Polycyclic Aromatic Hydrocarbons in Peat Mounds of the Permafrost Zone

Eurasian Soil Science - The accumulation of polycyclic aromatic hydrocarbons (PAHs) in the profiles of permafrost-affected peat mounds is related to certain groups of plant residues produced in the...     

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.     

冬季秸秆还田和土地管理对水稻生长期CH4排放的影响

利用田间试验研究了冬季3种土地管理方式下（种麦、休闲和淹水）秸秆施用（4800kg·hm^-2和0）对后续稻季CH。排放的影响。结果表明,休闲混施和休闲不施处理CH4平均排放通量显著高于种麦混施和种麦不施处理（P〈0．05）,但显著低于淹水混施和淹水不施处理（P〈0．05）;淹水混施处理CH4平均排放通量显著高于淹水不施处理（P〈0．05）,而休闲混施和休闲不施处理、种麦混施和种麦不施处理间无显著差异（P〉0．05）。水稻生长期CH4排放通量与5、10cm处土温呈极显著正相关（P〈0．01）,而与土壤肌无显著相关性（p〉0．05）。改冬季淹水和休闲稻田为种植小麦或在水稻移栽前对休闲稻田实施除草措施能显著减少稻田CH4排放量,是一种既增加农作物产量又能达到减少温室气体CH4排放的农业措施,具有很大的应用推广价值。     

Characterization of Polycyclic Aromatic Hydrocarbons Created in Lubricating Oils

Used lubricating oils are majorsources of polycyclic aromatic hydrocarbons (PAHs) inmarine environments. This study presents an improvedmethod for characterization PAHs in used lubricatingoils. Recoveries of sixteen certified PAHs spikedinto used lubricating oil indicated this method wasmore precise and efficient than those reportedpreviously. Aromatic and aliphatic compounds in usedlubricating oil were extracted by dimethylsulfoxide,then separated by a silica gel column using hexane anddichloromethane as solvents. Finally, gaschromatography-mass spectrometry was used inqualitative and quantitative analysis of various PAHsin oil samples. Sixteen certified PAHs andeighty-three other PAHs were identified and quantified usingPAH standards and previously reported retentionindices as references. The improved method was usedto determine PAH profiles in lubricating oil samplescollected from a gasoline-driven automobile aftervarious driving distances. One hundred and eightyaromatic compounds, including ninety-nine PAHs, wereidentified by the gas chromatographic method. Theseresults suggested that the new method was superior tomethods described in previous studies. Theconcentrations of PAHs, including the comparativelytoxic 5-ring PAHs, increased rapidly even after theautomobile had only been driven for a short distance. 2- and 3-ring PAHs, most of them are alkylated,dominated the PAH profiles of the collected oil samples.     

Participation of Plants in the Formation of Polycyclic Aromatic Hydrocarbons in Peatlands

Eurasian Soil Science - The composition of polycyclic aromatic hydrocarbons (PAHs) in vegetation of natural hummocky peatlands in the forest-tundra subzone of the Komi Republic and its possible...     

Fenton Reagent Advanced Oxidation of Polynuclear Aromatic Hydrocarbons in Water

Aqueous oxidation of three polynuclear aromatic hydrocarbons, fluorene, phenanthrene and acenaphthene with the combination of hydrogen peroxide and ferrous ion, Fenton reagent, has been studied. The effect of variables such as concentration of both reactants, pH and presence of bicarbonate ion and humic substances has been investigated. Products resulting from oxidation have also been identified. From experimental results and kinetic data determined the process is confirmed as an advanced oxidation involving the generation of hydroxyl radicals. Oxidation rates are even higher than those from other advanced oxidation systems involving ozone, UV radiation and hydrogen peroxide. Reactivity is in the following decreasing order: Phenanthrene > Fluorene > Acenaphthene.     

土壤中多环芳烃和氨基甲酸酯等农药分析

应用超高效液相色谱和质谱串联技术对吉林省中部地区土壤中多环芳烃及氨基甲酸酯农药类成分进行含量测定分析。以超声波提取作为提取方法,以在线固相萃取作为纯化方法,以超高效色谱-三重四级杆质谱作为分析方法,共分离检测出12个多环芳烃类化合物,分别为:萘、苊、苊烯、氟、菲、蒽、芘、苯并[a]蒽、屈、苯并[a]芘、二苯并[a,h]蒽和茚并[1,2,3-cd]芘。11个氨基甲酸酯及其它类农药,分别为:灭多威,多菌灵,甲萘威,克百威,啶虫脒,涕灭威亚砜,涕灭威砜,苯醚甲环唑,阿维菌素,灭幼脲和氟虫腈。利用超声波提取和在线固相萃取法可以有效地提取纯化土壤中多环芳烃和氨基甲酸酯类农药。超高效液相色谱和质谱联用技术可以有效地分析食品中多环芳烃和有机氯农药类成分。     

土壤样品中多环芳烃分析方法研究进展

概述了国内外土壤样品中多环芳烃(PAHs)测定方法的研究状况,其中提取方法包括加速溶剂萃取方法、固相微萃取方法、超临界流体萃取方法、亚临界水萃取方法和流化床提取方法等,测定方法有HPLC法、GC法和免疫分析法等。重点介绍了PAHs的提取过程,同时总结了各种方法的优缺点。     

Phytoremediation of Alkylated Polycyclic Aromatic Hydrocarbons in a Crude Oil-Contaminated Soil

Phytoremediation uses plants and their associated microorganisms in conjunction with agronomic techniques to remove or degrade environmental contaminants. The objective of the field study was to evaluate the effect of vegetation establishment plus fertilizer addition on the biodegradation of alkylated polycyclic aromatic hydrocarbons in a crude oil-contaminated soil. Four replications of the following treatments were used: non-vegetated non-fertilized control; fescue (Lolium arundinaceum Schreb.) ? ryegrass (Lolium multiflorum L.) mixture + fertilizer; or bermudagrass (Cynodon dactylon (L.) Pers.) ? fescue mixture + fertilizer. Vegetation was successfully established at the site that had an initial total petroleum hydrocarbon (TPH) concentration of 9,175 mg/kg. While alkylated two-ring naphthalenes were degraded in all treatments equally, there was greater degradation of the larger three-ring alkylated phenanthrenes-anthracenes and dibenzothiophenes in the vegetated fertilized plots compared to the non-vegetated non-fertilized plots. In this field study, an increase in rhizosphere soil volume associated with increased root length along with nutrient additions resulted in increased total bacterial, fungal, and polycyclic aromatic hydrocarbon (PAH) degrader numbers that most likely resulted in increased biodegradation of the more recalcitrant alkylated polycyclic aromatic hydrocarbon compounds in the crude oil-contaminated soil.     

Effect of Composting on Polycyclic Aromatic Hydrocarbons Removal in Sewage Sludge

Changes in the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) identified by the US Environmental Protection Agency as priority pollutants were investigated during the composting process of sewage sludge mixed with rapeseed marc (9:1, weight base). Results showed that total PAHs concentrations of the sludge sampled in different seasons had far exceeded the accepted Europe Union cut-off limits for land application. Phenanthrene, fluorene and dibenz(a, h) anthracene were dominant PAHs in the sludge, accounting for 62.8~69.6% of the total amount of the 16 PAHs. Composting appeared to be an effective method for the removal of PAHs in sewage sludge. After 50 days of composting, a significant reduction of concentration of the total PAHs was detected as compared with the initial concentration in composting material. The significant relationship between the biodegradation of organic matter and the losses of Σ16 PAHs during composting indicated that microbial degradation was the key process responsible for the efficient removal of PAHs from the sludge. Among all tested PAHs, fluorene was the most recalcitrant and became the primary residual PAH in the composted material. The lower removal rate of fluorene during composting was a limiting factor for the potential land application of the sludge. Further studies are needed to enhance the removal of fluorene in order to achieve a safe utilization of this sludge.     

Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in Waste Wood

PAH-contaminated waste wood is a serious environmental problem. As an alternative to incineration and landfill disposal, wood containing PAHs may be detoxified by composting. The efficiency of this process depends on the composting conditions. The aerobic treatment of PAH-containing wood was therefore investigated under varying environmental conditions with particular attention to the kinetics of PAH degradation and wood mineralization. The composting of pine wood spiked with 2 g/kg phenanthrene, anthracene and pyrene each and subsequently artificially aged was studied on a laboratory-scale using a respiration analyzer. The temperature was found to highly influence both PAH degradation and wood decay. The fastest and most extensive PAH degradation and wood mineralization were found at 30°C. Higher temperatures particularly inhibited the degradation of anthracene and pyrene. The addition of urea markedly accelerated both PAH degradation and wood mineralization. Only small amounts of urea were needed to maximize PAH degradation, whereas higher amounts of urea were required to maximize wood mineralization. Urea hydrolyzes to ammonium carbonate, which in turn forms highly volatile ammonia. When more then 2 g/kg urea-N was added to the wood, excessive nitrogen disappeared as ammonia via the gas phase. Using nitrate instead of urea dramatically reduced both PAH degradation and wood mineralization. Although a slightly alkaline pH seemed to promote PAH degradation, it has to be taken into account that this experiment was carried out with nitrate as an N source rather than urea to avoid any N losses at high pH values. Glucose as a cosubstrate neither accelerated PAH degradation nor stimulated wood decay. Molasses as a cosubstrate actually inhibited PAH degradation since it contains much salt and alkalinized the rot material.     

Composting of Wood Containing Polycyclic Aromatic Hydrocarbons (PAHs)

The addition of various nitrogen sources, such as liquid hog manure and mineral medium, to pine wood accelerated the composting process in Dewar vessels, which was obvious from the increased decomposition temperature and the more intensive oxygen consumption and carbon dioxide production. During composting in Dewar vessels of artificially PAH-contaminated pine wood soaked with liquid manure, the PAH degradation was influenced by the inoculum used. The fastest PAH degradation was achieved by compost addition, but the most intensive carbon dioxide evolution was measured with hydrocarbon-polluted soil as an additive. After 61 days, the PAH content of the wood was reduced from each 1000 mg/kg to 26 mg/kg of phenanthrene and 83 mg/kg of pyrene. The relation between the microbial wood decay and PAH degradation shows that the detoxification at least of artificially PAH-polluted wood demands only a partial wood decay.

A pilot scale percolator was applied to composting of artificially contaminated pine wood and really polluted waste wood. After 27 days of remediation, the portion of residual PAHs was higher in the case of the really polluted material. The slower degradation in the real waste wood may be explained by the lower bioavailability of pollutants in comparison with the artificially contaminated wood. In really polluted wood, the degradation rate of PAHs depended on their degree of condensation (the higher the number of aromatic rings the smaller the degradation rate was).     

Biological Sources of Polycyclic Aromatic Hydrocarbons (PAHs) in the Amazonian Rain Forest

Hazardous polycyclic aromatic hydrocarbons (PAHs) widely occur in the environment and are believed to be mainly anthropogenic. Here we present strong indications for large biological sources of the PAHs naphthalene, perylene, and possibly also phenanthrene in the Amazonian basin. Termite nests, plant wood, and soils were sampled. Naphthalene is detected in plant wood and is accumulated in the nests of termites from the genus Nasutitermes. Perylene is found in all studied termite nests including six different genera. Phenanthrene occurs at substantial concentrations in wood, soil, and termite nests.     

Polycyclic Aromatic Hydrocarbons (PAHs) in Forest Floors of the Northern Czech Mountains

Forests of the Northern Czech mountains decline due to industrial emissions. To examine the state of soil contamination with PAHs we analyzed the concentrations of 20 PAHs in the O and A horizons of 4 lower and 4 upper slope sites under beech (Fagus sylvatica L.) in the Western (WE) and the Eastern Erzgebirge (EE, Kru?né Hory), the Isergebirge (IS, Jizerské Hory), and the Riesengebirge (RI, Krkono?e) at microsites affected and not affected by stem flow. Average PAH sum concentrations in the organic layers ranged between 2000 and 30000 μg kg^?1 increasing in the line WE <RI<EE<IS. PAH concentrations were significantly higher at upper than at lower slope sites indicating long-distance transport. Microsites affected by stem flow had significantly higher PAH concentrations but lower percentages of lower molecular PAHs than microsites not affected by stem flow. This was due to the water collecting effect of the beech bark. Lower molecular PAHs preferentially were sorbed to the bark or leached from the organic layers. PAH concentrations increased from Oi to Oa horizons but decreased in the mineral soil. This was the more pronounced the higher the molecular weight was. The slope of the regression line between the enrichment factors (concentration of a single PAH in the Oa divided by that in the Oi horizon) and the octanol-water partition coefficient decreased as the PAH concentration of the soils increased. This indicates that the microbial activity of organic layers may be reduced by soil contamination. Cluster analysis suggested that the sources of the PAH contamination in the WE were different from the other sites.     

Polycyclic Aromatic Hydrocarbons Content in Contaminated Forest Soils with Different Humus Types

The aim of the study was to determine polycyclic aromatic hydrocarbon (PAH) content in different forest humus types. The investigation was carried out in Chrzanów Forest District in southern Poland. Twenty research plots with different humus types (mor and mull) were selected. The samples for analysis were taken after litter horizons removing from a depth of 0–10 cm (from the Of- and Oh-horizon total or A-horizon). pH, organic carbon and total nitrogen content, base cations, acidity, and heavy metal content were determined. In the natural moisture state, the activity of dehydrogenase was determined. The study included the determination of PAH content. The conducted research confirms strong contamination of study soil by PAHs and heavy metals. Our experiment provided evidence that different forest humus types accumulate different PAH amounts. The highest content of PAHs and heavy metals was recorded in mor humus type. The content of PAHs in forest humus horizon depends on the content and quality of soil organic matter. Weaker degradation of hydrocarbons is associated with lower biological activity of soils. The mull humus type showed lower content of PAHs and at the same time the highest biological activity confirmed by high dehydrogenase activity.     

南京有机污染风险区农田土壤多环芳烃污染状况研究

采集南京地区不同有机污染风险区农田表层土壤,用超快速液相色谱仪检测样品中15种EPA优控的多环芳烃(PAHs)含量。结果表明,被检农田土壤多环芳烃总量分布于306.0~1251.3μg kg~(-1)之间,均值682.0μg kg~(-1),四环以上高环多环芳烃占较大比例(80%)。根据欧洲土壤质量标准,所检土壤样本已达污染水平。不同风险污染区农田土壤PAHs的含量由高至低为:钢铁工业区、有机垃圾处理区、化工工业区及炼油工业区。钢铁工业区附近主要的污染物为荧蒽、芘、屈和苯并[a]蒽,分别占到污染物总量的16%、13%、10%和10%。采用荧蒽/(荧蒽+芘)与茚并[1,2,3-cd]芘/(茚并[1,2,3-cd]芘+苯并[g,h,i]苝)比值对各地污染物来源进行分析,结果发现调查区域的PAHs污染物以燃烧源为主,生物质燃料为主要污染物,部分地区同时有石油燃烧污染。     

Distribution of Polynuclear Aromatic Hydrocarbons (PAHs) in the Soil of Tokushima,Japan

The distribution of polynuclear aromatic hydrocarbons (PAHs) inthe soil samples of rural, suburban and urban areas of TokushimaCity was studied, HPMC with UV and fluorescence detection wasused for the determination of PAHs. The separation was acquiredby an ODS column and acetonitrile-water as the mobile phase.Results showed that the distribution of PAHs in the samplingsites were similar but differed from that in river sediment. Amodel test suggested that the burning of rice straw and otherplants was not the main source of PAHs in the soil of this citybut could be one of the important sources of PAHs in the river ecosystem.     

Polycyclic Aromatic Hydrocarbons Formation in Sludge Incineration by Fluidised Bed and Rotary Kiln Furnace

Polycyclic Aromatic Hydrocarbons (PAHs) are typical pollutants arising from incineration. They are produced in any incomplete combustion principally due to inhomogeneities in a combustion chamber. The effects of the afterburning temperature on PAHs formation during sewage sludge incineration are discussed in this paper. Tests were performed inside the area of the wastewater treatment plant of `Bari Ovest' on a demonstrative plant (maximum throughput 250 kg hr^-1 of dewatered sludge at 20% solids concentration) equipped with a fluidised bed furnace (FBF) and a rotary kiln furnace (RKF) where sewage sludge was fed, either as it was taken from the dewatering section of the wastewater treatment plant, or previously spiked by different dosages of chlorinated hydrocarbons. Exhaust gases were sampled before the bag filter, where the pollutants can be considered representative of those arising from the process. Parallel sampling of flue gas at the stack was also carried out. In the FBF tests with sludge spiked with high dosages of chlorinated hydrocarbons highest values of PAHs concentrations (>3.9 μg Nm^-3) were detected before filtration, when the afterburning chamber was not in use. The operation of the afterburning chamber, at a temperature higher than 900 °C, allows to partially suppress PAHs formation up to values of 0.9—3.2 μg Nm^-3. PAHs removal efficiency of the exhaust gas treatment was calculated with a mean value for all the test of 72%.In RKF tests PAHs displayed much lower values before filtration (range 0.04—2.98 μg Nm^-3, mean value 0.51 μg Nm^-3) probably due to the longer gas residence time in the furnace (>6 s in comparison with values <2 s in fluidised bed furnace). Surprisingly, for RKF tests PAHs removal efficiency of gas treatment appeared quite unstable: some tests evidenced PAHs stripping in the scrubber, where the effluent of the wastewater treatment plant was used. No correlation was observed in RKF tests between PAHs concentration before the bag filter and the temperature of the afterburning chamber.     

黄河兰州段多环芳烃类有机污染物健康风险评价

近年来黄河兰州段的多环芳烃污染日渐严重。为研究黄河兰州段水体中多环芳烃类有机污染物对人体产生的潜在健康危害风险,根据黄河兰州段2004年11个采样点水质监测数据,应用美国环境保护局（USEPA）的健康风险评价方法对黄河兰州段多环芳烃类有机污染物通过饮水和皮肤接触途径进入人体的健康风险进行了初步评价。结果表明：黄河兰州段多环芳烃类有机污染物的非致癌风险指数值均小于1,其中萘的非致癌风险指数值在10^-3数量级,偏高于其他污染物。苯并（a）芘的致癌风险指数值在10^-4数量级以下。从位于西固八盘峡的1号采样点（S1）采集的水样中萘的非致癌风险指数值偏高。在所有采样点中,西固八盘峡的1号采样点（S1）污染较重,具有较高的健康风险。与国内其他地区相比,黄河兰州段萘的非致癌风险亦较高。常规的自来水处理工艺不能有效地去除源水中微量PAHs等有机污染物,因此地面水特别是饮用源水PAHs污染具有较大的健康风险。