Mass concentrations and lung cancer risk assessment of PAHs bound to PM1 aerosol in six industrial, urban and rural areas in the Czech Republic, Central Europe

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Mass concentrations and lung cancer risk assessment of PAHs bound to PM1 aerosol in six industrial, urban and rural areas in the Czech Republic, Central Europe Kamil Křůmal∗, Pavel Mikuška Institute of Analytical Chemistry of the Czech Academy of Sciences, Veveří 97, 602 00, Brno, Czech Republic

A R T I C LE I N FO

A B S T R A C T

Keywords: Polycyclic aromatic hydrocarbons Toxic equivalency factor benzo[a]pyrene Carcinogenic risk assessment Lifetime lung cancer risk

The daily concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) in PM1 aerosol samples, including 7 carcinogenic PAHs, were determined in six urban/rural areas in the Czech Republic in winter seasons between 2013 and 2017. The PM1 aerosol was collected on quartz fibre filters using high-volume samplers for 24 h and PAHs were analysed by GC-MS. The highest concentrations of PAHs were found in the industrial city Ostrava (60.8 ng m−3), which is one of the most polluted areas in the Czech Republic, while the lowest concentrations were obtained in the small town Čelákovice (11.7 ng m−3) and in the background rural area Košetice (12.3 ng m−3). Carcinogenic PAHs formed 43.9%–57.8% of total analysed PAHs. The toxic equivalence factors for individual PAHs adopted from literature and two unit risks (Cal-EPA and WHO) were used for the evaluation of carcinogenic risk of PAHs exposure. The inhalation cancer risk models assume a lifetime exposure (70 years), whereas our measurement was realized for a relatively short duration in winters where concentrations of PAHs are usually high. The average of PAHs concentrations will be lower for the whole year resulting in lower lung cancer risk values. The calculated lifetime lung cancer risk of PAHs exposure for the measured winter periods suggested 1545 cases per 1 million people in Ostrava (industrial area), 192–456 cases per 1 million people in other four investigated cities/towns and 182 cases per 1 million people in Košetice (rural area). The calculated lifetime lung cancer risk values are related only to ambient concentrations of PAHs in atmospheric aerosols. Nevertheless, other factors can influence and increase the lung cancer risk, e.g., occupation, smoking, indoor emissions of coal/wood combustion in stoves or genetic factors of individuals. Our results can also be underestimated due to the determination of PAHs only in PM1 aerosol.

1. Introduction PAHs are extensively investigated in atmosphere because some of them are considered to be carcinogenic/mutagenic, e.g., benzo[a] pyrene (BaP) as the usual marker for carcinogenic levels of PAHs (Alves, 2008). European Environment Agency (EEA) releases each year a report with an overview of air quality in Europe. Twenty seven countries (most from the European Union, EU) reported data of concentrations of BaP in 2016 from a total of 698 stations. Annual atmospheric concentrations of BaP exceeded the yearly limit value (1 ng m−3, measured in PM10) at 31% of measurement stations (13 countries), mainly in urban and suburban stations. Most of the monitoring stations that exceeded the yearly limit value were in Central Europe, especially in Poland (EEA, 2018). Similar conclusions were also obtained in previous years (EEA, 2015; 2016; 2017). Population is

exposed to PAHs by breathing ambient and indoor air, breathing smoke from fireplaces, smoking cigarettes, eating food-contaminated with PAHs, or by dermal contact (Abdel-Shafy and Mansour, 2016). After exposure and absorption, PAHs are rapidly distributed in the organism, circulated in the blood and are metabolized primarily in the liver (Abbas et al., 2018). An excess risk of lung cancer is significant health effect of inhalation of PAHs (Abdel-Shafy and Mansour, 2016; Li et al., 2019). The lung cancer risk assessment of ambient PAHs concentrations bound to PM based on toxic equivalency factors of individual PAHs was a subject of some studies (e.g., Bootdee et al., 2016; Jia et al., 2011; Li et al., 2019; Masiol et al., 2012; Mishra et al., 2016; Ramírez et al., 2011; Yan et al., 2019). Health effects from chronic exposure to PAHs may include breathing problems, asthma, lung function abnormalities, kidney and liver damage, cataract, decreased immune function or inducing geno-toxic damage (Abdel-Shafy and Mansour, 2016). EEA also

Peer review under responsibility of Turkish National Committee for Air Pollution Research and Control. ∗ Corresponding author. E-mail address: [email protected] (K. Křůmal). https://doi.org/10.1016/j.apr.2019.11.012 Received 21 August 2019; Received in revised form 4 November 2019; Accepted 5 November 2019 1309-1042/ © 2019 Turkish National Committee for Air Pollution Research and Control. Production and hosting by Elsevier B.V. All rights reserved.

Please cite this article as: Kamil Křůmal and Pavel Mikuška, Atmospheric Pollution Research, https://doi.org/10.1016/j.apr.2019.11.012

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require an enzymatic activation first (Abbas et al., 2018). This study presents the comparison of mass concentrations of PAHs determined in PM1 aerosol in industrial, urban and rural areas in the Czech Republic (Central Europe) and carcinogenic risk assessment of PAHs using benzo[a]pyrene equivalent concentration (BaP-eq), toxic equivalent factors (TEF) of individual compounds and two unit risks (calculated by the World Health Organization and the California Environmental Protection Agency). PAHs were studied in PM1 aerosol because this fraction is more dangerous to human health than PM2.5 and PM10 fractions (Falcon-Rodriguez et al., 2016) which are more frequently studied and monitored in atmosphere due to their WHO 24-h mean limits.

estimated the percent proportion of the EU-28 urban population which was exposed to BaP annual concentrations above the limit value (1 ng m−3), i.e., 25% in 2013 (EEA, 2015), 24% in 2014 (EEA, 2016), 20% in 2015 (EEA, 2017) and 21% in 2016 (EEA, 2018). Most monitoring programs and studies aim to analysis of 16 US-EPA (United States Environmental Protection Agency) priority PAHs, or BaP only (Abbas et al., 2018; Lammel, 2015). The list of 16 US-EPA PAHs contains acenaphthene, acenaphthylene, anthracene, benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[k] fluoranthene, chrysene, dibenz[a,h]anthracene, fluoranthene, fluorene, indeno[1,2,3-cd]pyrene, naphthalene, phenanthrene and pyrene. The International Agency for Research on Cancer (IARC; the cancer agency of the World Health Organization, WHO), determines the cancer-causing potential of different substances. The IARC includes benzo[a]pyrene into Group 1 and dibenz[a,h]anthracene into Group 2A. Other 6 members of US-EPA PAHs list are included in the Group 2B and 7 US-EPA PAHs in the Group 3 (IARC, 2019). The United States Environmental Protection Agency (US-EPA), another agency often used for risk assessment, maintains an electronic database the Integrated Risk Information System (IRIS), which contains information on human health effects from exposure to certain chemicals found in the environment. According to “Guidelines for carcinogen risk assessment” from 2005, there are five recommended standard hazard descriptors: “Carcinogenic to humans”; “Likely to be carcinogenic to humans”; “Suggestive evidence of carcinogenic potential”; “Inadequate information to assess carcinogenic potential”; and “Not likely to be carcinogenic to humans” (US-EPA, 2005). However, only benzo[a]pyrene is classified according to the latest Guidelines as “Carcinogenic to humans”. Other US-EPA PAHs are classified using criteria of Guidelines from 1986, i.e., Group B2, C or D (IRIS Assessments). Carcinogenicity assessment of PAHs by IARC and US-EPA is showed in Table 1. PAHs are reactive in the atmosphere even if they are often referred to be persistent organic pollutants (POPs) (Keyte et al., 2013; Lammel, 2015). PAHs react especially with OH and NO3 radicals and also with ozone and nitrogen dioxide in atmosphere. These atmospheric reactions lead to a formation of nitrated and oxygenated derivatives; some of them are stronger mutagens and carcinogens than parent PAHs (Keyte et al., 2013). Derivatives of PAHs are more toxic than their parent PAHs because of their direct toxic (mutagenic) potency, while parent PAHs

2. Experimental 2.1. Aerosol collection and sampling sites Atmospheric aerosols (PM1 fraction) were sampled daily for 24-h in six localities in the Czech Republic in winter, i.e., Mladá Boleslav (15–February 28, 2013), Ostrava-Radvanice (6 February – March 6, 2014), Čelákovice (21 January – February 5, 2015), Kladno-Švermov (2 February – March 1, 2016), Brno (18 January – February 1, 2017) and Košetice (23 January – February 5, 2017), on quartz fibre filters (Whatman, 150 mm diameter) using high-volume samplers (DHA-80 and DHA-77, Digitel) with air flow of 30 m3 h−1. High-volume samplers were equipped with a PM1 inlet (Digitel). Before collection of aerosol, all quartz fibre filters were heated at 500 °C for 24-h to remove organic contaminants. All sampling localities are showed in Fig. 1. Mladá Boleslav (small industrial town, approx. 44 thousand inhabitants) is located about 50 km northeast of Prague (capital of the Czech Republic). Mladá Boleslav is a centre of the Czech automobile industry. Ostrava (industrial city, approx. 292 thousand inhabitants) is the third largest city of the Czech Republic and is the principal city of the Moravian-Silesian Region which is one of the most polluted regions in the Czech Republic and also in the European Union. Recently, Ostrava was an important industrial centre with mining and metallurgical industry which lead to high air pollution. However, many of the heavy industries have been closed or transformed (Pokorná et al., 2015). The combination of a steel industry

Table 1 IARC and US-EPA classification of PAHs, and toxic equivalency factors (TEF) or relatively potency factors (RPF) of PAHs adopted from literature. Compound

IARC

US-EPA

TEF1

RPF2

TEF3

TEF4

TEF5

RPF6

Naphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benz[a]anthracene Chrysene Benzo[b]fluoranthene Benzo[k]fluoranthene Benzo[e]pyrene7 Benzo[a]pyrene Perylene7 Indeno[1,2,3-cd]pyrene Dibenz[a,h]anthracene Benzo[g,h,i]perylene

2B – 3 3 3 3 3 3 2B 2B 2B 2B 3 1 3 2B 2A 3

C D – D D D D D B2 B2 B2 B2 – Carc. – B2 B2 D

0.001 0.001 0.001 0.001 0.001 0.01 0.001 0.001 0.1 0.01 0.1 0.1 – 1 – 0.1 5 0.01

– – – 0.0005 0.0005 0.0005 0.05 0.001 0.005 0.03 0.1 0.05 0.002 1 – 0.1 1.1 0.02

0.001 0.001 0.001 0.0005 0.0005 0.0005 0.05 0.001 0.005 0.03 0.1 0.05 0.002 1 – 0.1 1.1 0.02

– – – – – – 0.001 0.001 0.1 0.01 0.1 0.1 0.1 1 – 0.1 1 0.01

0.001 0.001 0.001 0.001 0.001 0.01 0.001 0.001 0.1 0.01 0.1 0.1 – 1 – 0.1 1 0.01

– – – – 0 0 0.08 0 0.2 0.1 0.8 0.03 – 1 – 0.07 10 0.009

TEF/RPF adopted from: 1 Nisbet and LaGoy (1992); 2 Larsen and Larsen (1998); 3 Ramírez et al., 2011; 4 Masiol et al. (2012); 5 Bootdee et al. (2016); 6 Jia et al. (2011); 7 not included in US-EPA PAHs. IARC classification: 1 = Carcinogenic to humans; 2A = Probably carcinogenic to humans; 2B = Possibly carcinogenic to humans; 3 = Not classifiable as to its carcinogenicity to humans. US-EPA classification: Carc. = Carcinogenic to humans; B2 = Probable human carcinogen – based on sufficient evidence of carcinogenicity in animals; C = Possible human carcinogen; D = Not classifiable as to human carcinogenicity. 2

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Fig. 1. Sampling localities in the Czech Republic.

of PAHs on field blank filters were under the LODs.

with coking plants and long-range transport of polluted air from the Silesian Voivodeship in Poland still causes one of the worst air quality in the European Union (Mikuška et al., 2015; Pokorná et al., 2015). Radvanice (sampling site) is the most polluted part of Ostrava. Čelákovice is a small town (approx. 12 thousand inhabitants) situated about 27 km eastern of Prague. Švermov (sampling site) is northern part of the town Kladno (approx. 69 thousand inhabitants) which is situated about 25 km northwest of Prague. Recently, Kladno was important industrial centre of the Czech Republic with mining and steel industry resulting in damaged local environment. Brno (approx. 378 thousand inhabitants), the second largest city of the Czech Republic, is an industrial, political and economical centre of Moravia. Košetice (less than 1 thousand inhabitants) is classified as a background rural area and is situated away from residential areas and also out of reach of the most pollution sources in the Czech Republic. Sampling sites were, in general, placed in the centre of studied locality or near the industrial complex that was suspected for prevailing pollution at studied locality (the site was placed in the direction of the prevailing wind direction from industrial complex). Aerosols were sampled at height about 2 m above ground level. Big attention was payed to the selection of representative location of each campaign to avoid short-term peaks from local traffic and assess the impact of household heating on air quality in the residential district. That is why, a small-scale network of laser photometers (DustTrak) were built to measure 5 min integrates of PM2.5 concentrations over the whole campaign. More details can be found elsewhere (Pokorná et al., 2015). Dates and length of campaigns were chosen with respect to long-term stability of weather at studied locality.

2.3. Carcinogenic risk assessment of PAHs The health risk relating to an exposure of ambient carcinogenic PAHs to humans within their 70-year lifetime can be computed as (Křůmal et al., 2017):

Lifetime lung cancer risk = URBaP × BaPeq = URBaP ×

∑ (cPAHi × TEFi) i

We used two URBaP values; the first value 8.7 × 10−5 (ng m−3)−1 was calculated by the World Health Organization (Jia et al., 2011; WHO, 2000) and the second value 1.1 × 10−6 (ng m−3)−1 was calculated by the California Environmental Protection Agency (Jia et al., 2011; OEHHA, 2005). In the case of using the WHO URBaP value, the lung cancer may develop in 87 per 1 000 000 people with chronic inhalational exposure of 1 ng m−3 of BaP within their 70-year lifetime. In the case of using the CalEPA URBaP, the calculated cases are much lower, i.e., 1.1 per 1 000 000 people. The BaP-eq (benzo[a]pyrene equivalent concentration) index was calculated by multiplication of concentration of each individual PAH by its corresponding TEF, i.e., toxic equivalency factor for cancer potency relating to BaP (Křůmal et al., 2017; and references therein). TEF values, used for this study, were taken from literature (Table 1). 3. Results and discussion 3.1. PM1 concentrations

2.2. Sample preparation and GC-MS analysis

PM1 aerosol was measured in winter seasons because of its higher concentration resulting from wood/coal combustion for household heating which is the most significant emission source in winter in the Czech Republic (Křůmal et al., 2013; Mikuška et al., 2017). Mass concentrations of the PM1 aerosols (Table S1) measured in winter campaigns were in the range of 11.2–45.2 μg m−3 (average 26.0 μg m−3) in Mladá Boleslav 2013, 13.2–56.0 μg m−3 (average 29.4 μg m−3) in Ostrava-Radvanice 2014, 8.51–32.4 μg m−3 (average 17.6 μg m−3) in Čelákovice 2015, 4.34–48.3 μg m−3 (average 18.8 μg m−3) in KladnoŠvermov 2016, 20.5–55.3 μg m−3 (average 34.2 μg m−3) in Brno 2017 and 12.7–32.2 μg m−3 (average 24.5 μg m−3) in Košetice 2017. The highest concentrations of PM1 and the lowest average temperature were measured in Brno (urban area) in 2017. The PM1 concentrations at

Detailed description of determination of mass concentrations of collected PM1 aerosols, sample preparation of PAHs, i.e., extraction from filters and fractionation by column chromatography filled with activated silicagel (Křůmal et al., 2013), and GC-MS analysis of PAHs (Křůmal et al., 2013) are present in Supplementary material (Text S1). Prior to extraction of PAHs, recovery standards (phenanthrene-D10, chrysene-D12 and perylene-D12) were added to filters to correct of losses during sample preparation. Good procedure recoveries ranging from 86 to 106% were evaluated on PM1 samples spiked with recovery standards. The LODs for PAHs ranged between 1.25 and 38.7 pg m−3 depending on individual PAH and year of analysis. Mass concentrations 3

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3.2. PAHs concentrations

studied localities were influenced next to temperature also by other factors such as wind speed and direction, composition of emission sources, the type of material being combusted and localization of emission sources (local/regional sources, long range transport) etc. The mass concentrations of PM1 in Ostrava-Radvanice were lower than we had expected, because the whole Moravian-Silesian region belongs to the most polluted regions in the Czech Republic (Pokorná et al., 2015) and in Europe as well (EEA, 2015; 2016; 2017; 2018). In addition, the concentration of aerosol in Ostrava significantly increases during smog episode (Mikuška et al., 2015). However, the temperature during the whole campaign in winter 2014 was higher than usual, so the lower concentrations of PM1 were probably caused by lower wood/coal combustion for household heating (Guerreiro et al., 2016). At present, there is no limit for the mass concentration of PM1 particles in ambient air in the Czech Republic and in the EU. The PM1 concentrations found during our measurements were in more than half of measured days of the winter campaigns so high that exceeded the WHO 24-h mean limit (25 μg m−3) set for PM2.5 particles (Kuklinska et al., 2015), especially in urban areas (Mladá Boleslav, Ostrava-Radvanice, Brno) and also in rural area (Košetice). The PM1 concentrations also sometimes exceeded the WHO 24-h mean limit (50 μg m−3) set for PM10 particles (Kuklinska et al., 2015) during campaigns, i.e., once in Ostrava-Radvanice (industrial area) and twice in Brno (urban area).

Fifteen PAHs were quantified in all PM1 aerosol samples (Fig. 2, Table S1). Low molecular weight PAHs (naphthalene, acenaphthylene, acenaphthene) were not quantified due to their high volatility resulting in significant losses during the sample preparation. Benzo[b]fluoranthene and benzo[k]fluoranthene were poorly separated on used GC column, therefore, their concentrations were summarized. The highest concentrations of PAHs were found in OstravaRadvanice (industrial city) and the lowest in Čelákovice (small town) and in Košetice (rural area). The similar trend was observed in the contributions of PAHs to PM1 mass. Analysed PAHs formed 0.197% of PM1 mass in Ostrava-Radvanice, while the contributions in other localities were smaller, i.e., 0.114% in Kladno-Švermov and 0.053–0.061% in other investigated urban/rural localities (Table S1). Coal combustion (i.e., 58.6%) was determined as a main source of fine aerosol in Ostrava (Pokorná et al., 2015). In general, domestic emissions (combustion of coal/wood for household heating) belong to the main emission sources of PAHs in winter seasons (Guerreiro et al., 2016). The emission factors of PAHs from combustion of solid fuels in boilers of old construction, often still used in Central Europe, are much higher than those from modern-type boilers (Horak et al., 2017; Krpec et al., 2016; Křůmal et al., 2019; Šyc et al., 2011). However, the average temperature during sampling in Ostrava was 5.3 °C compared to other winter seasons, so the contribution of domestic emissions was probably lower. Industrial emissions are another significant source of PAHs in

Fig. 2. Average concentrations of PAHs and percent contributions of individual PAH to the sum of PAHs at investigated localities. 4

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Table 2 Winter concentrations of PAHs (ng m−3) in aerosols in some European cities. PM fraction

Locality

PAHs (ng m−3)

Reference

PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1 PM1

Mladá Boleslav (Czech Republic), urban site Ostrava-Radvanice (Czech Republic), industrial site Čelákovice (Czech Republic), small town Kladno-Švermov (Czech Republic), urban site Brno (Czech Republic), urban site Košetice (Czech Republic), rural site Madrid (Spain), 2010, urban roadside Madrid (Spain), 2010, urban roadside Thessaloniki (Greece), 2013, urban site Thessaloniki (Greece), 2013, urban background site Bologna (Italy), 2009, suburban site Brno (Czech Republic), 2009, urban site Šlapanice (Czech Republic), 2009, small town Brno (Czech Republic), 2010, urban site Šlapanice (Czech Republic), 2010, small town Zabrze (Poland), 2006, urban background site Zabrze (Poland), 2007, urban background site Złoty Potok (Poland), 2009, 2010, regional background site Katowice (Poland), 2009, 2010, urban background site Katowice (Poland), 2009, 2010, urban traffic site

15.6 60.8 11.7 25.5 20.7 12.3 4.10 0.755 2.82 8.31 5.70 22.2 21.0 39.8 38.7 46.4 128 23.1 139 186

This study This study This study This study This study This study Mirante et al. (2013) Mirante et al. (2013) Sarigiannis et al. (2015) Sarigiannis et al. (2015) Sarti et al. (2017) Křůmal et al. (2013) Křůmal et al. (2013) Křůmal et al. (2013) Křůmal et al. (2013) Klejnowski et al. (2010) Rogula-Kozłowska et al. (2013) Kozielska et al. (2015) Kozielska et al. (2015) Kozielska et al. (2015)

were in Košetice (rural area) and Brno (urban area, South Moravia close to Austria).

Moravian-Silesian Region (Ostrava as the principal city). The MoravianSilesian Region together with Silesian Voivodeship in the Czech-Polish border represent one of the most industrial regions in Central Europe with a great numbers of coke oven plants, steel plants, blast furnaces and rolling mills (Mikuška et al., 2015). The lowest contribution of PAHs in PM1 mass was observed in Košetice which is classified as a background rural area and is situated away from residential areas and also out of reach of the most pollution sources. We compared the concentrations of PAHs in winter at investigated localities in the Czech Republic with those available in the literature (Table 2). The concentrations of PAHs in PM1 in our study were higher than those in PM1 in other European cities, e.g., in Madrid in Spain (Mirante et al., 2013), in Thessaloniki in Greece (Sarigiannis et al., 2015), in Bologna in Italy (Sarti et al., 2017). The concentrations of PAHs in PM1 in this study were at the same level or higher than those PAHs measured in our previous study in Brno and Šlapanice (Křůmal et al., 2013). However, the concentrations of PAHs in PM1 in our study were at the same level or much lower than those in Upper Silesia in Poland (close to Ostrava-Radvanice), e.g., in Zabrze (Klejnowski et al., 2010; Rogula-Kozłowska et al., 2013), in Złoty Potok (Kozielska et al., 2015), in Katowice (Kozielska et al., 2015). The trend of percent contributions of individual PAH to the sum of PAHs (Fig. 2 and Fig. S1) was very similar during campaigns at all investigated localities. Higher portion of low molecular PAHs was observed in Mladá Boleslav, probably due to a heating plant situated inside the automobile factory for a combustion of brown and hard coal with an addition of biomass, which supplies heat to about two thirds of all households in Mladá Boleslav (Křůmal et al., 2017). The trends in Brno (urban area) and Košetice (rural area) were nearly identical (measurement in the same winter 2017). It seems that the combustion of solid fuels for household heating as the main source of PAHs dominate over other sources of PAHs during winter in the Czech Republic. However, the concentrations of PAHs were almost twice higher in Brno than those in Košetice, probably due to much higher number of local and regional emission sources (households) in Brno. The sum of mean concentrations of 7 analysed carcinogenic PAHs (c-PAHs; Group 1, 2A and 2B according to IARC) in PM1 were between 5.46 ng m−3 (rural area) and 33.9 ng m−3 (industrial area), which suggests that 43.9–57.8% of total analysed PAHs had carcinogenic potential. The higher values (above 50%) were in northwest part of the Czech Republic, i.e., Mladá Boleslav, Čelákovice and Kladno-Švermov (all of them close to thermal power plants used for brown coal), and Ostrava-Radvanice (industrial area). The lower values (below 50%)

3.3. Carcinogenic risk assessment of PAHs The benzo[a]pyrene equivalent concentration (BaP-eq) was established instead of the single benzo[a]pyrene concentration for evaluation and expression of health risk of PAHs to humans. The index is computed by multiplication of concentration of each individual PAH by its corresponding toxic equivalency factor or relatively potency factor (Křůmal et al., 2017). Toxic equivalency factors (TEF) and relatively potency factors (RPF) of PAHs used for calculation of toxicity in this study were adopted from literature (Table 1). The most used TEF in scientific papers were proposed by Nisbet and LaGoy (1992) who modified TEF presented in previous papers (Nisbet and LaGoy, 1992; and references therein) to be more appropriate for environmental exposures. Larsen and Larsen (1998) introduced RPF based on the authors' compilation of carcinogenicity studies in experimental animals (Larsen and Larsen, 1998). Other authors (e.g., Bootdee et al., 2016; Masiol et al., 2012; Ramírez et al., 2011) usually use combination of TEF values proposed by those two papers (Larsen and Larsen, 1998; Nisbet and LaGoy, 1992) or RPF values from the US-EPA's IRIS (Jia et al., 2011). Calculated BaP-eq averages for 15 analysed PAHs during all campaigns are showed in Table 3. Although different TEF values (Table 1) are applied, the calculated BaP-eq are very similar for individual campaigns and the highest values were found for the measurement in the industrial area (Ostrava-Radvanice 2014). Applying TEF values suggested by Nisbet and LaGoy (1992) or RPF values by Jia et al. (2011), the calculated BaP-eq indexes (Table 3) are higher because they are affected by higher TEF/RPF value for dibenz[a,h]anthracene. Nisbet and LaGoy (1992) report that a TEF of 1 for dibenz[a,h]anthracene appears to be appropriate for high doses but TEF of 5 is more appropriate for environmental exposures. Jia et al. (2011) used even higher RPF (10). The calculated lifetime lung cancer risk using WHO and CalEPA URBaP values are showed in Table S2 and Table 3. For example, applying the suggested TEF values (Nisbet and LaGoy, 1992) and WHO URBaP value of 8.7 × 10−5 (ng m−3)−1 for lifetime (70 years) PAH exposure, the corresponding lifetime lung cancer is 1.55 × 10−3 on average (range of 4.21 × 10−4 – 4.58 × 10−3) for the measurement in Ostrava-Radvanice 2014. Thus if 1 million people are exposed to 17.8 ng m−3 (Table 3) of ambient BaP-eq for 70 years, then lung cancer may develop in 1545 people on average (range of 421–4 583, Table 3, Fig. 3). Applying the Cal-EPA URBaP, the calculated lifetime lung cancer 5

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Table 3 The calculated lifetime lung cancer risk using WHO and Cal-EPA URBaP values. Mladá Boleslav 2013 (n = 14)

Ostrava-Rad. 2014 (n = 29)

Čelákovice 2015 (n = 16)

BaP-eq 17.8 (4.83–52.7)\1 2.64 (0.591–6.87)\1 TEF 1 2.21 (0.193–4.95)\1 RPF 2 1.33 (0.177–2.78)\1 9.73 (2.50–26.9)\1 1.90 (0.436–4.89)\1 TEF 3 1.33 (0.177–2.78)\1 9.73 (2.50–26.9)\1 1.90 (0.436–4.89)\1 TEF 4 1.64 (0.205–3.84)\1 10.6 (3.36–29.4)\1 2.01 (0.448–5.18)\1 TEF 5 1.57 (0.193–3.70)\1 10.1 (3.18–28.1)\1 1.92 (0.428–4.93)\1 RPF 6 4.04 (0.371–8.82)\1 32.6 (9.62–98.0)\1 4.67 (1.04–12.2)\1 Lifetime lung cancer risk per 1 million people - using WHO URBaP values 1 TEF 192 (16.8–430)\1 1545 (421–4583)\1 230 (51.4–598)\1 RPF 2 116 (15.4–242)\1 847 (217–2338)\1 165 (37.9–426)\1 TEF 3 116 (15.4–242)\1 847 (217–2338)\1 165 (37.9–426)\1 TEF 4 143 (17.8–334)\1 922 (292–2559)\1 175 (39.0–451)\1 TEF 5 137 (16.8–322)\1 878 (277–2448)\1 167 (37.3–429)\1 RPF 6 351 (32.2–767)\1 2834 (837–8529)\1 406 (90.8–1063)\1 Lifetime lung cancer risk per 1 million people - using Cal-EPA URBaP values TEF 1 2.43 (0.213–5.44)\1 19.5 (5.32–57.9)\1 2.90 (0.650–7.56)\1 RPF 2 1.46 (0.194–3.06)\1 10.7 (2.75–29.6)\1 2.09 (0.479–5.38)\1 TEF 3 1.46 (0.194–3.06)\1 10.7 (2.75–29.6)\1 2.09 (0.479–5.38)\1 TEF 4 1.81 (0.225–4.22)\1 11.7 (3.69–32.4)\1 2.22 (0.493–5.70)\1 TEF 5 1.73 (0.213–4.08)\1 11.1 (3.50–31.0)\1 2.11 (0.471–5.43)\1 RPF 6 4.44 (0.408–9.70)\1 35.8 (10.6–108)\1 5.13 (1.15–13.4)\1

TEF/RPF adopted from: (2011).

1

Nisbet and LaGoy (1992);

2

Larsen and Larsen (1998);

3

Kladno-Šv. 2016 (n = 29)

Brno 2017 (n = 15)

Košetice 2017 (n = 15)

5.25 3.89 3.89 4.13 3.96 9.18

(0.503–20.2)\1 (0.367–15.0)\1 (0.367–15.0)\1 (0.387–16.0)\1 (0.366–15.4)\1 (0.933–34.4)\1

3.47 2.61 2.61 2.67 2.54 6.38

(0.495–11.7)\1 (0.370–9.00)\1 (0.370–9.00)\1 (0.373–9.16)\1 (0.345–8.75)\1 (0.994–21.2)\1

2.09 1.52 1.52 1.55 1.46 3.96

(0.770–5.00)\1 (0.564–3.51)\1 (0.564–3.51)\1 (0.555–3.62)\1 (0.511–3.44)\1 (1.60–9.13)\1

456 338 338 359 344 799

(43.8–1757)\1 (32.0–1306)\1 (32.0–1306)\1 (33.7–1395)\1 (31.8–1341)\1 (81.2–2994)\1

302 227 227 232 221 555

(43.0–1016)\1 (32.2–783)\1 (32.2–783)\1 (32.4–797)\1 (30.0–761)\1 (86.4–1843)\1

182 133 133 135 127 344

(67.0–435)\1 (49.1–305)\1 (49.1–305)\1 (48.3–315)\1 (44.5–299)\1 (139–795)\1

5.77 4.28 4.28 4.54 4.35 10.1

(0.553–22.2)\1 (0.404–16.5)\1 (0.404–16.5)\1 (0.426–17.6)\1 (0.402–17.0)\1 (1.03–37.9)\1

3.82 2.87 2.87 2.94 2.79 7.02

(0.544–12.8)\1 (0.407–9.90)\1 (0.407–9.90)\1 (0.410–10.1)\1 (0.379–9.62)\1 (1.09–23.3)\1

2.30 1.68 1.68 1.70 1.61 4.36

(0.847–5.50)\1 (0.621–3.86)\1 (0.621–3.86)\1 (0.611–3.98)\1 (0.562–3.78)\1 (1.76–10.1)\1

Ramírez et al., 2011;

4

Masiol et al. (2012);

5

Bootdee et al. (2016);

6

Jia et al.

eq = 26.8 ng m−3) cases per 1 million people (Mikuška et al., 2015). Calculated lifetime lung cancer risk values were much lower in other investigated areas (Table 3) and the lowest values were obtained in Košetice (rural area). We analysed PAHs/c-PAHs only in PM1 aerosol, thus the real lifetime lung cancer risk values, calculated from PAHs concentrations in PM10 aerosol, are probably a little higher. For instance, 72.4% of 16 US-EPA PAHs were present in PM1 fraction in comparison with PAHs content in fraction PM10 in urban area in Poland (Zabrze, Upper Silesian region, approx. 70 km north of Ostrava) in winter 2006/2007 (Klejnowski et al., 2010) and 82.0% in winter 2007/ 2008 (Rogula-Kozłowska et al., 2013). The calculated lifetime lung cancer risk values are related only to ambient concentrations of PAHs in PM1. The concentrations of PAHs will be slightly higher in the PM2.5 fraction (fine aerosol), which is deposited in the lung (Falcon-Rodriguez et al., 2016). Thus the lifetime lung cancer risk values calculated from the PAHs concentrations adsorbed on fine particles will be also slightly higher. Nevertheless,

risk is much lower. Ostrava is known as one of the most polluted area in the Czech Republic. A few toxicological studies have demonstrated significant impact of air pollution in Ostrava region on the health of the population with an increased proportion of respiratory illnesses compared to other areas in the Czech Republic (Sram et al., 2013; Topinka et al., 2015). The WHO 24-h mean limit for PM10 (50 μg m−3) is frequently exceeded in Ostrava region in winter seasons due to high anthropogenic local emissions, transport of polluted air from Poland and also frequent temperature inversion episodes and smog formation (Leoni et al., 2018; Mikuška et al., 2015). Therefore, calculated lifetime lung cancer risk values for WHO URBaP and TEF adopted from Nisbet and LaGoy (1992) in the industrial city of Ostrava was more significant in colder winter with temperature inversion episodes in January of 2012 (Mikuška et al., 2015), i.e., 8.92 × 10−3 on an average in smog episode (average temperature of −10.1 °C) and 2.34 × 10−3 on an average after smog episode (average temperature of +0.9 °C). It means 8921 (smog, BaP-eq = 103 ng m−3) and 2336 (after smog, BaP-

Fig. 3. The calculated lifetime lung cancer risks per 1 million people using WHO URBaP values and TEF values adopted from the Nisbet and LaGoy (1992). 6

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doi.org/10.1016/j.apr.2019.11.012.

another factors can influence the lung cancer risk, e.g., occupation (incinerators, some industrial processes), smoking, indoor emissions of coal/wood combustion in stoves (during cooking) or genetic factors of individuals. The number of PAHs present in the environment is also significantly larger than 16 US-EPA PAHs (Petit et al., 2019), however, the knowledge about carcinogenic properties of other PAHs is limited. Therefore, the US-EPA 16 PAHs were selected for toxic effects PAHs studies based on the knowledge of their levels in the environmental samples, chance of exposure and relative toxicity (Samburova et al., 2017).

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4. Conclusion We determined 15 PAHs in the PM1 aerosol samples collected during winter campaigns (2013–2017) in six different localities in the Czech Republic (Central Europe), i.e., Mladá Boleslav, OstravaRadvanice, Čelákovice, Kladno-Švermov, Brno and Košetice. Ostrava represented industrial area and Košetice background rural area which is situated away from residential areas and also out of reach of the most pollution sources in the Czech Republic. Other 4 cities/towns presented urban areas. The highest average sum of concentrations of PAHs was found in Ostrava-Radvanice (60.8 ng m−3, industrial area) and the lowest in Čelákovice (11.7 ng m−3, small town) and Košetice (12.3 ng m−3, rural area). Analysed PAHs formed 0.197% of PM1 mass in OstravaRadvanice, while the contribution in other localities were smaller, i.e., 0.114% in Kladno-Švermov and 0.051–0.061% in other investigated localities. The average sums of concentrations of 7 analysed carcinogenic PAHs (Group 1, 2A and 2B according to IARC) in PM1 were between 5.46 ng m−3 (Košetice, rural area) and 33.9 ng m−3 (Ostrava, industrial area), which suggests that 43.9–57.8% of total analysed PAHs had carcinogenic potential. The carcinogenic risk assessment of PAHs was evaluated as lifetime lung cancer risk of PAHs exposure according to the WHO and Cal-EPA unit risks, the TEF values for individual PAH and the BaP-eq indexes. The calculated lifetime lung cancer risk of PAHs exposure for the measured winter periods suggested 1545 cases per 1 million people in Ostrava (industrial area), 192–456 cases per 1 million people in other four investigated cities/towns and 182 cases per 1 million people in Košetice (rural area). The concentrations of airborne particulate PAHs varied widely between the studied localities with the highest level in industrial site and the lowest concentration in rural site. The concentration of PAHs (especially benzo[a]pyrene) correlates with the lifetime lung cancer risk of PAHs. Industrial area (Ostrava-Radvanice) represents a site with the highest carcinogenic risk assessment of PAHs resulting in the highest lifetime lung cancer risk of PAHs exposure while the rural area (Košetice) is the place with the lowest carcinogenic risk assessment of PAHs and the lowest lifetime lung cancer risk of PAHs exposure. Other studied localities representing the urban area were among the results of industrial and rural site. To protect public health and reduce human exposure to PAHs, the improving the environmental and in particular air quality by reducing the concentration of PM due to the control of the main emission sources, such as residential heating, traffic and industry, and the transition from combustion to green renewable sources of energy is needed. Acknowledgement The work was supported by the Grant Agency of the Czech Republic (grant No. P503/12/G147) and by the Institute of Analytical Chemistry of the Czech Academy of Sciences (RVO:68081715). Appendix A. Supplementary data Supplementary data to this article can be found online at https:// 7

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