Living near a Major Road in Beijing: Association with Lower Lung Function, Airway Acidification, and Chronic Cough / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The effects of near-road pollution on lung function in China have not been well studied. We aimed to investigate the effects of long-term exposure to traffic-related air pollution on lung function, airway inflammation, and respiratory symptoms.</p><p><b>METHODS</b>We enrolled 1003 residents aged 57.96 ± 8.99 years living in the Shichahai Community in Beijing. Distances between home addresses and the nearest major roads were measured to calculate home-road distance. We used the distance categories 1, 2, and 3, representing <100 m, 100-200 m, and >200 m, respectively, as the dose indicator for traffic-related air pollution exposure. Lung function, exhaled breath condensate (EBC) pH, and interleukin 6 levels were measured. As a follow-up, 398 participants had a second lung function assessment about 3 years later, and lung function decline was also examined as an outcome. We used regression analysis to assess the impacts of home-road distance on lung function and respiratory symptoms. As the EBC biomarker data were not normally distributed, we performed correlation analysis between home-road distance categories and EBC biomarkers.</p><p><b>RESULTS</b>Participants living a shorter distance from major roads had lower percentage of predicted value of forced expiratory volume in 1 s (FEV1% -1.54, 95% confidence interval [CI]: -0.20 to -2.89). The odds ratio for chronic cough was 2.54 (95% CI: 1.57-4.10) for category 1 and 1.97 (95% CI: 1.16-3.37) for category 2, compared with category 3. EBC pH was positively correlated with road distance (rank correlation coefficient of Spearman [rs] = 0.176, P < 0.001).</p><p><b>CONCLUSIONS</b>Long-term exposure to traffic-related air pollution in people who live near major roads in Beijing is associated with lower lung function, airway acidification, and a higher prevalence of chronic cough. EBC pH is a potential useful biomarker for evaluating air pollution exposure.</p>

Impact of reclaimed water irrigation on antibiotic resistance in public parks, Beijing, China.

The abundance and distribution of antibiotics and antibiotic resistance genes (ARGs) in soils from six parks using reclaimed water in Beijing, China, were characterized. Three classes of commonly used antibiotics (tetracycles, quinolones, and sulfonamides) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The highest concentrations of tetracyclines and quinolones were 145.2 µg kg(-1) and 79.2 µg kg(-1), respectively. Detected tetG, tetW, sulI, and sulII genes were quantified by quantitative PCR. ARGs exhibited various abundances for different park soils. The integrase gene (intI1) as an indicator of horizontal gene transfer potential was also detected in high abundance, and had significant positive correlation with tetG, sulI, and sulII genes, suggesting that intI1 may be involved in ARGs dissemination. Both sulII and intI1 clones had high homology with some classes of pathogenic bacteria, such as Klebsiella oxytoca, Acinetobacter baumannii, Shigella flexneri, which could trigger potential public health concern.

Effect of long-term wastewater irrigation on potential denitrification and denitrifying communities in soils at the watershed scale.

Wastewater irrigation mitigates the problem of water shortage but leads to the potential accumulation of pollutants and causes corresponding changes in denitrifying communities and denitrification, hence the potential ecological risk of long-term wastewater irrigation should not be overlooked. We investigated the relative contributions of different environmental factors to the abundance and diversity of denitrifying communities harboring nirK, nirS, and nosZ genes and the relative importance of these biotic and abiotic variables in potential denitrification activity (PDA) in soils with wastewater irrigation for around 25 years at a large watershed scale. Results showed that soil physicochemical properties, pollutants, including heavy metals and PAHs, and vegetation are the major factor groups influencing the abundance and structure of the three denitrifying communities and PDA. NirK-, nirS-, or nosZ-harboring denitrifiers responded in different manners to environmental changes, and were mainly influenced by substrate concentration, carbon source, or pollutants, respectively. The structure of the three denitrifying communities was more relevant to the environmental changes than their abundance. Conversely, the abundance, rather than diversity, was correlated with PDA. Pollutants and vegetation could affect PDA by both direct and indirect paths through soil physicochemical properties including pH, carbon and nitrogen sources, or through the abundance of denitrifying functional genes. The abundance of denitrifying functional genes is a valuable index that integrates potential activity and various environmental factors, and is therefore a good predictor of denitrification in the presence of environmental changes.

Diverse and abundant antibiotic resistance genes in Chinese swine farms.

Antibiotic resistance genes (ARGs) are emerging contaminants posing a potential worldwide human health risk. Intensive animal husbandry is believed to be a major contributor to the increased environmental burden of ARGs. Despite the volume of antibiotics used in China, little information is available regarding the corresponding ARGs associated with animal farms. We assessed type and concentrations of ARGs at three stages of manure processing to land disposal at three large-scale (10,000 animals per year) commercial swine farms in China. In-feed or therapeutic antibiotics used on these farms include all major classes of antibiotics except vancomycins. High-capacity quantitative PCR arrays detected 149 unique resistance genes among all of the farm samples, the top 63 ARGs being enriched 192-fold (median) up to 28,000-fold (maximum) compared with their respective antibiotic-free manure or soil controls. Antibiotics and heavy metals used as feed supplements were elevated in the manures, suggesting the potential for coselection of resistance traits. The potential for horizontal transfer of ARGs because of transposon-specific ARGs is implicated by the enrichment of transposases--the top six alleles being enriched 189-fold (median) up to 90,000-fold in manure--as well as the high correlation (r(2) = 0.96) between ARG and transposase abundance. In addition, abundance of ARGs correlated directly with antibiotic and metal concentrations, indicating their importance in selection of resistance genes. Diverse, abundant, and potentially mobile ARGs in farm samples suggest that unmonitored use of antibiotics and metals is causing the emergence and release of ARGs to the environment.

Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil.

Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg(-1)) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC(50) values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC(50) concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs.