Nature Environment and Pollution Technology p-ISSN: 0972-6268 Vol. 16 No. 1 pp. 315-319 2017 An International Quarterly Scientific Journal e-ISSN: 2395-3454 Original Research Paper Open Access Polycyclic Aromatic Hydrocarbon Distribution in Soil and Their Ecological Risk Evaluation in Zhengzhou, China Shubo Cheng*† and Yongmei Zhang*(**) *Henan Safety and Emergency Research Center, Henan Polytechnic University, Jiaozuo, Henan, 454000, China **Emergency Management School, Henan Polytechnic University, Jiaozuo, Henan, 454000, China †Corresponding author: Shubo Cheng ABSTRACT Nat. Env. & Poll. Tech. Website: www.neptjournal.com Polycyclic aromatic hydrocarbon (PAH), as a primary organic pollutant in soil, is highly stable in soil and Received: 14-12-2016 does not degrade easily. Thus, it accumulates and may penetrate deeper soil, which will cause long- Accepted: 17-01-2017 term pollution of soil and underground water. To study PAH concentration distribution in soil in Zhengzhou, China, ecological risk evaluation of PAHs in soil was implemented. In this study, 30 soil samples from Key Words: different places in Zhengzhou were collected in August 2015. Concentration levels and distribution PAHs distribution characteristics of PAHs in the soil samples were analysed, and ecological risk evaluation of PAH Soil pollution in soil was conducted. Results indicated that among the 30 soil samples collected, the content Ecological risk evaluation scope of 16 PAHs under priority control of the US Environmental Protection Agency was 436.37- 4,784.13 µg.kg-1 with a mean value of 3,096.71 µg.kg-1. Detection rates of monomers were high, and not all benzo[k]fluoranthene (BkF) and dibenzo[a,h]anthracene were detected. All dibenzo[a]pyrenes with high carcinogenicity were detected with a content scope of 436.37-4,784.13 µg.kg-1 and a mean value of 23.01 µg.kg-1. A total of 27 soil samples exhibited severe PAH pollution, which indicated that overall soil pollution level in Zhengzhou was considerably severe. Only two samples were within ERL- ERM (effect range-low, effect range-median). However, the PAH contents of most samples were higher than ERM, indicating a high ecological risk of soil PAHs in Zhengzhou. Results will provide indispensable scientific basis for government sectors and relevant environmental protection departments to formulate a reasonable control scheme in determining the total amount of soil pollution and to implement human health protection measures. INTRODUCTION ergy sources. Numerous enterprises focused on chemical engineering production, such as chemical plants, steelworks, As an important chemical compound among persistent or- dockyards, electroplate factories, accumulator plants, pa- ganic pollutants prevalent in nature, polycyclic aromatic per mills, textile mills, and pharmaceutical factories, are hydrocarbon (PAH) is a chemical compound with stable distributed around Zhengzhou City. Although these chemi- properties formed through the connection of two or more cal enterprises significantly contribute to the urban con- benzene rings. PAH, an environmental pollutant with strong struction of Zhengzhou, they will inevitably cause envi- carcinogenicity, is a cancerogenic substance found predomi- ronmental pollution in Zhengzhou. Moreover, dense popu- nant in nature. As one of the most poisonous and harmful lation and heavy traffic aggravate the accumulation of or- organic pollutants in the environment, PAHs have drawn ganic pollutants and harm human health and the ecological significant attention because of their durability and poten- environment. Therefore, soil in Zhengzhou is taken as the tial carcinogenicity. PAHs have thus far been found nearly research object. The PAH content in the soil samples was among all environmental media. PAHs in nature were origi- determined to measure the PAH pollution level in nally derived from spontaneous fire and plant decomposi- Zhengzhou, as a reference for scientific method and basis tion. However, incomplete combustion of fossil fuels and for determining PAH sources and pollution regulation in timbers has become an important source of PAHs in envi- Zhengzhou. ronmental media in this modern time. As a source and sink of PAH migration and conversion, soil has become a re- STATE OF THE ART search hotspot. PAHs distribution in soil and their pollution risks have been Zhengzhou, the provincial capital of Henan Province, investigated in foreign research. Greenberg analysed the China, is a large city and economic center with high urbani- concentration levels of 15 urban and rural PAHs in air for zation level and continuously increasing demand for en- two years in New Jersey, USA, and conducted a compara- 316 Shubo Cheng et al. tive analysis of urban PAH concentration levels during sum- contents in water and suspended matters for 12 months in mer and winter; results show that PAH concentration was Xijiang River in Guangdong Province and analyzed their higher in winter than in summer (Greenberg et al. 1967). effects on the environment (Deng et al. 2006). Wang Brown detected the concentration of dust on urban road analyzed PAH distributions in Bohai gulf and its neigh- surface and heavy metals in suspended matter in gutterways bouring sea areas in China (Wang et al. 2015). Zhang during rainstorm; the analysis of source features of PAHs analyzed PAH distribution in surface deposits on the coast revealed that PAH minutia features of the two were similar, of Weihai City, Shandong Province, China, and determined and pollution sources of the two were identical (Brown et their hazard degree (Zhang et al. 2016). These studies show al. 2006). Dahle studied PAH concentration and spatial dis- that in recent years, the improvement in the collection of tribution in bottom sediments between Norway and Russia environmental data on PAHs in various countries has en- and evaluated the degree of influence of PAHs on humans riched the research achievements on PAH distribution and in these areas (Dahle et al. 2006). Amaraneni studied the their pollution risk. Most studies indicate that PAHs are distribution of pesticides and heavy metals in water bodies prevalent in the environment and become rich in soil and and deposits in shrimp ponds surrounding lakes and bottom mud. At present, soil organic matters can turn the wetlands in India and evaluated their effects on humans soil as the main storage and transfer station for PAH-like (Amaraneni 2006). Olivella analysed PAH content in rain- chemical compounds by absorbing and restoring PAHs. water in northern Italy and those in Maggiore lake water; Moreover, with the rapid development in industry and agri- findings show that rainwater was the main source of PAHs culture as well as the large-scale application of fossil fuels, in Maggiore lake water (Olivella 2006). Bourotte compared many PAH pollutants are emitted in the air, and PAHs emit- PAH content between urban soil and natural forest soil in ted from urban areas diffuse in the atmosphere and move Sao Paulo and found that PAH concentration in urban soil with airflow. Some PAHs in air will deposit nearby (urban was 4.5 times of that in forest soil, whereby high PAH pollu- areas or suburbs) through dry and wet deposition action, tion with a significant amount of contribution came mostly and then enter and pollute soil, water bodies, deposits, and from industry and transportation (Bourotte et al. 2009). organisms. Therefore, by analysing the concentration lev- Agarwal studied PAH concentration level, distribution char- els and distribution features of PAHs in soil in Zhengzhou, acteristics, and potential toxicity in roadside soil of major China, the main sources of PAHs within the research area communication lines in New Delhi; results indicated that were identified, and ecological risk evaluation on PAHs PAHs in the research area were derived mainly from motor was conducted. Results will provide an indispensable sci- vehicle exhaust emission and coal combustion (Agarwal entific basis for government sectors and relevant environ- 2009). Maliszewska-Kordybach studied pollution level, mental protection departments to formulate a reasonable distribution characteristics, and PAH sources in farmland control scheme of soil pollution to implement human health soil in Poland; results indicated that PAHs in farmland soil protection measures. in Poland were derived mostly from coal combustion MATERIALS AND METHODS (Maliszewska-Kordybach et al. 2009). Orecchio studied PAH pollution in the soil of a botanical garden beside one Sample collection: Zhengzhou has a vast territory. To guar- waste coal gas production field in Palermo, Italy, and evalu- antee the reliability of coverage and data analysis of col- ated pollution risks generated to the environment (Orecchio lected soil, 30 soil samples were collected from two differ- 2010). Von studied PAH distribution and sources in surface ent places in each area, among 6 municipal districts soil in five different places in Kelang Valley, Malaysia; (Zhongyuan District, Erqi District, Jinshui District, Huiji results indicated that all PAHs in the research area were District, Guancheng District, Shangjie District) under the derived primarily from pyrolysis, combustion of petroleum jurisdiction of Zhengzhou City, 5 county-level cities and biomass, industry, and non-point source pollution (Von (Gongyi City, Xinzheng City, Dengfeng City, Xinmi City, et al. 2012). On domestic research, Liu analysed PAH con- and Xingyang City), 1 county (Zhongmu County), and 3 centration levels, alternative distribution,