The Yunlin County Government has contracted National Taiwan University (NTU) to conduct a cohort study on air pollution and health among residents near the No. 6 Naphtha Cracker Complex, which is located in Miliao Township, Yunlin County, Taiwan since 2009. In this year, Public Health Bureau of Yunlin County contracted NTU to conduct a sustainable environmental epidedmiological cohort study to clarify the comprehansive environmental exposure and health status of residents in Yunlin County. The study areas are 10 townships surrounding the petrochemical complex, including Baojhong, Taisi, Sihhu, Dongshih, Mailiao, Lunbei, Erlun, Citong, Yuanchang and Huwei. These townships are classified as three zones based on their distance to the petrochemical complex. Zone A includes Mailiao and Taisi which are within 10km radius of the petrochemical complex; Zone B includes Baojhong, Sihhu, Dongshih and Lunbei, townships which are located 10-20km radius of the petrochemical complex; and Zone C includes Erlun, Citong, Yuanchang and Huwei townships which are located within 20-30km radius from the petrochemical complex.
The NTU research team adopted a multiple-disciplinary approach to conduct this study, including epidemiological cohort study, biomarker analysis, and environmental pollutant monitoring. For the established epidemiological cohort with a total of 3,230 residents, we analyzed all cancer incidence rate (ICD-9:140-165, 170-176, 179-208) after the operation of No. 6 Naphtha Cracker Complex (1999-2010), and analyzed biological monitoring of 1,755 residents’ urinary Cr, Cu, Hg, and Tl levels and 341 residents’ urinary 1-hydroxypyren (1–OHP) levels, and conducted the follow-up survey for 246 residents. By selecting from the epidemiological cohort, we conducted the blood metabolomics analysis for extreme high and low exposure groups (with the differences of more than twenty-folds urinary V and 1-OHP levels), and analyzed urinary environmental toxic chemicals for high and low exposure children groups (with the differences of more than four-folds urinary V and 1-OHP levels). In this year, we recruited a susceptible cohort of 103 new subjects, including 57 pregnant women and 46 new-born babies, and followed up 63 1-year babies, 30 2-years babies, and 8 3-years babies to conduct questionnaire survey and biospecimen preservation. For environmental monitoring, we used the data of Taisi, Lunbei, and Douliou air monitoring station during 1996-2013 to investigate the changes of air pollutants concentrations befrore and after the operation of No. 6 Naphtha Cracker Complex development, and analyzed the data of Taisi photochemical monitoring station and Mailiao photochemical monitoring mobiles to understand the No. 6 Naphtha Cracker Complex’ exposure impact of volatile organic compounds (VOCs) in Zone A. In addition, we evaluated the spatial distributions of PM10 samples for heavy metals, PM2.5 samples for polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), SO2, NO2, and NOx for a total of 85 samples in Zone A in three seasons from September 2013 to August 2014.
In the established epidemiological cohort of 3,230 residents during 2009-2011, the all cancer incidence rate (unit: 1,000 person year) of older than 35-year-old residents in Zone A during 2008-2010 was 2.82 times higher than that during 1999-2007, 3.54 times for older than 35-year-old female residents, and 9.04 times for older than 35-year-old female residents with no smoking, betel nut chewing, and hepatitis C. In Zone C, the times were 2.04, 1.70, and 1.91, respectively. After adjusting confounding factors, poisson regression analysis showed that the all cancer incidence rate of older than 35-year-old female residents in Zone A during 2008-2010 was 1.60 times higher than that in Zone C (95% CI 1.07-2.39), 1.55 times (95% CI 1.00-2.38) for older than 60-year-old residents, 2.17 times (95% CI 1.16-4.08) for older than 60-year-old female residents.
For biomarkers, the combined results in these years showed that the urinary Sr, V, As, Pb, Hg, Tl, and 1-OHP levels of older than 35-year-old residents in Zone A were significantly higher than those in Zone C. And, the significant different intensity on the metabolites of lipid, amino acid, intermediate compound in the metabolism of carbohydrates, and glycoprotein were found between the residents of extremely high exposure group with extremely high levels of urinary V and 1-OHP and the residents of matched extremely low exposure group.
For environmental pollution, the SO2 concentration of Taisi air monitoring station in Zone A increased 0.33 ppb/year under the downwind direction of northwest after the operation of No. 6 Naphtha Cracking Complex, 0.11 ppb/year for NO2. For the Lunbei air monitoring station in Zone B, the increase of SO2 was 0.11 ppb/year under the downwind direction of west after the operation of No. 6 Naphtha Cracking Complex. The data of Taisi photochemical monitoring station found that the high concentrations of ethylene, propylene, and benzene were all from the direction of downwind of No. 6 Naphtha Cracking Complex. And, the results of spatial sampling in Zone A showed that the concentrations of NOx, SO2, PAHs, and metals in winter were significantly higher than those in summer. In winter, the NOx and SO2 concentrations of the downwind area of Taisi township in Zone A were significantly higher than those in the upwind area of Mailiao township. In summer, it showed the reverse outcome because of the seasonal change of wind directions. Then, the petrochemical-related VOCs concentrations in Mailiao township were significantly higher than those in Taisi township in Zone A.
In the preliminary conclusion, we found the worse air quality, the increased urinary Sr, V, As, Pb, Hg, Tl, and 1-OHP levels, and the elevated all cancer incidence rate of residents in Mailiao and Taisi townships when compared to those in Erlun, Citong, Yuanchang, and Huwei townships after the operation of No. 6 Naphtha Cracking Complex.
