食品中多环芳烃及卤代多环芳烃的研究进展

综述了多环芳烃及卤代多环芳烃的性质、毒性及国内外食品中的污染情况和研究现状,并对目前的分析测定方法进行了介绍,希望为我国开展食品领域内多环芳烃和卤代多环芳烃的研究提供参考。     

Occurrence and profiles of chlorinated and brominated polycyclic aromatic hydrocarbons in waste incinerators

Chlorinated polycyclic aromatic hydrocarbons (CIPAHs) have been reported to occur in urban air. Nevertheless, sources of CIPAHs in urban air have not been studied, due to the lack of appropriate analytical methods and standards. In this study, we measured concentrations of 20 CIPAHs and 11 brominated PAHs (BrPAHs) in fly ash and bottom ash from 11 municipal/hazardous/industrial waste incinerators, using analytical standards synthesized in our laboratory. Concentrations of total CIPAHs and BrPAHs in ash samples ranged from <0.06 to 6990 ng/g and from <0.14 to 1235 ng/g, respectively. The concentrations of CIPAHs were approximately 100-fold higher than the concentrations of BrPAHs. 6-CIBaP and 1-CIPyr were the dominant compounds in fly ash samples. The profiles of halogenated PAHs were similar to the profiles reported previously for urban air. 1-BrPyr was the predominant BrPAH in fly ash. Concentrations of 6-CIBaP, 9,10-Cl2Phe, 9-CIAnt, and 6-BrBaP in fly ash were significantly correlated with the corresponding parent PAH concentrations. Significant correlation between sigmaCIPAH and sigmaPAH concentrations suggests that direct chlorination of parent PAHs is the mechanism of formation of CIPAHs during incineration of wastes; nevertheless, a comparable correlation was not found for BrPAHs. There was no significant correlation between the capacity and temperature of an incinerator and the concentrations of sigmaCl-/BrPAHs in ash samples, although lower concentrations of all halogenated PAHs were found in stoker-type incinerators than in fixed grate-type incinerators. Toxicity equivalency quotients (TEQs) for CIPAHs in ash samples were calculated with CIPAH potencies. Average TEQ concentrations of CIPAHs in fly ash and bottom ash were15800 pg-TEQ/g and 67 pg-TEQ/g, respectively. Our results suggest that the extent of dioxin-like toxicity contributed by CIPAHs in ash generated during waste incineration is similar to that reported previously for dioxins. Waste incineration is an important source of Cl-/BrPAHs in the urban atmosphere.     

Factors governing the atmospheric deposition of polycyclic aromatic hydrocarbons to remote areas

Polycyclic aromatic hydrocarbons (PAH) were measured in bulk atmospheric deposition collected in three remote areas of Europe during 1997-1998. Mean total PAH fluxes over a period of 18 months were 1560 +/- 750 and 1150 +/- 630 ng m(-2) mo(-1) in the Pyrenees and the Alps, respectively. In the Caledonian mountains (Scandinavia) the observed mean fluxes were 1900 +/- 940 ng m(-2) mo(-1) (6 month collection). Similar qualitative PAH compositions (p values <0.05) in the bulk atmospheric deposition have been observed between sites, which are dominated by the more volatile parent compounds. The main differences between lakes are related to the high molecular weight compounds. Atmospheric deposition of PAH to these remote sites appears to be independent of their concentrations in the atmosphere, which are similar between sites (in the range of 1.8-3.0 ng x m(-3)), being controlled mainly by particle deposition, followed by precipitation and air temperature. A multilevel regression model including these three variables accounted for 74% of the total variability in total PAH bulk deposition; however, the contribution of each variable in the model is compound and site-dependent. The deposition of high molecular weight PAH depends more on particle deposition and precipitation, whereas air temperature is the main factor controlling the deposition fluxes of the low molecular weight PAH.     

Spatial and temporal distribution of polycyclic aromatic hydrocarbons in sediments from Michigan inland lakes

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in sediment cores collected from 11 inland lakes in Michigan for examination of spatial and temporal trends in accumulation and sources. Concentrations of PAHs varied widely among these lakes; the highest concentrations were found in sediment collected from Cass Lake, located in an urbanized watershed. Concentrations of PAHs were correlated with watershed population density on a spatial scale. PAH concentrations have decreased over time since the 1980s in nine of the 11 lakes studied, most of which are located in suburban and rural areas. The rate of decline in PAH concentration was faster in Gratiot Lake, a remote lake with no known local sources of pollution in recent years. Concentrations of PAHs in surface sediments from Cass and Cadillac Lakes were greater than the threshold for adverse effects. Despite the wide variations in total PAH concentrations, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene, and benzo[k]fluoranthene were the major PAHs in all of the lakes studied. The proportions of individual PAHs within the total PAH concentrations have changed both temporally and spatially, suggesting a shift in the sources of PAHs in the environment. A general increase in the proportion of high-molecular-weight PAHs suggests an increase in combustion-related sources recently.     

Emission of polycyclic aromatic hydrocarbons in China

Emission of 16 polycyclic aromatic hydrocarbons (PAHs) listed as U.S. Environmental Protection Agency (U.S. EPA) priority pollutants from major sources in China were compiled. Geographical distribution and temporal change of the PAH emission, as well as emission profiles, are discussed. It was estimated that the total PAH emission in China was 25,300 tons in 2003. The emission profile featured a relatively higher portion of high molecular weight (HMW) species with carcinogenic potential due to large contributions of domestic coal and coking industry. Among various sources, biomass burning, domestic coal combustion, and coking industry contributed 60%, 20%, and 16% of the total emission, respectively. Total emission, emission density, emission intensity, and emission per capita showed geographical variations. In general, the southeastern provinces were characterized by higher emission density, while those in western and northern China featured higher emission intensity and population-normalized emission. Although energy consumption in China went up continuously during the past two decades, annual emission of PAHs fluctuated depending on the amount of domestic coal consumption, coke production, and the efficiency of energy utilization.     

Aqueous photodegradation of polycyclic aromatic hydrocarbons

Photodegradation of 12 polycyclic aromatic hydrocarbons was studied in aerated pure water, solutions of Suwannee River fulvic acid, and natural waters using polychromatic light (>290 nm). Quantum yields in pure water varied from 3.2 x 10(-5) to 9.2 x 10(-3). No obvious relationships were evident among the quantum yields and molecular properties. Photodegradation rate constants in solutions of Suwannee River fulvic acid or natural waters were largely unchanged compared to rate constants in pure water. Estimates of PAH photodegradation rates in natural waters can thus be obtained employing the quantum yields in pure water, PAH absorption, and solar irradiance. Calculated rate constants for photodegradation in surface waters during the summertime at mid-latitude varied from 3.2 x 10(-3) to 7.6 h(-1).     

食品中多环芳烃的研究进展

简述了近年来关于食品中多环芳烃的形成机理、分析方法及控制措施的研究进展,以期为解决食品中多环芳烃的污染问题提供依据。     

Alternative normalization method of atmospheric polycyclic aromatic hydrocarbons pollution level recorded by tree bark

An alternative normalization method was developed for evaluating atmospheric polycyclic aromatic hydrocarbons (PAHs) pollution level when using tree bark as a passive sampling medium. Perylene (PER), which mainly stems from natural biogenic processes, was proposed as a "natural internal compound" (NIC) of atmospheric PAHs accumulation processes from air into the bark, and a concentration ratio of target PAH to PER (RPAH/PER) was used to minimize the uncertainty in the evaluation of atmospheric PAHs pollution level. Systematic investigation of the effects of intrinsic bark characteristics and extrinsic seasonal meteorological conditions on the partition processes of atmospheric PAHs indicated that RPAH/PER is as an alternative index as compared to bark mass concentration (BMCPAH, ng/g dry bark), lipid mass concentration (LMCPAH, ng/g lipid of bark), and area mass concentration (AMCPAH, ng/m2 surface area of bark) for the evaluation of atmospheric PAHs pollution and that it allows more flexible sampling of tree barks. Clearly, the methodology should be expected to be useful for the objective evaluation of atmospheric pollution levels of other persistent organic pollutants when using tree bark and other passive sampling media if corresponding NICs are found in the future.     

Contribution of biomass burning to atmospheric polycyclic aromatic hydrocarbons at three European background sites

Radiocarbon analysis of atmospheric polycyclic aromatic hydrocarbons (PAHs) from three background areas in Sweden, Croatia, and Greece was performed to apportion their origin between fossil and biomass combustion. Diagnostic ratios of PAHs implied that wood and coal combustion was relatively more important in the northern European site, while combustion of fossil fuels was the dominant source of PAHs to the two central-southern European background sites. The radiocarbon content (delta14C) of atmospheric PAHs in Sweden ranged between -388 per thousand and -381 per thousand, while more depleted values were observed for Greece (-914 per thousand) and Croatia (-888 per thousand). Using a 14C isotopic mass balance model it was calculated that biomass burning contributes nearly 10% of the total PAH burden in the studied southern European atmosphere with fossil fuel combustion making up the 90% balance. In contrast, biomass burning contributes about 50% of total PAHs in the atmosphere at the Swedish site. Our results suggest that the relative contributions of biomass burning and fossil fuels to atmospheric PAHs may differ considerably between countries, and therefore, different national control strategies might be needed if a further reduction of these pollutants is to be achieved on a continental-global scale.     

两种方法检测食用油脂中的多环芳烃

分别建立同位素内标定量-QuEChERS净化-气相色谱-三重四级杆串联质谱法(方法一)和GPC自动净化-高效液相色谱-荧光检测法(方法二)两种方法,为检测食用油脂中欧盟优先控制的16种多环芳烃(EU15+1PAHs)提供了快速有效的方法。分别对104份食用油脂样品进行分析比较,对比两方法检测结果。结果表明:两方法均满足国内外对食品中PAHs检测的要求,方法一、方法二精密度实验RSD值分别小于5.4%、6.81%,平均加标回收率除个别外,分别在71.3%~111.6%、93.1%~119%范围内,RSD值分别小于5.0%、5.5%;标准曲线线性方程相关系数分别大于0.998、0.990,方法一定量限范围为0.23~0.50μg/kg,方法二定量限为0.9μg/kg、检出限为0.3μg/kg;英国食品化学分析实验室能力验证(FAPAS)盲样测定结果均达到规定检测结果;两方法对104份油样的两组检测结果无统计学差异,整体分析和分不同油种比较结果基本一致。结论:建立了针对食用油中EU15+1PAHs的分析方法,两方法均满足相应检测要求,且具有良好的准确性和实用性。     

两种方法检测食用油脂中的多环芳烃

分别建立同位素内标定量-QuEChERS净化-气相色谱-三重四级杆串联质谱法（方法一）和GPC自动净化-高效液相色谱-荧光检测法（方法二）两种方法,为检测食用油脂中欧盟优先控制的16种多环芳烃（EU15+1PAHs）提供了快速有效的方法。分别对104份食用油脂样品进行分析比较,对比两方法检测结果。结果表明:两方法均满足国内外对食品中PAHs检测的要求,方法一、方法二精密度实验RSD值分别小于5.4%、6.81%,平均加标回收率除个别外,分别在71.3%¹11.6%、93.1%¹19%范围内,RSD值分别小于5.0%、5.5%;标准曲线线性方程相关系数分别大于0.998、0.990,方法一定量限范围为0.23⁰.50μg/kg,方法二定量限为0.9μg/kg、检出限为0.3μg/kg;英国食品化学分析实验室能力验证（FAPAS）盲样测定结果均达到规定检测结果;两方法对104份油样的两组检测结果无统计学差异,整体分析和分不同油种比较结果基本一致。结论:建立了针对食用油中EU15+1PAHs的分析方法,两方法均满足相应检测要求,且具有良好的准确性和实用性。      

Searching ingredients polluted by polycyclic aromatic hydrocarbons in feeds due to atmospheric or pyrolytic sources

The primary aim of the proposed work is to propose the potential sources of pollution by polycyclic aromatic hydrocarbons (PAHs) in feeds and ingredients. To reach this propose the development of a simple, fast, quantitative and economic method for determining PAHs using liquid-liquid extraction (LLE), clean-up and detection by liquid chromatography with fluorescence detection (LC-FD) in polluting feeds and ingredients was developed. The overall method quantification limits range from 0.020 to 4.0μg/kg and analyte recoveries are between 70% and 105% with relative standard deviations (RSD) lower than 20%. Molecular patterns of PAHs were used to study their distribution in the selected samples by cluster analysis, separating them in two groups: contaminated by atmospheric or pyrolytic sources. In order to find a relationship between the nutritional composition (protein, fibre, ash and fat content), and the hypothetical toxicity of selected feeds, a partial least squared (PLS) analysis was used, showing that fibre was a major contributor. Moreover, the complete data set of 27 feed samples and 25 feed ingredients x 13 PAH concentrations were analysed by PCA to find out what ingredients were controlling PAH pollution.     

Occurrence of polycyclic aromatic hydrocarbons in smoked cheese

The presence of polycyclic aromatic hydrocarbons (PAH) in smoked cheeses of different origin was studied. The samples were subjected to an initial extraction of fat and an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography/mass spectrometry (GC/MS) operating in selective ion-monitoring mode (SIM). The results revealed the presence of numerous polycyclic aromatic hydrocarbons in the exterior zone of the samples, some of them with methyl groups. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Polycyclic aromatic hydrocarbons with varying degrees of carcinogenicity were identified, including benzo(a)pyrene in concentrations, which, although they did not exceed the limit established for this compound in the rind of ripened cheeses, do exceed the limit of 0.03 microg/kg fixed for other foods smoked with smoke flavorings. Significant differences in the number and concentration of PAH in smoked cheese also were observed from rind to interior, the rind being the most contaminated zone.     

Occurrence, profiles, and photostabilities of chlorinated polycyclic aromatic hydrocarbons associated with particulates in urban air

The atmospheric levels of 12 chlorinated polycyclic aromatic hydrocarbons (ClPAHs) associated with particulates at an urban site in Japan were investigated. Only 7 of the 12 species studied were detected in air samples collected monthly during 2002. 1-Chloropyrene (1-ClPy) was detected at the highest concentration (7.5 pg m(-3) (annual mean)), followed by 6-chlorobenzo[a]pyrene (6-ClBaP; 5.6 pg m(-3)) and 9,10-dichlorophenanthrene (5.1 pg m(-3)). The concentrations of the ClPAHs tended to be higher in winter than in summer, with the exception of the 6-ClBaP concentration, which was high in both summer and winter. Correlation analysis also indicated that the behavior of 6-CIBaP differed significantly from that of the other ClPAHs. Comparison of the atmospheric ClPAH concentration profile normalized to 1-CIPy concentration with that for a traffic air sample revealed significant differences between the profiles. The behavior of the atmospheric ClPAHs was also influenced by the origin of the associated particulates, which varied according to season. The positions of chlorination in the detected ClPAHs were consistent with those where the frontier electron density was high. This means that the atmospheric ClPAHs were formed by secondary reactions with chlorine atoms. The photostabilities of the ClPAHs were also investigated in laboratory experiments using a chemical model system. The ClPAHs decayed according to first-order reaction rate kinetics, with photostabilities increasing in the order 6-ClBaP < 1-ClPy < 7-ClBaA < ClPhe < ClFluor, consistent with the trend for the parent PAHs. The photolyses of chlorophenanthrenes and 7-chlorobenz[a]anthracene were confirmed to proceed by initial abstraction of chlorine, followed by oxidative degradation.     

高脂食品中多环芳烃研究

多环芳烃具有非极性强特点,易在脂质含量丰富食品中造成污染。该文对富脂肉类等高脂肪食品中多环芳烃来源、形成及污染现状、检测方法等进行概述,并对控制其中多环芳烃污染方法进行总结和讨论。     

食用油中多环芳烃的研究进展

多环芳烃(PAHs)是指2个或2个以上苯环以稠环形式相连的一类化合物,具有基因毒性和致癌性.对食用油中PAHs的来源、检测方法及控制和脱除方法进行了详尽的阐述,并指出PAHs前处理方法和控制、脱除方法是未来的研究方向.