Combination of nZVI and DC for the in-situ remediation of chlorinated ethenes: An environmental and economic case study.

Over the past two decades, the use of nanoscale zero-valent iron (nZVI) has emerged as a standard method of contaminated groundwater remediation. The effectiveness of this method depends on key intrinsic hydrogeological parameters, which can affect both reactivity of the nanoparticles and their migration in the aquifer. In the case of low hydraulic permeability, the migration of nanoparticles is limited, which negatively influences remediation. An application of nZVI reinforced with a DC electric field led to a significant increase in the efficiency of remediation, as demonstrated by long-term monitoring at a former industrial site in Horice (Czech Republic). For the method testing, a 12 × 9 m polygon was defined around well IS4, where the original contamination was predominantly composed of DCE (7300 µg/l), and with a total concentration of chlorinated ethenes of 8880 µg/l. During the first stage of the activities, 49 kg of nZVI was injected and monitored for two years. Subsequently, the electrodes were installed, and for three years, the synergistic action of nZVI within an applied DC field was monitored. Based on 32 monitoring campaigns performed over the six years, the combined method was compared with an application of the only nZVI in technical, environmental and economic terms. Technically, the method requires annual reinstallation of anodes as a result of their oxidative disintegration. Environmentally, the method provides significantly improved chlorinated ethane reduction, remediation of low permeable zones, and extended efficiency. Economically, the method is five times cheaper when compared to the nZVI used alone.

Children's Experiences and Awareness about Impact of Digital Media on Health.

Previous research has focused on the associations between technology use and children's health, using mainly quantitative designs. This qualitative study describes technology's impact on physical and mental health from children's perspectives. The differences between children's experiences and awareness of the health-related consequences associated with digital media use were examined. Focus groups and interviews were conducted with children between the ages of 9 and 16 in nine European countries (N = 368). Results of this study indicate that children's experiences of health-related technology impacts are different from their awareness of these impacts. Children's direct experiences with media were less extreme in contrast to their awareness of health problems, which typically involved extreme examples of possible consequences, such as killing people, kidnapping, blindness, and developing learning or psychological disorders. The results are discussed in the context of the "media panic" and "third person effect" theories.

The impact of digital media on health: children's perspectives.

OBJECTIVES: Previous research has mainly focused on the effects of excessive digital media use or overuse on the health of children, primarily utilizing quantitative designs. More research should be conducted on general populations of children, rather than focusing exclusively on excessive technology users. This qualitative study describes technology's impact on physical and mental health from children's perspectives. METHODS: Focus groups and interviews were conducted with children between the ages of 9 and 16 in 9 European countries (N = 368). During focus groups and interviews, researchers asked what children perceive as being potentially negative or problematic while using the internet and technology. RESULTS: In this study, children reported several physical and mental health problems without indicating internet addiction or overuse. Physical health symptoms included eye problems, headaches, not eating, and tiredness. For mental health symptoms, children reported cognitive salience of online events, aggression, and sleeping problems. Sometimes they reported these problems within 30 min of technology usage. This suggests that even shorter time usage can cause self-reported health problems for some children. CONCLUSIONS: Qualitative methodology helps to understand what children's perspectives are concerning the impact of digital media on health. We recommend future studies focused on average technology users and low technology users to determine whether average levels of technology usage relate to health problems of children. Parents and teachers should also be informed about the possible physical and mental health issues associated with children's average usage of technology.