Past, present, and future perspectives on the assessment of bioavailability/bioaccessibility of polycyclic aromatic hydrocarbons: A 20-year systemic review based on scientific econometrics.

Bioaccessibility/bioavailability (bioac-bioav) is an important criterion in the risk assessment of polycyclic aromatic hydrocarbons (PAHs), especially in the restoration of contaminated sites. Although, the bioac-bioav concept is widely employed in PAH risk assessment for both humans and wildlife, their growth and integration in risk assessment models are seldom discussed. Consequently, the relevant literature listed on Web of Science (WOS)™ was retrieved and analyzed using the bibliometric software Citespace in order to gain a comprehensive understanding of this issue. Due to the limitations of the literature search software, we manually searched the articles about PAHs bioac-bioav that were published before 2000. This stage focuses on research on the distribution coefficient of PAHs between different environmental phases and laid the foundation for the adsorption-desorption of PAHs in subsequent studies of the bioac-bioav of PAHs. The research progress on PAH bioac-bioav from 2000 to the present was evaluated using the Citespace software based on country- and discipline-wise publication volumes and research hotspots. The development stages of PAH bioac-bioav after 2000 were divided into four time segments. The first three segments (2000-2005, 2006-2010, and 2011-2015) focused on the degradation of PAHs and their in vivo (bioavailability)-in vitro (bioaccessibility) evaluation method and risk assessment. Meanwhile, the current (2016-present) research focuses on the establishment of analytical methods for assessing PAH derivatives at environmental concentrations and the optimization of various in vitro digestion methods, including chemical optimization (sorptive sink) and biological optimization (Caco-2 cell). The contents are aimed at supplying researchers with a deeper understanding of the development of PAH bioac-bioav.

[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).

Mortality effects assessment of ambient PM2.5 pollution in the 74 leading cities of China.

BACKGROUND: Ambient fine particulate matter (PM2.5) pollution is currently a most severe and worrisome environmental problem in China. However, current knowledge of the health effects of this pollution is insufficient. OBJECTIVES: This study aims to provide an overall understanding regarding the long-term mortality effects of current PM2.5 pollution in China and the potential health benefits of realizing the goals stipulated in the ongoing action plan of Air Pollution Prevention and Control (APPC) and the targets suggested by the WHO. METHODS: Three typical causes and all-cause of PM2.5-related mortality were considered. The log-linear exposure-response function was adopted, and a meta-analysis was used to determine the exposure-response coefficients, based on newly available data in China and abroad. RESULTS: In the 74 leading cities of China, approximately 32% of the reported deaths, with a mortality rate of 1.9‰, were associated with PM2.5 in 2013, in which deaths from cardiovascular, respiratory and lung-cancer causes accounted for 20% of the reported deaths, with a mortality rate of 1.2‰. The regional difference is remarkable for the mortalities and proportions of the different causes. If the PM2.5 concentration goals of the APPC plan, the first interim and the guideline targets of the WHO could be achieved, the PM2.5-related all-cause mortality would be reduced by 25%, 64% and 95%, respectively, compared with that of 2013. CONCLUSIONS: PM2.5 pollution in China has incurred great health risks that are even worse than those of tobacco smoking. The health benefits of the APPC plan could be outstanding, although there is still great potential to improve future air quality.

Bioaccessibility, sources and health risk assessment of trace metals in urban park dust in Nanjing, Southeast China.

Arsenic, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn total concentrations and bioaccessibilities in 15 urban park dust samples were determined. The oral bioaccessibility measured by the Simple Bioaccessibility Extraction Test (SBET) decreased in the order of Pb>Cd>Zn>Mn>Cu>Co>V>Ni>As>Cr. The Tomlinson pollution load index (PLI) and geoaccumulation index (I(geo)) were calculated to evaluate the pollution extent to which the samples were contaminated. Sources were identified using principal component analysis and Pb isotope compositions. Most elements except Co and V were considered to mainly originate from anthropogenic sources. Non-carcinogenic and carcinogenic risks to humans through urban park dust exposure were assessed using the oral bioaccessibilities of the elements. Ingestion was the main pathway for non-carcinogenic risk. The hazard quotients were below the safe level (=1) for all elements, however, Pb (0.154) and As (0.184) posed potential higher risks to children than adults. The carcinogenic effects occurring were below the acceptable level (10(-4)) for As and <10(-6) for Cd, Co, Cr, and Ni.

Selection of optimal river water quality improvement programs using QUAL2K: a case study of Taihu Lake Basin, China.

In recent years, water quality degradation associated with rapid socio-economic development in the Taihu Lake Basin, China, has attracted increasing attention from both the public and the Chinese government. The primary sources of pollution in Taihu Lake are its inflow rivers and their tributaries. Effective water quality improvement programs need to be implemented in these rivers to improve the water quality of Taihu Lake, and to ensure sustainable development in the region. To ensure effectiveness and efficiency, it is important that the optimal water quality improvement program for a specific situation be selected. The aim of this study was to facilitate the selection of this optimal program. The QUAL2K model for river and stream water quality was used to simulate the effects of a range of water quality improvement scenarios in the Hongqi River, which is a polluted tributary in the Taihu Lake Basin. These scenarios consisted of a series of three water treatment technologies in different configurations, from upstream to downstream. The results showed that the optimal scenario comprised a bio-contact oxidation system upstream, followed by an ecological floating bed, and a vertical moveable eco-bed downstream. The reduction rates achieved by this scenario for biochemical oxygen demand (BOD), ammonia nitrogen (NH(3)-N), total nitrogen (TN), and total phosphorus (TP) were 49.50%, 32.81%, 35.94%, and 45.27%, respectively. The QUAL2K model proved to be an effective tool in the comparative evaluation of potential water quality improvement programs. The method applied in this study can prevent the implementation of water quality improvement programs that would not achieve the desired goals.