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Trichloroethylene (TCE) is one of the most ubiquitous halogenated organic compounds of concerns of carcinogens in groundwater in Taiwan. Bioremediation has been recognized as a cost-effective approach in reducing TCE concentration. Five pilot-scale wells were constructed to monitor TCE concentrations in contaminated groundwater. With injection of EOS®, TCE was effectively degraded to 42%–93% by the end of 175 days. The biostimulation with EOS® was useful in establishing a micro-site anaerobic but with limited contribution. Dilution of the aquifer movement also caused the TCE reduction among injection and monitoring wells. The degradability was affected by the location and the proximity from the injection well. TCE concentrations found to be negatively correlated with the associated Dehalococcoides spp. and functional genes levels. Dhc concentration of 108 copies L−1 caused the initial 40% of TCE degradation. The well with the optimal degradation owned tceA of 109 cells L−1. T-RFLP results indicate the wells with the superior TCE degradability also performed the highest Shannon index number (means the highest diversity), which occurred on the same day that Dhc levels started to enlarge. Desulfovibrio desulfuricans and Desulfuromonas chloroethenica were predominant species identified in the T-RFLP fingerprint profile. In brief, a variety of different factors including well locations, geochemical indicators, and microbial contribution were useful to explain the site-specific optimal TCE remediation approach. The consistence among TCE degradation, Dhc growing pattern, functional gene levels, and the dynamics of the microbial community structure present the novelty of this study. • TCE degradation achieved approximately 40% when Dehalococcoides sp. levels achieved 108 copies L−1. • T-RFLP results indicate the superior TCE degradability correlated with the highest diversity estimated by H index. • Desulfovibrio desulfuricans and Desulfuromonas chloroethenica were predominant species in the T-RFLP profile. • The TCE degradation of 42%-93% was due to EOS® injection in a micro-site anaerobic condition and dilution of the aquifer. [ABSTRACT FROM AUTHOR]

Enhanced monitored natural attenuation was conducted with molasses injections to an in situ trichloroethylene (TCE)-contaminated groundwater site. Three pilot-scale wells were conducted for monitoring and substrate injections. At most 97.0% of the TCE was effectively degraded after about 600 days. TCE detected in the injection wells attained Tier 2 Groundwater Regulation in Taiwan for non-drinking water sources. The reaction rates of Cl–VOCs in one of the injection wells explained the mechanism how these dechlorinating species transferred TCE to cis-DCE and VC in anaerobic conditions. The magnitude of the 1st order kinetic growth rates of Dehalococcoides (Dhc) were consistent with the associated TCE degradability. The qPCR and T-RFLP results concluded existence of crucial dechlorinating species including Dhc, which performed critical level of 106 copy L−1 to trigger the TCE degradation. The detected t ceA and vcrA ranging from 2.07 × 103 to 6.57 × 105 copy L−1confirmed the pathway of TCE degradation. The two injection wells with the optimal TCE degradation showed increases of bacterial diversity estimated by the Shannon Index. The Shannon index explained the superiority of an increased bacterial diversity. The nonmetric multidimensional scaling results suggested that the bacterial dynamic was affected by the TCE degradation stages. The bacterial community structures were analogous when TCE was well degraded. • The molecular results provided evidence of existence of crucial dechlorinating species including Dehalococcoides spp. • Dehalococcoides spp. With the critical abundance of 106 copy L−1 was critical for TCE degradation. • Detections of tceA (as high as 107 copy L−1) and vcrA confirmed the pathway of TCE degradation. • The optimal TCE degradation was observed with increases of bacterial diversity estimated by the Shannon Index. • Nonmetric multidimensional scaling result indicated the bacterial community dynamic depended on the TCE degradation stages. [ABSTRACT FROM AUTHOR]

Objective: Pulmonary involvement is common in patients with systemic sclerosis (SSc), and this condition causes substantial morbidity and mortality. Disrupted immunity from the disease or associated medication may render such patients subject to tuberculosis (TB) infection. However, the relationship between SSc and TB has not yet been investigated., Methods: Using the Taiwan National Health Insurance Research Database, 838 patients with SSc diagnosed in Taiwan during 2000-2006 were identified and followed for emergence of TB infection. Incidence rate ratios (IRR) of TB compared to 8380 randomly selected age-, sex-, and comorbidity-matched controls without SSc were calculated. The Cox proportional hazards model was used for multivariate adjustment to identify independent risk factors for TB infection., Results: The risk of TB infection was higher in the SSc cohort than in controls (IRR 2.81, 95% CI 1.36-5.37; p = 0.004), particularly for pulmonary TB (IRR 2.53, 95% CI 1.08-5.30; p = 0.022). Other independent risk factors for TB infection in patients with SSc were age ≥ 60 years [hazard ratio (HR) 3.52, 95% CI 1.10-11.33; p = 0.035] and pulmonary hypertension (PH; HR 6.06, 95% CI 1.59-23.17; p = 0.008). Mortality did not differ for SSc patients with or without TB., Conclusion: In this nationwide study, the incidence of TB infection was significantly higher among patients with SSc than in controls without SSc. Special care should be taken in managing patients with SSc who are at high risk for TB, especially those aged ≥ 60 years or who also have PH.