Haiyang Chen

Contamination features and health risk of soil heavy metals in China.

China faces a big challenge of environmental deterioration amid its rapid economic development. To comprehensively identify the contamination characteristics of heavy metals in Chinese soils on a national scale, data set of the first national soil pollution survey was employed to evaluate the pollution levels using several pollution indicators (pollution index, geoaccumulation index and enrichment factor) and to quantify their exposure risks posed to human health with the risk assessment model recommended by the US Environmental Protection Agency. The results showed that, due to the drastically increased industrial operations and fast urban expansion, Chinese soils were contaminated by heavy metals in varying degrees. As a whole, the exposure risk levels of soil metals in China were tolerable or close to acceptable. Comparatively speaking, children and adult females were the relatively vulnerable populations for the non-carcinogenic and carcinogenic risks, respectively. Cadmium and mercury have been identified as the priority control metals due to their higher concentrations in soils or higher health risks posed to the public, as well as, arsenic, lead, chromium and nickel. Spatial distribution pattern analysis implied that the soil metal pollutions in southern provinces of China were relatively higher than that in other provinces, which would be related to the higher geochemical background in southwest regions and the increasing human activities in southeast areas. Meanwhile, it should be noticed that Beijing, the capital of China, also has been labeled as the priority control province for its higher mercury concentration. These results will provide basic information for the improvement of soil environment management and heavy metal pollution prevention and control in China.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Rizhao coastal area (China) using diagnostic ratios and factor analysis with nonnegative constraints.

In this study, sources of polycyclic aromatic hydrocarbons (PAHs) found in surface sediments of the Rizhao coastal area (China) were apportioned using diagnostic ratios and factor analysis with nonnegative constraints (FA-NNC). Bivariate plots of selected diagnostic ratios showed that the sources of PAHs identified in surface sediments seemed to be mixed sources dominated by petroleum-related. Literature PAH source profiles were modified based on the first-order degradation reaction in the atmosphere and sediments, and were considered as comparison for source identification. Five significant factors were determined with the diagnostic tools including coefficient of determination, cumulative percent variance and Exner function. By visually comparing PAH patterns and from the sum of squares of differences between modeled and modified literature PAH profiles, the potential sources were apportioned with the FA-NNC. The main contribution sources of PAHs originated from diesel engine (27.22%), followed by traffic emission (25.03%), gasoline engine (18.95%), coal power plant (14.77%) and coal residential (14.03%). Energy consumption was the predominant reason for PAH pollution in that region.

Source apportionment and health risk assessment of trace metals in surface soils of Beijing metropolitan, China

Understanding the exposure risks of trace metals in contamination soils and apportioning their sources are the basic preconditions for soil pollution prevention and control. In this study, a detailed investigation was conducted to assess the health risks of trace metals in surface soils of Beijing which is one of the most populated cities in the world and to apportion their potential sources. The data set of metals for 12 elements in 240 soil samples was collected. Pollution index and enrichment factor were used to identify the general contamination characteristic of soil metals. The probabilistic risk model was employed for health risk assessment, and a chemometrics technique, multivariate curve resolution-weighted alternating least squares (MCR-WALS), was applied to apportion sources. Results suggested that the soils in Beijing metropolitan region were contaminated by Hg, Cd, Cu, As, and Pb in varying degree, lying in the moderate pollution level. As a whole, the health risks posed by soil metals were acceptable or close to tolerable. Comparatively speaking, children and adult females were the relatively vulnerable populations for the non-carcinogenic and carcinogenic risks, respectively. Atmospheric deposition, fertilizers and agrochemicals, and natural source were apportioned as the potential sources determining the contents of trace metals in soils of Beijing area with contributions of 15.5%-16.4%, 5.9%-7.7% and 76.0%-78.6%, respectively.

Environmental distribution and associated human health risk due to trace elements and organic compounds in soil in Jiangxi province, China

The government of China launched its first national soil quality and pollution survey (NSQPS) during April 2006 to December 2013. Data gathered in several earlier soil surveys were rarely used to understand the status of pollution. In this study, the dataset collected at the provincial level was analyzed for the first time. Concentrations, distribution, diversity, and human health risks of trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se, V and Zn) and organic pollutants (benzene hexachloride (BHCs), dichlorodiphenyltrichloroethanes (DDTs), phthalic acid esters (PAEs), polycyclic aromatic hydrocarbon (PAHs), polychlorinated biphenyls (PCBs), and petroleum hydrocarbons (PHCs)) in surface soil samples collected across Jiangxi province,China were presented. The results showed that, the proportion of contaminants with concentrations higher than their corresponding regulatory reference value ranged from 0.12% to 17%. It is worth note that, the local residents are exposed to moderate non-carcinogenic and carcinogenic risks at some sites. The comprehensive analysis of soil pollutants provide baseline information for establishing a long-term soil environmental monitoring program in Jiangxi province, China.

Source apportionment of sediment PAHs in the Pearl River Delta region (China) using nonnegative matrix factorization analysis with effective weighted variance solution.

Considering the advantages and limitations of a single receptor model, in this study, a combined technique of nonnegative matrix factorization analysis with effective weighted variance solution (NMF-EWV) was proposed for source apportionment. Utilizing NMF, major linear independent factor loadings with nonnegative elements were extracted to identify potential pollution sources. Then, these physical reasonable factor loadings were regarded as source profiles to apportion contributions using effective weighted variance solutions. Evaluation results indicated that the NMF-EWV method reproduced the source profiles well, and got a reasonable apportionment results for the synthetic dataset. The methodology of the NMF-EWV was also applied to recognize sources and apportion the contributions of polycyclic aromatic hydrocarbons (PAHs) collected from freshwater and marine sediments in the Pearl River Delta (PRD) region which is one of the most industrialized and economically significant regions of China. Apportionment results showed that traffic tunnel made the largest contribution (46.49%) for the freshwater PAH sediments in the PRD, followed by coal residential source (29.61%), power plant (13.45%) and gasoline engine (10.45%). For the marine sediments, traffic tunnel was also apportioned as the largest source (57.61%), followed by power plant (22.86%), gasoline engine (17.71%) and coal residential source (1.82%). Traffic-related sources were the predominant reasons for PAH pollution in that region.

Current status and associated human health risk of vanadium in soil in China

A detailed assessment of vanadium contamination characteristics in China was conducted based on the first national soil pollution survey. The map overlay analysis was used to evaluate the contamination level of vanadium and the non-carcinogenic risk assessment model was calculated to quantify the vanadium exposure risks to human health. The results showed that, due to the drastically increased mining and smelting activities, 26.49% of soils were contaminated by vanadium scattered in southwest of China. According to Canadian soil quality guidelines, about 8.6% of the national soil pollution survey samples were polluted, and pose high non-carcinogenic risks to the public, especially to children living in the vicinity of heavily polluted mining areas. We propose the area near the boundary of Yunnan, Guizhou, Guangxi, and Sichuan provinces as priority control areas due to their higher geochemical background or higher health risks posed to the public. Finally, recommendations for management are proposed, including minimization of contaminant inputs, establishing stringent monitoring program, using phytoremediation, and strengthening the enforcement of relevant laws. Therefore, this study provides a comprehensive assessment of soil vanadium contamination in China, and the results will provide valuable information for Chinas soil vanadium management and risk avoidance.

A framework of characteristics identification and source apportionment of water pollution in a river: a case study in the Jinjiang River, China.

A framework for characteristics identification and source apportionment of water pollution in the Jinjiang River of China was proposed in this study for evaluation. A total of 114 water samples which were generated between May 2009 and September 2010 at 13 sites were collected and analysed. First, support vector machine (SVM) and water quality pollutant index (WQPI) were used for water quality comprehensive evaluation and identifying characteristic contaminants. Later, factor analysis with nonnegative constraints (FA-NNC) was employed for source apportionment. Finally, multi-linear regression of the absolute principal component score (APCS/MLR) was applied to further estimate source contributions for each characteristic contaminant. The results indicated that the water quality of the Jinjiang River was mainly at the third level (65.79%) based on national surface water quality permissible standards in China. Ammonia nitrogen, total phosphorus, mercury, iron and manganese were identified as characteristic contaminants. Source apportionment results showed that industrial activities (63.16%), agricultural non-point source (16.50%) and domestic sewage (12.85%) were the main anthropogenic pollution sources which were influencing the water quality of Jinjiang River. This proposed method provided a helpful framework for conducting water pollution management in aquatic environment.

Characterization of antibiotics in a large-scale river system of China: Occurrence pattern, spatiotemporal distribution and environmental risks

Antibiotics and antibiotic resistance genes in the river system have received growing attention in recent years due to their potential threat to aquatic ecosystems and public health. Recognizing the occurrence and distribution of antibiotics in river environment and assessing their ecological risks are of important precondition for proposing effective strategies to protect basin safety. In this study, a comprehensive investigation was conducted to identify the contamination and risk characteristics of antibiotics in the aquatic environment of Hai River system (HRS) which is the largest water system in northern China. To attain this objective, several tools and methods were considered on the data set of water and sediment samples collected in the past ten years. The occurrence pattern, concentration levels and spatiotemporal distribution of antibiotics in the HRS were characterized utilizing statistical and comparative analysis. Risk quotients were employed to assess the adverse ecology effects caused by single antibiotic or their mixtures. Screening tool with priority factor and accumulation growth factor was used auxiliarily to prioritize antibiotics that should be of highly concern. Results indicated that the occurrence frequencies and concentration levels of 16 representative antibiotics in HRS were generally higher than those reported in global waters. Most antibiotics showed significant seasonal and spatial variations. Comparatively speaking, sulfamethoxazole, norfloxacin, erythromycin and roxithromycin posed higher risks to aquatic organisms in the HRS individually, and the combination of tetracycline and enrofloxacin indicated synergistical actions. Overall, due to their potential risks, considerable levels or quick increasing trends, 13 antibiotics were identified as priority contaminants in the HRS and should be paid special attention to be strictly regulated in the future.

Source apportionment for sediment PAHs from the Daliao River (China) using an extended fit measurement mode of chemical mass balance model

To minimize the selection uncertainties of source profiles and obtain the higher model performance, an extended fit measurement mode for chemical mass balance model (EFMM-CMB) was proposed and applied to estimate source contributions for sediment PAHs from the Daliao River around which is the important industrial bases with oil, chemical and steel factories in the northeast part of China. Based on least squares fitting method, EFMM-CMB initially calculated the fit measurement index to every one of the possible combinations that can be made from the source profiles. Any successful applications of the fitting method were ranked according to performance measures, and then determined by maximizing an overall fitting index for a unique solution. Apportionment results from two case scenarios showed that the values of performance measures for EFMM-CMB were better to that for CMB8.2 results. With species selection of high molecular weight PAHs, power plant (45.75%), biomass burning (29.34%) and traffic tunnel (10.59%) were identified as the major sources of sediment PAHs from the Daliao River region.

Source Apportionment of Water Pollution in the Jinjiang River (China) Using Factor Analysis With Nonnegative Constraints and Support Vector Machines

Source apportionment studies of water pollution can greatly improve the knowledge of the human impact on the aquatic environment. Factor analysis (FA) has been widely used to identify sources of water pollution because of its relative ease of implementation. Generally, the method of identifying the sources was by qualitatively comparing source emission characteristics with factor loadings derived from FA. However, this traditional method was somewhat coarse to express the nonlinear relationship between source emission characteristics and factor loadings. In this study, by treating source identification using source emission characteristics and factor loadings as a pattern recognition problem, a source apportionment method was proposed by combining the factor analysis with nonnegative constraints (FA-NNC) with the support vector machine (SVM). Data sets on water quality of the Jinjiang River (China), which were sampled between May 2009 and September 2010 at 13 sites, have been collected to evaluate this proposed method. The apportionment results showed that the identified sources using the combined models were similar to the comprehensive analysis results obtained from qualitatively comparing source emission characteristics with factor loadings. Industrial activities, including papermaking and textiles, metal handicrafts manufacture, chemical and metal producing, metal refining and iron ore mining were identified as the main pollution sources with contribution ratio of 79.58%, followed by agricultural non-point sources (20.42%). These results provide policy and decision makers with a useful help for supporting the management of water pollution in the Jinjiang River. Meanwhile, this study will provide a useful direction for developing source apportionment approach to support the management of water pollution.