Distribution, sources and transport of polycyclic aromatic hydrocarbons (PAHs) in karst spring systems from Western Hubei, Central China.

Karst groundwater is an important water resource but it is vulnerable to contaminants, due to the distinctive geological features of abundant transmissive fractures and conduits in the karst area which connect the surface to the underground systems. Anthropogenic activity-derived polycyclic aromatic hydrocarbons (PAHs) on the surface environment could enter groundwater easily and rapidly and threaten water security in karst areas. Samples in the multimedia environment from 10 specific karst spring systems from Western Hubei of Central China were collected to analyze 16 priority PAHs and to investigate their transport in these karst spring systems. The total concentrations of PAHs in the soil, river water, river sediments, spring water, and spring sediments ranged between 6.04 and 67.7 ng g-1, 4.56 and 11.4 ng L-1, 29.9 and 1041 ng g-1, 4.09 and 222 ng L-1, and 5.88 and 83.0 ng g-1, respectively. Levels of PAHs in this area were relatively low when compared to other karst areas. Proportions of low-molecular-weight (LMW)-PAHs in the water, sediments and soil (average 58.2-78.8%) were much higher than those of high-molecular-weight (HMW)-PAHs. The proportion of LMW-PAHs in the sediments (especially in river sediments) was higher than that in the soil. Characteristic ratio analysis and principal component analysis showed that PAHs were from high-temperature combustion of the mixture of coal and biomass, and vehicle emission, where coal and biomass combustion were the dominant sources. Significant correlations of PAH compositions in different media of karst spring systems were observed, especially in the Yuquangdong (YQD)-Migongquan (MGQ), Jiuzhenziquan (JZZQ), Xianyudong (XYD) and Fengdong (FD) karst spring systems, indicating the rapid PAH transport from the recharge area soil to the discharge area of spring water and sediments.

How Do Chinese National Scenic Areas Affect Tourism Economic Development? The Moderating Effect of Time-Limited Rectification.

Based on panel data on 124 prefecture-level and above cities from 2003 to 2018, this study investigated the impact of CNSAs on tourism economic development and the moderating effect of time-limited rectification by comprehensively using the quasi-DID model, the static spatial Durbin model, and the dynamic spatial Durbin model. The results showed that the impact of CNSAs on tourism economic development has a heterogeneous characteristic in terms of tourists and revenue. In addition, the spatial spillover effect and the path dependence have effectively promoted tourism economic development. Furthermore, the effectiveness of time-limited rectification has been proved in this study, while the "beggar-thy-neighbor" effect has, to some extent, weakened the promotional effect of CNSAs on tourism economic development, especially in terms of international tourists and international tourism revenue. Finally, relevant policy implications for the superior department in charge, local governments, and the management department of CNSAs are outlined to provide a practical reference for promoting the high-quality development of the tourism economy in China.

Predictors of the authenticity of Internet health rumours.

BACKGROUND: The Internet is becoming an important source of health information; however, unverified health rumours may be included in health-related search results. There is a critical need to provide health information seekers with methods that are specifically geared towards the identification of the authenticity of health rumours. METHODS: Using 453 health rumours collected from a definitive online reference of rumours in China, this study investigates which features contribute to distinguishing between true and false rumours with a logistic regression model. RESULTS: There are measurable differences between true and false health rumours on the Internet. The lengths of rumour headlines and statements and the presence of pictures are negatively correlated to the probability that a rumour is true, whereas a rumour is more likely to be true if it contains elements such as numbers, source cues and hyperlinks. Finally, dread health rumours are more likely to be true than wish ones. CONCLUSIONS: Despite the growing number of studies on rumours, the identification of the authenticity of rumours has received little attention. This study proposes some rules of thumb to help online users ascertain rumour veracity and make decisions.