Polycyclic Aromatic Hydrocarbon Profiles of Some Brands of Canned Fish in the Nigerian Market

Concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were determined in selected popular brands of canned fish (mackerel, sardine, and tuna) consumed in Nigeria with a view to providing information on the health risk associated with consumption of these products. The concentrations of PAHs were measured by gas chromatography equipped with flame ionization detection (GC-FID) after dichloromethane/hexane extraction and clean-up. The concentrations of Σ16 PAHs in these brands of canned fish varied from 174.6 to 350.8 μg/kg, 187.4 to 592.5 μg/kg, and 204 to 264.6 μg/kg for mackerel, sardine, and tuna, respectively. Benzo(a)pyrene was detected in 48% of the investigated brands at concentrations higher than the maximum tolerable limit of 5 μg/kg. The daily intake of PAHs from the consumption of any brand of these canned fish ranged from not detected (nd) to 54.3 ng BaP/kg bw/day, nd to 56.4 ng PAH2/kg bw/day, nd to 86.4 ng PAH4/kg bw/day, and nd to 153.7 ng PAH8/kg bw/day. The estimated margin of exposure (MOE) values (BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE) in a significant proportion of the brands was less than 10,000, which indicates a potential health risk for the consumers of these brands of canned fish.     

微生物降解多环芳烃的研究进展

多环芳烃(PAHs)是具有严重危害的环境污染物质。介绍PAHs的降解菌,降解机理和PAHs的生物修复方面的研究进展。土壤中PAHs的生物修复被认为是解决污染的有效方法,目前,菲的生物降解途径已经比较清楚,但对结构更为复杂的多环芳烃研究较少。文章还对消除环境中多环芳烃的相关生物技术提出展望。     

Bioremediation of Polycyclic Aromatic Hydrocarbons in Creosote-Contaminated Soil by Peniophora incarnata KUC8836

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are present in products made from creosote, coal tar, and asphalt. When wood pile treated with creosote is placed in soil, PAHs can contaminate it. Creosote has been used for wood preservation in the past and is composed of approximately 85% PAHs and 15% phenolic compounds. PAHs cause harmful effects to humans and the environment because of their carcinogenic and mutagenic properties. White rot fungi can degrade not only lignin, but also recalcitrant organic compounds such as PAHs. Among numerous white rot fungi used in previous studies, four species were selected to degrade PAHs in a liquid medium. From this evaluation of the degradation of PAHs by the four fungal isolates, two species were ultimately selected for the highest rates of removal. Following 2 weeks of incubation with Peniophora incarnata KUC8836, the degradation rates of phenanthrene, fluoranthene, and pyrene were 86.5%, 77.4%, and 82.6%, respectively. Mycoaciella bispora KUC8201 showed the highest degradation rate for anthracene (61.8%). Hence, bioremediation of creosote-contaminated soil with an initial concentration of 229.49 mg kg^?1 PAHs was carried out using the two selected fungi because they could simultaneously degrade 13 more PAHs than the comparison species. More importantly, isolates of P. incarnata KUC8836 were discovered as powerful degraders of PAHs by producing laccase and manganese-dependent peroxidase (MnP), with 1.7- and 1.1-fold higher than the comparison species, respectively. Therefore, the white rot fungus may be proposed for the removal of PAHs and xenobiotic compounds in contaminated environments.     

多环芳烃污染生物修复研究进展

多环芳烃(polycyclic aromatic hydrocarbon,PAHs)是一类对环境有严重危害的持久性有机污染物。具有高生物富集性、致癌性、致毒性和难降解性,修复治理PAHs污染环境备受国内外政府及学者的关注。目前主要采用物理、化学以及生物方法对多环芳烃污染的土壤和水体进行修复。其中生物修复是一种高效、经济和生态可承受的环保技术,具有成本低、无二次污染等优点。本文从植物修复、微生物修复以及植物-微生物联合修复方面,阐述了国内外生物修复PAHs污染的最新研究进展。指出了生物修复PAHs污染环境需要进一步解决的问题,并对未来发展趋势进行了展望。     

Polycyclic Aromatic Hydrocarbons (PAHs) Pollution in Agricultural Soil in Tianjin,China

Representative soil samples (n = 60) collected from suburban agricultural land in Tianjin were analyzed to determine 16 PAHs in this study. Accelerated solvent extraction, GPC (Gel Permeation Chromatography), and SPE (Solid Phase Extraction) clean-up procedures were employed for PAH preparation prior to analysis with gas chromatography–mass spectrometry. The concentrations of the total PAHs (T-PAHs) ranged from 228.6 ng/g to 14722.1 ng/g with the mean value of 613.1 ng/g. Bap concentrations in many sites exceeded the suggested standards. Spatial variation of PAHs in soil was illustrated; the pollution status and comparison to other cities were also investigated. Severe PAH soil pollution was observed in some sites near urban areas. Higher PAH concentrations were detected at the downwind side of the urban areas, indicating the influence of human activities. Two indicative ratios (Fl/(Fl+Pyr, Baa/(Baa+Chr)) and principal component analysis were used to identify the possible sources of PAHs. These suggested that coal combustion was still the most important source of PAHs in Tianjin, which coincided well with the previous studies. These data can be further used to assess the health risk associated with soils polluted by PAHs and can help local government find proper ways to reduce PAHs’ pollution in soils.     

藻类对多环芳香烃(PAHs)的富集和代谢

概述了藻类对PAHs的富集和代谢的研究进展。环境中多环芳香烃(PAHs)的污染能导致严重的健康问题,利用生物特别是微生物去除污染环境中的PAHs是一项新的技术。藻类对PAHs的富集与有机污染物的类型、藻类的种类及藻类的生物量有关,活细胞和死细胞对PAHs均有富集能力。还阐述了PAHs在真菌、细菌和藻类体内代谢的途径以及代谢过程中起关键作用的酶,PAHs在藻类中的代谢途径和细菌及真菌都不同,谷胱甘肽转移酶(GST)在藻类代谢PAH过程中起重要作用,但细胞色素P450酶所起的作用则不详。     

城市污泥和化肥对水稻土种植的通菜中多环芳烃(PAHs)的影响

在水稻土上施用城市污泥和化肥盆栽通菜,应用GC／MS联机检测技术对通菜中17种多环芳烃化合物进行了分析。结果表明,各处理通菜中的∑PAHs含量在0．414-5.404mg/kg之间,依次是佛山污泥＋化肥＞广州污泥＋化肥＞化肥＞广州污泥＞佛山污泥＞空白,致癌性PAHs化合物的总含量（∑PAHscarc)在0.068-0.944mg/kg之间,绝大部分化合物在通菜中的含量大于在根系中的含量,与空白对照相比,施用城市污泥和化肥均使通菜中的∑PAHs含量明显提高,各处理通菜中的PAHs都只是以一种或几种化合物为主,主要是3,4个苯环的化合物,显示不同的分布特征,。     

好氧细菌对多环芳烃降解机制的研究进展

多环芳烃(PAHs)是指两个或两个以上的苯环以线性排列、弯接或簇聚方式构成的一类碳氢化合物。这类化合物广泛分布于环境中, 具有潜在的致畸性、致癌性和遗传毒性。在自然环境中, 好氧细菌对PAHs的生物降解是一种很重要的方式, 凸显其在清除环境PAHs污染物中具有广阔的应用前景。在过去二十多年中, 科学家们已经从基因水平上对好氧细菌降解PAHs的机制进行了深入的研究, 其中包括PAHs降解基因的多样性、与PAHs降解有关的基因以及细菌群体PAHs遗传适应机制等。在此, 就好氧细菌对多环芳烃降解机制的研究进展进行了综述和讨论。     

好氧细菌对多环芳烃降解机制的研究进展

多环芳烃(PAHs)是指两个或两个以上的苯环以线性排列、弯接或簇聚方式构成的一类碳氢化合物.这类化合物广泛分布于环境中,具有潜在的致畸性、致癌性和遗传毒性.在自然环境中,好氧细菌对PAHs的生物降解是一种很重要的方式,凸显其在清除环境PAHs污染物中具有广阔的应用前景.在过去二十多年中,科学家们已经从基因水平上对好氧细菌降解PAHs的机制进行了深入的研究,其中包括PAHs降解基因的多样性、与PAHs降解有关的基因以及细菌群体PAHs遗传适应机制等.在此,就好氧细菌对多环芳烃降解机制的研究进展进行了综述和讨论.     

Comparison of Photocatalytic Oxidation and Ozonation in Degrading of Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants. Photocatalytic oxidation (PCO) was used to degrade individual PAHs dissolved in aqueous solution and results were compared to those used for ozonation treatment of PAHs in aqueous phase and adsorbed on soil reported previously. Both PCO and ozonation showed high effectiveness and efficiency in degrading PAHs within only minutes of time. Ozonation showed higher performance in the degradation of PAHs in aqueous solution than in soil, whereas the treatment efficiency of PCO was higher than that of ozonation in degrading PAHs in aqueous solution. Both methods have advantages over each other but they have their own limitation(s) in practical application.     

污染土壤中多环芳烃的共代谢降解过程

1　前　言多环芳烃是一类普遍存在于环境中的重要有机污染物 ,因其致癌性、致畸性、致突变性而被认为是危险物质。由于其水溶性低 ,辛醇 水分配系数高 ,因此 ,该类化合物易于从水中分配到生物体内、沉积层中。土壤成为多环芳烃的重要载体 ,多环芳烃污染土壤的生物修复也因此倍受关注。多环芳烃在土壤中有较高的稳定性 ,其苯环数与其生物可降解性明显呈负相关关系。很少有能直接降解高环数多环芳烃的微生物。研究表明 ,高分子量的多环芳烃的生物降解一般均以共代谢方式开始[1 3] 。共代谢作用可以提高微生物降解多环芳烃的效率 ,改变微生物碳…     

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.     

Synthesis of Polycyclic Aromatic Hydrocarbons and Acetylene Polymers in Ice: A Prebiotic Scenario

The recent evidences of presence of subsurface oceans of liquid water and ice on Saturn's moons, and the possible presence and astrobiological importance of polycyclic aromatic hydrocarbons (PAHs) in these environments, provide strong motivation for the exploration of the prebiotic chemistry in ice and to test if PAHs could be experimentally synthesized in ice surfaces under atmospheres containing methane as carbon source. In this work, we present a new design for prebiotic‐chemistry experiments in ice matrix. Using this design, a mixture of products including PAHs, polar aromatic compounds, and hydrophilic acetylene‐based polymers was obtained. We propose that acetylene generation in a methane/nitrogen atmosphere and subsequent polymerization to PAHs and polyynes could be a favored pathway in the presence of water freeze–melt cycles. These results shed light on the processes involved in PAH synthesis in icy environments and on the physical factors that drive the different competing pathways in methane/nitrogen atmospheres.     

A Perspective on the Toxicity of Low Concentrations of Petroleum-Derived Polycyclic Aromatic Hydrocarbons to Early Life Stages of Herring and Salmon

This article presents a critical review of two groups of studies that reported adverse effects to salmon and herring eggs and fry from exposure to 1 μg/L or less of aqueous total polycyclic aromatic hydrocarbons (TPAH), as weathered oil, and a more toxic aqueous extract of “very weathered oil.” Exposure media were prepared by continuously flowing water up through vertical columns containing gravel oiled at different concentrations of Prudhoe Bay crude oil. Uncontrolled variables associated with the use of the oiled gravel columns included time- and treatment-dependent variations in the PAH concentration and composition in the exposure water, unexplored toxicity from other oil constituents/degradation products, potential toxicity from bacterial and fungal activity, oil droplets as a potential contaminant source, inherent differences between control and exposed embryo populations, and water flow rate differences. Based on a review of the evidence from published project reports, peer-reviewed publications, chemistry data in a public database, and unpublished reports and laboratory records, the reviewed studies did not establish consistent dose (concentration) response or causality and thus do not demonstrate that dissolved PAH alone from the weathered oil resulted in the claimed effects on fish embryos at low μg/L TPAH concentrations. Accordingly, these studies should not be relied on for management decision-making, when assessing the risk of very low–level PAH exposures to early life stages of fish.     

Estimation of Excess Cancer Risk on Time-Weighted Lifetime Average Daily Intake of PAHs from Food Ingestion

The purposes of this study were to quantify the time-weighted, lifetime average, daily intake (LADI) of polycyclic aromatic hydrocarbons (PAHs) through food ingestion and to estimate the excess cancer risk based on lifetime dietary PAH intake. Twenty-seven different food commodities were selected from the 2001 Korean National Health and Nutrition survey based on their frequent consumption and high PAH level. The foods were analyzed for the profile of 14 PAH congeners using high performance liquid chromatography (HPLC) and fluorescence detector. Considering the toxic equivalent (TEQ) level converted with the toxic equivalent factors (TEFs), the highest total TEQ level of PAHs in foods was detected from roasted laver at 1.2 ug TEQ/kg. For the PAH exposure assessment according to ingested foods, the average body weight was separated according to the following age groups, 1–6, 7–19, 20–64 and over 64 years, and the daily food ingestion rates from the National Health and Nutrition survey were used. The estimated Lifetime Average Daily Intake (LADI) of PAHs was 3.22 × 10^–3 ug/kg/day for carcinogenic effects and was higher in the younger age groups under 20 years old than in the older groups. The dietary excess cancer risk estimated using the cancer potency of benzo(a)pyrene (7.3(mg/kg/day)^?1) was 2.3 × 10^?5, which is equivalent to a probability of tumor eruption in the upper gastrointestinal tract of two per hundred thousand persons.     

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.     

多环芳烃微生物降解基因的研究进展

多环芳烃(PAHs)是环境中普遍存在的一类有机污染物,微生物的降解是PAHs去除的主要途径。近年来,有关PAHs微生物降解途径和代谢产物的研究已有很多报道。小分子PAHs一般可以直接被微生物降解,而大分子PAHs则需要微生物以共代谢的方式降解。在过去20年中,微生物降解PAHs的基因相继被发现,各种基因在调控PAHs降解过程中的功能也越来越清晰。本文概述了PAHs微生物降解基因方面的研究进展,详细介绍了微生物对萘、菲的降解基因,最后对PAHs微生物降解基因的应用前景进行了展望。     

Degradation of Polycyclic Aromatic Hydrocarbons in the Rhizosphere of Festuca arundinacea and Associated Microbial Community Changes

A phytoremediation growth chamber study was conducted to evaluate the contribution of soil microbial diversity to the contaminant degradation. Target contaminant removal from soil was assessed by monitoring concentrations of polycyclic aromatic hydrocarbons (PAHs), along with changes in the bacterial community structure over a time period of 10 months in the presence of tall fescue (Festuca arundinacea). Enhanced degradation of PAHs was observed in rhizosphere soil, with a maximum reduction in pyrene at a rate 36% higher than that noted for the unvegetated control. The dissipation of < 4-ring PAHs, 4-ring PAHs, and > 4-ring PAHs in unvegetated soil was 70%, 54%, and 49% respectively, whereas a higher dissipation rate was observed in tall fescue treated soil of 78%, 68%, and 61% at the end of the study. Microbial enumeration results showed greater total bacterial numbers and PAH-degrading bacteria in rhizosphere soil when compared to unvegetated soil. The results from the terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that there was a shift in the rhizosphere bacterial community during the phytoremediation process.     

Investigating Polycyclic Aromatic Hydrocarbons Profiles in Higher Plants Using Statistical Models

Thirty-six higher plants sampled from Olomoro, Irri, Uzere, and Oginni exploration sites in the Niger Delta region of Nigeria were subjected to GC/MS analysis to assess the occurrence, distribution and profiles of polycyclic aromatic hydrocarbons (PAHs) contained in them. The Σ₂₈PAHs ranged from 335 to 3094 ng/g. The results of the nonparametric regression models showed that PAHs concentration in a plant cannot be used in isolation to deduce the total PAHs concentration in soils hosting the plant since PAHs concentration in a plant is influenced by the presence (or absence) of other plants in that location. A combination of Factor analysis (FA) and principal component analysis (PCA) were used to recognize PAHs concentration patterns among the plants in the studied locations and individual PAHs compounds. Woody annuals and perennial plants formed similar patterns in Oginni and Irri locations. Three main clusters were formed by all the compounds with naphthalene and 2-methylnaphthalene standing as outliers in all the four locations.

Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.     

南亚热带典型地区农业土壤中多环芳烃和有机氯农药研究

参考美国EPA标准方法对南亚热带潮汕地区农业土壤中持久性有机污染物多环芳烃（PAHs）和有机氯农药（OCPs）进行分析,并对其分布和来源进行研究,最后探讨了不同种植方式下污染物的污染特征。结果表明：该区农业土壤中PAHs含量范围从22．1ng／g到1256．9ng／g,与其它地区的污染程度和一些土壤环境质量标准相比,该区处于中等污染水平。高温裂解是土壤PAHs的主要来源。OCPs在被禁止20a后在土壤中仍有残留,残留水平从4．6ng／g到1021．5ng／g,其中HCHs和DDTs的残留未超过国家土壤环境质量标准。早期使用残留是其主要污染源,但新近仍有DDT和硫丹的输入。PAHs和OCPs的污染主要集中在土壤表层和亚表层,且随着深度的加深,污染逐渐减少,但40cm以下,污染变化很小。菜地土壤PAHs污染水平低于稻田土壤,而OCPs污染水平高于稻田土壤。