Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: In the era of information overload, are Big Data Analytics the answer to access and better manage available knowledge? Over the last decade, the use of online data in public health issues, i.e., Infodemiology, has been proven useful in assessing various aspects of human behavior. Google Trends is the most popular tool to gather such information, and has been used in several topics up to this point, with health and medicine being the most focused-on subject. Online behavior is monitored and analyzed in order to examine the actual human behavior, so as to predict, better assess, and even prevent health related issues that constantly arise in everyday life. Objective: This systematic review aims at reporting and further presenting and analyzing the methods, tools, and statistical approaches for Google Trends studies in health related topics from 2006 to 2016, so as to provide an overview of the usefulness of said tool and be a point of reference for future research on the subject. Methods: Following the PRISMA guidelines for selecting the studies, the term ‘Google Trends’ was searched for in the Scopus and PubMed databases from 2006 to 2016, applying specific criteria for types of publications and topics. A total of 109 published papers were extracted, excluding duplicates and the ones that did not fall inside the topics of health and medicine or the selected article types. The published papers were then further categorized according to their methodological approach, namely visualization, seasonality, correlations, forecastings, and modeling. Results: All the examined papers consisted –by definition- of time series analysis, and all but two included data visualization. 23.08% studies used Google Trends data for examining seasonality, while correlations and modeling have been preformed in 39.42% and 32.69% of the studies, respectively. Only 8.65% of the studies have used Google Trends data for predictions and forecastings in health related topics, thus it is evident that a gap exists in forecasting using Google Trends data. Conclusions: The monitoring of online search queries can provide insight on human behavior, as this field is significantly and continuously growing, and will be proven more than valuable in the future for assessing behavioral changes and providing ground for research using data that could not have been accessed otherwise.

Present technologies for wastewater treatment do not sufficiently address the increasing pollution situation of receiving water bodies, especially with the growing use of personal care products and pharmaceuticals (PPCP) in the private household and health sector. The relevance of addressing this problem of organic pollutants was taken into account by the Directive 2013/39/EU that introduced (i) the quality evaluation of aquatic compartments, (ii) the polluter pays principle, (iii) the need for innovative and affordable wastewater treatment technologies, and (iv) the identification of pollution causes including a list of principal compounds to be monitored. In addition, a watch list of 10 other substances was recently defined by Decision 2015/495 on March 20, 2015. This list contains, among several recalcitrant chemicals, the painkiller diclofenac and the hormones 17β-estradiol and 17α-ethinylestradiol. Although some modern approaches for their removal exist, such as advanced oxidation processes (AOPs), retrofitting most wastewater treatment plants with AOPs will not be acceptable as consistent investment at reasonable operational cost. Additionally, by-product and transformation product formation has to be considered. The same is true for membrane-based technologies (nanofiltration, reversed osmosis) despite of the incredible progress that has been made during recent years, because these systems lead to higher operation costs (mainly due to higher energy consumption) so that the majority of communities will not easily accept them. Advanced technologies in wastewater treatment like membrane bioreactors (MBR) that integrate biological degradation of organic matter with membrane filtration have proven a more complete elimination of emerging pollutants in a rather cost- and labor-intensive technology. Still, most of the presently applied methods are incapable of removing critical compounds completely. In this opinion paper, the state of the art of European WWTPs is reflected, and capacities of single methods are described. Furthermore, the need for analytical standards, risk assessment, and economic planning is stressed. The survey results in the conclusion that combinations of different conventional and advanced technologies including biological and plant-based strategies seem to be most promising to solve the burning problem of polluting our environment with hazardous emerging xenobiotics.