Pollution and health risk of potentially toxic metals in urban road dust in Nanjing, a mega-city of China

Risk assessment of exposure to particulate output of a demolition site

Whilst vehicular and industrial contributions to the airborne particulate budget are well explored, the input due to building demolition is relatively unknown. Air quality is of importance to human health, and it is well known that composition of airborne particles can have a significant influence on both chronic and acute health effects. Road dust (RD) was collected before and after the demolition of a large building to elucidate changes in elemental profile. Rainfall and PM10 mass concentration data aided interpretation of the elemental data. Quantification of Al, As, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Rh, S, Si, Sn, Ti, V and Zn was carried out. It was found that only Al, K, Mg, Si and S increased in concentration across all size fractions after the building demolition. Risk assessment was then carried out on elements with applicable reference dose values to assess the potential health risks due to the demolition. Significant risk to children was observed for chromium and aluminium exposure. PM10, monitored 40 metres from the demolition site, indicated no abnormal concentrations during the demolition; however, rainfall data were shown to affect the concentration of PM10. The elemental data observed in this study could possibly indicate the role of increased sulphur concentrations (in this case as a result of the demolition) on the buffer capacity of RD, hence leaching metals into rainwater.

Single Exposure to near Roadway Particulate Matter Leads to Confined Inflammatory and Defense Responses: Possible Role of Metals

Inhalation of traffic-associated atmospheric particulate matter (PM2.5) is recognized as a significant health risk. In this study, we focused on a single ("subclinical response") exposure to water-soluble extracts from PM collected at a roadside site in a major European city to elucidate potential components that drive pulmonary inflammatory, oxidative, and defense mechanisms and their systemic impacts. Intratracheal instillation (IT) of the aqueous extracts induced a 24 h inflammatory response characterized by increased broncho-alveolar lavage fluid (BALF) cells and cytokines (IL-6 and TNF-α), increased reactive oxygen species production, but insignificant lipids and proteins oxidation adducts in mouse lungs. This local response was largely self-resolved by 48 h, suggesting that it could represent a subclinical response to everyday-level exposure. Removal of soluble metals by chelation markedly diminished the pulmonary PM-mediated response. An artificial metal solution (MS) recapitulated the PM extract response. The self-resolving nature of the response is associated with activating defense mechanisms (increased levels of catalase and glutathione peroxidase expression), observed with both PM extract and MS. In conclusion, metals present in PM collected near roadways are largely responsible for the observed transient local pulmonary inflammation and oxidative stress. Simultaneous activation of the antioxidant defense response may protect against oxidative damage.

Spatial distribution and health risk assessment of toxic metals associated with receptor population density in street dust: a case study of Xiandao District, Changsha, Middle China

Spatial characteristics of the properties (dust organic material and pH), concentrations, and enrichment levels of toxic metals (Ni, Hg, Mn and As) in street dust from Xiandao District (Middle China) were investigated. Method of incorporating receptor population density into noncarcinogenic health risk assessment based on local land use map and geostatistics was developed to identify their priority pollutants/regions of concern. Mean enrichment factors of studied metals decreased in the order of Hg ≈ As > Mn > Ni. For noncarcinogenic effects, the exposure pathway which resulted in the highest levels of exposure risk for children and adults was ingestion except Hg (inhalation of vapors), followed by dermal contact and inhalation. Hazard indexes (HIs) for As, Hg, Mn, and Ni to children and adults revealed the following order: As > Hg > Mn > Ni. Mean HI for As exceeded safe level (1) for children, and the maximum HI (0.99) for Hg was most approached the safe level. Priority regions of concern were indentified in A region at each residential population density and the areas of B at high and moderate residential population density for As and the high residential density area within A region for Hg, respectively. The developed method was proved useful due to its improvement on previous study for making the priority areas of environmental management spatially hierarchical and thus reducing the probability of excessive environmental management.

Residents health risk of Pb, Cd and Cu exposure to street dust based on different particle sizes around zinc smelting plant, Northeast of China

The residents health risk of Pb, Cd and Cu exposure to street dust with different particle sizes (<100 and <63 μm) near Huludao Zinc Plant (HZP) was investigated in this study. The average concentrations of Pb, Cd and Cu in the <100-μm and <63-μm dust were 1,559, 178.5, 917.9 and 2,099, 198.4, 1,038 mg kg(-1), respectively. It showed that smaller particles tended to contain higher element concentrations. Metals in dust around HZP decreased gradually from the zinc smelter to west and east directions. There was significantly positive correlation among Pb, Cd and Cu in street dust with different particle sizes. The contents of Pb, Cd and Cu in dust increased with decreasing pH or increasing organic matter. Non-carcinogenic health risk assessment showed that the health index (HI) for children and adult exposed to <63-μm particles were higher than exposed to <100-μm particles, which indicated that smaller particles tend to have higher non-carcinogenic health risk. Non-carcinogenic risk of Pb was the highest in both particle sizes, followed by Cd and Cu. HI for Pb and Cd in both particle sizes for children had exceeded the acceptable value, indicated that children living around HZP were experiencing the non-carcinogenic health risk from Pb and Cd exposure to street dust.

Contamination and risk assessment of metals in road-deposited sediments in a medium-sized city of China

Road-deposited sediment (RDS) is a valuable environmental medium for characterizing contamination of metals in urban areas and the associated risks to human health. A total of 62 RDS samples were collected for metal test in four urban areas in a medium size city in eastern China. The areas that represented different land uses consisted of intense traffic area (ITA), commercial area (CA), residential area (RA), and riverside park area (RPA). The effects of particle size and different land uses on metal contamination and health risk were the major focus in this study. The test results showed that RDS in ITA appeared to have higher metal content, enrichment factor (EF), ecological risk index (RI), and the non-cancer and cancer risks than in the other areas. The metal contamination and health risk increased inversely with particle size. The particles less than 63 μm were found to be most critical in development of metal contamination and health risk. The EF was measured to be greater than 2.0 in the four areas, indicating a moderate enrichment. The measured RI ranged between 50 and 200, indicating considerable to moderate risks. The non-cancer risk for children was high in the four areas but was low for adults in all test areas except in ITA. The cancer risk of Cr for children was high in all test areas. Based on the test results, the contamination control and management for metals in RDS shall focus on the effects from such factors as particles (<63 μm) and the land use for intense traffic (ITA).

Ecological and human health hazards of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in road dust of Isfahan metropolis, Iran

This study investigates trace elements and PAHs content in road dust of Isfahan metropolis, central Iran. The mean concentrations of As, Cd, Cu, Ni, Pb, Sb and Zn are 22.15, 2.14, 182.26, 66.63, 393.33, 6.95 and 707.19 mg kg(-1), respectively. When compared with upper continental crust, the samples generally display elevated trace element concentrations, except for Co and Cr. The decreasing trend of calculated enrichment factors (EFs) is Cd>Pb>Sb>Zn>Cu>As>Ni>Cr>Co. Calculated potential ecological risk reveals that among the analyzed metals, Cd and Pb, have a higher potential ecological risk. Statistically, two identified main sources of trace elements include road traffic emissions and resuspension of soil particles. As, Cd, Cu, Pb, Sb and Zn in Isfahan road dust are strongly influenced by anthropogenic activity, mainly traffic emissions, while Co, Cr and Ni originate from resuspension of soil natural parent particles. The sum of 13 major PAHs (∑13PAHs) mass concentration ranges from 184.64 to 3221.72 μg kg(-1) with the mean being 1074.58 μg kg(-1). PAHs sources are identified using PCA analysis. It is demonstrated that the PAHs in Isfahan road dust are mainly derived from traffic emission, coal combustion and petroleum. Toxic equivalent concentrations (TEQs) of PAHs in the road dust ranges between 25.021 μg kg(-1) and 230.893 μg kg(-1). High correlation coefficients (r(2)=0.909 and 0.822, p<0.01) between Benzo[a]pyrene, Benzo[b+k]fluoranthene and toxicity equivalent concentrations of road dust indicate that Benzo[a]pyrene and Benzo[b+k]fluoranthenes are major TEQ contributors. The total incremental life time cancer risk (ILCR) of exposure to PAHs from Isfahan metropolis urban dust is 4.85 × 10(-4) for adult and 5.02 × 10(-4) for children. Estimated results of ILCR indicate that Isfahan residents are potentially exposed to high cancer risk via both dust ingestion and dermal contact.

Metal status in human endometrium: relation to cigarette smoking and histological lesions

Human endometrium is a thick, blood vessel-rich, glandular tissue which undergoes cyclic changes and is potentially sensitive to the various endogenous and exogenous compounds supplied via the hematogenous route. As recently indicated, several metals including Cd, Pb, Cr and Ni represent an emerging class of potential metalloestrogens and can be implicated in alterations of the female reproductive system including endometriosis and cancer. In the present study, we investigated the content of five metals: Cd, Cr, Ni, Pb and Zn in 25 samples of human endometrium collected from Polish females undergoing diagnostic or therapeutic curettage of the uterine cavity. The overall mean metal concentration (analyzed using microwave induced plasma atomic emission spectrometry MIP-OES) decreased in the following order: Cr>Pb>Zn>Ni>Cd. For the first time it was demonstrated that cigarette smoking significantly increases the endometrial content of Cd and Pb. Concentration of these metals was also positively correlated with years of smoking and the number of smoked cigarettes. Tissue samples with recognized histologic lesions (simple hyperplasia, polyposis and atrophy) were characterized by a 2-fold higher Cd level. No relation between the age of the women and metal content was found. Our study shows that human endometrium can be a potential target of metal accumulation within the human body. Quantitative analyses of endometrial metal content could serve as an additional indicator of potential impairments of the menstrual cycle and fertility.