黄河三角洲石油化工区农田土壤-玉米体系PAHs的分布特征及风险评价

为明确黄河三角洲石油开采区表层土壤和玉米中多环芳烃（PAHs）的含量及其污染水平,采集农田土壤和玉米各71个样品,检测农田土壤和玉米各部位中16种PAHs含量,并采用内梅罗指数法和健康风险评价模型评估了农田土壤中多环芳烃的生态健康风险。结果表明,农田土壤、玉米根、茎和叶中多环芳烃的含量分别为256.6-1936、291.4-680.9、324.9-527.9、289.5-2400 μg/kg。农田土壤中多环芳烃以4-6环为主。多环芳烃在玉米根茎叶富集系数大小排序为：叶 > 茎 > 根。玉米不同组织中PAHs浓度与相应农田土壤中PAHs浓度的进行相关分析结果表明,农田土壤中PAHs含量与玉米根、茎中PAHs含量均存在极显著正相关关系,相关系数分别为0.98（P<0.01）、0.98（P<0.01）,表明玉米根和茎的多环芳烃主要来源于农田土壤中,农田土壤中PAHs的含量影响着PAHs在玉米根茎中的积累和分布。玉米叶中PAHs含量与农田土壤中PAHs含量与玉米根、茎中PAHs含量不存在相关关系,表明玉米叶中多环芳烃并非来自土壤中PAHs的迁移,可能来源于大气。内梅罗指数结果表明,农田土壤PAHs达到了中度污染,其中BaA、Pyr和BbF达到了偏重污染;健康风险评价结果表明,农田土壤PAHs对儿童和成人的平均非致癌风险分别为0.44和0.12（均小于1）,表明农田土壤多环芳烃对成人和儿童的非致癌风险是可接受;农田土壤PAHs对儿童和成人的平均致癌风险分别为3.6×10^-5、9.0×10^-6,没有超过致癌风险水平上限（10^-4）,致癌风险尚在可接受范围内。3种暴露途径中,皮肤接触是土壤PAHs的最主要暴露方式,其次是经口摄食,吸入暴露途径甚微,可忽略不计。PAHs对儿童健康的威胁风险要大于成人,所以应尽可能避免儿童直接接触或误食土壤等其他介质的污染物。     

南淝河沉积物中半挥发性有机污染物分析

采用GC/MS对南淝河沉积物中半挥发性有机污染物进行了分析,共检测出包括多环芳烃和酞酸酯在内的有机化合物有54种,沉积物中有机污染物种类多。对EPA优先控制污染物中的16种多环芳烃（PAHs）进行了定量监测,结果表明多环芳烃的总量已达到30.61mg/Kg。与国外生态风险评价标准对比表明有多种多环芳烃化合物的含量超过风险评价指标的低值,有的甚至超过高值,已有可能对生态环境产生了影响,为较高生态风险区,PAHs污染比较严重。     

贵阳市表层土壤中多环芳烃的分布特征及来源解析

运用高效液相色谱仪对贵阳市区及近郊的表层土壤中16种多环芳烃(PAHs)进行了定量分析,对其分布特征、污染水平以及来源进行了探讨.结果表明:土壤中PAHs含量为61～ 1560 μg·kg-1,城区土壤样品中PAHs含量为247～1560 μg·kg-1,郊区土壤样品中PAHs含量为61 ～339 μg· kg-1,土壤中4环、5环PAHs含量较高,在土壤PAHs含量中占有绝对优势;参照国外环境标准,对区域表层土壤PAHs的污染现状进行了评价,结果显示,贵阳市表层土壤受到一定程度的PAHs污染.利用相关系数法和典型源三角图法对PAHs的可能来源进行了解析,发现贵阳市的土壤主要受到燃煤排放以及混合污染源——燃煤与汽车尾气排放PAHs的联合污染.     

大辽河水系表层水中多环芳烃的污染特征

采用GC/MS对大辽河水系的浑河、太子河和大辽河表层水和悬浮物中的多环芳烃 (PAHs) 进行了定量分析,探讨了大辽河水系表层水和悬浮物中多环芳烃分布特征与来源.结果表明,水样和悬浮颗粒物中PAHs总量浓度分布范围分别为：水样946.1～13 448.5 ng·L^-1;悬浮颗粒物317.5～238 518.7 ng·g^-1.多环芳烃的浓度分布表现为太子河>大辽河>浑河,靠近工业区的PAHs浓度明显高于城市和非工业区.水样中PAHs以3～5环为主,悬浮颗粒物样中PAHs以2环为主.PAHs特定分子比率分析表明,大辽河水系受到石油输入和热解的复合PAH污染,采样站位附近石油化工和钢铁工业是PAHs的主要来源.与世界其他河流和海洋地区相比,水和悬浮颗粒物中污染浓度较高,具有一定的生态风险.     

石油污染土壤自然衰减过程多环芳烃降解基因动态特征

新疆石油污染土壤中微生物多环芳烃(polycyclic aromatic hydrocarbons,PAHs)降解功能基因研究甚少,且环境因子和功能基因之间相关性仍不清楚。【目的】揭示新疆石油污染砂质土壤自然衰减过程中多环芳烃降解关键基因结构和变化规律。【方法】以新疆准东油田为研究区,分析同一采油区不同石油污染年限土壤理化因子和多环芳烃含量变化,采用扩增子测序研究石油自然衰减过程中多环芳烃降解酶基因结构变化规律,利用Mental检验探讨其环境驱动因子。【结果】石油污染时间1年和3年的土壤中有多项理化指标与背景土存在显著性差异,而污染5年土壤与背景土之间仅2项指标具有显著性差异,随石油自然衰减逐渐恢复至正常。石油污染1年的土壤中16种多环芳烃除苊烯和?以外,其余14种多环芳烃均高于石油污染3年和5年土壤,多环芳烃总量和含油率污染1年土壤均显著高于污染3年和5年的土壤,多环芳烃会在污染后短时间内迅速被降解。扩增子测序结果显示,萘双加氧酶基因分类操作单元(operational taxonomic units,OTUs)序列随污染年限延长逐渐增多;芳环羟化双加氧酶基因OTUs序列BLAST(...     

石油污染土壤水改旱田后污染物组份及微生物群落结构变化

对沈抚灌区水改旱田不同年限土壤的石油污染物浓度及组分进行了分析,并采用变性梯度凝胶电泳和磷脂脂肪酸分析方法,分析了污染土壤微生物群落结构的变化.结果表明：1)石油污染土壤水改旱田后,年限越长,总多环芳烃在总石油烃中所占的比重越大,高分子量多环芳烃在总多环芳烃中所占比重也越大;2)总磷脂脂肪酸量与总石油烃呈显著正相关,与总多环芳烃相关性不显著;3)两种方法对土壤微生物群落结构的分析得出的结论一致,石油污染土壤微生物群落结构主要与其相对地理位置有关,当污染物的浓度达到一定程度时,土壤微生物群落结构会发生明显的改变.     

多环芳烃污染土壤微生物修复研究进展

多环芳烃是我国土壤环境质量标准中要求严格管控的一类持久性有机污染物,利用微生物技术修复有机污染土壤具有绿色、经济等突出特点,应用前景广泛。目前多学科的协同发展和新技术的研究应用,为多环芳烃土壤微生物转化机制与污染生态过程等方面带来了新的认识,同时对修复技术的实际应用与调控提供了新的思考方向。本文以多环芳烃污染土壤微生物修复为主体,从污染土壤微生物修复应用技术、多环芳烃微生物降解特征、土壤体系污染物归趋规律与微生物作用及土壤污染微生物群落响应与研究技术等方面进行综合评述,并针对现存应用技术瓶颈和理论空白作进一步思考和展望。     

沈阳市铁西区老工业搬迁区土壤多环芳烃的健康风险评价

采用美国能源部风险评估信息系统的暴露量化方法和美国环保局健康风险评估手册的风险表征方法,评估了沈阳市铁西区老工业搬迁区土壤中15种多环芳烃对户外劳作者的健康风险.沈阳市铁西区老工业搬迁区土壤中多环芳烃含量为290.9～8492.37μg·kg-1,搬迁区户外劳作者由于土壤中多环芳烃引起的非致癌危害指数范围为6.39×10-6 ～ 3.04×10-4,致癌风险范围为2.08×10-7 ～7.52×10-6,可判定对人体健康的危害较小.沈阳市铁西区老工业搬迁区致癌多环芳烃含量最高暴露点致癌风险值为7.52×10-6,未超过致癌风险水平上限(10-4),致癌风险尚在可接受范围内.多环芳烃中苯并(a)芘对综合致癌风险贡献最大,贡献率高达61.0％,应注意防范土壤中该污染物引起的健康危害.沈阳市铁西区老工业搬迁区户外劳作者受到的非致癌危害和致癌风险主要由经口摄入途径和皮肤接触途径贡献,两种途径对非致癌危害和致癌风险贡献率分别达到99％和100％,呼吸摄入引起的非致癌危害和致癌风险则相对较小.     

多环芳烃污染土壤生物修复研究进展

多环芳烃 (Polycyclic aromatic hydrocarbons,PAHs) 是一类广泛分布于环境中的持久性污染物,结构稳定、难以降解,对生态环境和生物具有“三致”毒害性,其环境去除和修复备受关注。绿色、安全、经济的生物修复技术被广泛应用于PAHs污染土壤的修复。本文从土壤中PAHs的来源、迁移、归趋和污染水平总结了目前我国土壤多环芳烃污染的基本状况;归纳了具有PAHs降解作用的微生物、植物种类及机理;比较了微生物修复、植物修复和联合修复3类主要的生物修复技术。指出植物与微生物的互作机理的解析,抗逆菌株、植株的筛选与培育,实际应用的安全和效能评估应成为多环芳烃污染土壤修复领域未来的研究方向。     

土壤－植物系统中多环芳烃和重金属的行为研究

对土壤中多环芳烃和重金属的行为研究表明,与对照相比,０—２０ｃｍ以上表土层存在多环芳烃和重金属积累,２０ｃｍ以下土层未发现积累;与春、秋两次采样结果相比,土壤中多环芳烃的含量有所下降,表明土壤微生物对多环芳烃有一定降解作用,且其降解程度与土壤－植物系统的生态结构有关．菲在地下水中检出浓度较高,表明这一污染物有向下迁移的可能性．此外,柳树对土壤中重金属Ｃｄ的积累有明显的削减与净化作用．本研究表明,严格限制污水中多环芳烃和重金属的污染负荷以及设计合理的生态结构是避免多环芳烃和重金属在土壤中积累的关键．     

Accumulation of phenanthrene by roots of intact wheat (<Emphasis Type="Italic">Triticum acstivnm</Emphasis>L.) seedlings: passive or active uptake?

Background  

Polycyclic aromatic hydrocarbons (PAHs) are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment.     

Estimation of Toxicity Equivalency and Probabilistic Health Risk on Lifetime Daily Intake of Polycyclic Aromatic Hydrocarbons from Urban Residential Soils

In this study, toxicity equivalents and health risks, based on concentration of 16 priority polycyclic aromatic hydrocarbons (PAHs) in urban residential soils were estimated for the human population in Gwalior, India. Benzo(a)pyrene total potency equivalents (BaP TPE) were estimated for assessment of human health risk from direct contact with PAH-contaminated soil. Potential risk to contaminated groundwater from leaching of carcinogenic PAHs was assessed by estimating the index of additive cancer risk (IACR). On the basis of lifetime average daily intake of 16 PAHs through ingestion of PAH-contaminated soils, lifetime cancer risk to human adults and children was estimated. The concentration of probable human carcinogenic PAHs in soils accounted for 38% of ∑16PAHs. BaP TPE and index of additive cancer risk (IACR) were lower than guideline values of 0.6 mg kg^?1 and <1, respectively. Estimated lifetime average daily intakes of PAHs via soil ingestion were lower than recommended dose. However, the ILCR for human adults was within acceptable limits recommended by regulatory agencies, but may need action for children in Gwalior, India.     

Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soils in Winter around Zhongyuan Oilfield,China

The degree of contamination with polycyclic aromatic hydrocarbons (PAHs) in soil samples in winter was determined. The contents of PAHs in samples were analyzed with HPLC. The PAHs contents of soil samples in winter around three different oily sludges from high to low represented the Third Wenming Plant of the oily sludge (3W), the Third Mazhai plant of the oily sludge (3M), and the Fourth Wener Plant of the oily sludge (4W), respectively. PAHs with 2–4 rings were major pollutants in oily sludge. Based on Nemero index P, the classification evaluation showed that soils around oily sludge were heavily polluted in winter. The health risk assessment and ecological risk assessment in soil in winter around oily sludge in Zhongyuan Oil Field was also analyzed.     

Assessing the Bioavailability and Risk from Metal-Contaminated Soils and Dusts

Exposure to contaminated soil and dust is an important pathway in human health risk assessment. Physical and chemical characteristics and biological factors determine the bioaccessibility/bioavailability of soil and dust contaminants. Within a single sample, contamination may arise from multiple sources of toxic elements that may exist as different species that impact bioavailability. In turn, the bioaccessibility/bioavailability of soil and dust contaminants directly impacts human health risk. Research efforts focusing on development and application of in vitro and in vivo methods to measure the bioaccessibility/bioavailability of metal-contaminated soils have advanced in recent years. The objective of this workshop was to focus on developments in assessing the bioaccessibility/bioavailability of arsenic-contaminated soils, metals’ contamination in urban Canadian residences and potential children's exposures to toxic elements in house dust, an urban community-based study (i.e., West Oakland Residential Lead Assessment), bioavailability studies of soil cadmium, chromium, nickel, and mercury and human exposures to contaminated Brownfield soils. These presentations covered issues related to human health and bioavailability along with the most recent studies on community participation in assessing metals’ contamination, studies of exposures to residential contamination, and in vitro and in vivo methods development for assessing the bioaccessibility/bioavailability of metals in soils and dusts.     

Polycyclic Aromatic Hydrocarbons in Surface Soils of Kunming,China: Concentrations,Distribution, Sources,and Potential Risk

The concentrations, distribution, possible sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in surface soils were studied in Kunming, which is situated in a lake basin of the Yunnan-Guizhou plateau. 15 PAHs were analyzed in 40 surface soil samples (0–5 cm layer) collected from six types of land uses in the Kunming urban area. Meanwhile, the potential sources of PAHs in surface soils of Kunming were investigated by PAH composition ratios, isomer ratios, and principal component analysis (PCA). The total concentrations of 15 PAHs ranged from 101.64 to 6,208.25 ng/g (dry weight basis). The concentrations in different land uses increased in an order as: green space (541.43 ng/g) < education area (756.49 ng/g) < business area (810.17 ng/g) < residential area (1,034.36 ng/g) < industrial area (1,166.79 ng/g) < roadside greens (2,146.76 ng/g). The results of sources identification suggested that PAHs in surface soils of the Kunming urban area were greatly affected by combustion activities which came mainly from coal combustion and vehicular traffic. In addition, the toxic equivalency factors (TEFs) were used to estimate benzo[a]pyrene-equivalent concentration in surface soils of Kunming, and the risk level of PAHs in Kunming's urban surface soils was low as a whole.     

Contamination,source identification,and risk assessment of polycyclic aromatic hydrocarbons in agricultural soils around a typical coking plant in Shandong,China

Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. Investigation of the contamination, distribution, and sources of PAHs in agricultural soils around Rong Xin coking plant, China, was conducted, and the potential human health risks were addressed. The total concentration of the 16 PAHs (∑₁₆PAHs) on the United States Environmental Protection Agency priority list had a range from 1774 to 4621 µg/kg (mean 3016 µg/kg). Meanwhile, seven carcinogenic PAHs (∑PAH_7c) owned the total concentrations of 684–2105 µg/kg, and they had the benzo[a]pyrene equivalent (BaP_eq) concentrations at 139.616–1672.850 µg/kg. All soil samples were dominated by PAHs with two to four rings. Data analyses for the potential sources of PAHs showed that the PAHs in soils were principally from pyrogenic sources. Ecological risk assessment of soil PAHs showed that the BaP_eq concentrations of ∑PAH_7c accounted for 99% of the total ∑₁₆PAHs, being a major carcinogenic contributors of ∑₁₆PAHs. Higher levels of PAHs and higher total BaP_eq concentrations in this study indicate a potential carcinogenic risk for humans. Therefore, long-term exposure to coking plants may increase the PAH concentrations in the environment and further raise a potential risk to human health.     

城市土壤质量演变及其生态环境效应

城市化是人类活动影响下自然生态系统向人工生态系统的急剧变化形式,它引起一系列生态环境条件的改变。城市对土壤资源的数量和质量产生深刻的影响,包括土壤地表封闭引起的土壤生态功能彻底消失,土壤物理性质恶化,土壤形态学特征和演变过程深受人为作用的影响。短程变异增加而总体多样性降低,土壤污染加剧,土壤养分富集等多方面,城市过程中土地利用变化对土壤产生一系列生态环境效应,如养分径流输出增加,热缓冲能力下降,污染转移危险性上升等,有必要迅速开展城市化过程中土壤质量演变及其生态环境效应的系统研究,为我国城市可持续发展提供理论依据。     

Evaluation of the Soil Contamination of Tangier (Morocco) by the Determination of BTEX,PCBs, and PAHs

Benzene, toluene, ethylbenzene, and xylenes (BTEX), twelve polycyclic aromatic hydrocarbons (PAHs) and seven polychlorinated biphenyls (PCBs), were selected as pollutants to evaluate the contamination of soils in the urban and industrial areas of Tangier (Morocco). PAHs and PCBs were determined by gas chromatography-mass spectrometry (GC-MS) after a microwave-assisted extraction (MAE) and gel permeation chromatography (GPC) clean-up. BTEX were directly determined by head-space GC-MS. Results obtained in this study show the presence of high levels of BTEX and PAHs in the soil near the urban waste deposit. However, the analysis of pollutants in the other sampling sites provided comprehensive evidence that soils of Tangier city are not contaminated.     

Toxicity and Bioaccumulation of Petroleum Mixtures with Alkyl PAHs in Earthworms

The toxicities of three oil products with boiling-point ranges representative of petroleum hydrocarbons were tested on earthworms (Eisenia fetida) to investigate the correlation between bioaccumulated concentrations of polycyclic aromatic hydrocarbons (PAHs) and toxicity. The toxicities to earthworms were in the sequence: kerosene > diesel > bunker-C. After 14 days, the LC50s of the soils contaminated with kerosene, diesel, and bunker-C were 1079, 9135, and 15,609 mg/kg, respectively. Analysis of the body residue concentrations of PAHs in the earthworms showed that the accumulation of alkyl PAHs predominated that of the 16 priority PAHs. Principal component analysis (PCA) identified 12 PAHs, including four alkylated naphthalenes, as the oil constituents that affected mortality in the kerosene-contaminated soil. For the diesel-contaminated soil, eight PAHs were identified, including dibenzothiophene. It was not clear which compounds affected mortality in the bunker-C soil. Across the three series, biota-to-soil accumulation factors (BSAFs) ranged from 10^–2.05 to 10^3.98, and generally increased as the hydrophobicity (K_ow) or molecular weight of the alkyl PAHs increased. The toxicity endpoints of each oil product can be used as reference values in the risk assessment of soils contaminated with petroleum, and individual PAHs screened out have implications for future toxicity assessment of petroleum hydrocarbons.