Long-term PM2.5 exposure is associated with asthma prevalence and exhaled nitric oxide levels in children.

BACKGROUND: Exhaled nitric oxide concentration (FENO) is a marker of airway inflammation. This study aimed to evaluate the association of air pollution exposure with FENO levels and asthma prevalence with respiratory symptoms in school children. METHODS: We analyzed 4736 school children who reside in six townships near industrial areas in central Taiwan. We evaluated asthmatic symptoms, FENO, and conducted the environmental questionnaire. The personal exposure of PM2.5, NO, and SO2 was estimated using land-use regression models data on children's school and home addresses. RESULTS: Annual exposure to PM2.5 was associated with increased odds of physician-diagnosed asthma (OR = 1.595), exercise-induced wheezing (OR = 1.726), itchy eyes (OR = 1.417), and current nasal problems (OR = 1.334) (P < 0.05). FENO levels in the absence of infection were positively correlated with age, previous wheezing, allergic rhinitis, atopic eczema, near the road, and for children with high exposure to PM2.5 (P < 0.05). An increase of 1 µg/m3 PM2.5 exposure was significantly associated with a 1.0% increase in FENO levels for children after adjusting for potential confounding variables, including exposures to NO and SO2. CONCLUSIONS: Long-term exposures to PM2.5 posed a significant risk of asthma prevalence and airway inflammation in a community-based population of children. IMPACT: Annual exposure to PM2.5 was associated with increased odds of physician-diagnosed asthma and nasal problems and itchy eyes. Long-term exposures to PM2.5 were significantly associated with FENO levels after adjusting for potential confounding variables. This is first study to assess the association between FENO levels and long-term air pollution exposures in children near coal-based power plants. An increase of 1 µg/m3 annual PM2.5 exposure was significantly associated with a 1.0% increase in FENO levels. Long-term exposures to PM2.5 posed a significant risk of asthma prevalence and airway inflammation in a community-based population of children.

Health impact assessment of PM2.5 from a planned coal-fired power plant in Taiwan.

PURPOSE: To investigate the impact of a planned coal-fired power plant (CFPPT) in Shenao on air quality and health at subnational levels in Taiwan. METHODS: We applied the Gaussian trajectory transfer-coefficient (GTx) model to estimate annual average PM2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) increments in 19 Taiwanese cities and counties caused by CFPPT operation. A population health risk assessment was performed by incorporating evidence of the health effects of PM2.5 provided by prospective studies and estimating long-term PM2.5 exposure. Additionally, we considered ischemic heart disease, stroke, lung cancer, and chronic obstruct pulmonary disease as the primary outcomes. The population-attributable fraction was used to estimate the county-level mortality burden attributable to CFPPT-generated PM2.5 in 2025. RESULTS: The estimated annual PM2.5 increments ranged from 0.004 µg/m3 (Taitung County) to 0.28 µg/m3 (Hsinchu County) due to the Shenao CFPPT. The total and premature deaths attributable to PM2.5 from Shenao CFPPT operation in Taiwan during 2025-2040 would be 576 (95% confidence interval [CI]: 537-619) and 145 (95% CI: 136-155), respectively. Notably, we estimated 198 (95% CI: 169-234) deaths and 58 (95% CI: 51-66) premature deaths, respectively, in New Taipei City, which accounted for over a quarter of the total deaths. Overall, the mortality rate attributable to the Shenao CFPPT in Taiwan was 6 per 10,000. CONCLUSION: A scientific approach should be adopted for assessing the impacts of CFPPT operation on population health, which can serve as a valuable policymaking reference for the government.

Increased cancer incidence of Changhua residents living in Taisi Village north to the No. 6 Naphtha Cracking Complex.

BACKGROUND/PURPOSE: Cancer risks of residents living north to the No. 6 Naphtha Cracking Complex has not been studied before. METHODS: Our study subjects were recruited in 2014-16 from three zones north to the No. 6 Naphtha Cracking Complex, which included 229 participants from the Taisi Village (average 5.5 km from the complex), 1333 participants from the other 14 villages in Dacheng Township (9.2 km), and 372 participants from the Zhutang Township (19.9 km). Their occurrence of cancer in years-post-complex-operation (YPO) was defined by having a new cancer recorded (ICD-9: 140-208) in National Health Insurance Research Database since 1999. Poisson regression was conducted to compare incidence rate ratio among three zones in 10-16 YPO. RESULTS: We found that all-cause cancer incidence of 10-16 YPO (per 1,000 person-years) in Taisi Village (8.44) was higher than that in Dacheng (3.42) and Zhutang (2.72). Taisi residents had significantly higher concentrations of V, Cr, Mn, Ni, Cu, As, Cd, and Tl than Dacheng and Zhutang residents. The all-cause cancer incidence rate ratio between 10-16 and 0-9 YPO was 8.44 for Taisi residents. All-cause cancer incidence rate of Taisi residents was 2.55 times higher than Dacheng residents (95% CI: 1.89-3.45) and 2.43 times higher than Zhutang residents (95% CI: 1.54-3.84) in 10-16 YPO. CONCLUSION: We conclude that all-cause cancer risk was significantly increased for Taisi residents living near the No. 6 Naphtha Cracking Complex for 10-16 years after the complex began operating.

Probabilistic framework for assessing the arsenic exposure risk from cooked fish consumption.

Geogenic arsenic (As) contamination of groundwater is a major ecological and human health problem in southwestern and northeastern coastal areas of Taiwan. Here, we present a probabilistic framework for assessing the human health risks from consuming raw and cooked fish that were cultured in groundwater As-contaminated ponds in Taiwan by linking a physiologically based pharmacokinetics model and a Weibull dose-response model. Results indicate that As levels in baked, fried, and grilled fish were higher than those of raw fish. Frying resulted in the greatest increase in As concentration, followed by grilling, with baking affecting the As concentration the least. Simulation results show that, following consumption of baked As-contaminated fish, the health risk to humans is <10(-6) excess bladder cancer risk level for lifetime exposure; as the incidence ratios of liver and lung cancers are generally acceptable at risk ranging from 10(-6) to 10(-4), the consumption of baked As-contaminated fish is unlikely to pose a significant risk to human health. However, contaminated fish cooked by frying resulted in significant health risks, showing the highest cumulative incidence ratios of liver cancer. We also show that males have higher cumulative incidence ratio of liver cancer than females. We found that although cooking resulted in an increase for As levels in As-contaminated fish, the risk to human health of consuming baked fish is nevertheless acceptable. We suggest the adoption of baking as a cooking method and warn against frying As-contaminated fish. We conclude that the concentration of contaminants after cooking should be taken into consideration when assessing the risk to human health.

Use of seasonal influenza virus titer and respiratory symptom score to estimate effective human contact rates.

BACKGROUND: We linked viral titers and respiratory symptom scores for seasonal influenza to estimate the effective contact rate among schoolchildren. METHODS: We analyzed 274 diary-based questionnaires. In addition, 2 sets of influenza data from published studies were used to investigate the relationship between viral titer, total symptom score, and normalized contact rate in children. RESULTS: The mean number (SD) of contacts for children in grades 7 to 9 ranged from 9.44 ± 8.68 to 11.18 ± 7.98 person⁻¹ day⁻¹; contact behavior was similar across school grades. The mean number of contacts was 5.66 ± 6.23 person⁻¹ day⁻¹ (range, 0 to 44 person⁻¹ day⁻¹) for the age group of 13 to 19 years. Estimated contact age, household size, contact duration, and contact frequency were the variables most strongly associated with total number of contacts. We also found that a reduction in total respiratory symptom scores among infected individuals had a positive correlation with an increase in the normalized contact rate. CONCLUSIONS: The relationship between daily virus titer and respiratory symptom score can be used to estimate the effective contact rate in explaining the spread of an airborne transmissible disease. The present findings can be incorporated into population-dynamic models of influenza transmission among schoolchildren.

Assessing trends and predictors of tuberculosis in Taiwan.

BACKGROUND: Variety of environmental and individual factors can cause tuberculosis (TB) incidence change. The purpose of this study was to assess the characteristics of TB trends in the period 2004 - 2008 in Taiwan by month, year, gender, age, temperature, seasonality, and aborigines. METHODS: The generalized regression models were used to examine the potential predictors for the monthly TB incidence in regional and national scales. RESULTS: We found that (i) in Taiwan the average TB incidence was 68 per 100,000 population with mortality rate of 0.036 person-1 yr-1, (ii) the highest TB incidence rate was found in eastern Taiwan (116 per 100,000 population) with the largest proportion of TB relapse cases (8.17%), (iii) seasonality, aborigines, gender, and age had a consistent and dominant role in constructing TB incidence patterns in Taiwan, and (iv) gender, time trend, and 2-month lag maximum temperature showed strong association with TB trends in aboriginal subpopulations. CONCLUSIONS: The proposed Poisson regression model is capable of forecasting patterns of TB incidence at regional and national scales. This study suggested that assessment of TB trends in eastern Taiwan presents an important opportunity for understanding the time-series dynamics and control of TB infections, given that this is the typical host demography in regions where these infections remain major public health problems.

A probabilistic transmission and population dynamic model to assess tuberculosis infection risk.

The purpose of this study was to examine tuberculosis (TB) population dynamics and to assess potential infection risk in Taiwan. A well-established mathematical model of TB transmission built on previous models was adopted to study the potential impact of TB transmission. A probabilistic risk model was also developed to estimate site-specific risks of developing disease soon after recent primary infection, exogenous reinfection, or through endogenous reactivation (latently infected TB) among Taiwan regions. Here, we showed that the proportion of endogenous reactivation (53-67%) was larger than that of exogenous reinfection (32-47%). Our simulations showed that as epidemic reaches a steady state, age distribution of cases would finally shift toward older age groups dominated by latently infected TB cases as a result of endogenous reactivation. A comparison of age-weighted TB incidence data with our model simulation output with 95% credible intervals revealed that the predictions were in an apparent agreement with observed data. The median value of overall basic reproduction number (R0) in eastern Taiwan ranged from 1.65 to 1.72, whereas northern Taiwan had the lowest R0 estimate of 1.50. We found that total TB incidences in eastern Taiwan had 25-27% probabilities of total proportion of infected population exceeding 90%, whereas there were 36-66% probabilities having exceeded 20% of total proportion of infected population attributed to latently infected TB. We suggested that our Taiwan-based analysis can be extended to the context of developing countries, where TB remains a substantial cause of elderly morbidity and mortality.

Extreme temperature increases the risk of stillbirth in the third trimester of pregnancy.

Epidemiological studies have reported the association between extreme temperatures and adverse reproductive effects. However, the susceptible period of exposure during pregnancy remains unclear. This study aimed to assess the impact of extreme temperature on the stillbirth rate. We performed a time-series analysis to explore the associations between temperature and stillbirth with a distributed lag nonlinear model. A total of 22,769 stillbirths in Taiwan between 2009 and 2018 were enrolled. The mean stillbirth rate was 11.3 ± 1.4 per 1000 births. The relative risk of stillbirth due to exposure to extreme heat temperature (> 29 °C) was 1.18 (95% CI 1.11, 1.25). Pregnant women in the third trimester were most susceptible to the effects of extreme cold and heat temperatures. At lag of 0-3 months, the cumulative relative risk (CRR) of stillbirth for exposure to extreme heat temperature (29.8 °C, 97.5th percentile of temperature) relative to the optimal temperature (21 °C) was 2.49 (95% CI: 1.24, 5.03), and the CRR of stillbirth for exposure to extreme low temperature (16.5 °C, 1st percentile) was 1.29 (95% CI: 0.93, 1.80). The stillbirth rate in Taiwan is on the rise. Our findings inform public health interventions to manage the health impacts of climate change.

County-Wide Mortality Assessments Attributable to PM2.5 Emissions from Coal Consumption in Taiwan.

Over one-third of energy is generated from coal consumption in Taiwan. In order to estimate the health impact assessment attributable to PM2.5 concentrations emitted from coal consumption in Taiwan. We applied a Gaussian trajectory transfer-coefficient model to obtain county-wide PM2.5 exposures from coal consumption, which includes coal-fired power plants and combined heat and power plants. Next, we calculated the mortality burden attributable to PM2.5 emitted by coal consumption using the comparative risk assessment framework developed by the Global Burden of Disease study. Based on county-level data, the average PM2.5 emissions from coal-fired plants in Taiwan was estimated at 2.03 ± 1.29 (range: 0.32-5.64) µg/m3. With PM2.5 increments greater than 0.1 µg/m3, there were as many as 16 counties and 66 air quality monitoring stations affected by coal-fired plants and 6 counties and 18 monitoring stations affected by combined heat and power plants. The maximum distances affected by coal-fired and combined heat and power plants were 272 km and 157 km, respectively. Our findings show that more counties were affected by coal-fired plants than by combined heat and power plants with significant increments of PM2.5 emissions. We estimated that 359.6 (95% CI: 334.8-384.9) annual adult deaths and 124.4 (95% CI: 116.4-132.3) annual premature deaths were attributable to PM2.5 emitted by coal-fired plants in Taiwan. Even in six counties without power plants, there were 75.8 (95% CI: 60.1-91.5) deaths and 25.8 (95%CI: 20.7-30.9) premature deaths annually attributable to PM2.5 emitted from neighboring coal-fired plants. This study presents a precise and effective integrated approach for assessing air pollution and the health impacts of coal-fired and combined heat and power plants.

Quantitative links between arsenic exposure and influenza A (H1N1) infection-associated lung function exacerbations risk.

The objective of this study was to link arsenic exposure and influenza A (H1N1) infection-induced respiratory effects to assess the impact of arsenic-contaminated drinking water on exacerbation risk of A (H1N1)-associated lung function. The homogeneous Poisson process was used to approximate the related processes between arsenic exposure and influenza-associated lung function exacerbation risk. We found that (i) estimated arsenic-induced forced expiratory volume in 1 second (FEV(1) ) reducing rates ranged from 0.116 to 0.179 mL/µg for age 15-85 years, (ii) estimated arsenic-induced A (H1N1) viral load increasing rate was 0.5 mL/µg, (iii) estimated A (H1N1) virus-induced FEV(1) reducing rate was 0.10 mL/logTCID50, and (iv) the relationship between arsenic exposure and A (H1N1)-associated respiratory symptoms scores (RSS) can be described by a Hill model. Here we showed that maximum RSS at day 2 postinfection for Taiwan, West Bengal (India), and the United States were estimated to be in the severe range of 0.83, 0.89, and 0.81, respectively, indicating that chronic arsenic exposure and A (H1N1) infection together are most likely to pose potential exacerbations risk of lung function, although a 50% probability of lung function exacerbations risk induced by arsenic and influenza infection was within the mild and moderate ranges of RSS at day 1 and 2 postinfection. We concluded that avoidance of drinking arsenic-containing water could significantly reduce influenza respiratory illness and that need will become increasingly urgent as the novel H1N1 pandemic influenza virus infects people worldwide.

Risk-based probabilistic approach to assess the impact of false mussel invasions on farmed hard clams.

The purpose of this article is to provide a risk-based predictive model to assess the impact of false mussel Mytilopsis sallei invasions on hard clam Meretrix lusoria farms in the southwestern region of Taiwan. The actual spread of invasive false mussel was predicted by using analytical models based on advection-diffusion and gravity models. The proportion of hard clam colonized and infestation by false mussel were used to characterize risk estimates. A mortality model was parameterized to assess hard clam mortality risk characterized by false mussel density and infestation intensity. The published data were reanalyzed to parameterize a predictive threshold model described by a cumulative Weibull distribution function that can be used to estimate the exceeding thresholds of proportion of hard clam colonized and infestation. Results indicated that the infestation thresholds were 2-17 ind clam(-1) for adult hard clams, whereas 4 ind clam(-1) for nursery hard clams. The average colonization thresholds were estimated to be 81-89% for cultivated and nursery hard clam farms, respectively. Our results indicated that false mussel density and infestation, which caused 50% hard clam mortality, were estimated to be 2,812 ind m(-2) and 31 ind clam(-1), respectively. This study further indicated that hard clam farms that are close to the coastal area have at least 50% probability for 43% mortality caused by infestation. This study highlighted that a probabilistic risk-based framework characterized by probability distributions and risk curves is an effective representation of scientific assessments for farmed hard clam in response to the nonnative false mussel invasion.

Assessing the exacerbations risk of influenza-associated chronic occupational asthma.

The purpose of this article was to conduct a risk-based study based on a linkage of experimental human influenza infections and fluctuation analysis of airway function to assess whether influenza viral infection was risk factor for exacerbations of chronic occupational asthma. Here we provided a comprehensive probabilistic analysis aimed at quantifying influenza-associated exacerbations risk for occupational asthmatics, based on a combination of published distributions of viral shedding and symptoms scores and lung respiratory system properties characterized by long-range peak expiratory flow (PEF) dynamics. Using a coupled detrended fluctuation analysis-experimental human influenza approach, we estimated the conditional probability of moderate or severe lung airway obstruction and hence the exacerbations risk of influenza-associated occupational asthma in individuals. The long-range correlation exponent (alpha) was used as a predictor of future exacerbations risk of influenza-associated asthma. For our illustrative distribution of PEF fluctuations and influenza-induced asthma exacerbations risk relations, we found that the probability of exacerbations risk can be limited to below 50% by keeping alpha to below 0.53. This study also found that limiting wheeze scores to 0.56 yields a 75% probability of influenza-associated asthma exacerbations risk and a limit of 0.34 yields a 50% probability that may give a representative estimate of the distribution of chronic respiratory system properties. This study implicates that influenza viral infection is an important risk factor for exacerbations of chronic occupational asthma.

Associations of soluble metals and lung and liver toxicity in mice induced by fine particulate matter originating from a petrochemical complex.

Adverse health effects have been observed in nearby residents due to exposure to petrochemical-derived chemicals. The objective of this study was to examine associations of soluble metals with lung and liver toxicity in fine particulate matter (PM2.5) in the vicinity of a petrochemical complex. PM2.5 was collected in the vicinity of a petrochemical complex of Mailiao Township (Yunlin County, Taiwan) to investigate lung and liver toxicity in BALB/c mice. The PM2.5 concentration was 30.2 ± 11.2 µg/m3, and the PM2.5 was clustered in major local emissions (19.1 µg/m3) and minor local emissions (14.1 µg/m3) using a k-means clustering model. The PM2.5 (50 and 150 µg/kg) and PM2.5-equivalent soluble nickel (Ni), vanadium (V), and lead (Pb) concentrations were intratracheally instilled into BALB/c mice. PM2.5 and V significantly decreased the tidal volume after exposure (p < 0.05). The peak expiratory flow (PEF) and peak inspiratory flow (PIF)/PEF ratio were significantly altered by 150 µg/kg V (p < 0.05). V and Pb significantly increased total protein and lactate dehydrogenase (LDH) levels in bronchoalveolar lavage fluid (BALF) (p < 0.05). Interleukin (IL)-6 in BALF significantly increased after exposure to Pb (p < 0.05) accompanied by lung inflammatory infiltration. PM2.5 and Pb significantly increased levels of 8-isoprostane (p < 0.05). The level of caspase-3 activity significantly increased after exposure to Pb (p < 0.05). LDH in the liver was significantly increased by PM2.5 (p < 0.05). 8-Isoprostane in the liver was significantly increased by PM2.5 and Pb (p < 0.05). IL-6 in the liver was significantly increased by PM2.5, Ni, V, and Pb after exposure (p < 0.05), accompanied by liver inflammatory infiltration. Our results demonstrated that V in PM2.5 was associated with an increase in 8-isoprostane for all emissions and major local petrochemical emissions. In conclusion, V contributes to in vivo liver toxicity induced by PM2.5 in the vicinity of a petrochemical complex.

Assessing the airborne titanium dioxide nanoparticle-related exposure hazard at workplace.

The purpose of this study was to investigate the effects of size and phase composition on human exposure to airborne titanium dioxide (TiO(2)) nanoparticles (NPs) at workplaces. We reanalyzed published data of particle size distribution of airborne TiO(2) NPs during manufacturing activities and linked a physiologically based lung model to estimate size- and phase-specific TiO(2) NP burdens in target lung cells. We also adopted a cell model to simulate the exposure time-dependent size/phase-specific cell uptake of TiO(2) NPs in human dermal and lung cells. Combining laboratory, field, and modeling results, we proposed two major findings: (i) the estimated median effective anatase TiO(2) NP concentration (EC50) for cytotoxicity response on human dermal fibroblasts was estimated to be 24.84 (95% CI: 7.3-70.2) nmolmL(-1) and EC50 estimate for inflammatory response on human lung epithelial cells was 5414 (95% CI: 3370-7479) nmolmL(-1) and (ii) packers and surface treatment workers at the TiO(2) NP production workplaces are unlikely to pose substantial risk on lung inflammatory response. Nevertheless, our findings point out that TiO(2) NP production workers have significant risk on cytotoxicity response at relatively high airborne anatase TiO(2) NP concentrations at size range 10-30nm.

Empirical models to predict parsimoniously the mass and number concentrations of ultrafine particulate in ambient atmosphere.

The main objective of this study was to develop parsimonious empirical models for predicting the mass and number concentrations of ultrafine particulate (UFP, aerodynamic diameter < 0.1 or 0.18 microm) in the atmospheric environment. We found strong correlations existed between the mass/number concentration of UFP and the mass concentration of PM(2.5) (aerodynamic diameter < 2.5 microm) by fitting the experimental data. Therefore, we were easily able to obtain UFP mass and number concentrations by using the presented empirical models. The empirical equations should be used with care since limitations existed.

Model-based assessment for human inhalation exposure risk to airborne nano/fine titanium dioxide particles.

This paper proposed a model-based approach to assess inhalation risk levels to manufacturing workers in titanium dioxide (TiO2) production factories. The risk level-based analytical schemes were present for investigations of job-related airborne nano/fine TiO2 dust exposures. A Hill model was used to reconstruct dose-response function based on data from rats exposed by chronic inhalation to poorly soluble fine and nanosized particles. A physiologically based lung model was used to predict surface area-based TiO2 burdens in alveolar surface and interstitial granuloma, respectively. The exposure effect was characterized by polymorphonuclear leukocytes (PMN) elevation effect on lung surface and lung tumor proportion on interstitium. Combining laboratory, field, and modeling results, two major findings were proposed to the current epidemiological studies: (i) the estimated median effective surface area-based TiO2 lung burden (EC50) for PMN elevation effect is 0.11 m2 g(-1) lung (95% CI: 0.04-0.2) and EC50 for lung tumor proportion is 1.15 m2 g(-1) lung (95% CI: 0.65-1.89) and (ii) the estimates of risk curves are the pivotal results for public policy. The results demonstrate that packers in US factories have approximately 85.77 fold (95% CI: 63.84-94.33) of standard PMN counts of 10(6), whereas 86.97 fold (95% CI: 66.72-94.54) for surface treatment workers in EU factories at risk of 0.5. The lung had approximately 45% (95% CI: 15%-54%) tumor proportion for packers in US factories, whereas 48.19% (95% CI: 20-53.79%) for surface treatment workers in EU factories at risk of 0.5. The findings point out that dry/wet treatment and ore handlers in US and maintenance mechanics in EU factories were unlikely to pose substantial lung cancer risks.

Cluster analysis of fine particulate matter (PM2.5) emissions and its bioreactivity in the vicinity of a petrochemical complex.

This study evaluated associations between the bioreactivity of PM2.5in vitro and emission sources in the vicinity of a petrochemical complex in Taiwan. The average PM2.5 was 30.2 µg/m3 from 9 February to 23 March 2016, and the PM2.5 was clustered in long-range transport (with major local source) (12.8 µg/m3), and major (17.3 µg/m3) and minor industrial emissions (4.7 µg/m3) using a k-means clustering model. A reduction in cell viability and increases in the cytotoxicity-related lactate dehydrogenase (LDH), oxidative stress-related 8-isoprostane, and inflammation-related interleukin (IL)-6 occurred due to PM2.5 in a dose-dependent manner. The PM2.5 from major industrial emissions was significantly correlated with increased 8-isoprostane and IL-6, but this was not observed for long-range transport or minor industrial emissions. The bulk metal concentration was 9.52 ng/m3 in PM2.5. We further observed that As, Ba, Cd, and Se were correlated with LDH in the long-range transport group. Pb in PM2.5 from the major industrial emissions was correlated with LDH, whereas Pb and Se were correlated with 8-isoprostane. Sr was correlated with cell viability in the minor industrial emissions group. We demonstrated a new approach to investigate particle bioreactivity, which suggested that petrochemical-emitted PM2.5 should be a concern for surrounding residents' health.

Oxidative stress risk analysis for exposure to diesel exhaust particle-induced reactive oxygen species.

We constructed a probabilistic risk-based framework to assess the human oxidative stress (OS) risk from diesel exhaust particle (DEP)-induced reactive oxygen species. A human respiratory tract model was used to estimate DEP concentration and cumulative doses in lung regions for three occupational groupings (driver, homeworker and student) in northern, central, and southern Taiwan. Dose-response profiles were reconstructed in terms of the specific ratio of the reduced and oxidized forms of glutathione (GSH/GSSG ratio) for the human macrophage cell (THP-1) and human bronchial epithelial cell (BEAS-2B). The highest estimated median daily cumulative dose of DEP with 95% CI was for driver in northern Taiwan (DEP(2.5): 0.716 (0.443-1.197) mg and DEP(0.18): 0.584 (0.417-0.822) mg), significantly higher than that of the other settings. The driver in northern Taiwan setting had the highest cumulative dose-response calculated over a 2-year exposure period: 0.57 (0.41-0.76) and 0.70 (0.53-0.87) for DEP(2.5) and 0.40 (0.25-0.70) and 0.47 (0.34-0.80) for DEP(0.18), respectively, in THP-1 and BEAS-2B cells. Our results implicate that potential risks of OS from above-critical exposure to DEP(2.5) in all settings are found, whereas from DEP(0.18) in the driver in northern Taiwan setting is also alarming.

Probabilistic integrated risk assessment of human exposure risk to environmental bisphenol A pollution sources.

Environmental bisphenol A (BPA) exposure has been linked to a variety of adverse health effects such as developmental and reproductive issues. However, establishing a clear association between BPA and the likelihood of human health is complex yet fundamentally uncertain. The purpose of this study was to assess the potential exposure risks from environmental BPA among Chinese population based on five human health outcomes, namely immune response, uterotrophic assay, cardiovascular disease (CVD), diabetes, and behavior change. We addressed these health concerns by using a stochastic integrated risk assessment approach. The BPA dose-dependent likelihood of effects was reconstructed by a series of Hill models based on animal models or epidemiological data. We developed a physiologically based pharmacokinetic (PBPK) model that allows estimation of urinary BPA concentration from external exposures. Here we showed that the daily average exposure concentrations of BPA and urinary BPA estimates were consistent with the published data. We found that BPA exposures were less likely to pose significant risks for infants (0-1 year) and adults (male and female >20 years) with <10(-6)-fold increase in uterus weight and immune response outcomes, respectively. Moreover, our results indicated that there was 50 % risk probability that the response outcomes of CVD, diabetes, and behavior change with or without skin absorption would increase 10(-4)-10(-2)-fold. We conclude that our approach provides a powerful tool for tracking and managing human long-term BPA susceptibility in relation to multiple exposure pathways, and for informing the public of the negligible magnitude of environmental BPA pollution impacts on human health.

The distance-to-source trend in vanadium and arsenic exposures for residents living near a petrochemical complex.

Biological monitoring of vanadium (V) and arsenic (As) for residents living near a big petrochemical complex has not been previously studied. This study aims to investigate distance-to-source trends in urinary levels and dispersion-estimated concentrations of V and As in areas surrounding a petrochemical complex in central Taiwan. Our study subjects were 1424 residents living in the townships up to ~40 km from the petrochemical complex, and categorized as near (Zone A), further (Zone B) and furthest (Zone C) from the complex. Urinary and ambient V and As levels were analyzed by inductively coupled plasma mass spectrometry. Two-stage dispersion model was used to estimate V and As concentrations at each study subject's address. Multiple linear regression models were used to study the effects of distance-to-source and estimated air concentrations of V and As on the urinary V and As levels of study subjects. Area-wide levels of both V and As showed a high-to-low trend in urinary levels (µg/g-creatinine) from Zone A (V with 2.86±2.30 and As with 104.6±147.9) to Zone C (V with 0.73±0.72 and As with 73.8±90.8). For study subjects, urinary V and As levels were decreased by 0.09 and 1.17 µg/g-creatinine, respectively, with 1 km away from the emission source of the petrochemical complex, and urinary V levels were significantly elevated by 0.38 µg/g-creatinine with a 1 ng/m(3) increase in estimated ambient V concentrations at their addresses. Our study concludes a distance-to-source gradient in V and As exposures exists for residents living near a petrochemical complex with oil refineries and coal-fired power plants and two-stage dispersion model can predict such a trend for V when inhalation is the major exposure route, but not for As that exposure may be from multiple sources and exposure routes.