Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Nansi Lake, China

Polycyclic aromatic hydrocarbons (PAHs) were measured in surface sediments and dated core sediments from the Nansi Lake of China to investigate the spatial and temporal distribution characteristics. The concentrations of 16 kinds priority PAH compounds were determined by GC-MS method. And ²¹⁰Pb isotope dating method was used to determine the chronological age of the sediment as well as the deposition rate. The results indicated that the total PAHs concentration ranges in surface and core sediment samples were 160 ~32,600 and 137 ~ 693 ng/g (dry wt.), respectively. The sediment rate and the average mass sedimentation were calculated to be 0.330 cm·year^???1 and 0.237 g·cm^???2·yr^???1 and the sediment time of the collected core sample ranged from 1899 to 2000. The peak of PAH concentrations came at recent years. The source analysis showed PAHs mainly came from the contamination of low temperature pyrogenic processes, such as coal combustion. The PAHs concentrations were lower than ERL and LEL values for most collected samples. However, in several surface sediment samples especially in estuary sites, the PAHs concentrations were not only higher than ERL and LEL values, but also higher than ERM values.     

Characteristics and sources of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Shanghai, China

A field campaign was conducted to measure and analyze 13 polycyclic aromatic hydrocarbons (PAHs) in six major zones in the city of Shanghai, P.R. China from August 2006 to April 2007. Ambient air samples were collected seasonally using passive air samplers, and gas chromatography–mass spectroscopy was used in this field campaign. The results showed that there was a sequence of 13 PAHs at Phen > FA > Pyr > Chr > Fl > An > BaA > BbFA > BghiP > IcdP > BkFA > BaP > DahA and the sum of these PAHs is 36.01 ± 10.85 ng/m³ in gas phase. FL, Phen, FA, Pyr, and Chr were the dominant PAHs in gas phase in the city. They contributed 90% of total PAHs in the gas phase. Proportion of measured PAHs with three, four, five, and six rings to total PAHs was 53%, 42%, 3%, and 2%, respectively. The highest concentration of ΣPAHs (the sum of 13 PAHs) occurred in the wintertime and the lowest was in the summer. This investigation suggested that traffic, wood combustion, and metal scrap burn emissions were dominant sources of the concentrations of PAHs in six city zones compared with coal burning and industry emissions. Further, the traffic emission sources of PAHs in the city were attributed mostly to gasoline-powered vehicles compared with diesel-powered vehicles. It was revealed that the seasonal changes in PAHs in the city depended on different source types. Metal scrap burn was found to be the major source of PAHs during the autumn, while the PAH levels in the atmosphere for winter and spring seasons were mainly influenced by wood and biomass combustion. Comparisons of PAHs among different city zones and with several other cities worldwide were also made and discussed.     

Historical changes in the concentrations of polycyclic aromatic hydrocarbons (PAHs) in Lake Peipsi sediments

The distribution of 11 individual polycyclic aromatic hydrocarbons (PAHs) was analysed in a (210)Pb dated sediment core from the deepest area of Lake Peipsi and in four surface sediment samples taken from littoral areas. According to the concentrations in the core three groups of PAHs may be distinguished: (1) relatively stable concentrations of PAHs within the whole studied time interval; (2) very low concentrations in sediments accumulated before intensive anthropogenic impact (from 19th century up to the 1920s) following a slight increase and (3) an overall increase in PAH concentrations since the 1920s up to the present. Comprehensive analysis of PAHs in the core and monitoring data obtained in the 1980s together with the lithology of sediments show that an increase of anthropogenically induced PAHs correlates well with the history of fuel consumption in Estonia and speaks about atmospheric long-distance transport of PAHs. The continuous increase of PAH concentrations since the 1920s do not support the earlier hypothesis about the dominating impact of the oil shale fired power plants near the lake, because their emissions decreased significantly in the 1990s. The concentration of PAHs in the deep lake core sample correlates well with the content of organic matter, indicating absorption and co-precipitation with plankton in the sediment.     

Spatial distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in soils from typical oil-sewage irrigation area, Northeast China

Air pollution is one of the major environmental problems in India, affecting health of thousands of 'urban' residents residing in mega cities. The need of the day is to evolve an 'effective' and 'efficient' air quality management plan (AQMP) encompassing the essential 'key players' and 'stakeholders.' This paper describes the formulation of an AQMP for mega cities like Delhi in India taking into account the aforementioned key 'inputs.' The AQMP formulation methodology is based on past studies of Longhurst et al., (Atmospheric Environment, 30, 3975-3985, 1996); Longhurst & Elsom, ((1997). Air Pollution-II, Vol. 2 (pp. 525-532)) and Beatti et al., (Atmospheric Environment, 35, 1479-1490, 2001). Further, the vulnerability analysis (VA) has been carried out to evaluate the stresses due to air pollution in the study area. The VA has given the vulnerability index (VI) of 'medium to high' and 'low' at urban roadways/intersections and residential areas, respectively.     

Spatial distribution and seasonal variation of polycyclic aromatic hydrocarbons (PAHs) contaminations in surface water from the Hun River, Northeast China

The objectives of this study were to investigate the levels, dispersion patterns, seasonal variation, and sources of 16 priority polycyclic aromatic hydrocarbons (16 EPA-PAHs) in the Hun River of Liaoning Province, China. Samples of surface water were collected from upstream to downstream locations, and also from the main tributaries of the Hun River in dry period, flood period, and level period, respectively. After appropriate preparation, all samples were analyzed for 16 EPA-PAHs. Total PAHs concentrations varied from 124.55 to 439.27 ng l^?1 in surface water in dry period, 1,615.75 to 5,270.04 ng l^?1 in flood period, and 2,247.42 to 7,767.9 ng l^?1 in level period. The 16 EPA-PAHs concentrations were significantly increased in the order of level period > flood period > dry period. The composition pattern of PAHs in surface water was dominated by low molecular weight PAHs, in particular two- to three-ring PAHs. In addition, two-ring PAH accounted for 39.33 to 88.27 % of the total PAHs in level period. Low molecular weight PAHs predomination together with higher levels of PAHs in flood and level period suggested a relatively recent local source of PAHs. Special PAHs ratios such as phenanthrene/anthracene and fluoranthene/pyrene indicated that under dry weather season conditions, the PAHs found in surface water were primarily from petrogenic source, while under wet weather season conditions they were from mixed source of both petrogenic inputs and combustion sources. The comparison of PAHs contamination among different types of areas in China suggested that atmospheric depositions might be the most important approaches of PAHs into water system. Although the Hun River exists low PAHs ecological risk now, potential toxic effects will be existed in the future especially in flood and level period.     

气溶胶与降尘中多环芳烃的含量分布研究

通过广东省茂名市区四个不同功能点大气气溶胶和降尘中多环芳烃的含量分布研究发现 :1、气溶胶中优控多环芳烃大大高于降尘中的含量 ,为降尘的 5.97～ 1 9.3倍 ;以石化厂区为例 ,非优控多环芳烃在气溶胶中的相对含量更高 ,为降尘的 2 4 .7倍。2、气溶胶中优控多环芳烃和非优控多环芳烃的分布为随分子量增加而含量增高的趋势 ,但降尘中优控多环芳烃的高含量相对集中于萤蒽至苯并 (b)萤蒽之间。3、不同功能区由于排放源的差别所表现出的气溶胶和降尘中优控多环芳烃总量及总量比值、部分强致癌和致癌物含量及含量比值均存在差异。4、对气溶胶和降尘中多环芳烃研究可以对降尘中非优控多环芳烃降解和溶解量进行估算。以石化厂区为例 ,降尘中非优控多环芳烃比原始含量已减少76%。     

Vertical distribution of polycyclic aromatic hydrocarbons (PAHs) in Hunpu wastewater-irrigated area in northeast China under different land use patterns

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in groundwater and soil profiles from upland field and paddy field in the Hunpu wastewater-irrigated area of northeast China. In the study area, the peak concentrations of total PAHs were within or just below the topsoil, and the contents decline with depth at various trend verified by the Spearman's rank correlation test. The total PAH concentrations in upland soil layers ranged from 46.8 to 2,373.0 microg/kg (dry wt.), while the concentrations in paddy soil layers ranged from 23.1 to 1,179.1 microg/kg (dry wt.). The 16 priority PAHs were all detected in the analyzed soil samples, and naphthalene (Nap), phenanthrene (Phe), fluoranthene (Fla), chrysene (Chr), and benzo[a]pyrene (Bap) were selected for further study in terms of their vertical distributions. The concentrations of both total and individual PAHs in upland soil were generally higher than those in the corresponding layers of paddy soil. The concentrations of total and individual PAH were notably different between the corresponding horizons in upland and paddy soil were probably attribute to the different sources and properties of the PAHs and soil; different methods of soil tillage and plant growing. Special PAH compound ratios, such as phenanthrene/anthracene, fluoranthene/pyrene, LMW/HMW, and parent PAH ratios (Ant/178, Fla/202, BaA/228, and Ilp/276) were used to identify the source of soil PAHs. The data suggests that the possible sources of PAHs in the Hunpu wastewater-irrigation area are the incomplete combustion of coal, petroleum and crude oil, automobile exhausts. These sources lead to pollution of the soil and groundwater by wet/dry deposition and vertical downward migration.     

Effect of vehicle exhaust on the quantity of polycyclic aromatic hydrocarbons (PAHs) in soil

PAHs are formed during the incomplete combustion of organic substances containing carbon and hydrogen and are one of the first atmospheric pollutants identified as carcinogens. Most of the PAH environmental burden is found in the soil (95%). Soil samples collected from different roadsides were analyzed for seven polycyclic aromatic hydrocarbons (PAHs). The quantitative and qualitative analysis was carried out by UV Spectrophotometer. The individual PAH value ranged from 0.1 to 18.0 mg/kg. Phenenthrene and Pyrene were found to be the most abundant compounds. Vehicle emissions are the principal source of PAH in the Roadside soils. The highest concentration was found at site S2 (Hasthtnagri Roadside) which shows the highest traffic density.     

Levels of polycyclic aromatic hydrocarbons (PAHs) in the Densu River Basin of Ghana

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in Densu River Basin in Ghana were measured using gas chromatograph. Surface water samples were collected from nine stations, namely, Potroase, Koforidua Intake, Suhyien, Mangoase, Asuboi, Nsawam Bridge, Afuaman, Ashalaga, and Weija Intake in the Densu Basin. Total PAH concentrations varied from 13.0 to 80.0 ??g/mL in the Densu River, with a mean value of 37.1 ??g/mL. The two- to three-ring PAHs (low-molecular-weight PAHs) were found to be dominant in the Densu River Basin. Total PAH concentrations showed the following pattern: Koforidua Intake (80.0 ??g/mL) > Asuboi (50.8 ??g/mL) > Afuaman (47.9 ??g/mL) > Weija Intake (45.0 ??g/mL) > Suhyien (27.6 ??g/mL) > Nsawam (23.5 ??g/mL) > Ashalaja (22.9 ??g/mL) > Potroase (23.3 ??g/mL) > Mangoase (13.0 ??g/mL). According to the Agency for Toxic Substances and Disease Registry (ATSDR), background levels of PAHs in drinking water supplies in the USA range from 0.004 to 0.024 ??g/mL. PAH levels from all sites exceeded the range set by ATSDR. B[a]P contributed the highest carcinogenic exposure equivalent (0.3 ??g/mL), followed by B[a]A (0.132 ??g/mL) and B[b]F (0.08 ??g/mL), contributing 52.6%, 23.2%, and 4.6%, respectively, of the total carcinogenicity of surface water PAH in the Densu River Basin. The carcinogenic potency was estimated to be 0.57 ??g/mL. The presence of PAHs was an indication of the water sources being contaminated, with potential health implications.     

Atmospheric polycyclic aromatic hydrocarbons (PAHs) in the urban air of Delhi during 2003

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Delhi were evaluated to study particulate PAHs profiles during the different seasons of 2003. Samples of urban suspended particulate matter were collected during January 2003 to December 2003 at three locations (Okhla, Dhaulakuan and Daryaganj), using a high volume sampler provided with glass fiber filters. Samples were analyzed using the gas chromatography technique. The annual average concentrations of total PAHs were found as 1,049.3 ng/m(3) at Okhla, 1,344.37 ng/m(3) at Daryaganj, and 1,117.14 ng/m(3) at Dhaulakuan. The seasonal average concentrations were found to be maximum in winter and minimum during the monsoon season. Principal Component Analysis (PCA) of the data was also carried out and the results indicate that diesel and gasoline driven vehicles are the principal sources of PAHs at all the three sites under investigation. Other sources might come from stationary combustion sources such as cooking fuel combustion and industrial emission.     

Apportioning variability of polycyclic aromatic hydrocarbons (PAHs) and chlordanes in indoor and outdoor environments

Measurements of semi-volatile organic compounds (SVOCs) in air are subject to substantial variability and uncertainty. This study apportions total variance of polycyclic aromatic hydrocarbons (PAHs) and chlordanes to variability and uncertainty components. Concentrations of PAHs and chlordanes were measured inside and outside of 116 residences in three large cities in the U.S. during 1999-2000. Total variance was apportioned to between-city, between-tract, between-residence, and seasonal variation, as well as measurement uncertainty using variance component analysis and log-transformed data for frequently detected compounds. Outdoors, seasonal variation was the greatest portion (44-67%) of total variance, and city effects were significant (19-24%). Indoors, seasonality dominated variability of PAH measurements (>50%). Gas-phase PAHs varied more within city than between cities; particulate-phase PAHs varied significantly between cities but were largely homogeneous within cities. Gas-phase chlordanes showed larger intra-urban variation (63%) than seasonal variation (18%). Measurement uncertainty was generally below 10% with a few exceptions occurring at very low concentrations. Results indicate a need to collect multiple-season samples to account for the large temporal variation between seasons. Samples from centrally located monitoring stations could be representative of ambient SVOCs. Variance component analysis is useful to weigh influential factors in SVOC concentrations, identify and apportion sources, evaluate method performance, and design effective monitoring programs.     

Distribution and source of polycyclic aromatic hydrocarbons (PAHs) in the surface soil along main transportation routes in Jiaxing City, China

Polycyclic aromatic hydrocarbons (16 EPA-PAHs) in urban surface soil from Jiaxing City were determined using HPLC. The total concentration of 16 EPA-PAHs was detected from 18.73 to 441.34 pg/g. Individual PAH occupation analysis demonstrates that four-ring PAHs comprise as much as 44.16% and were prevalent in the composition of PAH pollutants. The other components were two-ring PAHs (7.36%), three-ring PAHs (17.28%), five-ring PAHs (16.16%), and six-ring PAHs (15.04%). Source analysis on the characteristic ratios of anthracene(Ane)/[Ane+phenanthrene(Phe)], fluoranthene(Fla)/[Fla+pyrene(Pyr)], and benzo[a]pyrene(Bap)/benzo[g,h,i]perylene(Bgp) reveals that PAH pollutants originated mainly from coal combustion, but vehicular emission as a source was not negligible. All PAHs discussed in the paper have similar source in most sampling sites. The spatial distributions of pollution sources were closely related to geographic location, geographic condition, and living habit of indigenes. A linear relationship between 2-3-ring PAHs, 4-6-ring PAHs, SOM, and ∑PAHs were investigated and significant correlativity were expatiated lastly. It revealed that coefficient between 2-3-ring PAHs and ∑PAHs is 0.56, between 4-6-ring PAHs and ∑PAHs is 0.99, between SOM and ∑PAHs is 0.82.     

Source analysis of particulate matter associated polycyclic aromatic hydrocarbons (PAHs) in an industrial city in northeastern China

Particle-associated polycyclic aromatic hydrocarbon (PAH) concentrations were investigated at eight sampling sites during cold periods where heating is used (heating period) (February to March, 2005) and warm periods where heating is not required (non-heating periods) (August to September 2006) in the urban area of Anshan, an iron and steel city in northeastern China. Eleven PAH species were measured using GC-MS. The total average concentrations of PAHs ranged from 46.14 to 385.60 ng m(-3) in the heating period and from 5.28 to 146.40 ng m(-3) in the non-heating period. The lowest concentration of ∑PAHs was observed at Qianshan, a monitoring site far from the city and industrial area, and the highest concentration occurred in the site located at the factory area of Anshan Iron and Steel Incorporation. Moreover, ambient PAH profiles were studied and high molecular weight PAH (including 4-6 rings) species occurred in the high fractions. Toxic equivalent factors analysis gave the potential carcinogenic risks in Anshan. For the heating sampling period, BaP equivalent concentration is in the range of 41.98 to 220.83 ng m(-3), and 9.23 to 126.00 ng m(-3) for the non-heating sampling period. By diagnostic ratio analysis, traffic emission and combustion (coal or biomass) were potential sources for PAHs in Anshan. Finally, PCA results indicated the major sources were vehicle emission, steel industry emission, and coal combustion for both heating and non-heating seasons, which agreed with the results from the diagnostic ratio analysis.     

Genotoxicity of the sediments collected from Pearl River in China and their polycyclic aromatic hydrocarbons (PAHs) and heavy metals

The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P?相似文献   

Field evaluation of a passive sampler of polycyclic aromatic hydrocarbons (PAHs) in an urban atmosphere (Bologna, Italy)

A simple device consisting of a Petri dish containing cellulose paper soaked with paraffin oil (hereinafter defined "artificial leaf", AL) was deployed in a typical urban site and partitioning of a set of PAHs between the atmosphere and AL was investigated. Gas-phase PAHs rapidly equilibrate with AL, thus rendering it a promising cost-effective tool for spatial and temporal trends studies of air quality.     

Gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) emissions from commercial restaurants in Hong Kong

Commercial cooking emissions are important air pollution sources in a heavily urbanized city. Exhaust samples were collected in six representative commercial kitchens including Chinese restaurants, Western restaurants, and Western fast-food restaurants in Hong Kong during peak lunch hours. Both gaseous and particulate emissions were evaluated. Eight gaseous and twenty-two particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in this study. In the gaseous phase, naphthalene (67-89%) was the most abundant PAH in all of the exhaust samples. The contribution of acenaphthylene in the gaseous phase was significantly higher in emissions from the Chinese restaurants, whereas fluorene was higher in emissions from the Western cooking style restaurants (i.e., Western restaurants and Western fast-food restaurants). Pyrene is the most abundant particulate PAH in the Chinese restaurants (14-49%) while its contribution was much lower in the Western cooking style restaurants (10-22%). Controlled cooking conditions were monitored in a staff canteen to compare the emissions from several different local cooking styles, including deep frying, steaming, and mixed cooking styles (combination of steaming and frying). Deep frying produced the highest amount of total gaseous PAHs, 6 times higher than the steaming. However, steaming produced the highest particulate emissions. The estimated annual gaseous PAH emissions for the Chinese restaurants, Western restaurants, and Western fast-food restaurants were 255, 173, and 20.2 t y(-1) whereas 252, 1.9, and 0.4 t y(-1) were estimated for particulate phase PAH emissions. The study provides useful information and estimates for PAH emissions from commercial cooking exhaust in Hong Kong.     

Characterizing ecological risk for polycyclic aromatic hydrocarbons in water from Lake Taihu, China

Lake Taihu provides vital ecological services for humans in China; it receives a great deal of attention regarding its ecological and environmental conditions. In this study, the ecological risks of eight individual polycyclic aromatic hydrocarbons (PAHs) in water were assessed using probabilistic distributions of the hazard quotient based on Monte Carlo simulation. The results show that the 95th percentile of the hazard quotients ranged from 0.00074 to 2.831, and the ecological risk of Flua was highest, followed by, in descending order of risk, B[a]P?>?Pyr?>?Ant?>?Phe?>?Flu?>?Ace?>?Chr. The probabilities of hazard quotients exceeding a decision criteria of 0.3 were 18.09%, 6.51%, 3.76%, and 2.85% for Flua, B[a]P, Pyr, and Ant, respectively, indicating their potential ecological risks to aquatic organisms. The spatial distribution of hazard quotients for these four individual PAHs with potential ecological risk were obtained using Geographic Information System (GIS), and similar spatial distribution patterns were also observed in the lake. The highest ecological risks of these four individual PAHs to aquatic organisms were found in Meiliang Bay, followed by Gonghu Bay and Xukou Bay. The uncertainty within the ecological risk assessment was also discussed.