Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)
Graphical abstract
Introduction
Economic growth of developing countries has been steadily increasing through the years due to their rapid urbanization and increasing industrial activities [1]. Along with this growth is the increasing number of challenges that are associated with urbanization, such as the decline of public health and the deteriorating urban environment mainly caused by air and water pollution [2], [3]. The US Environmental Protection Agency (USEPA) listed priority pollutants that must be regulated and the list includes polycyclic aromatic hydrocarbons (PAHs) that are often associated with urbanization [4], [5], [6].
PAHs are potentially carcinogenic substances that are gaining the attention of environmental sectors due to their persistence in the environment and adverse health effects [7]. They are labeled as persistent organic pollutants (POPs), a group of toxic chemical substances that resist degradation and have a tendency to bioaccumulate in the food chain, and have become a public concern due to the significant risks they present to their surroundings [8], [9]. Major concerns include emissions from industrial activities and incomplete combustion of fuels since they contribute a large amount of PAHs in the atmosphere and can be widely dispersed to neighboring areas via long-range transport [10], [11], [12], [13].
There are existing efforts to mitigate the contamination of PAHs in the atmosphere and surface waters. Monitoring methods have been conducted for several years to perform risk assessments of possible PAH contamination and identify their dominant sources [14], [15], [16]. However, chemical analyses of the samples take an excessive amount of time and effort, making it expensive to conduct intensive monitoring activities of a number of PAHs [17]. Water quality models address this problem by using the available data to determine spatial and temporal patterns of PAHs in different media while, mathematical models help simulate PAH concentration at a given time frame using the physical and chemical characteristics of each media. [18]. To simulate the transport processes associated with multiple media, recent studies have applied the modeling approach [19]. The models help compartmentalize complex systems of the environment using boxes that are connected by mass fluxes. Each box represents an environmental medium and can characterize one or more state variables [20]. Greenfield and Davis and Hauck et al. were able to simulate PAH concentrations and evaluate their spatial variability using a multimedia fate model [21], [22]. Unfortunately, these existing models are limited to mass transfers and have yet to perform a watershed-scale simulation of PAH transport.
This study addressed the need to have a watershed-scale PAH model by developing a multimedia model coupled with the Soil and Water Assessment Tool (SWAT) for Taehwa River (TR) watershed in Ulsan, South Korea. Ulsan City is the industrial capital of South Korea and has the largest per-capita GDP in the country. The industrial complex in Ulsan is located at the western-most part of city and has more than 200 companies in operation. The plants and factories are mostly involved in steel machinery, petrochemical, and transport equipment, which are expected to be major sources of PAHs. The interactions between the atmosphere, water body, and soil were considered to simulate PAH transport within the watershed, while the SWAT model provided the hydrologic characteristics of TR basin. This study is the first watershed-scale PAH model that was able to investigate the spatial distribution, temporal patterns, and fate and transport of PAHs in a watershed.
Section snippets
Study area
Ulsan city is situated in the north-eastern part of Gyeongsangnam-do, a southern province of South Korea. The Taehwa River (TR) flows from east to west across the metropolitan city and has a length of 47.54 km (129°0⿲E129°25⿲E, 35°27⿲N35°45⿲N). The river originates from Ssalbawi, Gajisan, Sangbuk-myeon, and Ulju-gun and drains an area of 646.96 km2 to Ulsan Bay. Samho Station was assigned as the outlet for the Eastern TR watershed Fig. 1. About 64% of the Eastern watershed was covered by
Sensitivity analysis of PAH soil
The hydrologic module of the SWAT model was calibrated Fig. 3. A detailed discussion is included in the Supplementary (Section 3). The sensitivity of the PAH soil parameters was investigated. Ten parameters out of the 21-parameter sensitivity analysis were found to be the most sensitive. Table 2 shows the sensitivity ranking of each parameter, while Table 3 shows the calibrated values. The most sensitive parameter was the regression coefficient coeffenratio,2 from Eq. (7), which is derived from
Conclusion
This study developed a PAH model for the Taehwa River watershed by coupling a multimedia model with SWAT. It was able achieved its objective by simulating the following: the transport of PAH compounds in the atmosphere, soil, and water body; the PAH temporal patterns in soil and water; and the PAH spatial distribution in the watershed. The following conclusions were also made in this study:
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Sensitivity analyses of the PAH soil and PAH water parameters were able to determine the critical
Acknowledgements
This study was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2061034) and as The Chemical Accident Prevention Technology Development Project by the Korea Ministry of Environment (MOE).
References (50)
- et al.
Emission, contamination and exposure, fate and transport, and national management strategy of persistent organic pollutants in South Korea
- et al.
Global atmospheric emission inventory of polycyclic aromatic hydrocarbons (PAHs) for 2004
Atmos. Environ.
(2009) - et al.
Long-range transport of polycyclic aromatic hydrocarbons (PAHs) from the eastern Asian continent to Kanazawa, Japan with Asian dust
Atmos. Environ.
(2007) - et al.
PAH source fingerprints for coke ovens, diesel and, gasoline engines, highway tunnels, and wood combustion emissions
Atmos. Environ.
(1995) - et al.
Atmospheric polycyclic aromatic hydrocarbons: source attribution, emission factors and regulation
Atmos. Environ.
(2008) - et al.
Monitoring PAH contamination in water: comparison of biological and physico-chemical tools
Sci. Total Environ.
(2013) - et al.
Polycyclic aromatic hydrocarbons and their molecular diagnostic ratios in urban atmospheric respirable particulate matter
Atmos. Res.
(2005) - et al.
Polycyclic aromatic hydrocarbon (PAH) contamination in San Francisco Bay: a 10-year retrospective of monitoring in an urbanized estuary
Environ. Res.
(2007) - et al.
A multimedia fate model to evaluate the fate of PAHs in Songhua River, China
Environ. Pollut.
(2012) - et al.
A PAH fate model for San Francisco Bay
Chemosphere
(2005)
Model and input uncertainty in multi-media fate modeling: benzo[a]pyrene concentrations in Europe
Chemosphere
Improving the spatial resolution of atmospheric polycyclic aromatic hydrocarbons using passive air samplers in a multi-industrial city
J. Hazard. Mater.
Polycyclic aromatic hydrocarbons (PAHs) in soils from a multi-industrial city South Korea
Sci. Total Environ.
Modelling the fate of hydrophobic organic contaminants in a boreal forest catchment: a cross disciplinary approach to assessing diffuse pollution to surface waters
Environ. Pollut.
Meteorological effects on the levels of fecal indicator bacteria in an urban stream: a modeling approach
Water Res.
A global sensitivity analysis tool for the parameters of multi-variable catchment models
J. Hydrol.
Component-based development and sensitivity analyses of an air pollutant dry deposition model
Environ. Model. Softw.
Fluxes of polycyclic aromatic hydrocarbons to marine and lacustrine sediments in the northeastern United States
Geochim. Cosmochim. Acta
Sedimentary transport and fate of polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation on a blanket peat South Yorkshire, UK
Sci. Total Environ.
Inherent properties of air pollutants
Fundamentals of Air Pollution
Photodegradation and biodegradation study of benzo(a)pyrene in different liquid media
J. Photochem. Photobiol. A: Chem.
Atmospheric concentrations and air-soil gas exchange of polycyclic aromatic hydrocarbons (PAHs) in remote, rural village and urban areas of Beijing-Tianjin region, North China
Sci. Total Environ.
Polycyclic aromatic hydrocarbons in urban soils of different land uses in Beijing, China: distribution, sources and their correlation with the citys urbanization history
J. Hazard. Mater.
Degradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils by Fentons reagent: a multivariate evaluation of the importance of soil characteristics and PAH properties
J. Hazard. Mater.
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