剩余污泥中PCDD/Fs与有机金属化合物的分布特征

分析测定了24座污水处理厂的剩余污泥中多氯代二苯并二英/呋喃(PCDD/Fs)、有机锡和有机铅化合物的浓度及其同系物分布特征,并计算了PCDD/Fs的国际毒性当量(I-TEQ)值。结果表明,剩余污泥中的PCDD/Fs总浓度为104.1~1 661.0pg·g~(-1)和2.51~75.21pg·g~(-1)(I-TEQ),I-TEQ值低于我国土地利用限值;三丁基锡、二丁基锡和二氯二苯基锡的浓度分别为247~3 886ng·g~(-1)、126~629ng·g~(-1)和84~2 133ng·g~(-1);有机铅化合物的总浓度为85~668ng·g~(-1),表明有机铅化合物对环境的潜在影响仍然存在。     

工业区及周边农业区土壤中二噁英污染水平及暴露风险

选取复合产业工业区及周边农业区土壤进行研究,重点研究了土壤中二噁英的污染水平及土壤摄食暴露风险。通过对14个采样点(包括1个背景点)的研究发现,工业区ΣPCDD/Fs的质量浓度为:1.00×10~3~1.87×10~4 ng/kg,毒性当量为:I-TEQ 3.32~22.9 ng/kg;农业区果园地ΣPCDD/Fs的质量浓度为:117~795 ng/kg,毒性当量为:I-TEQ 0.479~1.11 ng/kg;农业区菜地ΣPCDD/Fs的质量浓度为:717~1.48×10~3 ng/kg,毒性当量为:I-TEQ 1.35~1.76 ng/kg。背景点土壤中二噁英浓度相对较低,质量浓度值为:132 ng/kg,毒性当量为:0.331 ng/kg。对工业区及周边农业区土壤二噁英土壤摄食暴露风险研究结果表明,儿童土壤摄食暴露风险要高于成年人;同时无论是儿童还是成年人,其二噁英的土壤摄食暴露量都比较低。     

SO_2抑制二噁英从头合成的实验及其过程模拟

实验研究了不同温度下SO2对二噁英(PCDD/Fs)从头合成的抑制特点,运用HSC Chemistry 6.1软件对主要无机化学反应过程进行模拟,探究了SO2的抑制机理。结果表明,SO2对PCDD/Fs总浓度和I-TEQ浓度的抑制效果随温度的升高而增强。PCDD/Fs总浓度和I-TEQ浓度抑制率从200℃不足20%分别提高到300℃时的75.6%和77.3%及400℃时的89.2%和80.5%;SO2的添加促进了PCDD/Fs尤其是PCDDs同系物分布的低氯代化。在从头合成的高温段和低温段,SO2分别侧重抑制PCDFs和PCDDs。相平衡计算和Gibbs自由能计算表明,SO2优先与催化剂CuCl2反应生成无催化活性的CuSO4,其次与氯源Cl2反应,最终实现PCDD/Fs的生成抑制。模拟结果对现有硫基抑制机理进行了验证和补充,对高效、廉价抑制剂的开发及工程使用具有重要意义。     

珠江口海域沉积物中总氮总磷的空间分布特征

随着珠江三角洲经济的快速发展,各类废水排放量不断增加,导致珠江口及邻近海域呈现不同程度的污染。为了解珠江口及其邻近海域沉积物中氮、磷污染程度和水生生态环境的现状,采集了珠江口及其临近海域13个站位(珠江主干流入海口8个站位和渡头河入海口5个站位)的表层沉积物样品,研究了珠江口及其邻近海域表层沉积物中的总氮总磷含量以及其空间分布特征。研究结果表明珠江口及其临近海域表层沉积物总氮浓度范围为0.27～0.81 mg/g,均值为0.53 mg/g。珠江主干流入海口一侧污染相对较为严重,表层沉积物中总氮含量均值为0.70 mg/g,显著高于渡头河支流入海口一侧。表层沉积物中总磷浓度为0.28～0.96 mg/g,均值为0.49 mg/g,各位点浓度差异较大,整体并未达到污染程度。珠江口沉积物总氮总磷含量并无相关性,氮污染程度高于磷污染程度。研究结果为全面评价广东近海海水生态健康状况以及管理保护提供科学依据。     

Zn、Cd 化合物对模拟飞灰中二噁英生成的影响

催化剂是二噁英(PCDD/Fs)从头合成的关键因素,但已有研究仍不足。在实验室条件下利用模拟飞灰(MFA)研究不同金属催化剂对PCDD/Fs生成量及分布的影响。结果表明,ZnO抑制PCDD/Fs的生成,ZnCl₂对PCDD/Fs生成催化作用远大于CdCl₂,生成PCDD/Fs浓度分别为431.78、6.32 ng·g^-1。ZnCl₂催化下生成PCDD/Fs浓度是ZnO的338倍,CdCl₂催化下生成PCDD/Fs浓度是CdO的3倍。Zn、Cd化合物催化下生成PCDD/Fs氯化程度低。利用主成分分析(PCA)研究催化剂对PCDD/Fs分布的影响,结果表明不同金属催化剂作用下,17种有毒PCDD/Fs分布变化显著。同时ZnCl₂催化下,反应气氛中氧含量的提高导致PCDD/Fs生成量增加,但是对PCDD/Fs分布的影响有限。     

SO2抑制二英从头合成的实验及其过程模拟

实验研究了不同温度下SO₂对二 英（PCDD/Fs）从头合成的抑制特点,运用HSC Chemistry 6.1软件对主要无机化学反应过程进行模拟,探究了SO₂的抑制机理。结果表明,SO₂对PCDD/Fs总浓度和I-TEQ浓度的抑制效果随温度的升高而增强。PCDD/Fs总浓度和I-TEQ浓度抑制率从200℃不足20%分别提高到300℃时的75.6%和77.3%及400℃时的89.2%和80.5%;SO₂的添加促进了PCDD/Fs尤其是PCDDs同系物分布的低氯代化。在从头合成的高温段和低温段,SO₂分别侧重抑制PCDFs和PCDDs。相平衡计算和Gibbs自由能计算表明,SO₂优先与催化剂CuCl₂反应生成无催化活性的CuSO₄,其次与氯源Cl₂反应,最终实现PCDD/Fs的生成抑制。模拟结果对现有硫基抑制机理进行了验证和补充,对高效、廉价抑制剂的开发及工程使用具有重要意义。     

Zn、Cd化合物对模拟飞灰中二英生成的影响

催化剂是二英(PCDD/Fs)从头合成的关键因素,但已有研究仍不足。在实验室条件下利用模拟飞灰(MFA)研究不同金属催化剂对PCDD/Fs生成量及分布的影响。结果表明,Zn O抑制PCDD/Fs的生成,Zn Cl2对PCDD/Fs生成催化作用远大于Cd Cl2,生成PCDD/Fs浓度分别为431.78、6.32 ng·g-1。Zn Cl2催化下生成PCDD/Fs浓度是Zn O的338倍,Cd Cl2催化下生成PCDD/Fs浓度是Cd O的3倍。Zn、Cd化合物催化下生成PCDD/Fs氯化程度低。利用主成分分析(PCA)研究催化剂对PCDD/Fs分布的影响,结果表明不同金属催化剂作用下,17种有毒PCDD/Fs分布变化显著。同时Zn Cl2催化下,反应气氛中氧含量的提高导致PCDD/Fs生成量增加,但是对PCDD/Fs分布的影响有限。     

河南某医疗废物焚烧厂周边土壤污染特征的研究

为研究医疗废物焚烧厂周边土壤污染状况,以河南省某典型医疗废物焚烧厂为研究对象,对其周围土壤中17种多氯二苯并对二噁英/呋喃(PCDD/Fs)的含量进行了监测。研究结果表明：医疗废物焚烧厂周边土壤中的PCDD/Fs的TEQ浓度为3.8～154 ngTEQ/kg;医疗废物处理厂周边土壤中PCDFs对总TEQ浓度的贡献率均高于PCDDs,且毒性单体贡献最大的是2,3,4,7,8-PeCDF,单体质量浓度最大的是1,2,3,4,6,7,8-HpCDF。     

高分辨气相色谱-高分辨质谱分析2,5-二氯酚工业品中的二英及多氯联苯

建立了高分辨气相色谱-高分辨质谱方法分析2,5-二氯酚工业品中的二英(PCDD/Fs)和多氯联苯(PCBs)。比较了2,5-二氯酚工业品经甲苯直接溶解后净化、溶解于0. 15 mol/L Na OH水溶液中再与正己烷液液萃取后净化两种前处理方法对PCDD/Fs及PCBs出峰峰型和回收率的影响。对于空白样品,两种方法 PCDD/Fs及PCBs回收率相差不大。对于实际样品,先溶解于碱液再液液萃取的方法明显优于直接溶解后净化,除PCB 169回收率为49%外,其他所有PCDD/Fs和PCBs组分的回收率都大于80%,均满足标准HJ 77. 3—2008和EPA1668C(2010)的质控要求; PCDD/Fs和PCBs的检出限分别为0. 005 0～0. 044和0. 016～0. 12 ng/kg;将本方法应用于2,5-二氯酚工业品分析,PCDD/Fs毒性当量浓度为100和135 ng TEQ/g,PCBs毒性当量浓度为6. 5和21 ng TEQ/g。     

炉排式生活垃圾焚烧炉烟气中二噁英异构体组分特征

为了解炉排式生活垃圾焚烧炉二噁英产生、排放水平及其异构体组分特征,选取深圳市某垃圾焚烧发电厂4台炉排式焚烧炉,于2013年10月21~26日对其烟气净化设施进、出口断面同步进行废气二噁英监测,并通过高分辨气相色谱/高分辨质谱联用仪(HRGC-HRMS)分析获得二噁英浓度和异构体组分特征。结果表明,炉排式生活垃圾焚烧炉烟气中二噁英主要由高氯代PCDD/Fs组成,当量毒性贡献最大的有毒单体为2,3,4,7,8-PeCDF;二噁英排放浓度范围在0.015~0.072 TEQng/Nm~3之间;有毒六氯代HxCDF单体及其浓度总和均与二噁英I-TEQ呈现出较高相关性,相关系数R~2均在0.96以上,均可作为炉排式垃圾焚烧炉烟气中二噁英I-TEQ的指示物。     

Dioxin,Dioxin–Like PCBs and Indicator PCBs in Some Medicinal Plants Irrigated with Wastewater in Ismailia,Egypt

Wastewater is often leaden with various contaminants that may accumulate in soils and can under some conditions enter the agricultural food chain. Concentrations of PCDD/Fs, DL-PCBs and NDL-PCBs have been determined using GC/HRMS in three of the commonly used medicinal plant (henna, rosemary, and moghat) grown on raw wastewater. In the case of henna and rosemary plants, all wastewater irrigated samples showed higher content of the studied contaminants than freshwater irrigated samples, while moghat samples, whether irrigated with freshwater or wastewater, had more or less the same content of the studied contaminants. Concentrations in plant samples ranged between 0.00004 and 0.865 pg WHO TEQ/g wet w for PCDDs, and between 0.03 and 1.86 pg WHO TEQ/g wet w for the PCDFs. Levels of PCB TEQ ranged from 0.005 to 0.76 pg/g wet w. In descending order, rosemary, henna, and moghat had the highest concentrations of total TEQ (PCDD/Fs + DL-PCBs). The congeners pattern in henna and rosemary samples was generally characterized by the dominance of PCDFs with a significant contribution from the lower (mono- to tri-) PCDFs. In moghat samples the profile was dominated by PCDDs, with OCDD contributing 100% to PCDDs. PCBs contribution to the total TEQ was on average 25%, 7% and 2% in rosemary, moghat and henna respectively. For NDL-PCBs, the sum concentration of 17 PCBs congeners increased from 2.65 to 4.13 ng/kg wet w in henna, and from 4.64 to 7.16 ng/ kg wet w in rosemary due to the irrigation with wastewater. Congener PCB 28 was the main contributor (60%) to sum 6 indicators in all samples, followed by PCB 52 (18%) and PCB 101 (6%).     

大气悬浮颗粒物和植物树叶中二噁英分布特征的研究

采用同位素稀释、高分辨气相色谱/高分辨质谱(HRGC/HRMS)联用技术,分析了广州市某一地区两采样点大气悬浮颗粒物和大叶榕、龙眼树树叶中二噁英的含量。结果表明,两地点大气悬浮颗粒物中二噁英质量浓度(10.87 pg/Nm3和10.34 pg/Nm3)和毒性当量(0.119 pg/Nm3和0.121 pg/Nm3)接近,而大叶榕、龙眼树树叶中二噁英质量浓度分别为268.4 ng/kg.dry和972.5 ng/kg.dry,毒性当量为3.99 ng/kg.dry和15.11 ng/kg.dry。通过分析大气和树叶样品中17种有毒同系物的分布特征,可推断这两种植物树叶中的二噁英主要来源于大气干沉降。此外,龙眼、大叶榕树叶中六氯代以上的有毒PCDD/Fs质量分数较高,说明高氯代二噁英在树叶中较稳定,易累积到较高的水平。     

医疗废物焚烧炉启炉过程二噁英排放特性

选择了位于华东地区的某医疗废物焚烧处置设施开展启炉过程与正常工况下烟气和飞灰的二噁英排放特性对比研究。数据显示, 启炉后期烟气中二噁英的浓度达到1.68 ng I-TEQ·m^-3, 在焚烧炉温度稳定以后12 h, 达到2.77 ng I-TEQ·m^-3, 飞灰中二噁英毒性当量水平也达到4.5 ng I-TEQ·g^-1。启炉过程中烟气中气相二噁英所占比例逐渐增加, 从平均占到50%增加到超过90%。启炉过程中烟气二噁英排放速率高于其正常达标时的排放水平, 最高值为58.1 mg I-TEQ·h^-1, 超过正常排放的40倍。一个启炉周期二噁英的排放总量达到0.785 mg I-TEQ, 达标正常工况下二噁英的年排放总量为8.4 mg I-TEQ, 按照平均每年3次启炉来计算, 启炉过程二噁英的排放量占到全年正常排放的28%。     

载气流量及升温速率对污染土壤中多氯联苯热脱附的影响

利用小型管式炉进行了载气流量和升温速率对多氯联苯污染土壤的热脱附过程影响的实验研究。结果表明流量的增大对多氯联苯含量和毒性当量的去除效率影响不大,载气流量小于400 ml·min^-1时,气相中的脱附量明显增大,载气流量大于400 ml·min^-1则脱附量变化较小,而多氯联苯的毒性当量则随着载气流量增大呈线性增加趋势。实验结果还表明污染土壤中多氯联苯变化速率与升温速率呈明显的正线性相关,随着升温速率增加,污染土壤中多氯联苯去除效率总体呈上升趋势,毒性当量去除效率降低。总体结果分析可以看到升温速率越大,总体效果也越好。污染土壤经热脱附处理后气固相的二 英毒性当量则有不同程度提升,尤其气相内检测到了大量多氯二苯并呋喃生成。     

Characteristics of PAHs,PCDD/Fs,PCBs and PBDEs in the Sediment of Lake Baikal,Russia

The levels of PAHs, PCDD/Fs, PCBs, and PBDEs in Lake Baikal were monitored for the first time using deep water sediment. The sediment samples were collected from 15 stations in four regions of Lake Baikal: Ol’khon Island (n = 8), the Angara River estuary (n = 2), the Selenga River delta (n = 2), and the Baikal pulp and paper mill (BPPM) (n = 3). The highest average concentrations of PCDD/Fs (20.24 pg/g d.w.) and PCBs (68.72 ng/g d.w.) were found at Ol’khon Island. The highest total PBDE concentrations were found at BPPM, with a mean concentration of 575.76 pg/g d.w. For PCBs, PCB-52, and PCB-69 were dominant, making up 11% of the total 209 PCB congeners. BDE-209 contributed 60% of PBDEs in Lake Baikal. According to the TPEQ concentration of PAHs, PAHs contributed the most to Lake Baikal contamination. The sources of contamination of PAHs, PCDDs, and PCBs in Lake Baikal are identified as combustion, runoff from the use of the pesticides (PCP) and insulating oil, specifically for PCBs. The source of PBDEs is assumed to be production, use and disposal of products containing PBDEs, in addition to atmospheric long-range transport and deposition.     

Ecological Risk and Health Risk Assessment of Dioxin-like PCBs in Liaohe Estuarine Wetland Soils,China

Forty one soil samples were collected from Liaohe estuarine wetland in May 2009 for assessing the distribution, ecological risk, and health risk of dioxin-like PCBs (dl-PCBs). The total concentrations of 12 dl-PCBs ranged from 0.36–1.36 ng/g, with a mean value of 0.77 ng/g. The dominant dl-PCBs were Tetra-CBs, which contributed to 43.9% of the total. The ecological risk of dl-PCBs was analyzed based on the toxic equivalent (TEQ) approach. In this study, the TEQ concentrations of dl-PCBs in soils varied from 0.06–22.55 pg/g, with a mean value of 8.18 pg/g. Human health risk was evaluated based on the non carcinogenic and carcinogenic risk method. Non carcinogenic risk was measured using a hazard quotient (HQ) values for 95% upper control limit (UCL) and maximum concentrations of dl-PCBs. HQ values were lower than 1 under both exposure scenarios, which indicated that the non carcinogenic risk of dl-PCBs was negligible. Carcinogenic risk was estimated based on the criteria of ingestion, dermal contact and inhalation of soils. Carcinogenic risk values were less than 10^?6, which exhibited negligible cancer risk for infant, child and adult, respectively, through ingestion, dermal contact, and inhalation pathway.     

五氯酚在飞灰表面低温反应生成二口恶英特性

在管式炉上研究了不同试验条件飞灰/五氯酚生成二口恶英的分布特性.采用色质联机(HRGC/LRMS)测定了PCP中以及生成产物中的二口恶英含量.结果表明，生成产物中的二口恶英主要以气态形式存在，总的二口恶英中以PCDDs为主，比例高于97％，PCDDs中主要同系物是六至八氯代PCDDs.分析了飞灰含量以及氧含量对二口恶英生成的影响，二口恶英生成量随着飞灰中含碳量的增加而增大，氧含量是控制二口恶英生成的关键因素，氧含量在6.7％时生成的二口恶英总量及毒性当量值最小.对试验中产生的二口恶英进行了质量平衡，为进一步研究垃圾焚烧过程中二口恶英排放以及分布特性打下基础.     

三氯新中二噁英同类物的指纹特征

作为三氯新生产过程中的一种副产物,二口恶英污染物在三氯新中的存在已经引起了广泛关注。采用高分辨气相色谱-质谱测定了三氯新样品中的二口恶英同类物,共检测到7种2,3,7,8位氯取代同类物,即2,3,7,8 TCDD(四氯代二苯并二口恶英)、1,2,3,7,8 PeCDD(五氯代二苯并二口恶英)、1,2,3,4,6,7,8 HpCDD(七氯代二苯并二口恶英)、2,3,7,8 TCDF(四氯代二苯并呋喃)、1,2,3,7,8 PeCDF(五氯代二苯并呋喃)、2,3,4,6,7,8 HxCDF(六氯代二苯并呋喃)、1,2,3,4,6,7,8 HpCDF(七氯代二苯并呋喃),其含量分别为0 25、0 44、2 65、0 88、2 15、1 02和4 21pg·g-1。四至八氯代二口恶英总量中,四氯代二苯并呋喃最多。在检测到的7种有毒二口恶英中,对毒性当量贡献较大的同类物有2,3,7,8 TCDD和1,2,3,7,8 PeCDD。三氯新样品中二口恶英同类物分布的指纹特征与环境样品差别较大,二口恶英类污染物的产生与三氯新的生产工艺有关。     

Levels,Sources, and Risk Assessment of Polychlorinated Biphenyls (PCBs) in Soils from Industrial Areas: A Case Study from Saudi Arabia

ABSTRACT

The objective of this study was to assess the pollution levels, sources, and human health risk of polychlorinated biphenyls (PCBs) in soils of industrial areas of the central and eastern regions of Saudi Arabia. Therefore, the surface soil samples from industrial areas (cement kiln, oil refinery, electric power plant, steel industry, and desalination plant) were collected and analyzed by High-Resolution Gas Chromatography-Mass Spectrometry/Mass Spectrometry-Time of Flight (HRGC-MS/MS-TOF) to quantify the levels of 26 PCBs (including 12 dioxin-like PCBs and 14 indicator-PCBs). The investigated 26 PCBs were detected in all soil samples. The total PCBs concentration (from tri-CBs to hepta-CBs) ranged from 171 to 4892 pg g^?1 with an average of 1369 pg g^?1 in soils of the central region and of 142–1231 pg g^?1 with an average of 302 in soils of the eastern region, showing higher values at cement factory and/or oil refinery sites. Overall, the indicator-PCBs were the main congeners and contributed dominantly to the total mass of PCBs in comparison with the dioxin-like PCB congeners, with the most abundant for PCB-180 in the soil samples of the central region. Among individual dioxin-like PCBs, PCB-126 had the highest average value of the toxicity equivalence (TEQ). The TEQ values of ∑12dioxin-like PCBs did not exceed the Canadian soil quality guidelines of dioxin (4 pg TEQ g^?1). Based on human health risk assessment via ingestion, dermal contact, and inhalation, low adverse effects of PCBs could be expected as indicated by lower values of cancer risk (≤10^?6). The principal component analysis indicated that there is a different source of PCBs with similar or different PCB profiles.