城乡结合带农田土壤多环芳烃空间分布特征及来源解析-以南京市周岗镇为例

为了解城乡结合带农田土壤PAHs的污染特征及分布规律,本文以南京市江宁区周岗镇为例,就该地区表层农田土壤中15种优控PAHs组分的含量、空间分布特征及来源进行了研究。结果表明:有14种PAHs普遍被检出(苊未检出),以高环(4～6环)PAHs为主;PAHs总量范围在24.49～750.04μg kg-1之间,平均为230.89μg kg-1,有48.28%的土样受到了污染;与国内其他地区农田土壤相比,研究区PAHs含量处于中低水平;空间趋势面分析表明,14种PAHs在东西和南北方向上呈现出明显的规律增减性;从空间分布格局来看,研究区土壤中14种PAHs含量差异较大,整体呈现由东北向西南递减的趋势,且个别点位存在PAHs的富集现象,存在局部点源污染;采用主成分及多元线性回归分析污染来源,结果显示,研究区PAHs来源主要为煤、生物质燃烧,其次为汽油、柴油燃烧,贡献率分别为71%和29%,这与当地的工业发展水平关系密切。     

城乡结合带农田土壤多环芳烃空间分布特征及来源解析

为了解城乡结合带农田土壤PAHs的污染特征及分布规律,本文以南京市江宁区周岗镇为例,就该地区表层农田土壤中15种优控PAHs组分的含量、空间分布特征及来源进行了研究。结果表明:有14种PAHs普遍被检出（苊未检出）,以高环（4 ~ 6环）PAHs为主;PAHs总量范围在24.49 ~ 750.04 μg kg?1之间,平均为230.89 μg kg?1,有48.28%的土样受到了污染;与国内其他地区农田土壤相比,研究区PAHs含量处于中低水平;空间趋势面分析表明,14种PAHs在东西和南北方向上呈现出明显的规律增减性;从空间分布格局来看,研究区土壤中14种PAHs含量差异较大,整体呈现由东北向西南递减的趋势,且个别点位存在PAHs的富集现象,存在局部点源污染;采用主成分及多元线性回归分析污染来源,结果显示,研究区PAHs来源主要为煤、生物质燃烧,其次为汽油、柴油燃烧,贡献率分别为71%和29%,这与当地的工业发展水平关系密切。     

基于地理探测器的封丘县农田土壤重金属分布影响因素研究

以河南省封丘县为研究区，利用反距离加权插值法研究了农田土壤重金属Cd、Cu、Cr、Pb、Zn和As的空间分布特征；同时，应用基于地理探测器模型定量研究了8个因子对土壤重金属空间分布的影响。结果表明：研究区土壤Cd、Cr、Pb和Zn含量超过了黄河下游潮土背景值，而Cu和As含量低于黄河下游潮土背景值；其中有极少量样点Cd含量超过农用地土壤污染风险筛选值，而其他均未超标。在空间分布上，Cd、Cr、Pb含量的高值区分别主要分布在研究区中部、西南部和北部，As含量的高值区分布在研究区北部和西南部，Cu和Zn含量的高值区在研究区南北方向呈带状分布。Cd、Pb和As含量的低值区主要分布在研究区南部，Cr、Cu、Zn和As含量的低值区主要分布在研究区中部。地理探测器分析表明，土壤重金属空间分布受到自然因子和人为因子的共同作用，有机质含量是影响较大的自然因子，人口密度是影响较大的人为因子。两因子之间的交互作用均大于单因子的作用，其中有机质含量与各因子的交互作用对重金属空间分布的影响较显著。     

基于地统计学的樱桃园土壤重金属污染评价及来源解析

为研究天水市樱桃园土壤重金属污染的空间分布特征,实地采集0~20 cm土壤样品,测定重金属Pb、Cd、Cr、Cu、Zn含量,并运用多元统计分析等方法定量分析了研究区土壤表层重金属污染程度。结果表明:以甘肃省土壤背景值作为评价标准,除Cd元素外,其他元素的均值都超过了甘肃省土壤背景值;从土壤重金属元素空间分布格局来看,研究区东北部土壤重金属污染较西南部严重;从土壤重金属元素污染源来看,造成樱桃园土壤重金属污染最主要的因素为成土母质、农药;5种重金属元素均存在不同来源的污染,污染来源不单一,属于混合源污染。     

太原小店污灌区农田土壤多环芳烃的污染特征及其来源

[目的]对太原小店污灌区农田土壤多环芳烃(PAHs)的污染特征及来源进行分析,为该区农田土壤环境质量评价及土壤污染防治对策的制定提供科学依据。[方法]采集太原小店污灌区15个表层土壤样品,利用GC/MS分析16种US EPA优控多环芳烃(PAHs)的含量,并对其来源和生态风险进行探讨。[结果]所有样品的16种PAHs均被检出,其检出率为100%。研究区农田土壤中总PAHs的浓度为0.315~7.661μg/g,平均值为3.568μg/g。在组成上,2,3环含量约占总量的64.2%,4环含量约占总量的14.2%,5,6环含量约占总量的21.6%,低环和中环PAHs含量所占的比例较高。根据特征比值法及调查结果判定,农田土壤中PAHs污染来源一方面与灌溉水质及灌溉历史有很大的关系,另一方面,主要通过燃煤或化石燃料产生的PAHs在大气干湿沉降和风力输送作用下进入到土壤环境中。[结论]与国内外其他地区的相关研究比较,小店污灌区农田土壤PAHs含量处于中高等污染水平。依据Maliszewska-Kordybach建议的分级标准评价,该区域所有采样点PAHs总量均超标;但基于我国《土壤环境质量标准(征求意见稿)(GB15618-2008)》提出的16种多PAHs污染物总量的农业用地标准值,该区域均未超出此标准。     

土壤中多环芳烃的分布特征及其来源分析

利用气相色谱法分析了南充市10个不同功能区表层土壤中美国环保署规定的16种优控多环芳烃（PAHs）的含量和组分特征,运用同分异构体比率揭示了其污染来源。研究表明,该区土壤中PAHs的含量在9.1～2269.1μg·kg-1之间,而且工业区的残留量大于农业区和居民区的残留量。按PAHs的环数来分,在工业污染区PAHs的含量总的趋势是四环〉二环〉三环〉五环〉六环;农业和居民区二环〉三环〉五环〉四环〉六环。该污染状况与国内外相关研究比较,处于中等污染水平。煤、木材和化石的燃烧是该地区土壤中PAHs污染的主要来源,苯并（a）蒽和菲是主要的超标化合物。     

黄淮海平原农田土壤磷素空间分布特征及影响因素研究

根据505个样点表层(0～20 cm)土壤磷素的化验数据,在ArcGIS9.0平台上运用地统计学方法研究了黄淮海平原土壤磷素的空间分布特征及其影响因素.结果表明,该区土壤全磷和速效磷含量均属中等水平,全磷含量达(0.73±0.18)g·kg-1,速效磷含量达(21.31±16.08)mg·L-1.土壤全磷空间分布总体上呈团状或块状,其中高值区(＞0.80 g·kg-1)主要分布于河北中南部、山东西部以及山东、安徽、江苏三省交汇处,并由黄淮海中部地区向南北方向逐渐减少;低值区(＜0.50 g·kg-1)主要分布于黄淮海南北两地.土壤速效磷含量总体上呈小团块状分布,其空间分布较全磷复杂.高值区(＞24.0 mg·L-1)主要分布在黄淮海平原的中部地区,并向东北和正南方向减少.低值区(＜12.0 mg·L-1)主要分布于黄淮海平原南、北部边缘.全磷和速效磷高值区主要分布区地理位置大体一致,均是在黄淮海平原中部区域一带,并以此区域向北降低.不同土壤类型由于成土母质本身含磷量空间分布差异,产生了土壤磷素空间变异.土壤质地、磷肥使用量及部分理化性状影响土壤磷素含量.     

彭州市新黄村地震灾后土壤有机碳含量分布特征及影响因素

以典型地震灾区彭州市新黄村为研究对象,应用地统计学和GIS相结合的方法,分析了该区土壤有机C含量分布特征及其影响因素。结果表明,该区域内表层土壤有机C含量为24.83g/kg,其空间分布呈带状,自西部高值区(31g/kg)向东部低值区(13g/kg)递减;不同土地利用方式典型土壤剖面有机C含量总体趋势是随深度的增加而减少,水田、旱地土壤0～20cm有机C含量最高,荒地土壤20～40cm有机C含量最高。影响因素分析表明,不同土地利用方式中水田有机C含量极显著高于荒地,旱地显著高于荒地,水田和旱地差异不显著;地震及震后人类活动能改变土壤有机C含量。     

遵义市土壤锌空间分布特征研究

为了解遵义市土壤锌空间分布现状及其影响因素,在遵义市采集了701个表层土壤样本,分析了样品中的锌含量。利用GS+软件构建半变异函数模型,采用普通克里格法预测了遵义市土壤锌含量空间分布特征,并进一步探讨土壤理化性质对土壤锌含量及其空间分布的影响。结果表明,遵义市土壤全锌含量变幅为40.51～315.74 mg·kg~(-1),平均值为107.9 mg·kg~(-1),土壤锌含量高值区和低值区主要集中在遵义市东南部和西南部。土壤全锌含量与pH无显著相关关系,与有机质和海拔高度呈极显著正相关关系。研究表明,遵义市土壤锌的分布地域差异明显,造成这种差异的主要因素是成土母质、有机质和海拔高度。     

紫阳县土壤硒的分布特征研究

为了探讨紫阳县土壤硒含量水平及分布特征,采集了859个表层土壤样品,用原子荧光分析了其硒含量,在GS+软件中构建了变异函数,用GIS软件绘制了紫阳县土壤全硒含量分布图,同时分析了该区土壤硒含量水平、分布特征及与地层的关系。结果表明:研究区最低土壤硒含量0.0015 mg kg~(-1),最高硒含量36.6854 mg kg~(-1),平均值0.9429 mg kg~(-1),变异系数2.21,土壤硒含量服从对数正态分布,变程3900 m,块金值为0.0273,空间异质性指数为0.108,说明研究区土壤硒含量的变异主要是由结构性因素引起的,空间自相关性强。土壤中硒含量变化范围大,分布不均匀,中间较低,南北高,呈现出两条连续分布的富硒区,占紫阳县总面积的71.7%,富硒区分布与寒武-奥陶-志留系(除梅子垭组)的黑色含碳岩系分布一致,是富硒区土壤硒的主要来源。     

Distribution of Polycyclic Aromatic Hydrocarbons in Soils of an Arid Urban Ecosystem

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants produced by incomplete combustion sources such as home heating, biomass burning, and vehicle emissions. PAH concentrations in soils are influenced by source inputs and environmental factors that control loss processes and soil retention. Many studies have found higher concentrations of these pollutants in soils within cities of temperate climates that have a centralized urban core. Less is known about the factors regulating PAH abundance in warm, arid urban ecosystems with low population densities but high traffic volumes. The relative importance of sources such as motor vehicle traffic load and aridland ecosystem characteristics, including temperature, silt, and soil organic matter (SOM) were explored as factors regulating PAH concentrations in soils near highways across the metropolitan area of Phoenix, AZ (USA). Highway traffic is high compared with other cities, with an average of 155,000 vehicles/day. Soils contained low but variable amounts of SOM (median 2.8?±?1.8% standard deviation). Across the city, median PAH concentrations in soil were low relative to other cities, 523?±?1,886 ??g/kg, ranging from 67 to 10,117 ??g/kg. Diagnostic ratio analyses confirmed that the source of PAHs is predominantly fuel combustion (i.e., vehicle emissions) rather than petrogenic, biogenic, or other combustion sources (coal, wood burning). However, in a multiple regression analysis including traffic characteristics and soil properties, SOM content was the variable most strongly related to PAH concentrations. Our research suggests that dryland soil characteristics play an important role in the retention of PAH compounds in soils of arid cities.     

Characteristics,sources, and in situ phytoremediation of polycyclic aromatic hydrocarbon in rural dumpsites

Purpose

Without precaution to deal with gas emissions and leachate generation, dumpsites have become a severe environmental problem in many developing countries. The objectives of this study were to investigate the pollution status of polycyclic aromatic hydrocarbons (PAHs) in dumpsite soil in rural areas of China and to verify phytoremediation effectiveness with Sedum alfredii Hance and alfalfa (Medicago sativa L.) under complex pollution conditions in PAH-contaminated soil.

Materials and methods

In this study, we collected soil cores from four dumpsites in rural areas of North China (Hebei Province) for analysis, and correspondingly conducted an in situ phytoremediation experiment using Sedum alfredii Hance and alfalfa (Medicago sativa L.) at one of these sites, monitoring the total PAH concentration in soil.

Results and discussion

Results showed generally moderate pollution by PAHs in soil samples from dumpsites with pockets of heavy pollution. PAH concentrations in dumpsite soil ranged from 827 to 1101 ng/g (dry weight). High-molecular-weight PAHs were present in higher proportions at oldest dumpsite in operation. Certain molecular ratios of PAHs can be used to diagnose the source of PAHs in soil, and it indicated that the main sources were combustion of domestic coal and biomass, as well as the automobile exhaust and kitchen exhaust. A 17-month in situ phytoremediation experiment resulted in the effective removal of PAHs in the Sedum alfredii and alfalfa plots, with total PAH concentrations decreasing by 82.4% and 81.3%, respectively. Furthermore, PAH concentrations in plants correlated to plant growth conditions.

Conclusions

This study indicated that the soils of the dumpsites were generally moderately polluted by PAHs, and some parts of the area were heavily polluted. Both Sedum alfredii and alfalfa absorbed PAHs from soil, and PAH concentrations in these two plants correlated to the growth conditions of the plants. Phytoremediation can effectively be used for PAH removal in open dumpsites.

     

Composition,distribution and sources of polycyclic aromatic hydrocarbons in sediments of the western harbour of alexandria,egypt

Aim and Background  Little data are available on the levels of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Mediterranean Sea Coast of Egypt in general and the Alexandria coastal zone in particular. It was therefore deemed necessary to set up a monitoring programme to determine the current concentrations of PAHs in bottom sediments, and to identify any area where high concentrations of these potential hazardous contaminants were present in the Western Harbour of Alexandria. Methods  The composition, distribution and the source of PAHs in surficial sediments of the harbour were investigated. To document the spatial PAH input, surficial sediment samples from 23 locations throughout the harbour were analysed. as]Results and Discussion The total PAH load determined in the surficial sediment samples ranged from 8 to 131150 ng g¹ dry wt, generally with most of the samples having total concentrations of PAHs greater than 5000 ng g¹ dry weight. The highest concentration of total PAHs was recorded in sediments of the inner harbour. Ratio values of specific compounds such as phenanthrene to anthracene, fluoranthrene to pyrene, methyl-phen-anthrene to phenanthrene, methyl-dibenzothiophenes to dibenzothiophenes, alkylated to non-alkylated and high molecular weight to low molecular weight PAH, were calculated to evaluate the possible source of PAH contamination in the harbour sediments. Conclusions  Two main sources of PAH in the study area have been found: pyrolytic and petrogenic. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed for most samples. The dominant sources of PAH appear to be the combustion processes through run-off, industrial and sewage discharges, and atmospheric input. The concentrations of PAHs were generally above levels expected to cause adverse biological effects. Recommendations and outlook  Information from this study and any other relevant studies should be useful in designing future strategies for environmental protection and management of the harbour.     

Sediment–pore water partition of PAH source contributions to the Yellow River using two receptor models

Purpose

Understanding the fate and behavior of polycyclic aromatic hydrocarbon (PAH) sources in aquatic systems is important for the efficiency of control policies. In this work, a new approach??organic carbon-normalized sediment?Cpore water partition coefficients of PAH source contributions (logK??_Osource)??was developed to study the sediment?Cpore water partition of PAH source contributions. The focus of this study was the Yellow River, which is the second largest river in China and one of the largest rivers in the world.

Materials and methods

Sixteen priority US Environmental Protection Agency PAHs were analyzed in 14 surface sediments and 11 pore water samples. Principal component analysis?Cmultiple linear regression (PCA-MLR) and Unmix models were employed to estimate the source contributions of PAHs in sediments and pore water samples. Finally, logK??_Osource values were calculated according to the modeled source contributions of PAHs.

Results and discussion

??PAHs (sum of the 16 PAH concentrations) in 14 sediment samples and 11 pore water samples from the Yellow River were 1,415?±?726?ng?g^?1 dry weight (dw) and 123?±?57.4???g?l^?1, respectively. The source apportionment results indicate the following: (1) for sediment samples, the contributions to ??PAHs from vehicular emissions, coal combustion, and petrogenic sources were 41.07?C61.05, 38.83?C45.56, and 11.18?C14.92?%, respectively, and (2) for pore water samples, vehicular emissions were the most significant contributor (45.51?C69.39?%), followed by petrogenic sources (29.80?C34.22?%) and coal combustion (7.35?C21.59?%). Coal combustion had the highest logK??_Osource values (4.15?C4.26) among the three categories, followed by vehicular emissions (3.51?C3.57) and petrogenic sources (3.30?C3.43).

Conclusions

The possible categories of PAH sources identified by hierarchical cluster analysis, PCA-MLR, and Unmix models were consistent, indicating that vehicular emissions, coal combustion, and petrogenic sources were three important categories. The logK??_Osource values indicate that contributions from coal combustion had a higher partition for the sediment phase compared with the other two source categories.     

Particle-associated Polycyclic Aromatic Hydrocarbons in the Atmosphere of Hong Kong

Polycyclic aromatic hydrocarbons (PAHs) in total suspended particulates (TSP) collected at six rural and urban stations in Hong Kong from 1993–1995 using high volume air samplers were identified using GC-MS (gas chromatography-mass spectrometry). The results showed that the PAHs exhibited distinct spatial and seasonal variability. The total PAH content (ΣPAH) in the samples ranged from 0.41 to 48 ng m^-3. The unsubstituted analogs are the characteristic products of high temperature combustion processes. The highest average ΣPAH was measured at the street-level station in Mong Kok indicating that vehicles were high PAHs contributors. The rural station at Hok Tsui exhibited the lowest PAH level, however; influences of city plumes could be seen when northerly or northeasterly winds prevailed in the winter. All stations experienced the highest loading of PAHs in autumn and the lowest in summer; the former was 2.8 times greater than the latter. This seasonal variability is due to the Asian monsoon system, precipitation, micrometeorology, and the rate of photodegradation. In summer, Hong Kong experiences relatively clean oceanic air and high rates of precipitation and photodegradation, while upon the onset of the winter monsoon, local air mass is replaced by polluted air streams from the Asian continent. Benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(e)pyrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were the dominant species in the samples. The PAH distribution patterns at different stations were similar within each season. However, seasonal variations existed. For example, phenanthrene contributed up to 14% of the total PAH in summer, while the dominance of benzo(b)fluoranthene, benzo(k)fluoranthene was more significant in autumn and winter.     

Pyrogenic polycyclic aromatic hydrocarbons in soils of reserved and anthropogenically modified areas: Factors and features of accumulation

The accumulation features of pyrogenic polycyclic aromatic hydrocarbons (PAHs) in soils were analyzed depending on the type of burning material and the combustion conditions (the temperature, oxygen access, and dispersion of the combustion products). The PAH accumulation features in the soils of three reserved areas of forest, steppe, and peat fires were revealed. The distribution features of the PAHs resulting from the anthropogenic pyrogenic processes (the household combustion of wood and the inflammation of coal dumps) in soils were established. The differences in the qualitative composition of the PAHs arriving to the soils from the different pyrogenic sources were shown.     

One-Hundred-Year Sedimentary Record of Polycyclic Aromatic Hydrocarbons in Urban Lake Sediments from Wuhan, Central China

The concentrations and depositional fluxes of polycyclic aromatic hydrocarbons (PAHs) were investigated in a dated sediment core collected from Donghu Lake, central China. Total concentrations of 16 PAHs ranged from 33.32 to 937.24 ng?g^?1 based on dry weight. Depositional fluxes of total PAHs, ranging 15.84?C387.37 ng?cm^?2?year^?1, were in relatively higher levels compared with those in the cores collected from other areas of China. The concentrations and fluxes of total and individual PAHs changed dramatically with depth, reflecting energy usage changes and closely following the historical economic development in central China. Since the initiation of the ??Reform and Opening-Up policy?? in the late 1970s, the levels of PAHs, especially the high-molecular-weight carcinogenic PAHs, increased rapidly and reached the highest value in recent years, indicating the growth of incomplete combustion of coal and petroleum with the development of economy in this area. Furthermore, analysis of isomer ratios and principle component analysis commonly revealed the main contribution of anthropogenic pyrolytic source to PAH contamination in the largest urban lake of China.     

Polycyclic aromatic hydrocarbons (PAHs) in rural soils of Dongjiang River Basin: occurrence,source apportionment,and potential human health risk

Purpose

A comprehensive study was conducted to investigate the presence of polycyclic aromatic hydrocarbons (PAHs) in Dongjiang River Basin (DRB) soils and to evaluate their sources and ecological and health risk. In addition, factors affecting the distribution and fate of PAHs in the soils such as emission density, soil organic matter, degradation, etc. were studied.

Materials and methods

Surface soil (0–20 cm) samples from 30 sampling sites in the rural areas of DRB were collected and analyzed for 17 polycyclic aromatic hydrocarbons (16 EPA priority PAHs and perylene). Positive matrix factorization model was used to investigate the source apportionment of these PAHs, and an incremental lifetime cancer risk (ILCR) was used to estimate the integrated lifetime risks of exposure to soil-borne PAHs through direct ingestion, dermal contact, and inhalation collectively.

Results and discussion

The total PAH concentrations in the rural soils in DRB range from 23.5 to 231 μg/kg with a mean concentration of 116 μg/kg. The predominant PAHs in the rural soils were naphthalene, fluoranthene, phenanthrene, and benzo(b)fluoranthene. Cluster analysis was performed to classify the soil PAHs into three clusters, which could be indicative of the soil PAHs with different origins and different properties. Source apportionment results showed that coal, biomass, oil, commercial creosotes, and vehicle contributed 24 %, 24 %, 17 %, 17 %, and 18 % of the total soil PAH burden, respectively. The ILCR results indicated that exposure to these soil-borne PAHs through direct ingestion, dermal contact, and inhalation collectively produces some risk.

Conclusions

PAHs in the soils of the DRB will produce long-term influences on rivers and oceans via soil erosion and river transport. Therefore, PAHs in rural soils of DRB have potential impacts on the water supply and human health risk.