南京大气细粒子中重金属污染特征及来源解析简

利用2011年1月、4月、7月和10月在南京市区和北郊采集的气溶胶样品,研究了南京大气细粒子中Zn、Pb、Hg、As和Cd 5种重金属的污染水平,通过元素相关性分析和因子分析方法,对细粒子中这些重金属的污染来源进行了初步解析。结果表明,南京大气细粒子及其重金属污染严重,北郊普遍比市区严重;As严重超标,Cd在南京北郊超标约5倍,Zn在市区与北郊的质量浓度均高于其他重金属元素。每种重金属的浓度均随季节而变化。市区细粒子中,As和Zn可能主要与燃煤、轮胎灰尘和建筑扬尘等有关,Pb、Hg和Cd主要来自交通尘、城市垃圾焚烧等。北郊细粒子中,As、Hg和Zn主要来源于燃煤、钢铁冶炼等工业,Pb和Cd主要与农作物秸秆燃烧、汽车尾气、道路扬尘等影响有关。     

北运河沉积物/水界面上重金属迁移转化规律

分析测定了6种元素(Cr、Co、Mn、Cu、Pb、Zn)在北运河水系10个采样点水体和表层沉积物中的含量和形态分布,利用SPSS 19.0统计软件对重金属在不同形态中的含量进行相关性分析。结果显示,北运河下游重金属污染程度高于上游;Cr、Cu、Pb、Zn在底泥可提取态中所占比例相当高,多数采样点都超过10.0%。所研究的重金属多数在底泥Fe-Mn结合态与悬浮物、可交换态、硫化物和有机质结合态均存在相关性;Mn是北运河地化循环中最为活跃的元素。     

荆马河沉积物的生物毒性及其农田利用

本文论述了荆马河沉积物的污染状况,对其生物毒性进行分析评估,并探讨了该沉积物农田利用的适宜性,提出了农业综合利用底泥的有效途径及相应采取的措施。     

底泥生长基质中重金属的迁移特征及生物有效性

河道底泥中重金属含量较高,重金属的迁移性及生物有效性是限制疏浚底泥土地施用或用作废弃场地修复基质资源化利用途径的主要因素。以沈阳细河待疏浚底泥为材料,通过盆栽实验的方法研究了河道底泥与碱性粉煤灰、炉渣和锯木屑配比基质中重金属在紫花苜蓿体内累积、迁移及生物有效性的变化。结果发现,配比底泥基质上紫花苜蓿生物量、株高及株径均好于纯底泥处理,其中底泥、粉煤灰、炉渣、锯木屑以2：0．5：0．5：0．5配比的s2处理中紫花苜蓿生物量是纯底泥处理的11．7倍。与底泥对照相比,配比底泥基质上植株体内重金属含量极显著降低,而且地上部重金属含量显著低于根部含量;底泥基质中紫花苜蓿地上部和根部对Cd、Cu、Pb、Zn的富集系数（BCF）显著低于底泥处理,但转移系数（TF）无显著变化,富集系数（BCF）和转移系数（TF）均小于1．0。紫花苜蓿种植后底泥基质中重金属含量显著低于农用污泥重金属控制标准,除Cd含量略高外,Cu、Pb和Zn含量低于土壤环境质量三级标准。这些结果表明,城市重污染河道底泥经过合理处置后,重金属浓度、活性及生物有效性降低,在其土地施用或废弃地修复中可以用作一些耐性植物的生长基质。     

扬州市城区地表水底泥重金属污染现状与风险评价

对扬州市城区地表水底泥进行等距离布点采样.分析cd、Cu、Pb、Zn 4种重金属的含量,并应用潜在生态危害指数法对重金属潜在生态风险进行了评价.结果表明:4种重金属的潜在生态风险由高到低的顺序为Cd>Pb>Cu>Zn,其中Cd的潜在生态风险程度已达很强;扬州市城区地表水底泥重金属潜在生态风险程度为强.各条河流底泥重金属潜在生态风险程度由强到弱顺序为古运河>二道河>宝带河>小秦淮河>新城河>水院池塘(对照);从空间上看,扬州市城区东部的地表水底泥重金属潜在生态风险程度高于西部,北部高于南部.     

3种含铁材料对重金属和砷复合污染底泥稳定化处理

选用3种含铁材料FeCl3、Fe(OH)3和FePO4,开展重金属和砷(As)复合污染底泥的稳定化处理实验,并用毒性浸出测试(TCLP)的结果和底泥交换态重金属(Pb、Cd、Cu、Zn)及As的含量来评价其稳定化效果。结果表明,(1)FeCl3和FePO4降低了底泥pH值,Fe(OH)3轻微地提高了底泥pH值。(2)FeCl3活化了底泥中Pb、Cd、Cu、Zn,使其浸出量和交换态含量增加,对As浸出量的影响不大,但使底泥中As交换态含量明显降低,且在最大添加量(8.00 g/kg)时As交换态含量未检测出;Fe(OH)3降低了Cd交换态和浸出量,稍增加了As交换态和浸出量,但对Pb、Cu、Zn交换态和浸出量影响不明显;FePO4明显降低了Pb的浸出量和交换态含量,略微降低了交换态Cd、Zn含量,对交换态Cu影响不大,但明显增加了As的浸出量和交换态含量。综上,FeCl3对As具有较好的稳定化效果,但明显活化了底泥中的4种重金属;Fe(OH)3亦对底泥中Cd有一定稳定化效果;FePO4对Pb的稳定化效果较好,但明显活化了底泥中的As。显然,3种含铁材料都不能实现底泥中重金属和As的同时稳定化。     

深圳市河流沉积物重金属污染特征及评价

分析了深圳市的深圳河、布吉河、龙岗河和茅洲河等4条河流沉积物中重金属的含量和富集状况,并对重金属污染的潜在生态危害进行了评价。结果表明：（1）1996-2003年,深圳河、布吉河、龙岗河和茅洲河沉积物中重金属的含量都有上升的趋势;布吉河和龙岗河沉积物中的重金属含量较高,特别是Cu、Zn和Cr的含量比其他两条河流高出较多,深圳河居中,茅洲河较小;这4条河流都以Cd、Cu、Cr和Zn的富集为主。（2）在研究时段内,这4条河流沉积物重金属污染的潜在生态危害指数（RI）都有上升的趋势;其中深圳河,布吉河和龙岗河的RI在多数年份都达到强或很强的程度,Cd、Hg、Cu为主要贡献元素;4条河流中,茅洲河受重金属污染最小,其RI为轻微或中等,只有Cd和Hg的生态危害系数为中等或强。针对深圳市河流沉积物中重金属的累积机理,建议通过改善区域水文条件、控制污染物的排放等措施加以控制和治理。     

微生物沥浸法去除底泥中的重金属

以硫酸亚铁盐为底物,培养以氧化亚铁硫杆菌为主要菌种的土著沥滤微生物,采用批式方法对湘江长沙段底泥进行微生物沥浸实验。实验结果表明,底物投加量与底泥固体浓度比(Sd/Sc)为1.5时已能满足底泥的微生物沥浸要求,进一步研究发现底泥固体浓度为13%、底物投加量为19.5 g/L、沥浸时间为6 d时,底泥中超标重金属Cd、Zn和Cu的去除率可分别达到83.1%、75.3%和61.2%;沥浸后底泥中大部分重金属以残渣态存在,且含量低于农用污泥中污染物控制标准,其中硫化物有机结合态Cu浸出较Zn、Cd需更低的pH,且Cu以间接机理浸出为主;以Fe2+为底物的沥浸体系中,黄铁矾的重吸附或共沉淀是沥浸实验后期重金属浸出率下降的原因之一。     

苕溪流域典型区域重金属污染特征

从苕溪流域景观单元角度研究重金属污染特征,因人类活动是重金属污染的主要来源,所以在苕溪流域内选择采集典型工业区、农业区和城镇生活区附近河道的沉积物,分析各典型区域重金属Pb、Cd、Cr、As、Hg、Cu和Zn的含量特征,并用潜在生态危害指数法评价。结果表明,按照《土壤环境质量标准》,苕溪流域典型工业区主要是Hg、Cu和As的污染,典型农业区和城镇生活区主要是Hg的污染。各元素间的相关性分析表明,在工业区:Zn-As、Zn-Pb和As-Pb之间存在相关关系,说明它们的同源性很高。在农业区:Cu-As、Cu-Cd之间存在显著相关关系,其来源有可能相似。在城镇生活区Zn-As、Zn-Cd之间存在很高的相关性,说明它们有很高的同源性。由多种重金属潜在潜在生态风险评价结果可知:苕溪流域典型工业区、城镇区和农业区的沉积物处于低潜在生态风险。     

中国台湾地区底泥重金属污染防治经验及启示

借鉴了中国台湾地区底泥重金属污染调查、评估和治理方法等内容,介绍了中国大陆地区底泥重金属污染工作进展,分析了大陆地区底泥重金属污染存在的主要问题,并提出底泥重金属污染防治工作的对策建议。     

大气中二（口/恶）（口/英）研究进展

二（口/恶）（口/英）是世界公认的强致癌物质,对人体健康危害极大.近年来,大气中二（口/恶）（口/英）的研究已成为各国环境化学家研究的热点.本文总结了近年来国际上有关大气中二（口/恶）（口/英）研究的进展情况,以及所取得的主要研究成果,并在此基础上指出了我国目前研究中存在的问题及以后所应开展的工作.     

Bioaccessibility of arsenic in various types of rice in an in vitro gastrointestinal fluid system

Rice can be a major contributor to dietary arsenic exposure because of the relatively high total arsenic concentration compared to other grains, especially for people whose main staple is rice. This study employed in vitro gastrointestinal fluid digestion to determine bioaccessible or gastrointestinal fluid extractable arsenic concentration in rice. Thirty-one rice samples, of which 60 % were grown in the United States, were purchased from food stores in New York City. Total arsenic concentrations in these samples ranged from 0.090 ± 0.004 to 0.85 ± 0.03 mg/kg with a mean value of 0.275 ± 0.161 mg/kg (n = 31). Rice samples with relatively high total arsenic (>0.20 mg/kg, n = 18) were treated by in vitro artificial gastrointestinal fluid digestion, and the extractable arsenic ranged from 53 % to 102 %. The bioaccessibility of arsenic in rice decreases in the general order of extra long grain, long grain, long grain parboiled, to brown rices.     

Bioaccessibility of arsenic in various types of rice in an in vitro gastrointestinal fluid system

Rice can be a major contributor to dietary arsenic exposure because of the relatively high total arsenic concentration compared to other grains, especially for people whose main staple is rice. This study employed in vitro gastrointestinal fluid digestion to determine bioaccessible or gastrointestinal fluid extractable arsenic concentration in rice. Thirty-one rice samples, of which 60 % were grown in the United States, were purchased from food stores in New York City. Total arsenic concentrations in these samples ranged from 0.090 ± 0.004 to 0.85 ± 0.03 mg/kg with a mean value of 0.275 ± 0.161 mg/kg (n = 31). Rice samples with relatively high total arsenic (>0.20 mg/kg, n = 18) were treated by in vitro artificial gastrointestinal fluid digestion, and the extractable arsenic ranged from 53 % to 102 %. The bioaccessibility of arsenic in rice decreases in the general order of extra long grain, long grain, long grain parboiled, to brown rices.     

Assessment of in situ biodegradation of monochlorobenzene in contaminated groundwater treated in a constructed wetland

The degradation of monochlorobenzene (MCB) was assessed in a constructed wetland treating MCB contaminated groundwater using a detailed geochemical characterisation, stable isotope composition analysis and in situ microcosm experiments. A correlation between ferrous iron mobilisation, decreasing MCB concentration and enrichment in carbon isotope composition was visible at increasing distance from the inflow point, indicating biodegradation of MCB in the wetland. Additionally, in situ microcosm systems loaded with 13C-labelled MCB were deployed for the first time in sediments to investigate the biotransformation of MCB. Incorporation of 13C-labelled carbon derived from the MCB into bacterial fatty acids substantiated in situ degradation of MCB. The detection of 13C-labelled benzene indicated reductive dehalogenation of MCB. This integrated approach indicated the natural attenuation of the MCB in a wetland system. Further investigations are required to document and optimise the in situ biodegradation of MCB in constructed and natural wetland systems treating contaminated groundwater.     

Bioaccumulation of decamethylcyclopentasiloxane in perch in Swedish lakes

Decamethylcyclopentasiloxane (D5), a high production volume chemical used in personal care products, enters the environment both via air and sewage treatment plant (STP) recipients. It has been found in fish, and there is concern that it may be a bioaccumulative substance. In this work D5 was analyzed in perch from six Swedish lakes that did not receive STP effluent, and in perch and sediment from six lakes that received STP effluent. In the lakes receiving the STP effluent, the D5 concentrations in sediment varied over three orders of magnitude and were correlated with the number of persons connected to the STP normalized to the surface area of the receiving body. In the lakes not receiving effluent, the D5 levels in perch were all below the LOQ, while D5 was above the LOQ in almost all perch from lakes that received effluent. The D5 concentrations in perch and sediment from the lakes receiving STP effluent were correlated. This shows that STP effluent is a much more important source of D5 to aquatic ecosystems than atmospheric deposition, and that the risk of adverse effects of D5 on aquatic life will be greatest in small recipients receiving large amounts of STP effluent. The bioaccumulation of D5 was compared to that of PCB 180 on the basis of multimedia bioaccumulation factors (mmBAFs), which describe the fraction of the contaminant present in the whole aquatic environment (i.e. water and surface sediment) that is transferred to the fish. In four of the six lakes the mmBAF of D5 was >0.3 of the mmBAF of PCB 180. Given that PCB 180 is a known highly bioaccumulative chemical, this indicates that the bioaccumulation of D5 in perch is considerable.     

Origins of Manganese in Air Participates in California

The proportions of manganese to other metals in samples of airborne fine particles taken at some sites in California have increased greatly since the beginning of 1985. Here, data are presented which indicate that the addition of manganese to leaded gasoline is largely responsible for this increase. Concentrations of manganese, silicon, titanium, iron, lead and other elements in airborne particles were measured using energy-dispersive X-ray fluorescence analysis. Coefficients of correlation among levels of manganese, iron and lead measured at twenty sites in California were calculated. Levels of manganese and iron are generally highly correlated because of the presence of large amounts of these elements in the earth’s crust. Levels of airborne manganese and lead at sites In Southern California are often highly correlated, suggesting a vehicular source of manganese. Observed manganese concentrations are apportioned into two major sources: the earth’s crust and motor vehicles. The apportionment indicates that vehicular emissions of manganese may account for a significant part of the total at urban sites in Southern California. At most other sites, the contribution from vehicles is found to be far smaller than that from the earth’s crust.     

饮用水中硝酸根的催化还原研究进展

由于化肥的过度使用 ,造成地下水中硝酸盐的污染日益严重。饮用水中高浓度的硝酸盐对人类健康会产生极大的威胁。本文综述了催化还原脱除水中硝酸根的研究进展和现状 ,并对其发展趋势进行了简单的论述。     

Residues of organochlorine pesticides in fishes in Sudan

Abstract

Cotton‐producing areas of the Centrol Sudan, bordered by the Blue and the White Nile, have been subjected to repeated applications of pesticides. This region is irrigated by a series of canals, the Gezira canals, which hold large amounts of fresh water. Lake Nubia at the Sudan‐Egypt border is another important fresh water reservoir and fisheries ground. Fish from both the Gezira and Lake Nubia showed elevated concentrations of pesticides, suggesting that continued pesticides application would endanger the equatic fauna of this region and the proposed fresh water fishery.     

Involvement of glutathione in the reduction of captan-induced in vivo inhibition of monooxygenases and liver toxicity in the rat

If given orally captan is relatively nontoxic, but it can be extremely toxic after parenteral exposure. Therefore, a single i.p. dose of captan (20 mg/kg) was given to male Sprague-Dawley rats and its effect on liver microsomal mixed function oxidases and certain serum enzymes (SDH, SGPT and SGOT) was studied. The single dose of captan caused marked depression of microsomal cytochrome P-450 and the activity of benzphetamine N-demethylase and aniline hydroxylase, and moderate elevation of the serum enzymes indicative of liver damage. However, reduced glutathione (100 mg/kg, i.p.) given prior to captan, appears to decrease the liver toxicity as measured by reduced inhibition of the microsomal enzymes and elevation of serum enzymes activity. The results suggest that glutathione and other compounds containing sulfhydryl groups may protect the subjects from captan-induced liver toxicity.     

Lead concentrations in birds of prey in Britain

This paper reports on lead (Pb) concentrations in the livers of 424 individuals of 16 raptor species found dead and sent for analysis to the Institute of Terrestrial Ecology, Monkswood, from the early 1980s to the early 1990s. Elevated Pb concentrations in liver (>20 ppm dry wt), within the range associated with Pb poisoning mortality in raptors, were recorded in one peregrine (4% of species sample) and one buzzard (2% of species sample). These birds are likely to have ingested lead gunshot in the flesh of their prey. Another one each of these species had liver Pb concentrations of 15-20 ppm dry wt, reflecting unusually high absorption of Pb. No individuals of any other species had >15 ppm dry wt liver Pb, although some had 6-15 ppm. The source of Pb in these birds was unknown, but it could have resulted from high Pb concentrations in prey items, including some containing lead shot. Median liver Pb concentrations were generally very low (ranging from <0.07 to 1.61 ppm dry wt for species with sample sizes exceeding 10). In sparrowhawks, for which a large sample was available, liver Pb concentrations in all but one individual were low (<2.6 ppm dry wt). Pb concentrations in juveniles were significantly lower than in adults, and were lowest in recently fledged birds.