Concentration and Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Urban Soil in the Typical Semi-Arid City of Xi’an in Northwest China

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, presenting potential threats to the ecological environment and human health. Sixty-two urban soil samples were collected in the typical semi-arid city of Xi’an in Northwest China. They were analyzed for concentration, pollution, and ecological and health risk of sixteen U.S. Environmental Protection Agency priority PAHs. The total concentrations of the sixteen PAHs (Σ16PAHs) in the urban soil ranged from 390.6 to 10,652.8 µg/kg with an average of 2052.6 µg/kg. The concentrations of some individual PAHs in the urban soil exceeded Dutch Target Values of Soil Quality and the Σ16PAHs represented heavy pollution. Pyrene and dibenz[a,h]anthracene had high ecological risk to aquatic/soil organisms, while other individual PAHs showed low ecological risk. The total ecological risk of PAHs to aquatic/soil organisms is classified as moderate. Toxic equivalency quantities (TEQs) of the sixteen PAHs varied between 21.16 and 1625.78 µg/kg, with an average of 423.86 µg/kg, indicating a relatively high toxicity potential. Ingestion and dermal adsorption of soil dust were major pathways of human exposure to PAHs from urban soil. Incremental lifetime cancer risks (ILCRs) of human exposure to PAHs were 2.86 × 10−5 for children and 2.53 × 10−5 for adults, suggesting that the cancer risk of human exposure to PAHs from urban soil is acceptable.

Levels of Polycyclic Aromatic Hydrocarbons in the Water and Sediment of Buffalo River Estuary, South Africa and Their Health Risk Assessment

“…The levels of PAHs in the water column of Buffalo River Estuary are given in Table 2 . All 16 priority PAHs of the United States Environmental Protection Agency (US EPA) were detected in the water samples collected from the estuary at varied concentrations, confirming the ubiquitous nature of the pollutants (Jiao et al 2012 ; Wang et al 2018 ). Individual levels of PAHs in the water phase ranged from nondetected (ND) to 24.91 μg/L (indeno(1,2,3-cd)pyrene).…”

“…The risk indices for the two groups were 1.97 × 10 −3 and 3.34 × 10 −3 , correspondingly. In particular, 5 of the 7 cPAHs, which are benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene exceeded the threshold value of 1 × 10 −4 (Wei et al 2015 ; Wang et al 2018 ).…”

“… where ADD derm represents the average daily doses by dermal contact (mg/kg/day); C stands for the concentration of PAHs in the water sample (mg/L); EF is the exposure frequency (350 days/year for both ingestion and dermal absorption); ED is the exposure duration (adult: 30 years; child: 6 years); BW represents the average body weight (adult: 70 kg; child: 15 kg); AT means the average time, i.e., ED × 365 days (adult: 10,950 days; child: 2190 days); SA stands for the exposed skin area (adult: 18,000 cm 2 ; child: 6600 cm 2 ); Kp (cm/h) is the dermal permeability coefficient (corresponding values are shown in Tables 4 and 5 ); ET is the exposure time of shower and bathing (adult: 0.58 h/day; child: 1 h/day); and CF represents the unit conversion factor ( L /1000 cm). Guidelines values provided by Department of Environmental Affairs, South Africa, and US EPA were used for the estimations (US EPA 1989 , 1992 ; Gerba 2006 ; DEA 2010 ; DTSC 2014 ; Feng et al 2016a ; Wang et al 2018 ).…”

Enhanced biodegradation of naphthalene byPseudomonassp. consortium immobilized in calcium alginate beads

“…Polycyclic aromatic hydrocarbons (PAHs) are considered as the potential health 105 hazard for living beings (Kumari et al, 2018). Environmental agencies including US-106 EPA, European Union, Environment-Canada, registered PAH as the priority pollutants 107 that require immediate human intervention (Wang et al, 2018). The physicochemical 108 properties of PAH make them a major contributor for soil and groundwater 109 contamination through bio-magnification (Norris, 2017).…”

Dechlorination of Hexachlorobenzene in Contaminated Soils Using a Nanometallic Al/CaO Dispersion Mixture: Optimization through Response Surface Methodology

“…In the past decades, contamination of subsurface soils by chlorinated hydrophobic organic compounds (CHOCs) such as hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) has become a significant environmental problem [ 1 ]. Due to leakage and release from various industries, CHOCs present significant threats to the environment and human health.…”