Vegetable fields have a high risk of heavy metal contamination from pollution sources in suburban and industrial areas of cities. Eighty-seven soil samples, 106 leafy vegetables and 48 road dust ...samples were collected from industrial areas of Shanghai, China. We studied the levels of heavy metals, health risk through consumption of leafy vegetables, and sources of Pb in soils, road dust and leafy vegetables. Soil Cd, Zn, Pb, Cu, Hg and As concentrations exceeded the soil background values in 73.6%, 97.7%, 52.3%, 37.8%, 95.1% and 20.2% soil samples, respectively, but were below the criteria for agricultural soil in China, with the exception of Hg. The concentrations of Cd, Zn, Pb, Cu and As in road dust were significantly higher than concentrations in soils, while Hg concentration in road dust was lower. Cd, Zn, Pb, Hg and Cu concentrations in soils and Zn, Pb and Cu concentrations in road dust were greatest near the municipal solid waste incineration power plant. Heavy metal concentrations in the edible tissues of vegetables were not correlated with their total values in soils and varied among vegetable species. The trends in transfer factors (TFs) in different vegetables were Cd>Zn>Cu>As>Hg>Pb. There was low health risk from heavy metal exposure by consumption of vegetables based on Hazard Quotients (HQM): As was the major contributor to HQM, followed by Cd and Pb. Parent material of the Yangtze River Estuary was the major source of Pb in soils, while coal-fired, stationary industrial emissions and municipal waste incineration emissions were the major sources of Pb in dust and vegetables based on use of the lead isotopic tracing method. Accumulation of Pb in leafy vegetables was through foliar uptake and directly related to atmospheric Pb.
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•Hg in soils and Zn and Cu in road dust were present at relatively high levels.•There was low health risk by consumption of vegetables.•Industrial and combustion emissions were the major sources of Pb in dust and vegetables.•Pb in leafy vegetables was mainly through foliar uptake.
A detailed investigation was conducted to understand the contamination characteristics of a selected set of potentially toxic metals in Shanghai. The amount of Pb, Zn, Cu, Cr, Cd and Ni were ...determined from 273 soil/dust samples collected within urban area. The results indicated that concentration of all metals except Ni in soils was significant, and metal pollution was even severer in roadside dust. A series of metal spatial distribution maps were created through geostatistical analysis, and the pollution hotspots tended to associate with city core area, major road junctions, and the regions close to industrial zones. In attempt of identifying the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Pb, Zn and Cu mainly originated from traffic contaminants; soil Ni was associated with natural concentration; Cd largely came from point-sourced industrial pollution; and Cr, Ni in dust were mainly related to atmospheric deposition.
Human activities have led to high accumulation of potentially toxic metals in urban soils and roadside dust of Shanghai.
Urban and suburban road dust samples were collected in the most populated city of China, Shanghai. Size fractions of dust particles were analyzed; metal levels of the dust were also measured. Human ...exposure to individual toxic metals through road dust was assessed for both children and adults. The results showed that dust particles from urban and suburban road were presented similar size distribution pattern, with most particles in the range of 100–400
μm. Urban road dust consisted of higher proportions of inhalable, thoracic and respirable particles with increased risk of adverse effects to human. In general, mean grain sizes of urban road dust were smaller than suburban dust. Total organic carbon contents and levels of Pb, Cd, Cu, Zn, Ni, Cr in urban dust were higher than those of suburban dust. But the concentrations of As and Hg from suburban dust were higher, indicting a different main source. The exposure pathway which resulted in the highest level of risk for human exposed to road dust was ingestion of this material, which was followed by dermal contact. Except for some locations, risk values of both cancer and non-cancer obtained in this study were in the receivable range on the whole. Children had greater health risks than adults. The overall risks of non-cancer in urban area were higher than those in suburban area, but the values of cancer in the two areas were comparable. As for the aggregate noncarcinogenic risk, Pb was of most concern regarding the potential occurrence of health impacts. Of the three carcinogenic metals As, Cr and Cd, the only mean risk higher than 10
−6 was Cr, accounting for a great percentage (95%) of the overall risk of cancer. Hence, potentially adverse health effects arising from Pb and Cr in road dust should arouse wide concern.
The distribution, sources, and potential risks of polychlorinated biphenyl （PCB） contamination in the rivers of Shanghai, China were investigated. Fourteen PCB congeners in surface waters and ...sediments, which were collected from 53 sampling sites, were quantified by gas chromatography-mass spectrometer （GC-MS）. The total concentrations of PCBs in the dissolved phase, in particulates, and in sediments ranged from not detected （nd） to 34.8 ng.L^-1, from 0.76 to 39.71 ng.L^-1, and from 1.46 to 46.11 ng.g^-1 （dry weight, dw）, respectively. The corresponding WHO toxic equivalents （TEQs） of dioxin-like polychlorinated biphenyls （dl-PCBs） ranged between nd-1135.63 pg TEQ-L^-1, 0.02-605.94 pg TEQ.L^-1, and 0.05-432.12 pg TEQ-g^-1 dw, respectively. Thepenta-CBs, especially PCB 118 and PCB 105, were the dominant congeners in all samples. Principle Component Analysis （PCA） indicated that the PCBs were mainly influenced by a historical accumulation of commercial PCB products, the burning of house coal, and emissions from municipal solid waste incineration （MSWI） and secondary metallurgy industries. The center of Shanghai was significantly affected by PCB contamination, followed by the industrial parklands and suburban towns, while the farmland of Chongming Island was the least affected area. Adverse biological and health effects would be likely in the central urban areas, industrial parks, and residential towns of Shanghai.
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•Concentrations and spatial distribution of HMs in the river network were influenced by intensive land use.•AVS and TOC in river sediments influenced the migration and transformation ...of Cd, Hg and Zn.•Hg and Cd were the main contributors of RI, HMs in the central city area showed the highest potential ecological risk.•HMs in the river network primarily originated from industrial activities, traffic emissions and coal-burning emissions.
Heavy metal pollution characteristics in the urbanized river network are closely related to urban land use. The existing studies mainly focused on the pollution characteristics of heavy metals in single rivers, but fewer studies reported the impact of land use on the concentrations and ecological risks of heavy metals in surface water and sediments of the urban river network. This study combined land use types with heavy metal pollution in rivers, and explored the specific impact of intensive land use on the characteristics of heavy metal pollution in rivers, which provided scientific basis for the study of heavy metal pollution in plain river networks. The concentrations, spatial variations and potential ecological risk levels of cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) in surface water and sediments from five different intensive land use areas of Shanghai river network (industrial areas, agricultural areas, central city, suburban towns and Chongming Island) were analyzed. Results showed the concentrations of Cd, Cr, Cu, Pb and Zn in surface water of the Shanghai river network were relatively low, but Hg pollution existed in some rivers. Influenced by intensive land use, heavy metal concentrations in the central city were generally higher than those in other areas. Heavy metals in sediments had considerable ecological risk, in which Hg and Cd were the main contributors, and showed the highest potential ecological risk in central city. Acid volatile sulfides (AVS) and total organic carbon (TOC) in river sediments affected the migration and transformation of Cd, Hg and Zn. Industrial activities, traffic emissions and coal-burning emissions were the main sources of heavy metals. Intensive land use caused by anthropogenic activities led to the weakening of hydrodynamic conditions and the discharge of a large number of pollutants into the river network. In the central city with intensive anthropogenic activities, heavy metals in the river network showed higher levels than those in other areas. This study found that intensive land use and high-intensity anthropogenic activities led to the high pollution level of heavy metals in the plain urbanized river networks. Quantitative analyses of the effects of intensive land use on heavy metal pollution in urbanized river networks were suggested to conduct further to protect the urban river water quality.
Experimental and computational simulations are conducted to assess the atmospheric gaseous deposition of polycyclic aromatic hydrocarbons (PAHs) and their uptake by four leafy vegetables (spinach, ...Chinese cabbage, Shanghai green cabbage, and romaine) during their growth in a greenhouse located in Shanghai. Sixteen individual PAHs on the US EPA priority list were measured in the aerials and roots of vegetables, air (both gas- and particle-phase), settled dust, and soil samples. Results showed that 2–3 ring PAHs were similarly dominant in the vegetable leaves, roots and airborne gas phase. However, 4–6 ring PAHs were dominant in the soils, dust, and airborne particle phase. Results also showed that the PAH concentrations in the vegetables were highest during the middle of the growth period. Both phenanthrene and anthracene in the vegetables had a significant positive correlation with chlorophyll-a and chlorophyll-b, indicating that the growth process influenced PAH concentrations in the vegetables. Furthermore, increasing dust-fall doses promoted PAH accumulation in Shanghai green cabbage and romaine, but inhibited PAH uptake in spinach and Chinese cabbage. Analyses using multivariate regressions and physical models found that gas-phase PAH absorption and soil absorption contributed to 90.6% and 9.4% of total PAH vegetable uptake, respectively. Although PAHs in the air were the dominant contributor to the total uptake, 13.2% of gas-phase PAHs resulted from soil volatilization. Atmospheric dust fall contributed to PAH uptake indirectly by increasing soil PAH concentrations. In addition, PAH uptake by vegetables via the air-shoot pathway displayed higher toxicity than the other pathways. This study provides a quantitative assessment of the pathways through which atmospheric PAHs lead to PAH contamination in a sample of commonly eaten leafy vegetables.
•The growth process influenced PAH concentrations in the vegetables.•Increasing dust-fall doses have different effects on different vegetables.•Gas-phase PAH absorption contributed to 90.6% of total PAH vegetable uptake.•Soil PAH absorption contributed to 9.4% of total PAH vegetable uptake.•PAH from soil evaporation contributed to 13.2% of the total air PAH concentrations.
The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) in urbanized river networks are strongly influenced by intensive land use, industrial activities and population density. ...The spatial variations and their influencing factors of 16 priority PAHs were investigated in surface water, suspended particulate matter (SPM) and sediments among areas under different intensive land uses (industrial areas, agricultural areas, inner city, suburban towns and island areas) in the Shanghai river network, East China. Source apportionment was carried out using isomer ratios of PAHs and Positive Matrix Factorization (PMF). Total concentrations of 16 PAHs ranged from 105.2 to 400.5 ng/L, 108.1 to 1058.8 ng/L and 104.4 to 19,480.0 ng/g in water, SPM and sediments, respectively. The concentrations of PAHs in SPM and sediments varied significantly among areas (p < 0.05), with the highest concentrations in inner city characterized by highly intensive land use and high population density. The PAH concentrations in sediments were positively correlated with those in SPM and were more strongly correlated with black carbon than with total organic carbon, indicating a stronger influence of prolonged anthropogenic contamination than the recent surface input in sediments. Biomass and coal combustion contributed strongly to total PAHs, followed by natural gas combustion in water and SPM, and vehicular emissions in sediments. Vehicular emissions were the strongest contributors in SPM and sediments of the inner city, indicating the strong influence of vehicular transportation to PAHs pollution in the urbanized river network.
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•PAHs were analyzed in water, SPM and sediments of Shanghai river network.•PAHs in SPM and sediments showed the highest concentrations in inner city.•Main factors affecting the partitioning and spatial variations of PAHs were analyzed.•Vehicle emissions in the urbanized and industrialized areas contributed strongly to PAHs.
Dietary consumption of contaminated vegetables may contribute to polycyclic aromatic hydrocarbon (PAH) exposure in humans; however, this exposure pathway has not been examined thoroughly. This study ...aims to characterize the concentrations of PAHs in six types of vegetables grown near industrial facilities in Shanghai, China. We analyzed 16 individual PAHs on the US EPA priority list, and the total concentration in vegetables ranged from 65.7 to 458.0 ng g−1 in the following order: leafy vegetables (romaine lettuce, Chinese cabbage and Shanghai green cabbage) > stem vegetables (lettuce) > seed and pod vegetables (broad bean) > rhizome vegetables (daikon). Vegetable species, wind direction, and local anthropogenic emissions were determinants of PAH concentrations in the edible part of the vegetable. Using isomer ratios and principal component analysis, PAHs in the vegetables were determined to be mainly from coal and wood combustion. The sources of PAHs in the six types of vegetables varied. Daily ingestion of PAHs due to dietary consumption of these vegetables ranged from 0.71 to 14.06 ng d−1 kg−1, with contributions from Chinese cabbage > broad bean > romaine > Shanghai green cabbage > lettuce > daikon. The daily intake doses adjusted by body weight in children were higher than those in teenagers and adults. Moreover, in adults, higher concentrations of PAHs were found in females than in males. For individuals of different age and gender, the incremental lifetime cancer risks (ILCRs) from consuming these six vegetables ranged from 4.47 × 10−7 to 6.39 × 10−5. Most were higher than the acceptable risk level of 1 × 10−6. Our findings demonstrate that planting vegetables near industrial facilities may pose potential cancer risks to those who consume the vegetables.
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•The 16 PAHs showed the highest concentrations in leafy vegetables.•Vegetable species and wind direction were all determinants of PAH concentrations.•Main sources of PAHs contributed differently to PAHs levels in different vegetables.•Female adult had the highest risks associated with carcinogenic PAHs in vegetables.
Daily dietary intake of PAHs from vegetables growing near industrial facilities can pose cancer risk; cancer risk was higher in children and female adults.
The environmental quality of heavy metals （Pb, Cd, Cr, As, Hg） in agricultural surface soil of Chongming Island was assessed by national, local and professional standards based on a large scale ...investigation, in which 28 samples from vegetable plots, 65 samples from paddy fields and 9 samples from watermelon fields were collected from whole island area. Results showed that the average concentration of Pb, Cd, Cr, As and Hg was 21.6 mg.kg^-l,0.176 mg.kg^-1, 69.4 mg.kg^-1, 9.209 mg.kg^-1 and 0.128 mg.kg^-1, respectively. Compared with the background value of Shanghai City soil, except for Pb and Cr, all the other heavy metals average concentrations in Chongming Island agricultural surface soil exceeded their corresponding natural-background values. The concentrations of Cd, As and Hg were 33.0%, 1.2% and 26.3% higher than the background value of Shanghai City, respectively. In addition, inverse distance interpolation （IDW） tool of GIS was also applied to study the spatial variation of heavy metals. The results indicated that most of agricultural soil quality was good, and the ratio of ecological, good soil, certified soil and disqualified soil were 1.26%, 97.1%, 1.47% and 0.12%, respectively. About 10.1%, 85.7%, 27.0%, 55.4% and 55.2% soil samples exceeded the Pb, Cd, Cr, As and Hg background value of Shanghai City, respectively. Among these three land use type soils, vegetable soil was most seriously polluted by heavy metals, which is probably related to the over-application of pesticides. The annual deposition fluxes of Pb, Cd, As and Hg were 7736μg·m^-2·a^-1, 208μg·m^-2·a^-1, 2238μg·m^-2·a^-1 and 52.8 μg·m^-2·a^-1 respectively. Crop straw burning was the important source of heavy metals of atmospheric deposition, and atmospheric deposition contributed a lot to heavy metals in agricultural soil in Chongming Island.
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