[Pollution Levels and Risk Assessment of Heavy Metals from Atmospheric Deposition in Nanjing].

In order to evaluate the pollution levels of and risk from heavy metals in the atmospheric deposition of different functional urban districts, dust samples were collected from 20 sampling sites in typical industrial, traffic, residential, and educational districts of Nanjing. The concentrations of As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Ti, V, and Zn were analyzed. The potential ecological risk and health risk were evaluated using the potential ecological risk index and U.S. EPA's health risk assessment models. Enrichment factors, correlation analysis, and principal component analysis were used to analyze the sources of heavy metals. Results showed that the concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn were the highest in the industrial district and the concentrations of Ba, Ni, Ti, and V were the highest in the traffic district. The value of the potential ecological risk index was the highest in the industrial district and lowest in the educational district. Meanwhile, the ecological risk of Cr was the highest, achieving a moderate ecological hazard level. None of the studied heavy metals had noncarcinogenic risk or carcinogenic risk, according to the results of health risk assessment. Source analysis indicated that heavy metals in the atmospheric deposition from the study areas were mainly from traffic and industrial activities, coal combustion, natural process and life sources.

Use of portable X-ray fluorescence spectroscopy and geostatistics for health risk assessment.

Laboratory analysis of trace metals using inductively coupled plasma (ICP) spectroscopy is not cost effective, and the complex spatial distribution of soil trace metals makes their spatial analysis and prediction problematic. Thus, for the health risk assessment of exposure to trace metals in soils, portable X-ray fluorescence (PXRF) spectroscopy was used to replace ICP spectroscopy for metal analysis, and robust geostatistical methods were used to identify spatial outliers in trace metal concentrations and to map trace metal distributions. A case study was carried out around an industrial area in Nanjing, China. The results showed that PXRF spectroscopy provided results for trace metal (Cu, Ni, Pb and Zn) levels comparable to ICP spectroscopy. The results of the health risk assessment showed that Ni posed a higher non-carcinogenic risk than Cu, Pb and Zn, indicating a higher priority of concern than the other elements. Sampling locations associated with adverse health effects were identified as 'hotspots', and high-risk areas were delineated from risk maps. These 'hotspots' and high-risk areas were in close proximity to and downwind from petrochemical plants, indicating the dominant role of industrial activities as the major sources of trace metals in soils. The approach used in this study could be adopted as a cost-effective methodology for screening 'hotspots' and priority areas of concern for cost-efficient health risk management.

Assessment of coronary artery by prospective ECG-triggered 256 multi-slice CT on children with congenital heart disease.

This study aims to investigate the imaging quality and radiation dose of prospective ECG-triggered 256 multi-slice computer tomography (MSCT) in accessing the coronary artery (CA) in children. Coronary arteries of 149 children were evaluated using prospective ECG-triggered 256 MSCT with the same system settings. A four-point scoring system was applied to study the capability of MSCT in detecting CA in these patients. Signal, noise and contrast-to-noise ratios (CNR) were analyzed to investigate the association of image quality with age. Then, volumetric CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) were utilized to study the association of radiation dose with age. The detection rate for original, proximal, middle, distal and the 11 segments of CA was 100, 97, 92, 81 and 92%, respectively; and there was no influence on age during the detection (all, P < 0.05). A negative correlation was found between ED and age (r = -0.664, P < 0.001). Significantly larger EDs were found in younger patients (age: <3 years; 1.2 ± 0.5 and 0.6 ± 0.2 mSv; P < 0.001), while higher DLPs were found in elder patients, although no correlation was found between ages versus DLP (r = 0.092, P = 0.262). Prospective ECG-triggered 256 MSCT has considerable performance for the evaluation of CA in children. However, great caution is needed for children under the age of three in the selection of this examination. Furthermore, the tube current could be further reduced for the examination of children ≥8 years.

[Pollution Evaluation and Risk Assessment of Heavy Metals from Atmospheric Deposition in the Parks of Nanjing].

Contents of heavy metals involving As, Cd, Cr, Cu, Ni, Pb and Zn from atmospheric deposition in 10 parks of Nanjing were analyzed. The pollution level, ecological risk and health risk were evaluated using Geoaccumulation Index, Potential Ecological Risk Index and the US EPA Health Risk Assessment Model, respectively. The results showed that the pollution levels of heavy metals in Swallow Rock Park, Swallow Rock Park and Mochou Lake Park were higher than the others. Compared to other cities such as Changchun, Wuhan and Beijing, the contents of heavy metals in atmospheric deposition of parks in Nanjing were higher. The evaluation results of Geoaccumulation Index showed that Pb was at moderate pollution level, Zn and Cu were between moderate and serious levels, while Cd was between serious and extreme levels. The ecological risk level of Cd was high. The assessment results of Health Risk Assessment Model indicated that there was no non-carcinogenic risk for all the seven heavy metals. For carcinogenic risk, the risks of Cd, Cr and Ni were all negligible (Risk < 1 x 10⁻6), whereas As had carcinogenic risk possibility but was considered to be acceptable (10⁻6 < Risk < 10⁻4).