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Distribution, fate, inhalation exposure and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons in some Asian countries Wenjun Hong, Hongliang Jia, Wan-Li Ma, Ravindra K Sinha, Hyo-Bang Moon, Haruhiko Nakata, Nguyen Hung Minh, Kai Hsien Chi, Wen-long Li, Kurunthachalam Kannan, Ed Sverko, and Yi-Fan Li Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b01090 • Publication Date (Web): 06 Jun 2016 Downloaded from http://pubs.acs.org on June 6, 2016

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Environmental Science & Technology

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Distribution, fate, inhalation exposure and lung cancer risk

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of atmospheric polycyclic aromatic hydrocarbons in some

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Asian countries

4

Wen-Jun Honga, Hongliang Jiaa, Wan-Li Mab, Ravindra Kumar Sinhac, Hyo-Bang

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Moond, Haruhiko Nakatae, Nguyen Hung Minhf, Kai Hsien Chig, Wen-Long Lib,

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Kurunthachalam Kannanh, Ed Sverkob, and Yi-Fan Lib,a,i*

7 8

a

International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), College of Environmental Science and Engineering, Dalian Maritime University,

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Dalian 116026, China

10 11

b

IJRC-PTS, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China

12 13

c

14

d

IJRC-PTS, Department of Zoology, Patna University, Patna 800 005, Bihar, India IJRC-PTS, Department of Marine Sciences and Convergent Technology, Hanyang

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University, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan city, Gyeonggi-do 426-791,

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Republic of Korea

17

e

IJRC-PTS, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan

18 19

f

DIOXIN LABORATORY, Center for Environmental Monitoring (CEM), Vietnam

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Environmental Administration (VEA), 556 Nguyen Van Cu, Long Bien, Ha Noi,

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Vietnam

22

g

Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei 112, Taiwan

23 24

h

IJRC-PTS, Wadsworth Center, New York State Department of Health, Department

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of Environmental Health Sciences, School of Public Health, State University of New

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York at Albany, Empire State Plaza, P.O. Box 509, Albany, New York 12201-0509,

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United States

28

i

IJRC-PTS-NA, Toronto, M2N 6X9, Canada

29 1

ACS Paragon Plus Environment


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*Corresponding author phone:

31

Yi-Fan

32

[email protected]

Li:

tel:

86-411-8472-8489;

fax:

86-411-8472-8489;

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E-mail:

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TOC

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Abstract

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A large-scale monitoring program, Asia Soil and Air Monitoring Program

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(SAMP-Asia) was conducted in five Asian countries, including China, Japan, South

38

Korea, Vietnam and India. Air samples were collected using passive air samplers with

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polyurethane foam disks over four consecutive three-month periods from September

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2012 to August 2013 to measure the seasonal concentrations of 47 polycyclic

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aromatic hydrocarbons (PAHs), including 21 parent and 26 alkylated PAHs, at 176

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sites (11 background, 83 rural and 82 urban). The annual concentrations of total 47

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PAHs (∑47PAHs) at all sites ranged from 6.29 to 688 ng/m3 with median of 82.2

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ng/m3. Air concentrations of PAHs in China, Vietnam and India were greater than

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those in Japan and South Korea. As expected, the air concentrations (ng/m3) were

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highest at urban sites (143±117) followed by rural (126±147) and background sites

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(22.4±11.4). Significant positive correlations were found between PAH concentrations

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and atmosphere aerosol optical depth. The average benzo(a)pyrene equivalent

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concentration (BaPeq) was 5.61 ng/m3. It was estimated that the annual BaPeq

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concentrations at 78.8% of the sampling sites exceeded the WHO guideline level. The

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mean population attributable fraction (PAF) for lung cancer due to inhalation

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exposure to outdoor PAHs was in order 8.8‰ (0.056‰-52‰) for China, 0.38‰

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(0.007‰-3.2‰) for Japan, 0.85‰ (0.042‰-4.5‰) for South Korea, 7.5‰

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(0.26‰-27‰) for Vietnam, and 3.2‰ (0.047‰-20‰) for India. We estimated a

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number of lifetime excess lung cancer cases caused by exposure to PAHs, which the

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concentrations ranging from 27.8 to 2,200, 1.36 to 108, 2.45 to 194, 21.8 to 1,730,

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and 9.10 to 720 per million people for China, Japan, South Korea, Vietnam, and India,

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respectively. Overall, the lung cancer risk in China and Vietnam were higher than that

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in Japan, South Korea, and India.

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Introduction

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Asia is one of the most prosperous areas of the world. However, rapid

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industrialization and urbanization in this region have resulted in a mass of

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environmental concerns. Several studies have focused on persistent organic chemicals,

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such as polychlorinated biphenyls (PCBs) (1-3), polybrominated diphenyl ethers

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(PBDEs) (1, 4), organochlorine pesticides (OCPs) (1, 5), short-chain chlorinated

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paraffins (SCCPs) (6), as well as polycyclic aromatic hydrocarbons (PAHs) (7, 8).

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PAHs are among the most toxic organic pollutants of concern in Asia, especially in

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China, where PAH concentrations are significantly higher than those in other

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countries (8-10).

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PAHs are a group of fused-ring aromatic compounds, which are contained in

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petroleum products and formed from the combusition of fossil fuels and biomass (11).

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The U.S. Environmental Protection Agency (US EPA) has designated 16 PAH

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compounds as priority pollutants, which are often targeted for measurement in

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environmental matrix by researchers (12). In recent years, lots of attentions have been

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paid on the PAH derivates, such as alkylated, oxygenated, halogenated and nitrated

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PAHs (13-14). Alkylated PAHs are classified according to the number of parent rings

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and the carbon number of alkylated substituents, and they are largely resulted from

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the release of oil or the combustion of fuels at low to moderate temperature. Previous

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studies have shown evidence of some alkylated PAHs being more toxic (15-16) and

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contain higher concentrations than their parent ones (17).

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Over the last three decades, studies on atmosphere PAHs have attracted much

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attention because some of them are highly carcinogenic or mutagenic (18). Several

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toxicological studies in animals (19) and occupational studies in humans (20)

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demonstrate an excess risk of lung cancer associated with PAH inhalation. PAHs can

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be metabolized and become reactive electrophilic intermediates that can form

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PAH-DNA adducts, a biomarker of DNA damage that has been related to cancer (21).

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Cancer is now the one of the leading cause of death around the world (22). Based on

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GLOBOCAN (http://globocan.iarc.fr/Default.aspx) estimates, about 14.1 million new 5



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cancer cases and 8.2 million deaths occurred in 2012 worldwide (23). Lung cancer

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(including trachea, bronchus and lung cancer) had replaced liver cancer in causing the

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largest number (37%) of total cancer deaths each year around (24). Although smoking

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and low fruit and vegetable intake are among the major causes of lung cancer,

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ambient air pollution also plays an important role in causing lung cancer, both in

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high-income countries and low-and-middle-income countries (24). Among the

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carcinogenicity of air toxic chemicals, PAHs make up the largest contribution to lung

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cancer (25, 26). A number of studies has been conducted on the health risks caused by

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air PAH exposure, especially in mainland of China (13, 27, 28).

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In this study, we measured 47 PAHs in air samples at 176 sampling sites collected

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from several Asian countries (East Asia: China, Japan, South Korea, Southeast Asia:

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Vietnam, and South Asia: India) from September 2012 to August 2013. The main

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objectives of this work are to investigate the levels of PAHs in the atmosphere for

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different seasons across the study area and to evaluate the lung cancer risk caused by

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inhalation exposure to PAHs.

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Materials and methods

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Sampling

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Passive air samplers (PASs) coupled with polyurethane foam (PUF) disks were

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deployed at 176 sites (11 background, 83 rural and 82 urban, see Table SI-1 and

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Figure SI-1, Supporting Information, SI) across China, Japan, South Korea, Vietnam

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and India from September 2012 to August 2013. Background sites were situated in

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remote areas, at least 10 km far away from any populated areas; rural sites were in

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agricultural regions; and urban sites were typically from business/residential regions.

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All rural and urban sites were chosen to ascertain that these sites were not located in

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industrialized areas or close to roads with heavy traffic, thereby to avoid the point

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sources nearby. Also all the sampling sites were chosen not in the area with high wind

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speed. PUF disks were developed for four periods: period 1 (September-November

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2012); period 2 (December 2012-February 2013); period 3 (March-May 2013); period

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4 (June-August, 2013). Detailed depiction on the sampling sites can also be found in 6


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SI (Section SI.1). After sampling, the sampled PUF disks were sent to the

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International Joint Research Center for Persistent Toxic Substances (IJRC-PTS)

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laboratories, where they were stored cold (-20 ℃) and in the dark until extraction.

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Sample extraction and analysis

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Samples were extracted and analyzed according to the methods established at the

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National Laboratory for Environmental Testing (NLET), Environment Canada.

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Detailed information on sample collection, treatment, analysis and air concentration

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calculation can be found in the SI (Section SI.2). Briefly, samples extraction and clean

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up were also reported in our previous studies (29-31). In the present study, 47 PAH

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compounds (including 21 parent- and 26 alkylated-PAHs) were determined. The

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detailed information on the 47 PAH compounds can be found in Table SI-2.

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Quality assurance/quality control

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All analytical procedures were monitored using strict quality assurance and control

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measures. The PAH was selected for quantification only if the gas chromatography

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retention time matched those of the standards within 0.05 min. Of the alkylated-PAH

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compounds

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2,6-dimethylnaphthalene vs 2,7-dimethylnaphthalene, and 4-methylchrysene vs

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6-methylchrysene could not be clearly resolved in gas chromatography-mass

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spectrometry chromatograms, and were presented in combination as (1,3 &

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1,7)-dimethylnaphthalene,

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6)-methylchrysene (32). One field blank and one laboratory blank were added for

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every 10 samples, all PAH compounds but naphthalene (2.34±1.55 ng/sample),

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1-methylnaphthalene (2.56±1.73 ng/sample) and 2-methylnaphthalene (2.48±1.67

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ng/sample) were under detection limit in field blanks. Surrogate standard recoveries in

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samples ranged from 68% to 115% (mean 87±19%). The final results were corrected

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using the corresponding period of the field blanks but not the surrogate recoveries.

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The method detection limits (MDLs) were calculated by conducting a replicate spike

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study (n=7) suggestion by US EPA (29). MDLs for PAHs ranged from 0.0241 to 3.12

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ng/sample (Table SI-3). Observations below the MDL were assigned a value of 2/3

studied,

1,3-dimethylnaphthalene

(2,6

&

vs

1,7-dimethylnaphthalene,

2,7)-dimethylnaphthalene,

and

(4

&

7



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the MDL.

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Calculation of air concentration

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The derivation of an air concentration requires the amount of chemical accumulated

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on the PUF disk and the effective air sample volume (VAIR) for the particular chemical

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(33-35). The detailed theory and method can be found in the SI.3, and only a brief

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description is given here. The uptake profile has two main phases: initially a linear

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constant uptake phase described by the sampling rate R (m3/d), and followed by the

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plateau or equilibrium phase that may develop for the more volatile PAHs as they

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approach equilibrium in the PUF disk (3, 33).

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The average air concentration of analyte during each sampling period, CAIR (mass/m3),

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is given by (1)

C AIR = m / VAIR 158

In eq (1), m is mass of analyte collected in the PUF disk and VAIR (m3) is the effective

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air sample volume given by VAIR = K PUF − A'VPUF (1 − e

− ( APUF / VPUF ) k A / K

PUF − A'

)t

)

(2)

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where APUF and VPUF are the planar surface area (cm2) and volume (cm3) of the PUF

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disk, kA is air-side mass transfer coefficient (cm/d), and t is the exposure time in days.

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The linear-phase sampling rates, R, ranged from 1.87-9.03 m3/d, with an average of

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3.5±1.9 m3/d for all individual PAHs. A default value for kA of 8300 cm/d was used

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which corresponds to a linear-phase sampling rate of 3.5 m3/d [Figure SI-2]. KPUF-A’ is

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related to the PUF-air partition coefficient, given by (36) (3)

K PUF − A' = K PUF − A × ρ 166

where ρ is the bulk density of the PUF. KPUF-A is calculated from the octanol-air

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partition coefficient of a chemical, KOA, which is known for PAHs as a function of

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temperature (37). The air concentrations given for PAHs represent results from both

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gaseous- and particle-phase sampling. The resulting air volumes were in the range of

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approximately 25.7-318 m3 (see Table SI-4 for detail). It has been realized that many

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of higher molecular weight PAHs are found in the particle phase (29), which has a 8


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lower sampling rate compared to the gas phase, the derived air concentrations are

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likely to be underestimating the true air concentrations (Figure SI-3). However, the

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spatial trends of the targeted PAHs should be captured in this study.

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Toxic equivalency factor: benzo(a)pyrene equivalency

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For assessment calculations, we ranked the carcinogenic PAHs according to their

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relative potency factor (RPF) to benzo(a)pyrene (BaP) (Table SI-16) (38). The BaP

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equivalent (BaPeq) concentration were calculated by multiplying each individual PAH

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concentration with its RPF and expressed as BaPeq (28).

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Population attributable fraction model

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To construct a dose-response profile describing the relationships between external

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B(a)Peq concentration and lung cancer risk response, the population attributable

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fraction (PAF) concept that builds on past well-defined models is used (26) PAF =

rr( C BaPeq ) − 1

(4)

rr( C BaPeq )

rr = 1 + { URR

((( IR / BW ) / IRm )×C BaPeq ×( 70 / 100 ))

− 1 } × sus

(5)

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Where rr is the relative risk associated with a given BaPeq concentration (27), URR is

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the unit relative risk at a benchmark of 100 µg/m3·year of BaP exposure, with the

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value of 1.3 for Asia continent (20), IR is the respiration rate (m3/d), BW is the body

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weight (kg), IRm is the mean value of per unit body weight respiration rate, sus is the

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genetic susceptibility, and 70 is the lifelong exposure period (year) (the detailed

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information of these variables can be found in Section S8, SI). Here, IR, BW, CBaPeq,

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and sus were treated probabilistically (Figure SI-16) (27, 39).

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Lifetime lung cancer risk model

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The lifetime lung cancer risk from PAHs in outdoor atmosphere was estimated by

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multiplying the sum of individual BaPeq concentrations and the unit risk (UR) of

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exposure to BaP (13, 28, 40). The equation for this calculation is as follows:

CancerRisk = C BaPeq × URBaP 195

(6)

Where CBaPeq is the BaPeq concentration, URBaP is the inhalation unit risk of exposure 9



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to BaP (specifically, “the calculated, theoretical upper limit possibility of contracting

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cancer when exposed to BaP at a concentration of one microgram per cubic meter of

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air for a 70-year lifetime”) (41). As in previous studies, two different URBaP values

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were used in the inhalation cancer risk assessment. CalEPA has estimated a URBaP at

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1.1 × 10-6 per ng/m3 based on data for respiratory tract tumors from inhalation

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exposure in hamsters (41, 42), and the World Health Organization (WHO) has

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estimated URBaP at 8.7 × 10-5 per ng/m3 based on an epidemiology study on

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coke-oven workers (43). Both URBaP values were used to calculate excess

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PAH-induced inhalation lifetime lung cancer risk in this study.

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Uncertainty and sensitivity analysis

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A Monte Carlo simulation using the software Crystal Ball 7.2 was implemented to

207

evaluated the uncertainty and variability of the predicted exposure risk in the present

208

study (44). The simulation selects a value of each variable according to its distribution

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function at random to calculate the lung cancer risk, and the model ran for 10000

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iterations. Rank correlation coefficients between each input variable and the output

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(lung cancer risk) were calculated, and then by squaring the output variance and

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normalizing it to 100%, the contribution of each input variable to the output

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variance was assessed, and the sensitivity of each input variable relative to one

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another was evaluated (45).

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Statistical analysis

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All statistical analysis was conducted using Microsoft Excel 2010 and SPSS 16.0 for

217

Windows. Data were expressed as means ± standard deviation and analyzed using

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one-way ANOVA. Significant differences were set at p < 0.01.

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Results and discussion

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PAH concentrations

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General distribution

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The spatial distribution of annual mean air concentrations of PAHs from 176 sampling

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sites are shown in Figure 1. In all 5 Asian countries, the annual mean concentrations

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of ∑47PAHs (sum of 21 parent and 26 alkylated PAHs) were in the range of 6.29-688 10


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(128±132, mean±SD) ng/m3 (Figure 1 (a)), among which 4.10-409 (76.9±74.6) ng/m3

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for 16 EPA priority PAHs (∑16EPA-PAHs) (Figure 1 (b)) and 1.56-381 (46.2±57.8)

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ng/m3 for 26 alkylated PAHs (∑26alkyl-PAHs) (Figure 1 (c)). Higher concentrations

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were generally observed in urban areas, and lower concentrations were in

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rural/background areas. It was not unexpected that strong urban-rural-background

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transect was presented in the study area. Concentrations of ∑47PAHs in air samples

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were in the order of urban (143±117 ng/m3) > rural (126±147 ng/m3) > background

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(22.4±11.4 ng/m3), showing the typical “urban-rural transect pattern” (2, 46) or

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“primary distribution pattern” (47). Local sources, such as coal combustion and

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on-road mobile emissions, are the principal sources in these urban areas (9). Levels at

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the background sites were obviously lower than that in urban and rural sites (p

Distribution, Fate, Inhalation Exposure and Lung Cancer Risk of

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