Polycyclic Aromatic Hydrocarbons In Vegetables Research Articles

Pollution level, source, and health risk assessment of PAHs in food products and environmental media in Nantong, China: A pilot case

The following study is an analysis of the pollution characteristics, dietary intake levels, and health effects of 16 polycyclic aromatic hydrocarbons (PAHs) in vegetables, fruits, and meat products in Nantong City, China. The PAHs content, pollution level, carcinogenic risk, and correlation of soil and local atmospheric environment in the crop irrigation area were determined. A total of agricultural products (n = 42), soil samples (n = 18), and air samples (n = 42) were freshly collected from selected irrigation areas in Nantong to detect the content of 16 US EPA PAHs. The total contents of PAHs in vegetables, fruits, and meat products were 16.4 − 136.5 ng/g, 86.0 − 225.1 ng/g, and 0.1 − 23.4 ng/g, respectively. Phe (32.00 −37.24%) and Pyr (27.25 −28.79%) were two PAHs with the highest pollution. The total contents of 16 PAHs in both soil and air were 31.5 − 288.2 ng/g and 1.08 − 28.85 ng/m3, respectively. The single PAHs with the highest pollution were BaP (36.48%) and Flu (21.45%). The characteristic ratio analysis method was used to trace the source of PAHs. Accordingly, PAHs in the three types of food sources primarily originated from the burning of coal, oil or biomass, and was consistent with the air or soil pollution sources. The total exposure to PAHs in vegetables, fruits, and meat products was 18.81 − 66.82 ng/d, 5.69 − 8.62 ng/d, and 0.82 − 2.45 ng/d, respectively. The lifetime incremental carcinogenic risk was 4.20 × 10−7 − 6.41 × 10−6, 1.0 × 10−7 − 7.8 × 10−7, and 1.9 × 10−8 − 2.0 × 10−7, which corresponds to a relatively low−risk level. In comparison, the total exposure of soil and air were 4.15 × 10−7 − 1.54 × 10−6 mg·kg−1·d−1 and 2.71 × 10−6 − 1.40 × 10−5 mg·kg−1·d−1, respectively, and the non−carcinogenic and carcinogenic risk of soil were 3.07 × 10−5 − 1.21 × 10−4 and 1.09 × 10−8 − 3.98 × 10−8, respectively. The carcinogenic risk of air was 8.42 × 10−6 − 4.35 × 10−5, indicating that the risk of cancer is within the acceptable range; however, it cannot be ignored.

Concentrations, Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Vegetables Cultivated in the Environs of Rivers Niger - Benue Lokoja, Nigeria

Concentrations, Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Vegetables Cultivated in the Environs of Rivers Niger - Benue Lokoja, Nigeria

Distribution and health risk assessment on dietary exposure of PAHs in vegetables and fruits of Asir, Saudi Arabia

GC/MS/MS was used to examine quantities, sources, and hazards of polycyclic aromatic hydrocarbons (PAHs) in vegetable, leafy vegetables and fruit samples collected from Asir (Saudi Arabia). PAHs were varied from 10.11 to 604.43 (average 147.04), 38.35–798.21 (average 261.30), and 10.32–204.85 (average 90.65) ng/g, respectively. The order of ∑FPAH (fossil fuel PAHs) was Coriander > Eggplant > Grape, with 763.31, 575.93, and 204.85 ng/g, respectively. However, the order of ∑CARC (carcinogenic PAHs) was Carrot > Pear > Dill with 404.73, 35.91, and 34.01 ng/g, respectively. In addition, the order of ∑COMB (combustion PAHs) was cauliflower > lettuce > banana, with 42.31, 69.62, and 11.61 ng/g, respectively. Generally, the order of different PAH categories was ∑FPAHs > ∑CARC > ∑COMB. The hazard index (HI) for phenanthrene, Pyrene, fluoranthene, and anthracene was 10.73, 2.25, 1.65, and 1.13, respectively, indicating undesirable consequences. Phenanthrene recorded HQ > 1, indicating a probable deleterious effect, and other PAHs recorded HQ of about one, indicating that no harmful health effects from them. The diagnostic ratio of PAHs in fruits and vegetables indicated pyrolytic and petrogenic origins, via incomplete combustion of organic components. Finally, PAHs recorded in our samples were slightly greater than other regions of Saudi Arabia and that recorded in Asian and African countries.

Levels, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in vegetable bases of northwest China.

Dietary consumption of contaminated vegetables is the main route of human exposure to polycyclic aromatic hydrocarbons (PAHs). However, there is a lack of research on PAHs in vegetables from northwest China. In this study, the concentrations, sources, and risk assessment of PAHs in the soil and vegetables of Urumqi, an urbanized city in Xinjiang, China, were investigated. The total concentrations of 16 PAHs in soil and vegetable samples ranged 10.58-77.20 and 93.7-1071.8ng/g, with average values of 2.86 and 242.76ng/g, respectively. Among vegetable samples, the concentrations were in the order: leafy vegetables (299.08ng/g) > fruits (192.65ng/g) > vegetable roots (152.05ng/g). The source apportionment of PAHs was identified using positive matrix factorization. The primary sources of PAHs in soil samples are oil spills, traffic emissions, coal combustion, and coke combustion. The main sources of PAHs in vegetable samples are oil spills and burning of grass, wood, coal, and coke. In soil samples, the ecological risk caused by PAHs is at a safe level, and the incremental lifetime cancer risks (ILCRs) of ingestion exposure exceed 1.0 × 10-6, which will pose potential risks to human body. The ILCRs of vegetable samples revealed that all groups had potential risks from onion and cabbage consumption (ILCRs > 1.0 × 10-6). In particular, adult women had a higher risk of cancer (ILCRs > 1.0 × 10-4). These results emphasize the importance of combating PAHs pollution in vegetable bases.

The analysis and probabilistic health risk assessment of polycyclic aromatic hydrocarbons in vegetables and fruits samples marketed Tehran:Chemometrics

<p>The aim of current study was to evaluate the polycyclic aromatic hydrocarbons (PAHs) concentration and probabilistic health risk in vegetables and fruits samples of Tehran city, Iran during 2018-2019 using magnetic solid-phase extraction (MSPE)and gas chromatography-mass spectrometry(GC-MS).The limit of detection (LOD) and limit of quantitation (LOQ) ranged 0.040-0.084 and 0.121-0.253 μg/kg, respectively. The results showed that the highest PAH levels corresponded to acenaphthene(135.1±7.1µg/kg) and naphthalene (114.1±5.0 µg/kg) , whereas the lowest concentrations were those of Benzo(a)pyrene (not detected), Benzo(k)fluoranthene (not detected), Indeno(l,2,3-cd)pyrene (not detected), Benzo(b)fluoranthene (not detected) and Benzo(g,h,i)perylene (not detected). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to evaluate the correlation between the type and amount of 16 PAHs with vegetables and fruits samples. The results of Monte Carlo Simulation (MCS) revealed that the mean of incremental lifetime cancer risk (ILCR) in vegetables and fruits is 5.2×10-5 and 7.7×10-5higher than the acceptable risk level (10-6). Finally, the highest ILCR in fruits and vegetables was related to cucumber (5.1×10-4) and tomato (4.3×10-4), respectively. Therefore, monitoring the PAHs concentrations in both groups of vegetables and fruits is necessary.</p>

Concentrations and distributions of polycyclic aromatic hydrocarbon in vegetables and animal-based foods before and after grilling: Implication for human exposure.

The effects of grilling on health risks posed by polycyclic aromatic hydrocarbons (PAHs) in food remain poorly understood. The changes of concentrations, distributions, and risks of PAHs in vegetables and animal-based foods before and after grilling were investigated in this study. The sum of 16 (∑16) PAH concentrations in grilled vegetables and grilled animal-based foods were 60.4-1936 and 69.1-4668 ng/g, respectively. Grilling markedly increased the ∑16 PAH concentrations in most foods analyzed. Grilling clearly increased the low-molecular-weight PAH contributions to the ∑16 PAH concentrations in vegetables but increased the heavier PAH contributions to the ∑16 PAH concentrations in some animal-based foods. With the grilling, the total benzo[a]pyrene-equivalent concentrations of the 16 PAHs in Chinese chives and enoki mushrooms and most animal-based foods were improved significantly. Source assessments indicated that environmental sources contributed PAHs to the raw foods and high-temperature pyrolysis during grilling contributed large proportions of the PAHs in the grilled foods. The carcinogenic risks to humans from the exposure of PAHs in vegetables and animal-based foods were estimated. Grilling increased the total risks of PAHs in vegetables and animal-based foods by factors of 3.12 and 5.49, respectively. Total risks of PAHs in the 11 foods were 3.43 times higher when the foods were grilled than when raw. The results suggested that the negative effects of grilling on human health should be of great concern.

Potential Risk Assessment of Selected Polycyclic Aromatic Hydrocarbons in Vegetables Grown in Polluted and Non-polluted Areas of Sindh, Pakistan

Polycyclic Aromatic Hydrocarbons (PAHs) were determined in vegetables grown in Sindh, Pakistan. The vegetables were collected from both local markets and industrial areas where vegetation was carried out. All three types of vegetables, root vegetables, leafy vegetables and fruit vegetables were selected for analysis. The PAHs were extracted by Soxhlet extraction method and analysed by gas chromatography. The results showed that average concentration of PAHs in vegetables was ranged from 1.62±0.01 µg/kg to 144.52±2.51 µg/kg.  From seven PAHs analyzed, the fluorene was found to be present in almost all vegetable samples and was highest in bitter guard that is 144.52±2.51 µg/kg. Like fluorene, naphthalene and anthracene were also present in all the vegetables but their concentration was not very high (6.89±0.03 µg/kg for naphthalene and 2.18±0.01 for anthracene). Higher concentration of PAHs was observed in samples collected from industrial areas due to the fact that industrial smoke could easily be absorbed by the vegetables grown in those areas.

Dissipation of polycyclic aromatic hydrocarbons (PAHs) in soil amended with sewage sludge and sludge compost

In this study, greenhouse experiments were conducted under the condition of different amendment ratios and planting tall fescue (Festuca arundinacea). The amendment ratios of sewage sludge or sludge compost to soil were of 0, 10, 25, and 50% (w/w). The removal rates of PAH, catalase, and dehydrogenase activities of amended soil and accumulation of PAHs by vegetation were detected to investigate the differences of PAH dissipation in sludge-amended and compost-amended soils. The initial PAH concentrations in three amended soils increased with the more addition of sludge or compost. After 126-day experiment, maximum PAH removal rates were observed in sludge-amended and compost-amended soils with PAH concentration of about 200μgkg-1. And the removal of PAHs showed better efficiencies in compost soil rather than in sludge soil. The more catalase activity and dehydrogenase activity of soil were obtained, respectively, in sludge soil and compost soil. The results indicated that the mechanism of PAH dissipation in two types of amended soils were different. The abundant amount of microorganism dominated PAH dissipation in sludge soils, and PAHs dissipated mainly caused of intense activity of microorganism in compost soils. In addition, PAH accumulation in tall fescue suggested that the transference approach of PAHs was from soil to the roots, and then accumulated in the shoots of tall fescue. It was prone to store up more PAHs in vegetation in the condition of high molar weight of PAHs, more biomass of vegetation, and heavy PAH concentration in soil.

Accumulation characteristics and potential risk of PAHs in vegetable system grow in home garden under straw burning condition in Jilin, Northeast China

The accumulation characteristics and potential risk posed by polycyclic aromatic hydrocarbons (PAHs) in soils and vegetables grown in the home garden and agricultural field were investigated in this research. The average concentrations of 16 PAHs in soils and vegetables in the home garden were 508.9 ng/g and 197.3 ng/g, respectively, and in agricultural fields were 589.9 ng/g and 171.3 ng/g, respectively. The 16 PAHs concentrations of vegetables in the home garden were a little higher than in agricultural field. The most abundant PAHs in soils and vegetables was Phe, followed by Fla and Pyr in our study area. The concentrations of low-molecular-weight PAHs (L-PAHs) were higher in vegetables as compared to higher molecular weight 4–6 ring PAHs (H-PAHs). The results of plant concentration factor (PCF) indicated that L-PAHs have greater mobility in our research. Based on the results of PAH ratios, the main sources of the PAHs in soils were determined to be the combustion of biomass, coal, and petroleum. The total values of incremental lifetime cancer risk (ILCR) for males and females induced by soils and vegetables in home garden and agricultural field were all about 10−7 and 10−10. All the ILCRs value were lower than the baseline value, indicated that the carcinogenic risk for the soils and vegetables contaminated with PAHs in our study area for the residents was negligible.

Halogenated and parent polycyclic aromatic hydrocarbons in vegetables: Levels, dietary intakes, and health risk assessments

Halogenated polycyclic aromatic hydrocarbons (HPAHs) are attracting increasing concern because of their greater toxicity than their corresponding parent PAHs. However, human exposure to HPAHs via food consumption is not fully understood. In this study, daily intake via vegetable ingestion of 11 HPAHs and 16 PAHs and subsequent cancer risk were assessed for population in Beijing. A total of 80 vegetable samples were purchased from markets, including five leafy vegetables and three root vegetables. The concentrations of total HPAHs (∑HPAHs) were 0.357–0.874ng/g in all vegetables, lower than that of total PAHs (∑PAHs, 10.6–47.4ng/g). ∑HPAHs and ∑PAHs concentrations in leafy vegetables were higher than those in root vegetables, suggesting that the atmospheric deposition might be the dominant source of PAHs and HPAHs in leafy vegetables. Among the HPAH congeners, 2-BrFle and 9-ClFle were the predominant compounds and frequently detected in the vegetable samples. HPAHs and PAHs were also found in certificated vegetables at the concentrations of 0.466–0.751ng/g and 10.6–38.9ng/g, respectively, which were lower than those in non-certificated vegetables except for spinach. For leafy vegetables from local farms, the ∑PAHs and ∑HPAHs levels in the rape and Chinese cabbage samples significantly decreased with increasing the distance away from the incineration plant. The incremental lifetime cancer risks of HPAHs were below the acceptable risk level (10−6), suggesting that there might be little or no risk to consumers from these compounds in vegetables. For all population groups, children were the most sensitive population to PAHs and HPAHs, and their health issues should be paid more attention.

Determination and risk assessment of sixteen polycyclic aromatic hydrocarbons in vegetables

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are a group of organic environmental pollutants posing a potential risk to human health. This study was constructed to investigate the presence of 16 PAHs in six commonly consumed vegetables collected from the markets in Shandong, China by a quick, easy, cheap, effective, rugged, safe (QuEChERS)-based extraction method coupled with gas chromatography–mass spectrometry (GC–MS). Our results showed that the vegetables were polluted with PAHs at an alarming level, of which celery contained the highest total concentration of PAHs (Σ16 PAH), whereas cucumbers contained the lowest Σ16 PAH. Besides, the dietary exposure of PAHs was assessed in these vegetables based on the maximum Σ16 PAH. The results showed that the populations in Shandong were exposed to 23–213 ng/d of PAHs through these six vegetables, suggesting that vegetables are the major sources of PAHs in the diet. Hence, it is necessary to monitor the PAH levels in vegetables. Our study provides guidance for future legislative actions regarding PAH levels in vegetables in China.

[Concentrations and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soils and Vegetables influenced by Facility Cultivation].

The concentrations, sources, and health risks of 16 United States Environmental Protcction Agency(USEPA) priority polycyclic aromatic hydrocarbons (PAHs) in vegetables (leafy lettuce, amaranth, water spinach, and Shanghai green), in soils inside and outside the vegetable greenhouse, and in wet deposition were investigated by conducting an experiment on facility cultivation. The results showed that the average concentrations of total PAHs in vegetables and soils were 99.27 ng·g-1and 128.01 ng·g-1 in the greenhouse, and 109.11 ng·g-1 and 173.07 ng·g-1 out of the greenhouse. The concentrations of PAHs in the greenhouse were lower than those outside and the high ring-PAHs were lower than the low ring-PAHs both inside and outside. The PAH concentrations in suspended particular matter in dissolved phases of wet deposition were 2986.49 ng·g-1 and 61.9 ng·L-1, respectively. The low rings were easily enriched by the vegetables based on the shoot concentration factors. PAHs in soils and vegetables mainly originated from oil emissions and grass, wood, and coal combustion, while those in suspended particular matter in wet deposition were from petrogenic sources and the combustion of grass, wood, and coal. Petroleum combustion emissions were the main sources of PAHs in dissolved phases. We used the model of incremental lifetime cancer risks to evaluate the health risk of eating these vegetables. There was a potential risk of cancer for both children and adults for all vegetables except amaranth. The carcinogenic risk of vegetables outside the greenhouse was higher than the risk inside. Amaranth had a low carcinogenic risk with the value of incremental lifetime cancer risk lower than 10-6, while the risk of Shanghai green ranged between 10-4 and 10-6.

Composite of PAH-degrading endophytic bacteria reduces contamination and health risks caused by PAHs in vegetables

Vegetables accumulate polycyclic aromatic hydrocarbons (PAHs) at high concentrations when grown in contaminated sites. Inoculation with PAH-degrading endophytic bacteria (EBPAH) has been recognized as one of the most promising ways to remove PAHs from plant bodies; however, the performance of single endophytic bacteria is generally limited. This investigation used a composite of eight EBPAH to reduce the contamination and health risk posed by 16 EPA priority PAHs in vegetables including Chinese cabbage (Brassica chinensis L.) and pakchoi (Brassica campestris L.). Composite EBPAH have strong PAH degradation abilities, and more than 65% of ∑PAH were degraded after 10-day insuspension with composite EBPAH. Vegetable were contacted with composite EBPAH by seed soaking (SS) and leaf painting (LP) with an EBPAH cell incubation at OD600nm=0.2–1.5. Compared with those in non-inoculated controls, the ∑PAH concentrations in edible parts of Chinese cabbage and pakchoi colonized by composite EBPAH via SS and LP with bacterial suspension at OD600nm=0.2–1.5 were 42.07–70.77% and 15.79–53.20% lower, and the incremental lifetime cancer risk (ILCR) values for males and females were 31.78–84.08% and 26.60–83.40% smaller, respectively. SS was the optimal inoculation method for reducing PAH concentrations and ILCR values. Our results indicate that inoculating plants with composite EBPAH can lower the health risk posed by vegetables contaminated with PAHs, and may be used to mitigate plant PAH contamination.

Contamination, source identification, and risk assessment of polycyclic aromatic hydrocarbons in the soils of vegetable greenhouses in Shandong, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed in soil (n=196) and vegetable (n=30) collected from greenhouses, and also in the soil (n=27) collected from agriculture fields close to the greenhouses in Shandong Province, China. The total PAH concentration (∑16PAH) ranged from 152.2µg/kg to 1317.7µg/kg, within the moderate range in agricultural soils of China. Three-ring PAHs were the dominant species, with Phe (16.3%), Ace (13.1%), and Fl (10.5%) as the major compounds. The concentrations of low molecular weight (LMW ≤3 rings) PAHs were high in the east and north of Shandong, while the concentrations of high molecular weight (HMW ≥4 rings) PAHs were high in the south and west of the study area. The PAH level in soils in industrial areas (IN) was higher than those in transport areas (TR) and rural areas (RR). No significant difference in concentration of ∑16PAH and composition was observed in soils of vegetable greenhouses and field soils. PAH concentration exhibited a weakly positive correlation with alkaline nitrogen, available phosphorus in soil, but a weakly negative correlation with soil pH. However, no obvious correlation was observed between PAH concentration and organic matter of soil, or ages of vegetable greenhouses. ∑16PAH in vegetables ranged from 89.9µg/kg to 489.4µg/kg, and LMW PAHs in vegetables positively correlated with those in soils. The sources of PAHs were identified and quantitatively assessed through positive matrix factorization. The main source of PAHs in RR was coal combustion, while the source was traffic in TR and IN. Moreover, petroleum source, coke source, biomass combustion, or mixed sources also contributed to PAH pollution. According to Canadian soil quality guidelines, exposure to greenhouse soils in Shandong posed no risk to human health.

Spatial And Temporal Trends Of Organic Pollutants In Vegetation From Remote And Rural Areas.

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) used in agricultural, industrial, and domestic applications are widely distributed and bioaccumulate in food webs, causing adverse effects to the biosphere. A review of published data for 1977–2015 for a wide range of vegetation around the globe indicates an extensive load of pollutants in vegetation. On a global perspective, the accumulation of POPs and PAHs in vegetation depends on the industrialization history across continents and distance to emission sources, beyond organism type and climatic variables. International regulations initially reduced the concentrations of POPs in vegetation in rural areas, but concentrations of HCB, HCHs, and DDTs at remote sites did not decrease or even increased over time, pointing to a remobilization of POPs from source areas to remote sites. The concentrations of compounds currently in use, PBDEs and PAHs, are still increasing in vegetation. Differential congener specific accumulation is mostly determined by continent—in accordance to the different regulations of HCHs, PCBs and PBDEs in different countries—and by plant type (PAHs). These results support a concerning general accumulation of toxic pollutants in most ecosystems of the globe that for some compounds is still far from being mitigated in the near future.

Distribution and Health Risk Assessment on Dietary Exposure of Polycyclic Aromatic Hydrocarbons in Vegetables in Nanjing, China

In a market basket study made in Nanjing, China, in which the most common consumed nine kinds of vegetables foodstuffs were sampled, the contents of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed using gas chromatography with mass spectrometer detector (GC-MS). The results showed that the total amount of 16 PAHs was within the range of 60.5~312 ng g−1 (wet weight). The ranking of total concentrations for different types of vegetables in decreasing order was leafy vegetable, fruit vegetable, and rhizome vegetable. Source analysis suggested that coal, oil, or other incomplete combustion of biomass mainly contributed to the concentration of PAHs. The margin of exposure (MOE) approach with age/gender group-specific daily dietary exposure level was used to estimate the carcinogenic risk. The calculated total mean MOE in the case of BaP and PAH4 (sum of BaA, CHR, BbF, and BaP) was 14960 and 7723, respectively, for local residents. In addition, the MOEs in PAH4 for some groups of both male and female were below the critical limit of 10 000 proposed by EFSA. Therefore, health effect owing to the consumption of vegetables on local residents needs high concern.

Effects of Composted Sewage Sludge on Soil Properties and Vegetable Quality from Abandoned Quarries

The effects of composted sewage sludge on soil properties and vegetable quality were investigated in a field experiment for two years. The soil was amended with 3, 15 or 30 t/ha of compost. The results indicated that the vegetable net production increased with the amendment dosage of 3 and 15 t/ha, while the net production decreased in the application amount of 30 t/ha. However, the Vitamin C (Vc) content of the three vegetables was reverse. The heavy metals concentrations in vegetables and soils could meet the national food and soil environmental quality standards of China (II). The accumulation concentrations of Cd, As and Hg in the three vegetables increased with the increasing amendment dosage, while the concentrations of Cr and Pb changed significantly with different types of vegetable. Heavy metal accumulation ability was in the order of celery > lettuce > cabbage, except for Cr. The accumulation of different heavy metals in soil was related to the migration characteristic of heavy metals, plant absorption capacities and the amendment dosage. The concentration of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the soils increased with addition of 15 t/ha and 30 t/ha, while the change was not statistically significant between the amendment of 3 t/ha and the control. The concentration of PCBs and PAHs in vegetables was positively correlated with compost addition amounts. The dissipation rate of PCBs and PAHs followed the principle of first-order kinetics, and vegetables could improve the dissipation rate. Therefore, the application of compost as soil amendment to abandoned quarries is a feasible strategy for sludge disposal because appropriate amount of compost could enhance the soil fertility, while the long-term application should be considered seriously.

Accumulation, allocation, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soil-Brassica chinensis system.

Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs) in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi’an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA), rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 μg/kg d.w., with an average of 41 μg/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1×10−6). The concentration of total PAHs was (1052±73) μg/kg d.w. in vegetation (mean±standard error). The cancer risks posed by ingestion of vegetation ranged from 2×10−5 to 2×10−4 with an average of 1.66×10−4, which was higher than international excess lifetime risk limits for carcinogens (1×10−4). The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil) increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation.

Determination of Polycyclic Aromatic Hydrocarbons and Halogenated Polycyclic Aromatic Hydrocarbons in Vegetable by Gas Chromatography-Tandem Mass Spectrometry

建立了同时检测蔬菜中16种多环芳烃（PAHs）和11种卤代多环芳烃（X-PAHs）污染水平的分散固相萃取-气相色谱-串联质谱（GC-MS/MS）分析方法。样品中的多环芳烃和卤代多环芳烃经正己烷提取,N-丙基乙二胺吸附剂（PSA）和十八烷基键合硅胶吸附剂（C18）分散固相萃取净化剂净化,气相色谱-串联质谱方法测定,外标法定量。16种PAHs和11种X-PAHs在50,100和200μg/kg添加浓度下的回收率为74.7%～115.1%,相对标准偏差为1.6%～15.3%,方法检出限为0.03～7.4μg/kg。

In situ Determination of Phenanthrene Adsorbed onto Surface of Mangrove Leaves Using a Laser-Induced Nanosecond Time-Resolved Fluorescence System

Developing new methods for in situ determination of polycyclic aromatic hydrocarbons(PAHs) in plant leaves is of great significance to further achieve the field detection of PAHs in actual leaf samples.A set of laser-induced nanosecond time-resolved fluorescence(LITRF) system was employed to complete the in situ quantitative determination of the phenanthrene(Phe) that was adsorbed onto the leaf surfaces of three kinds of mangrove species,named Kandelia obovata(Ko),Bruguiera gymnorhiza(Bg) and Aegiceras corniculatum(Ac).Experimental results showed that the linear dynamic ranges for the in situ determination of the Phe that was adsorbed onto the leaf surfaces of Ko,Bg and Ac were 2-1400 ng/spot,1-1000 ng/spot and 4-2000 ng/spot,with the detection limits of 0.20,0.14 and 0.42 ng/spot,respectively.The relative standard deviations were less than 6.0%(n=9).The experimental recoveries for the Phe in Ko,Bg,and Ac were 89.6%-108.1%,78.2%-92.4% and 93.2%-112.9%,respectively.Satisfactory results were obtained for the in situ determination of the Phe that was adsorbed onto the surfaces of the lab-exposure mangrove leaf samples contaminated by the Phe.The sensitivity of the established method was much higher than that of the previously established fiber optical fluorimetry,and the linear dynamic range got improved.The LITRF method marked a significant step toward realizing the field detection of PAHs in vegetation.