体而言,合理地调控进水浓度、C/N比,选择最佳的湿地植物,可显著提高垂直流型人工湿地对生活污水的净化效果.     

溶解氧及碳氮比对SBR处理猪场厌氧消化液脱碳除氮效能的影响

猪场厌氧消化液因C/N低,常规的生物脱氮工艺存在COD去除效率低、脱氮效果差等问题.文章以模拟猪场厌氧消化液为处理对象,考察了不同溶解氧浓度(DO浓度均值为2.0和4.0 mg/L)及进水C/N(C/N=2.7、4和6)对SBR工艺脱碳除氮效能的影响.结果表明:CODcr去除率随C/N的增加而升高,并且提高C/N有利于氨氮和总氮的去除,它们的去除率随进水C/N值的增加均呈上升趋势,在C/N =6时分别达到86％和94％.     

Birth sex ratios in sheep over nine lambing seasons: years 7–9 and the effects of ageing

The birth sex ratio of a commercial flock of Suffolk cross sheep, Ovis aries, was studied over nine consecutive lambing seasons. In all data from 2704 lambs were recorded and analysed. The overall (1985–1993) birth sex ratio was 49.96% male lambs. Ewes with single lambs produced significantly more males (53.04%) than ewes with triplets (45.54% male). A significant positive correlation was found between the flock age and the birth sex ratio (1985–1992). As the flock aged the birth sex ratio changed from female biased to male biased, remained male biased for a number of years, and then became female biased again. This pattern is evident first in single, then in twin and later in triplet births. Among like sex twins (males and females) (1985–1993) more males (53.88%) were born in the first half and more females (45.57% males) in the second half of the lambing season. The difference between the two halves is significant.     

Chemical characteristics of aerosols at coastal station in Hong Kong.Ⅱ.Environmental behavior of trace elements during the April 1995 to April 1996

An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 at coastal region, Cape D‘Aguilar, in Hong Kong. The trace element composition of aerosol particles(TSP and PM10) were measured and analyzed by using the Instrumental Neutron Activation Analysis(INAA) and Inductive Couple Plasma-Mass Spectrometry(ICP-MS) techniques. The results showed that the polluted elements such as: V, Zn, As, Pb, Cd, Sb, I, Se, Bi, with high enrichment factor( E. F) values, are derived from anthropogenic sources ,while Sc, AI, Fe, Mn, Sm, La, Sr are less than 10 in E. F, these elements are related the crust and soil. The concentration of the trace elements are present seasonal variation i.e. summer low and winter high, whereas the V or noncrustal V(V^* ) present summer high and winter low, this phenomenon might be explained by local or regional oil combustion sources. Use three type of elemental ratio, e.g. La/Sm, Mn^*/V^* and Bi/Al indicate that both TSP and PM10 of La/Sm ratios are mainly related to soil and dust, Mn^*/V^* are probably represent fossil combustion and Bi/Al are possibly associated with refuse incineration, ferromanganese alloys and aluminum production. The varimax rotation factor analysis for trace elements was performed. By means of the absolute principal component analysis (APCA) and multiple regression, the contribution of trace elements to possible sources and overall means of trace elements were estimated. The results showed that the present station is impacted by the anthropogenic species, although the quantities are different during the summertime and wintertime.     

Prenatal diagnosis of haemoglobin disorders by cordocentesis at 12 weeks' gestation

Prenatal diagnosis of haemoglobin disorders is accepted to be a useful procedure to avoid births of infants with homozygous diseases. Advances in sampling and molecular techniques, such as polymerase chain reaction (PCR) and chorionic villus sampling (CVS), have made earlier and safer first-trimester prenatal diagnosis possible. However, these procedures need previous studies of at-risk couples, which can be very time-consuming when a number of different β-thalassaemia mutations occur in the region. We describe the possibility of making a first-trimester prenatal diagnosis by cordocentesis and fetal blood analysis at the 12th week of gestation. We found no statistically significant difference (p>0.05) between β/γ values in fetuses at the 12th and 18th weeks of gestation. In seven affected fetuses aborted at the 12th week of gestation, the diagnosis was confirmed in all cases by PCR analysis. These findings suggest that early cordocentesis could be an alternative procedure to CVS and PCR analysis.