珠江三角洲地区大气中多环芳烃的被动采样观测

研究了珠江三角洲地区大气中多环芳烃的含量与分布.利用大气被动采样装置,在包括香港在内的珠江三角洲地区共设立了21个大气被动采样点,样品采集时间为2005-08-15—10-14.结果表明,除主要存在于气相中的2～3环PAHs与部分4环PAHs外,聚氨酯泡沫材料(PUF)被动采样器也可在一定程度上采集大气颗粒物中的5～7环PAHs.珠江三角洲地区大气PAHs的含量与组成存在较大差异,珠江三角洲内地采样点PAHs的含量远远高于香港采样点,这主要是受采样点所处的地理位置、气候条件以及能源消费结构的影响.初步研究表明,PUF大气被动采样器可较好地运用于区域大气PAHs污染分布与特征对比研究.      

鞍山市大气PM10中多环芳烃(PAHs)的污染特征及其来源

2005年3月和8月在辽宁省鞍山市8个采样点采集PM₁₀样品,用液相色谱-质谱法分析了PM₁₀上负载的11种多环芳烃(PAHs),并探讨了其分布特征和来源.结果表明:鞍山市PM₁₀中ρ(PAHs)时空变化特征显著,冬季高于夏季,且工业区PAHs污染最严重;在PAHs中4环以上的组分占主导,冬季ρ(4环PAHs)较高,而在夏季ρ(5～6环PAHs)较高.运用比值法和主成分分析法对PAHs来源进行分析,发现冬季的主要污染源为燃煤排放、机动车尾气排放和炼钢工业排放;夏季主要污染源为燃煤排放、机动车尾气排放、生物质燃烧排放和炼钢工业排放等,来源较冬季复杂.机动车尾气排放对PAHs的贡献在2个季节都较为明显,冬季燃煤排放的贡献比重明显增加.      

广州市大气中多环芳烃分布特征、季节变化及其影响因素

对广州市大气中气态和颗粒态多环芳烃(PAHs)进行了连续一年的采样观测.结果表明,气态和颗粒态样品中PAHs的平均浓度值分别为312.9 ng/m³ 和 23.7 ng/m³,即多环芳烃主要存在于气相中,占大气总PAHs年平均的92.5%,且在夏季的比重要高于冬季.所检出的的气态多环芳烃以芴、菲、蒽等低环数化合物为主,其中菲占了总含量的60%以上;颗粒态多环芳烃则以高环数的化合物为主,各化合物所占的比重相当,其相对浓度无显著差别.气态多环芳烃在夏季达到高值,冬季降为低值;而颗粒态与其相反,夏季低值,冬季达到高值.在所测定的气象条件中,温度在影响气态多环芳烃浓度变化的因素中占了绝对优势,其次为风速,其它气象因素未观测到有较明显的影响作用;对颗粒态多环芳烃来说,则无绝对的影响因素,温度、风速和湿度同为重要影响因素,但随着分子量的增加,各因素的影响大小顺序略有不同.     

洋浦湾表层海水中多环芳烃的分布特征及来源分析

以海南洋浦湾海域的8个位点为监测对象,采用固相萃取法富集,超高效液相色谱(UPLC)测定表层海水中14种多环芳烃(PAHs)的含量,研究了PAHs的不同季节时空分布特征以及污染来源,并与国内外其他河口及海湾海水中PAHs质量浓度进行了比较。结果表明:洋浦湾海域水体中受到了一定程度的多环芳烃污染,14种PAHs总质量浓度范围为426.52~1 006.30 ng/L,平均总质量浓度为569.95 ng/L,其中萘的浓度最大,占PAHs总量的59.8%。2~5环PAHs分别占总浓度的59.8%、18.4%、20.6%、1.2%,5环在部分采样点中未有检出,6环均未检出。该海域PAHs含量具有明显的季节分布特征,冬季(均值690.70 ng/L)和春季(均值625.66 ng/L)PAHs含量明显高于秋季(均值481.94 ng/L)和夏季(均值481.51 ng/L),其中冬季各样点平均含量最高。旱季水体中PAHs质量浓度明显高于雨季。工业码头和港口PAHs浓度低于渡口、渔港等生活区。采用同分异构体比值法进行污染来源分析,表明春、夏、秋季洋浦湾表层水中PAHs主要来源于石油污染;冬季生活区主要为高温燃烧和石油的混合源,工业区则主要来自石油源。     

兰州大气细颗粒物中多环芳烃污染特征及来源分析

多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是环境空气中一类重要的有毒化合物,为探究兰州市大气细颗粒物(fine particulate matter,PM_(2.5))中PAHs的污染特征,于2012年冬季和2013年夏季采集兰州市PM_(2.5)样品共60个,并进行了GC/MS分析.结果表明,16种PAHs的冬、夏季平均总质量浓度分别为(191.79±88.29)ng·m~(-3)和(8.94±4.34)ng·m~(-3),冬季污染程度明显严重;降雪是导致兰州冬季大气PM_(2.5)中PAHs质量浓度降低最主要的气象因素;冬、夏季PAHs的环数分布均以4环比例最大,分别为51.40%和49.94%,5~6环比例夏季41.04%,高于冬季24.94%,2~3环比例冬季23.67%,高于夏季9.03%;通过PAHs的特征比值分析,兰州大气PM_(2.5)中PAHs的来源冬季以燃煤源和机动车尾气为主,其中柴油车比例较大;夏季汽油车对PAHs的相对贡献较大.     

白洋淀表层沉积物中多环芳烃的含量、分布、来源及生态风险评价

研究了白洋淀表层沉积物中US EPA 16种优先控制的多环芳烃(PAHs)的分布特征和污染来源,其w(PAHs)为101.3～1 494.8 ng/g (平均值为353.0 ng/g),与国内其他的湖泊和河流相比,整体处于中等污染水平. 安州采样点沉积物中w(PAHs)最高,污染最严重;其次为小田庄、烧车淀、王家寨;污染较轻的采样点为枣林庄、光淀、圈头和端村. 在16种多环芳烃单体中,菲、荧蒽、芘、苯并［b］荧蒽所占比例较大. w(荧蒽)/w(芘)和w(菲)/w(蒽)2个比值显示, 白洋淀沉积物中多环芳烃的含量和分布受石化材料燃料、煤炭及薪柴燃烧影响较大. 风险评价表明,安州采样点表层沉积物对生物存在潜在危害,而其他采样点沉积物潜在风险处于较低水平.      

基于被动采样技术的垃圾焚烧厂及周边大气中PAHs分布研究

垃圾焚烧是大气PAHs污染的重要来源,为监测垃圾焚烧过程产生的PAHs,利用被动采样技术对垃圾焚烧厂及周边大气中的多环芳烃(PAHs)进行了定量分析.结果表明,PAHs总量为146.29～396.30 ng·d-1,其中气相中PAHs为128.03～377.05 ng·d-1,颗粒相中PAHs为10.698～19.251 ng·d-1.气相中PAHs组成以菲、荧蒽、芴等低环化合物为主,菲的含量高达55.1%.选定松针作为被动植物样品,测得松针中PAHs的浓度为651.88～1 044.43 ng·g-1;考察土壤中PAHs的分布特征,测得土壤中PAHs浓度为35.04～998.89 ng·g-1.被动采样和松针、土壤中所含的PAHs分布特征相似,说明被动采样能反映PAHs在环境中的真实积累情况.此外,通过比较主动采样与被动采样结果,表明两者对大气中PAHs的富集能达到基本一致的效果.     

河北与京津地区非采暖期大气中的PAHs污染特征

对河北与京津地区42个样点非采暖期大气中多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)的研究表明,该区域大气中的PAHs浓度水平较高.2～3环PAHs主要分布在气相当中,颗粒相(大气可吸入颗粒物,PM10)中PAHs以4～6环为主.PAHs的高浓度样点在石家庄、唐山和邯郸地区分布最为集中.县城样点与城市样点的PM10和PAHs污染水平相近.临近区域广泛存在的大气污染很可能对北京市的大气环境造成影响.     

重工业城市岩溶地下水中多环芳烃污染特征及来源

为了确定岩溶区重工业城市地下水中多环芳烃的时空变化特征以及来源,采集柳州市丰枯水期23个地下水样品,利用16种多环芳烃的成分谱,结合其物理化学性质以及柳州市具体情况,分析多环芳烃在柳州市地下水系统中的变化及来源.结果表明:(1)柳州市丰水期地下水中ΣPAHs平均浓度柳北区柳东区柳西区鸡喇地下河,且PAHs浓度所占比重均随分子量的增大而减小;枯水期鸡喇地下河柳北区柳西区柳东区,且4环PAHs浓度所占比重均为最高,5~6环次之.(2)柳州市枯水期地下水PAHs呈现较高污染水平,丰水期污染水平较低;(3)化石燃料等有机物高温燃烧为PAHs主要来源,主要由工业过程、交通运输、取暖做饭等人类活动产生.     

莱州湾大气颗粒相中多环芳烃及其衍生物的赋存特征

多环芳烃作为一类典型的持久性有毒物质,一直是环境领域关注的热点和重点,有关多环芳烃衍生物的报道,尤其是有关大气中烷基和硝基多环芳烃的研究报道仍非常缺乏。本研究选取莱州湾刁龙嘴为采集区域,对大气颗粒相样品中16种母体多环芳烃（PAHs）、12种烷基多环芳烃（A–PAHs）和25种硝基多环芳烃（N–PAHs）进行分析。结果表明,16种母体多环芳烃（Σ₁₆PAHs）的浓度范围为517.2 ~ 64124.8 pg/m3;12种烷基化多环芳烃（Σ₁₂A–PAHs）的浓度范围为273.6 ~ 5897.3 pg/m3;25种硝基化多环芳烃（Σ₂₅N–PAHs）的浓度范围为113.5 ~ 1032.3 pg/m3。3种类型多环芳烃的浓度和污染模式均表现出明显的季节变化特征,其中,夏季,2环、3环的PAHs、A–PAHs和N–PAHs比例相对较高,而冬季4环及以上单体的比例偏高。PAHs的特征比值表明,莱州湾刁龙嘴地区PAHs的来源主要以柴油、煤及生物质燃烧为主。Σ₁₆PAHs、Σ₁₂A–PAHs和Σ₂₅N–PAHs与温度均呈现出显著的负相关性（R2 = 0.94,p < 0.01;R2 = 0.61, p < 0.01;R2 = 0.74,p < 0.01）,说明温度是影响颗粒相吸附芳烃类物质的一个主要因素。此外,三者之间Pearson相关关系表明,PAHs及其衍生物表现出相同的污染来源和相似的环境行为。     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.