上海食用鱼中短链氯化石蜡的污染特征

为了解长三角地区食用鱼中短链氯化石蜡(SCCPs)的污染特征,根据当地人的食鱼习惯,在上海采集了不同营养级的食用鱼8种,共计68尾,测定了肌肉中SCCPs含量并分析了其同族体的分布模式.结果表明,食用鱼肌肉中SCCPs的含量(干重,dw)范围为36～801 ng.g-1;同族体分布以C10-和C11-SCCPs为主,随着碳链长度的增加,SCCPs同族体含量所占比例随之降低,并且均以低氯(Cl6～Cl8)取代的SCCPs为主要组成部分,相对丰度之和占总丰度的61.46%～82.50%.上海食用鱼中SCCPs的含量在世界范围内处于中等水平,其分布模式与国内外研究一致.     

HRGC/ECNI-LRMS测定大辽河入海口表层沉积物中短链氯化石蜡

联合使用酸化硅胶层析柱和中性氧化铝层析柱净化处理沉积物样品中的短链氯化石蜡(SCCPs),并对净化条件进行优化,在此基础上,建立了沉积物中SCCPs的高分辨气相色谱/电子捕获负离子化-低分辨质谱(HRGC/ECNI-LRMS)分析方法.应用该方法分析研究了大辽河入海口表层沉积物中SCCPs的含量和各同系物组分的分布模式.结果表明,大辽河入海口表层沉积物中SCCPs以C10-SCCPs和C11-SCCPs为主,含量在64.9～407.0 ng/g之间,且随着向海洋方向延伸,SCCPs含量呈现下降趋势.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in surface soil from the Tibetan Plateau

Concentrations of Polychlorinated dibenzo-p-dioxins and dibenzofurans（PCDD/Fs） and polychlorinated biphenyls（PCBs） in soil samples from Tibetan Plateau were determined. The average concentration of total 2,3,7,8-PCDD/Fs was（2.30 ± 1.02） pg/g, and World Health Organization Toxicity Equivalency（WHO-TEQ） average concentration was（0.013 ± 0.010）pg WHO-TEQ/g. The average concentration of ∑PCBs（7 indicator PCB and 12 dioxin like-PCB congeners） was（16.2 ± 9.25） pg/g, and WHO-TEQ average concentration was 0.043 ±0.049 pg WHO-TEQ/g. Comparing to previous studies in similar environmental conditions,PCDD/Fs and PCBs in this study showed a relatively lower concentration. The altitude dependences of PCDD/Fs and PCBs were also studied. Total organic carbon（TOC） normalized concentrations presented a quadratic relation with the altitudes, and an inflection could be found on the parabola of the total concentrations and some congeners of high concentration.The concentrations decreased with altitudes below about 4500 m above sea level（a.s.l.）, while they increased with altitudes above it. These phenomena indicate that cold condensation of PCDD/Fs and PCBs would happen above 4500 m a.s.l, on the Tibetan Plateau.     

若尔盖高原湿地地表水与大气湿沉降中有机氯农药和多氯联苯研究

采用高分辨率气相色谱-高分辨率质谱联用法分析位于青藏高原东缘的若尔盖高原牧场地表水和大气湿沉降中有机氯农药(OCPs)和多氯联苯(PCBs)异构体含量的季节分布特征,探讨持久性有机污染物(POPs)在边远清洁地区的地球化学行为.结果表明,若尔盖地区地表水中∑HCHs、∑DDTs、HCB、∑6PCBs平均浓度分别为0.90,1.36, 0.95,1.35ng/L.大气降水中OCPs和PCBs平均浓度分别为0.363,0.118ng/L,最大值出现在11月初冬的降雪样品中.异构体按平均浓度排序为HCB > PCB28 > p,p’-DDD > p,p’-DDE > α-HCH > γ-HCH.PCBs以PCB28和PCB52为主,除少量的PCB101外,其余高氯代PCB化合物都未在沉降样品中检出.∑HCHs、∑DDTs、∑PCBs的大气沉降通量分别为0.058~0.268,0.087~0.311,0.049~0.188ng/(m2·d).高海拔地区POPs大气沉降模式可分为“海拔梯度降水型”和“高原型”2类.类似于极地冷凝作用,高原型降雪中的POPs的沉积通量高于降雨沉降通量,但持久性较强的PCB138、PCB153和PCB180则缺失.这一结果验证了高空大气远程迁移和局地的高山冷凝效应的区别.     

利用OMI遥感数据研究中国区域大气NO_2

利用臭氧观测仪（Ozone Monitoring Instrument,OMI）卫星遥感反演的NO2柱浓度数据,分析了自2004年以来中国地区对流层NO2柱浓度（TroNO2）和总NO2柱浓度（TotNO2）的时空特征及其影响的原因.中国区域平均TroNO2和TotNO2呈现上升的趋势,年平均分别增长了4.67%和2....     

川西高原积雪稳定性分布格局及其驱动因子分析

在气候变暖的背景下,川西高原积雪出现剧烈变化,对地区水循环过程、生态系统以及社会经济带来严重影响。基于MODIS积雪遥感数据以及环境因子数据,通过构建稳定度指标及最大熵模型探讨川西高原不同稳定性积雪的空间分布格局及其驱动因子,并对不同稳定性积雪的适宜分布区进行分析,结果表明：（1）川西高原大多数地区的积雪属于高度不稳定性积雪,其他稳定性积雪在川西高原分布面积较小;（2）川西高原积雪在海拔越高的地方稳定性越好;（3）不同稳定性积雪分布格局的影响因素存在差异,海拔和降水是影响稳定性积雪分布格局的主要因素。     

Hydrophobic organic chemicals in urban fog

The concentrations and aqueous/particle distributions of three classes of hydrophobic organic chemicals, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were measured during the autumn of 1986's fog events in the urban area of Zürich, Switzerland. Concentrations of the chemicals in fog were in the range of 10–110 ng ml⁻¹ for n-alkanes (C₁₉–C₃₅), 6–60 ng ml⁻¹ for PAHs (21 compounds) and 7–22 ng ml⁻¹ for PCBs (31 congeners). In many samples, the concentration of individual n-alkanes and PAHs exceeded their water solubility, probably due to their association with dissolved and/or colloidal organic matter. All of the PAHs, except for phenanthrene, were measured as part of the particulate phase. Both the n-alkanes and PCBs showed a trend of increasing particle association with increasing hydrophobicity, but the trends were distinctly different. The presence of PCBs, PAHs, and n-alkanes at these concentrations suggest that fog is an excellent scavenger of hydrophobic organic chemicals. For a forested area near Zürich, Switzerland, it was estimated that the deposition of n-alkanes and PAHs by fog may be about equal to deposition via rain, but that fog may be 100 times more important than rain for the deposition of PCBs.     

Trace elements and rare earth elements in wet deposition of Lijiang, Mt. Yulong region, southeastern edge of the Tibetan Plateau

In order to investigate the compositions and wet deposition fluxes of trace elements and rare earth elements (REEs) in the precipitation of the southeastern edge of the Tibetan Plateau, 38 precipitation samples were collected from March to August in 2012 in an urban site of Lijiang city in the Mt. Yulong region. The concentrations of most trace elements and REEs were higher during the non-monsoon season than during the monsoon season, indicating that the lower concentrations of trace elements and REEs observed during monsoon had been influenced by the dilution effect of increased precipitation. The concentrations of trace elements in the precipitation of Lijiang city were slightly higher than those observed in remote sites of the Tibetan Plateau but much lower than those observed in the metropolises of China, indicating that the atmospheric environment of Lijiang city was less influenced by anthropogenic emissions, and, as a consequence, the air quality was still relatively good. However, the results of enrichment factor and principal component analysis revealed that some anthropogenic activities (e.g., the increasing traffic emissions from the rapid development of tourism) were most likely important contributors to trace elements, while the regional/local crustal sources rather than anthropogenic activities were the predominant contributors to the REEs in the wet deposition of Lijiang city. Our study was relevant not only for assessing the current status of the atmospheric environment in the Mt. Yulong region, but also for specific management actions to be implemented for the control of atmospheric inputs and the health of the environment for the future.     

青藏高原淡水湖泊水化学组成特征及其演化

青藏高原淡水湖具有高生态价值和高脆弱性并存的特点.以海拔5 080 m±10 m的打加芒错湖水为研究对象,测试及分析了湖水化学组分,探讨了其主要离子来源、控制因子和湖泊水化学演化趋势.结果表明,湖水阳离子以Ca2+和Na+为主,阴离子以HCO3-为主,为HCO3-Ca型水;TDS为71.2～199.8 mg·L-1,矿化度低;受地表径流的稀释作用和富铝贫钙的地质背景约束湖区东南部水体的EC、Ca2+和HCO3-浓度均较低.湖水的Na+/(Na++Ca2+)为0.08～0.75,Cl-/(Cl-+HCO3-)为0.11～0.35,Ca/Na值为0.58,Mg/Ca值为0.12,HCO3/Na值为1.46,据Gibbs模型和元素化学计量分析表明,其化学组成主要受硅酸盐岩风化控制.湖区流域参与风化的矿物岩石包括斜长石(钙长石、钠长石)、钾长石、云母、石膏、盐岩等,但以斜长石风化为主,湖水的K/Na值平均为0.059,表明流域钾长石风化程度较低.湖水中方解石、白云石、石英、石膏等矿物饱和指数(SI)大于0,石盐的SI则小于0,揭示了青藏高原上淡水湖泊演变成咸水湖的变化趋势.     

Export of dissolved carbonaceous and nitrogenous substances in rivers of the “Water Tower of Asia”

Rivers are critical links in the carbon and nitrogen cycle in aquatic,terrestrial,and atmospheric environments.Here riverine carbon and nitrogen exports in nine large rivers on the Tibetan Plateau—the"Water Tower of Asia"—were investigated in the monsoon season from 2013 to 2015.Compared with the world average,concentrations of dissolved inorganic carbon(DIC,30.7 mg/L)were high in river basins of the plateau due to extensive topographic relief and intensive water erosion.Low concentrations of dissolved organic carbon(DOC,1.16 mg/L)were likely due to the low temperature and unproductive land vegetation environments.Average concentrations of riverine DIN(0.32 mg/L)and DON(0.35 mg/L)on the Tibetan Plateau were close to the world average.However,despite its predominantly pristine environment,discharge from agricultural activities and urban areas of the plateau has raised riverine N export.In addition,DOC/DON ratio(C/N,~6.5)in rivers of the Tibetan Plateau was much lower than the global average,indicating that dissolved organic carbon in the rivers of this region might be more bioavailable.Therefore,along with global warming and anthropogenic activities,increasing export of bioavailable riverine carbon and nitrogen from rivers of the Tibetan Plateau can be expected in the future,which will possibly influence the regional carbon and nitrogen cycle.     

青藏高原高寒湿地春夏两季根际与非根际土壤反硝化速率及nirS型反硝化细菌群落特征分析

反硝化是生态系统氮循环的关键过程.目前对于生态系统氮排放及反硝化细菌群落的研究大多基于人为影响显著的环境,对于人为干扰较低的自然生态系统的研究较少.本研究选取青藏高原黄河源区不同海拔（唐克、久治、玛多和达日）不同季节（春季和夏季）的高寒湿地植物根际与非根际土壤作为研究对象,采用¹⁵N同位素标记法测定反硝化速率,高通量测序技术测定nirS反硝化细菌群落组成及相对丰度,并探究环境因子（气温、海拔）和土壤理化性质（pH、土壤有机碳、铵态氮、硝态氮和亚硝态氮）对nirS型反硝化细菌群落的影响.结果表明,高寒湿地土壤反硝化速率范围为0.80~14.98 nmol·（g·h）^-1,对总N₂释放的贡献率为11.23%~71.16%.唐克、久治和达日的土壤样品,均呈现出根际土壤反硝化速率高于非根际的趋势（P<0.05）.Proteobacteria是青藏高原高寒湿地植物根际和非根际土壤中主要的反硝化细菌门;在属水平上,各土壤样本中相对丰度最高的是一种未分类的变形杆菌（unclassified Proteobacteria,2.86%~29.41%）,这表明主导青藏高原高寒湿地反硝化作用的可能有一些独特的未被鉴定的反硝化菌属,相对丰度其次为假单胞菌属（Pseudomonas,2.45%~26.52%）和贪铜菌属（Cupriavidus,0%~34.14%）.基于距离的冗余分析结果表明,高寒湿地的反硝化细菌群落结构主要受到海拔、pH、NO₂^-含量影响（P<0.05）;相关分析表明反硝化速率和Shannon指数与pH呈显著负相关（P<0.05）,且主要反硝化菌群相对丰度受到温度和pH的影响.本研究结果可为进一步了解青藏高原高寒湿地这一特殊生境中的氮循环提供参考依据.     

Observed levels and trends of gaseous SO2 and HNO3 at Mt. Waliguan, China: Results from 1997 to 2009

Long-term measurements of SO2 and HNO3,particularly those from the background sites,are rarely reported.We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan(WLG),the only global baseline station in the back-land of the Eurasian Continent.The concentrations of SO2 and HNO3 were observed at WLG from 1997 to 2009.The observed annual mean concentrations of SO2 and HNO3 at WLG were 1.28±0.41 and 0.22±0.19μg/m3,respectively.The HNO3 concentrations were much higher in warmer seasons than in colder seasons,while the SO2 concentrations showed a nearly reversed seasonal pattern.In most months,the concentration of HNO3 was significantly correlated with that of SO2,suggesting that some common factors influence the variations of both gases and the precursors of HNO3 may partially be from the SO2-emitting sources.The SO2 concentration had a very significant(P < 0.0001) decreasing trend(-0.2μg/(m3·yr)) in 1997-2002,but a significant(P < 0.05) increasing trend(+0.06 μg/(m 3 ·yr)) in 2003-2009.The HNO3 concentration showed no statistically significant trend during 1997-2009.While the decrease of SO2 in 1997-2002 agrees with the trend of global SO2 emissions,the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world.Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO2 and HNO3 at WLG in 2003-2009,with a rate of +0.13μg/(m3·yr) and +0.007μg/(m3·yr),respectively.     

Monitoring atmospheric nitrous oxide background concentrations at Zhongshan Station, east Antarctica

At present,continuous observation data for atmospheric nitrous oxide(N_2O) concentrations are still lacking,especially in east Antarctica.In this paper,nitrous oxide background concentrations were measured at Zhongshan Station(69°22′25″S,76°22′14″E),east Antarctica during the period of 2008–2012,and their interannual and seasonal characteristics were analyzed and discussed.The mean N_2O concentration was 321.9 n L/L with the range of 320.5–324.8 n L/L during the five years,and it has been increasing at a rate of 0.29% year-1.Atmospheric N_2O concentrations showed a strong seasonal fluctuation during these five years.The concentrations appeared to follow a downtrend from spring to autumn,and then increased in winter.Generally the highest concentrations occurred in spring.This trend was very similar to that observed at other global observation sites.The overall N_2O concentration at the selected global sites showed an increasing annual trend,and the mean N_2O concentration in the Northern Hemisphere was slightly higher than that in the Southern Hemisphere.Our result could be representative of atmospheric N_2O background levels at the global scale.This study provided valuable data for atmospheric N_2O concentrations in east Antarctica,which is important to study on the relationships between N2 O emissions and climate change.     

海拔梯度上川西高山土壤溶解性有机质(DOM)光谱特征

采用三维激发发射矩阵荧光光谱、平行因子分析（EEM-PARAFAC）和荧光区域积分方法（FRI）,研究川西高原3200~4000m高寒土壤DOM特征及其在海拔梯度上变化规律.结果表明,高寒土壤DOC含量为0.47~0.81g/kg,随着海拔梯度的升高而呈增加趋势,表层土中含量多高于亚表层土;土壤中DOM组分均呈5个组分,即芳香蛋白类物质I（酪氨酸类,Peak I）、芳香蛋白类物质II（BOD₅,Peak II）、富里酸类（Peak III）、微生物代谢产物（色氨酸类,Peak IV）和腐殖酸类（大分子腐殖酸,Peak V）;高山土壤DOM中以富里酸类有机质和腐殖酸类有机质组分为主,FRI值均随着海拔的升高而降低..川西高山土壤DOM荧光特征参数（荧光指数FI、自生源指数BIX、腐殖化指数HIX、新鲜度指数β：α）表明,土壤DOM的稳定性随着海拔升高而降低,生物有效性随着海拔升高而升高.因此,气候变暖可能将导致高海拔土壤DOM分解加剧而含量降低,但稳定性升高.     

散射辐射对青藏高原高寒草地总初级生产力模拟的影响

太阳辐射的散射组分能够增强植被冠层LUE（light use efficiency,光能利用率）,因此需要在生产力模型中显式地加入散射辐射的影响,从而更准确地模拟植被冠层光合作用.以青藏高原高寒草地为研究对象,改进光能利用率模型,增加散射辐射模块,利用站点通量观测数据估计模型关键参数;结合区域尺度气象数据和遥感数据,模拟了2003—2008年青藏高原高寒草地区域尺度GPP（gross primary production,总初级生产力）,并量化了GPP模拟的不确定性,进而通过分析模型改进前后GPP空间分布及其不确定性的差异量化了散射辐射的作用.结果表明:考虑散射辐射对LUE的影响后,模型参数优化效果明显提升,青藏高原高寒草地GPP的模拟效果得到提升;2003—2008年青藏高原高寒草地GPP模拟值呈现东南部较大,西北部较小的空间格局,与不考虑散射辐射的结果一致,但GPP平均值由312.3 g/（m2·a）增至341.7 g/（m2·a）,增幅约9.4%,说明不考虑散射辐射会低估青藏高原高寒草地GPP;GPP模拟值不确定性的空间分布与不考虑散射辐射的结果一致,但是平均不确定性大小有所降低,从9.15%降至8.66%.研究显示,若在青藏高原高寒草地的GPP模拟中不考虑散射辐射,虽不会影响其空间格局,但会低估GPP模拟值的大小,同时增加其不确定性.      

Vertical distributions of tropospheric SO2 based on MAX-DOAS observations: Investigating the impacts of regional transport at different heights in the boundary layer

Information on the vertical distribution of air pollutants is essential for understanding their spatiotemporal evolution underlying urban atmospheric environment. This paper presents the SO₂ profiles based on ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements from March 2018 to February 2019 in Hefei, East China. SO₂ decrease rapidly with increasing heights in the warm season, while lifted layers were observed in the cold season, indicating accumulation or long-range transport of SO₂ in different seasons might occur at different heights. The diurnal variations of SO₂ were roughly consistent for all four seasons, exhibiting the minimum at noon and higher values in the morning and late afternoon. Lifted layers of SO₂ were observed in the morning for fall and winter, implying the accumulation or transport of SO₂ in the morning mainly occurred at the top of the boundary layer. The bivariate polar plots showed that weighted SO₂ concentrations in the lower altitude were weakly dependent on wind, but in the middle and upper altitudes, higher weighted SO₂ concentrations were observed under conditions of middle-high wind speed. Concentration weighted trajectory (CWT) analysis suggested that potential sources of SO₂ in spring and summer were local and transported mainly occurred in the lower altitude from southern and eastern areas; while in fall and winter, SO₂ concentrations were deeply affected by long-range transport from northwestern and northern polluted regions in the middle and upper altitudes. Our findings provide new insight into the impacts of regional transport at different heights in the boundary layer on SO₂ pollution.     

短链及中链氯化石蜡在上海市松江区农田土壤中的污染渗透及生态风险

土壤是氯化石蜡重要的"源"和"汇",为了评估上海市松江区某农业区土壤中短链氯化石蜡（SCCPs）及中链氯化石蜡（MCCPs）的污染水平及渗透潜能,利用超声提取-复合硅胶柱一步净化-GC-ECNI-LRMS方法监测农田表层及不同深度（0~15、15~30、30~45 cm）土柱样品中SCCPs及MCCPs的含量水平、组成特征及潜在风险.结果表明:①表层土壤中SCCPs和MCCPs含量范围分别为52.58~237.56和417.21~1 690.82 ng/g,二者对应的氯含量分别为58.98%~63.85%和51.23%~56.50%.SCCPs同系物主要以C₁₀Cl_5~7为主,MCCPs同系物以C₁₄Cl_6~7为主.②单因素方差分析发现,MCCPs含量沿土柱深度变化显著（P < 0.01）,其同系物在上层、中层和深层的占比分别为60.5%、25.4%和14.1%.SCCPs同系物含量沿土柱深度分布均匀,MCCPs同系物含量沿土柱深度呈指数递减趋势.垂直分布曲线表明,低氯化、短碳链的氯化石蜡同系物（CPs）具有更高的土壤渗透潜力.③皮尔逊相关性分析发现,CPs含量和总有机碳（TOC）含量之间不存在显著相关性（P>0.05）.主成分分析表明,研究区土壤中SCCPs和MCCPs的来源不同,可能与环境条件以及不同商业CPs混合物的生产技术、原材料差异等有关.④风险商值法评价表明,土壤SCCPs和MCCPs的风险商（risk quotients,RQ）范围分别为0.01~0.05和0.01~0.06,均处于低风险水平（0.01~0.1）.应用人体暴露模型对儿童和成人的人体暴露值进行估算,两类人群的CPs日均暴露值均低于每日可耐受摄入量（TDI,10 μg/kg）,非饮食暴露导致的健康风险较低.研究显示,上海市松江区农田土壤中CPs污染含量处于中等水平,SCCPs沿土柱的渗透能力较强,该地区土壤生物风险商和人体健康暴露值均较低,产生的生态风险可忽略,但农作物富集造成的潜在健康威胁需要引起注意.      

青藏高原东麓贡嘎山东坡土壤中Pb的来源解析

选择青藏高原东麓典型山地——贡嘎山(东坡),根据不同海拔梯度(海拔2 000~4 500 m)差异设置8个采样点,根据土壤发育情况分别采集O层(有机层)、A层(矿物质层)和C层(母质层)样品,分析土壤中w(Pb)的海拔分布特征,并利用FA-MLR(因子回归分析)法、地球化学指标法和Pb同位素三元混合模型定量判识表层土壤中Pb的来源. 结果表明:①各层土壤中w(Pb)表现为O层〔(41.73±4.38)mg/kg〕>A层〔(30.47±2.17)mg/kg〕>C层〔(23.04±1.50)mg/kg〕(P<0.05). 随着海拔的增加,O层和A层中w(Pb)总体呈升高—降低—升高趋势;C层中w(Pb)随着海拔的变化无显著差异,表明贡嘎山东坡土壤中w(Pb)的地球化学背景值基本一致. ②各层土壤中206Pb/207Pb表现为O层208Pb/206Pb表现为O层>A层>C层. ③Pb同位素三元混合模型结果显示,表层(O层和A层)土壤中Pb可能受到化石燃料燃烧和矿物开采及金属冶炼活动的影响;根据FA-MLR法、地球化学指标法和Pb同位素三元混合模型这3种方法,得到O层中污染Pb所占比例分别达到84.9%、66.0%和63.7%,A层中分别为56.6%、27.8%和44.9%;在海拔分布上,Pb的污染在海拔2 770 m以下主要归因于当地化石燃料的燃烧,而在林线(约3 700 m)以上则来自矿物开采及金属冶炼活动.      

黄河源区鄂陵湖中多环芳烃的百年沉积记录

为研究黄河源区多环芳烃（PAHs）的污染历史,于2016年7月在鄂陵湖中采集了沉积物柱芯,采用²¹⁰Pb定年,利用气相色谱串联三重四级杆质谱仪（GC-MS/MS）分析了16种PAHs,运用有序聚类分析对PAHs的垂向分布进行分带,并采取主成分分析及多元线性回归定量分析了PAHs的来源.结果表明,鄂陵湖沉积柱的沉积速率为0.176cm/a,慢于青藏高原多数湖泊.总PAHs的含量为11.3~54.7ng/g,平均值为29.2ng/g,与其他高原和偏远地区湖泊沉积物相比,处于较低水平,可被视为PAHs的全球沉积物背景值.PAHs的垂向变化分为1948年以前、1948~1976和1976~2016年3个时间段,5~6环PAHs在1948~2016年间呈上升趋势,与青海省人口及大型牲畜数量显著相关,反映了鄂陵湖地区近70a来的人类活动以农牧业为主.PAHs来源分为本地源（23%）以及长距离迁移与本地混合源（77%）.本地源的垂向变化与5~6环PAHs一致,代表了青藏高原地区以牛粪饼为主要燃料的生物质燃烧源.     

Occurrence and bioaccumulation of polybrominated diphenyl ethers in sediments and paddy ecosystems of Liaohe River Basin, northeast China

Concentrations of 16 polybrominated diphenyl ether(PBDE) congeners were measured in river sediments, paddy soils and three species of paddy-field organisms(crab, loach and carp) collected from the Liaohe River Basin, northeastern China. The total contents of PBDEs(∑_(16)PBDEs) in sediments and paddy soils were in the ranges of 273.4–3246.3 pg/g dry weight(dw), and 192.1–1783.8 pg/g dw, respectively. BDE 209 was the dominant congener both in sediments and paddy soils. The concentrations of ∑_(16)PBDEs in sediments were significantly higher than those in the adjacent paddy soils, indicating a potential transport of PBDEs from river to paddy ecosystems via river water irrigation. The biota–soil accumulation factor(BSAF) was calculated as the ratio between the lipid-normalized concentration in paddyfield organisms and the total organic carbon-normalized concentration in paddy soil. The average BSAF values of ∑15PBDEs followed the sequence of crab(3.6) loach(3.3) carp(2.1). BDE 154 had the highest BSAF value, and a parabolic trend between BSAF values of individual PBDE congeners and their log KOWvalues was observed. In view of the fact that crab had the larger BSAF value and higher lipid content, the ecological risk and health risk for crab cultivation in paddy fields should be of particular concern.