1. Introduction
1.1 Background
1. Introduction
1.1 Background
Petrochemical industrial complex is a consortium of high-pollution facilities such as oil refineries and coal-fired power plants. These facilities emit multiple pollutants including sulfur oxides (SOx), nitrogen oxides (NOx), carbon dioxide (CO2), carbon monoxide (CO), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), vanadium (V), mercury (Hg), lead (Pb), manganese (Mn), copper (Cu), strontium (Sr), and thallium (Tl) (Chan et al. 2006; Driscoll et al. 2015; George et al. 2015; Hu et al.
2011; Nadal et al. 2004; Nadal et al. 2009). Cumulative exposure to such complex chemical mixtures may have synergistic effects on health, and warrant the use of novel analytical approaches for a comprehensive evaluation (Carpenter et al. 2002).
In Taiwan, Chan et al. have conducted for the past ten years, extensive environmental and epidemiological studies near No. 6 Naphtha Cracking Complex, the largest petrochemical complex in Taiwan. To date, Chan et al. have published 15 research articles in SCI journals, 12 master theses and doctoral dissertations, and annual reports documenting the environmental and health impacts of No. 6 Naphtha Cracking Complex on surrounding areas and residents (Table 1).
Environmental studies found significant increase of ambient pollutants within 10 km radius of the complex, including NOx, SOx, VOCs such as ethylene, propylene, propane, butane, and benzene, PAHs such as anthracene, chrysene, fluoranthene, phenanthrene, and pyrene, vinyl chloride monomers (VCM), and metals (詹長權 2010, 2011, 2012, 2013). For his doctoral dissertation, Shie did a comprehensive study of air toxics pollution in areas surrounding No. 6 Naphtha Cracking Complex from accidental and routine
emissions (謝瑞豪 2014). In 2011, he deployed a variety of air-monitoring instruments to evaluate the air toxin levels inside and downwind of No. 6 Naphtha Cracking Complex before and during a fire at the complex caused by a liquefied petroleum gas fuel leak.
They found high levels of combustion-related gaseous and particulate pollutants inside the complex and 10 km downwind for at least two days after the fire, demonstrating that a timely and comprehensive air monitoring is essential for tracing air pollution from industrial accidents (Shie and Chan 2013). Shie also used pollution rose to assess the level of SO2 in townships downwind to the complex in preoperational period (1995–1999) and two postoperational periods (2000–2004 and 2005–2009), and showed that in the postoperational periods, hourly SO2 levels exceeded the U.S. Environmental Protection Agency (EPA) health-based standard of 75 ppb (Shie et al. 2013). Pien established the protocols for analyzing heavy metals in particulate matters collected near No. 6 Naphtha Cracking Complex using Harvard Impactor, and in urine samples of residents living near the complex for her master thesis (邊瑋緒 2011). This methodology was later applied by Chio et al. to construct a two-stage dispersion model to assess the ambient concentrations of V and As in the vicinity of the complex, and by Yuan et al. to confirm association between model-estimated ambient V at home locations and individual urine concentrations of V in residents living near the complex (Chio et al. 2014; Yuan et al.
2015a). Yuan et al. established a kriging model to assess the ambient concentration of 16 PAHs surrounding the complex in 2015, and found significant association between estimated ambient levels of five PAHs including pyrene, benzo[a]anthracene, benzo[k]fluoranthene, fluoranthene, and dibenzo[a,h]anthracene, at home addresses and individual urinary concentrations of 1-hydroxypyrene (1-OHP) in residents living near the complex (Yuan et al. 2015b). These studies established urinary V and 1-OHP as exposure biomarkers for petrochemical industrial pollution within this area.
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In order to examine the health impact of petrochemical industrialization, Chen et al.
compared life expectancies and personal income between Yunlin County where No. 6 Naphtha Cracking Complex is located, and one reference county (Yilan County) which had no significant industrial activities, using data spanning 11 years before and after the complex began operations in 1999. Their findings showed Yunlin residents had lesser increases in life expectancy over time than Yilan residents, with male residents more vulnerable to the effects of industrialization, and no significant differences in individual income between the two counties (Chen et al. 2014).
Epidemiology studies were also conducted to further investigate the health impact of petrochemical industrial pollution on nearby residents, including chronic diseases such as cancer, chronic kidney disease, and hyperlipidemia, acute disease such as allergic diseases, asthma, and bronchitis, and subclinical abnormalities such as liver fibrosis. For his master thesis, Shen used primary data of demographic information, risk factors, biomarkers, and biochemical indices to investigate the adverse health effects, and secondary data of Taiwan Health Insurance Database (Registry for Catastrophic Illness Database) to retrospectively investigate the incidence of all cancers (ICD-9: 140-165, 170-176, 179-208) in 2,388 adults aged > 35 years at the time of recruitment (2009-2012), and aged >
20 years when the complex began operations in mid-1999, who have lived in Yunlin County for more than five years (沈育正 2014). Yuan et al. applied his methodology, and geographically classified the 2,388 participants into high exposure group (HE, lived in Mailiao and Taisi Townships, < 10 km from the complex), and low exposure group (LE, lived in Baojhong, Shihhu, Dongshih, Lunbei, Erlun, Citong, Yuanchang, and Huwei Townships, > 10 km from the complex). Temporally, Yuan et al. divided the 12 years participants lived near the complex since the operation of complex began with reported emissions of VOCs into the first period 1999-2007 (0-9 years after operation began) and
the second period 2008-2010 (10-12 years after operation began). Their results showed higher urine levels of carcinogens As, Cd, Hg, Pb, V, and PAHs biomarker 1-OHP at HE compared to LE, with Pb and V urine levels exceeding normal range, and significantly higher body mass index (BMI) and hepatitis C prevalence. Long-term SO2 pollution levels were also significantly higher in HE than LE areas. Significant exposure area effect on elevating the relative risks (RRs) of the all cancer crude cumulative incidence rates (CIRs) were found for elder subjects (1.52; 1.04-2.22), female subjects (1.41; 1.00-1.97), and elder female subjects (1.91; 1.15-3.19) after the complex had operated for 10-12 years (Yuan et al. 2018). Chen et al. conducted a similar study in Changhua County which is north of the complex, with 1,934 adult participants (aged > 20) recruited in 2014-2016 who have lived in this area for more than five years, geographically divided into three study zones: Taisi Village (average 5.5 km from complex), Dacheng Township (average 9.2 km from complex), and Zhutang Township (average 19.9 km from complex), comparing all cause cancer incidence rate (ICD-9: 140-208), and urine exposure biomarkers. Results showed urine levels of carcinogenic pollutants As, Cd, Cr, Ni, and V, as well as other pollutants Mn, Cu, and Tl were significantly higher for participants in Taisi Village compared to the other two study zones. Temporal increase for all cause cancer incidence rates (IRs) were found in all three study zones when comparing 1999-2007 period (0-9 years after operation began) to 2008-2014 period (10-16 years after operation began), with the highest crude incidence rate ratios (IRRs) in Taisi Village compared to the other two study zones. All cause cancer IRRs were higher for Taisi Village compared with the other two study zones for all subjects and male subjects, and higher for Taisi Villange than Dacheng Township for female subjects, after the complex had operated for 10-16 years, with hepatitis C and age significantly associated with higher all cause cancer IRRs (Chen et al. 2018).
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In addition to cancer, for his master thesis Ke analyzed 2,069 adult residents from the same epidemiology cohort that Shen used from Yunlin County, for urinary exposure biomarkers and the association with estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD). He found that decreased eGFR and increased odds ratio of CKD were associated with decreased distance from home address to complex, and increased levels of urine As ( 柯 登 元 2016). Jhuang conducted a similar study in Dacheng Township of Changhua County with 1,374 adult participants recruited from 2014-2016 for her master thesis. Her findings confirmed the association between decreased eGFR and increased risk of CKD with decreased distance from home location to complex, with increased urinary levels of Ni and Cr associated with decreased eGFR and increased risk of CKDs ( 莊 明 潔 2018). Shun’s master thesis discussed the association between serum heavy metals levels and hyperlipidemia and CKD in 1,000 Yunlin adult residents aged > 35 years from the same cohort as Shen and Ke. Her findings showed significant and positive association between serum Cr, As, and Hg with total cholesterol levels, serum Hg with low-density lipoprotein cholesterol levels (LDL-C), and serum As and Hg with risk of hyperlipidemia. She also found association between increased serum As, Cr, and Tl with decreased eGFR, and increased serum As and Cr with increased risk of CKD (孫稚翔 2017).
Epidemiology studies were also conducted in children and adolescents who lived near the complex during critical periods of biological development. Liu established for her master thesis, an analytical method for exposure biomarker urinary thiodiglycolic acid (TDGA), a major metabolite of VCM, and used this method to analyze urine samples from 268 schoolchildren recruited from four elementary schools in Mailiao Township of Yunlin County. She found children attending an elementary school less than 1 km from the VCM/polyvinylchloride (PVC) plants within the complex had higher urine
concentration of TDGA than children attending schools further away, and their urine levels of TDGA significantly reduced during summer vacation (劉力瑄 2014). These findings were later published and gained media attention, which eventually led to a temporary relocation of the children to another school further away from the complex (Huang et al. 2016). In 2018, Wang et al. found association between urine TDGA levels and subclinical abnormal levels of hepatic fibrosis indicators serum aspartate aminotransferase (AST) and fibrosis-4 score (FIB-4) in the same group of schoolchildren (Wang et al. 2019). Chen applied a similar study design on 447 adult residents in Dacheng and Zhutang Townships of Changhua County for his master thesis, and found residents living closer to the complex had increased urine levels of TDGA, and significant association between urinary TDGA concentrations and liver fibrosis level indicator FIB-4 (陳俊霖 2018). For her master thesis, Chiang recruited 587 11-1FIB-4 year old school children from junior high schools in Yunlin County from 2009 to 2011, who have lived at the same addresses for more than five years, and classified them as high exposure group (HE, lived in Mailiao, Taisi, Donshih Townships) and low exposure group (LE, lived in Erlun, Lunbei, Huwei, Baojhong, Sihhu, and Yuanchang Townships). Her study covered the time from 1999 to 2010, which was further divided into three periods: four years (1999-2002), eight years (1999-2006), and 12 years (1999-2010) after the complex began operations. Health data were obtained from Taiwan Health Insurance Database, choosing outpatient data for allergic rhinitis (ICD-9-CM: 477), bronchitis (ICD-9-CM: 490-491), and asthma (ICD-9-CM: 493). SO2 was used as an indicator of exposure from the complex, using hourly data measured at two air quality monitoring stations set up by the Taiwan Environmental Protection Administration (TEPA) at HE area Taisi Township and LE area Lunbei Township from 1995 to 2010. From 2001, SO2 concentration increased significantly in HE areas, and the three-year average of the 99th percentile of SO2
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concentration have exceeded U.S. EPA 75 ppb standards since 2003, and continued to do so with increasing concentrations up to 2010. Hazard ratios of children’s allergic rhinitis and bronchitis were significantly higher in HE compared to LE group for all three time periods, while for asthma the difference was only significant in the first time period. Boys had higher risk of developing allergic rhinitis and asthma, and children living near roads had higher risk of developing allergic rhinitis. Her results showed that association between SO2 exposure and acute respiratory effects occurred as early as < 2 years after the complex began operations, and lasted 8 to 12 years (Chiang et al. 2016; 江姿穎 2015). Killian recruited 168 preschool children aged 4-8 from four kindergartens within 13.7 km of the complex for her master thesis, and analyzed their urine concentrations of heavy metals and oxidative stress biomarkers, and at the same time used a food frequency questionnaire to assess individual’s intake of antioxidants. Her findings showed preschool children living closer to the complex had increased urinary levels of As, Cd, Cr, Ni, Pb, Mn, Cu, and Sr which were associated with elevated levels of urinary oxidative stress biomarker 8-hydroxy-2’-deoxyguanosine (8-OHDG). Increased intake of total oxidants resulted in a decrease of urine 8-OHDG that did not reach statistical significance (柯昀 君 2017).
In order to clarify the biological mechanism between industrial pollutants exposure and oxidative stress, Yuan et al. used nuclear magnetic resonance spectroscopy (NMR) to analyze serum metabolites of 160 residents from a prospective cohort in Yunlin County.
They found that exposure to V and PAHs may cause a reduction in amino acids and carbohydrates levels by elevating peroxisome proliferator-activated receptor (PPAR) signaling pathway, insulin signaling, and oxidative/nitrosative stress (Yuan et al. 2016).
In vitro study was also conducted, and results showed that exposure to PM2.5 from No. 6 Naphtha Cracking Complex emissions significantly correlated with reduced cell viability
and increased cytotoxicity-related lactate dehydrogenase, oxidative stress-related 8-isoprostane, and inflammation-related interleukin (IL)-6 (Chuang et al. 2018).
The findings of Chan et al. showed that adult, elderly, and children residents living near No. 6 Naphtha Cracking Complex are exposed to multiple hazardous industrial pollutants from routine and accidental emissions, and have increased risk of chronic and acute adverse health effects. Children and elderly residents may be more susceptible to these industrial pollutants exposure since children have immature physical development, and higher inhalation of air per unit time, and elderly residents may have compromised immune responses and underlying health conditions (Adler 2003; Makri and Stilianakis 2008). The complexity of industrial pollution and health effects on different age groups, with temporal and spatial differences in this industrial community, indicated that traditional models accessing single toxic exposure and disease are not sufficient in evaluating the health status of people living in this area. Comprehensive evaluation of multiple industrial pollutants exposure and the impact on biological mechanisms and pathways that underlie a range of common complex diseases are needed in order to provide information for future risk assessment and development of personal and community interventions. To achieve this, application of novel approaches were required (Juarez et al. 2014).
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Table 1. Studies on the Environmental and Health Impacts of No. 6 Naphtha Cracking Complex
Thesis / Dissertation SCI Journals External exposures
Accidental emissions (謝瑞豪 2014) (Shie and Chan 2013)Internal exposures
Respiratory disease (江姿穎 2015) (Chiang et al. 2016) Chronic kidney disease (柯登元 2016)(孫稚翔 2017) (莊明潔 2018)
Liver fibrosis (陳俊霖 2018) (Wang et al. 2019)
Hyperlipidemia (孫稚翔 2017)
Oxidative stress (柯昀君 2017)