Benchmarking the scientific research on wastewater-energy nexus by using bibliometric analysis

Human exposure to formaldehyde and health risk assessment: a 46-year systematic literature review

After confirming that formaldehyde (FA) is carcinogenic, many studies were conducted in different countries to investigate this finding. Therefore, according to the dispersion of related studies, a bibliometric review of the current literature was performed with the aim of better understanding the exposure to FA and the resulting health risk, for the first time, using the Scopus database and the two open-source software packages, Bibliometrix R package. After screening the documents in Excel, the data was analyzed based on three aspects including performance analysis, conceptual structure, and intellectual structure, and the results were presented in tables and diagrams. A total of 468 documents were analyzed over period 1977-2023, in which 1956 authors from 56 countries participated. The number of scientific publications has grown significantly from 1977 (n = 1) to 2022 (n = 19). Zhang Y., from the Yale School of Public Health (USA), was identified as the most impactful author in this field. The Science of the Total Environment journal was identified as the main source of articles related to exposure to formaldehyde by publishing 25 studies. The United States and China were the most active countries with the most international collaboration. The main topics investigated during these 46 years included "formaldehyde" and "health risk assessment", which have taken new directions in recent years with the emergence of the keyword "asthma". The present study provides a comprehensive view of the growth and evolution of studies related to formaldehyde and the resulting health risks, which can provide a better understanding of existing research gaps and new and emerging issues.

Current trends and future directions of global research on wastewater to energy: a bibliometric analysis and review

This paper presents a structured bibliometric analysis and review of the research publications recorded in the Web of Science database from 2000 to 2023 to methodically examine the landscape and development of the 'wastewater to energy' research field in relation to global trends, potential hotspots, and future research directions. The study highlights three main research themes in 'wastewater to energy', which are biogas production through anaerobic digestion of sewage sludge, methane generation from microbial wastewater treatment, and hydrogen production from biomass. The analysis reveals activated sludge, biochar, biomethane, biogas upgrading, hydrogen, and circular economy as key topics increasingly gaining momentum in recent research publications as well as representing potential future research directions. The findings also signify transformation to SDGs and circular economy practices, through the integration of on-site renewables and biogas upgrading for energy self-sufficiency, optimising energy recovery from wastewater treatment systems, and fostering research and innovation in 'wastewater to energy' supported by policy incentives. By shedding light on emerging trends, cross-cutting themes, and potential policy implications, this study contributes to informing both knowledge and practices of the 'wastewater to energy' research community.

Water, sanitation, and hygiene global research: evolution, trends, and knowledge structure

Water, sanitation, and hygiene (WASH) services play a crucial role in promoting public and environmental health as well as social and economic development. At the global level, particularly in the developing world, WASH issues continue to present significant challenges. These challenges have been further intensified by factors such as the COVID-19 pandemic, escalating conflicts, climate change, water scarcity, and rising inequality. The scientific community has actively engaged in constructive discussions on these issues, as evidenced by the notable research findings. Therefore, the aim of this study was to comprehensively examine and evaluate global knowledge on WASH. To search for relevant publications, the Scopus database was utilized using specific terms associated with WASH. VOSviewer 1.6.18 software was employed to generate network visualization maps, which assessed collaborative patterns and research trends in the field of WASH. The research output of countries was adjusted considering their gross domestic product (GDP) and population size. The total number of WASH-related publications, including all types of documents, was 1805. By narrowing the search to articles and reviews, the overall global productivity yielded 1589 documents: 1367 (86.0%) original articles and 222 (14.0%) review articles. The USA had the highest number of WASH publications (n = 668; 42.0%), followed by the UK (n = 396; 24.9%), Switzerland (n = 151; 9.5%), and Australia (n = 141; 8.9%). Ethiopia emerged as the leading country in terms of GDP per capita and the number of publications, followed by Uganda, Malawi, India, and Bangladesh. The USA, the UK, and Switzerland exhibited the most extensive collaboration among countries. The main research areas encompassed the role of WASH in sustainable development, the impacts of inadequate access to WASH services on gender equality, children, infants, and the outbreak of COVID-19 and other diseases, as well as the significance of hygiene practices and community and school-based WASH interventions in reducing infections. This study provides a novel analysis of global WASH-related research and highlights the distribution of outcomes across nations. Continued and increased collaboration between developed and developing nations will facilitate the sharing of responsibility for WASH research outcomes and the implementation of effective policies.

Human exposure to heavy metals and related cancer development: a bibliometric analysis

As notifications on carcinogenicity of heavy metals increase, more and more attention is paid recently to heavy metals exposure. In our study, the human exposure to heavy metals and cancer knowledge epistemology was investigated using bibliometric analysis. The bibliometric data of the research articles were retrieved using following keywords: "heavy metal," "trace element", "cancer", "carcinogen", and "tumor" in the Scopus database. Specifically, 2118 articles published between 1972 and 2023 were found, covering a total of 1473 authors, 252 sources, and 2797 keywords. Retrospective data obtained from 251 documents and 145 journals were further analyzed by performance analysis and techniques of science mapping. The number of studies conducted in this field increased from one article published in 1972 to 18 articles published in 2022 in the study of Michael P Waalkes. The most impactful author regarding the number of published papers was Masoudreza Sohrabi with 7 publications. In the majority of the published papers, the most popular keywords were "cadmium" and "carcinogenicity". However, in recent 4 years, the emphasis has been placed more on epidemiology studies. Our study provides general knowledge about the trend of publication on the role of heavy metals in causing cancer. The leading researchers in the field of the effects of heavy metals on the development of cancer were identified in our studies. Our results might also create a better understanding of new and emerging issues and can be used as a comprehensive road map for future researchers.

Mapping the scientific structure and evolution of renewable energy for sustainable development

The integration of renewable energy and sustainable development (RE&SD) can help overcome existing obstacles and create opportunities for renewable energy deployment to achieve sustainable development goals. In view of the limited research on science mapping and visualization analyses of RE&SD, this study sought to determine the scientific structure and evolution based on longitudinal and mapping change analysis. As an entity in the knowledge base, keyword and subject were considered essential information of documents. The co-word network was generated using SciMAT to reveal the dynamic aspects of the scientific research in the five subperiods. The thematic evolutionary analysis identified two main RE&SD thematic areas, with the current research hotspots that involved technological, environmental, sustainable energy innovation, and sustainable biofuel contributions. The alluvial diagram using MapEquation revealed significant structural changes from subject data. Clusters of subjects continued to grow, and more interdisciplinary integration was undergoing. This study provides a systematic study of RE&SD research, and the future research of RE&SD may inevitably consider renewable energy investment and renewable energy perspective approaches to achieve sustainable development goals.

Global research on Clostridium difficile-associated diarrhoea: A visualized study

BACKGROUND

Clostridioides (Clostridium) difficile (C. difficile) is still the most common cause of healthcare-associated diarrhoea and is increasing in prevalence as a community-acquired infection. In addition, the emergence of antibiotic resistance in C. difficile can increase the likelihood of the disease developing and/or spreading.

AIM

To provide an up-to-date picture of the trends in publications related to C. difficile infection, together with specific insights into hot-button issues in this field.

METHODS

Publications on C. difficile infections in the field of microbiology between 2001 and 2020 were identified from the Scopus database and Reference Citation Analysis. Bibliometric indicators were determined, including the number and type of publications, countries, affiliations, funding agencies, journals and citation patterns. VOSviewer was used to determine research areas and hot-button issues by identifying recurring terms with a high relative occurrence in the title and abstract.

RESULTS

A total of 8127 documents on ‘C. difficile-associated diarrhoea’ published between 2001 and 2020 were retrieved from the Scopus database. In the last decade, there has been a significant almost fourfold increase in the number of published papers on this topic. The United States was among the countries (44.11%) with the most publications, and the most involved institution was the University of Leeds in the United Kingdom (2.50%). Three clusters of research were identified and included ‘illness spectrum and severity, as well as the signs, symptoms and clinical pathogenesis of C. difficile’; ‘laboratory diagnosis and characterization of C. difficile’ and ‘risk factors for C. difficile infection’.

CONCLUSION

This study contains the most up-to-date and comprehensive data ever compiled in this field. More international research and cross-institutional collaborations are needed to address more global C. difficile concerns and to benefit from greater sharing of expertise, which will result in higher quality or more effective studies in the future. Promising research avenues in the near future may draw the attention of relevant scientists and funding organizations and open up novel C. difficile infection–based diagnosis and treatment approaches.

Mapping environmental impact assessment research landscapes in the Arab world using visualization and bibliometric techniques

Interests and concerns on environmental issues have attracted much attention over the past few decades. This is in harmony with the growing understanding of environmental impacts associated with human activities and their role in degrading ecosystems. In line with these concerns, considerable advances in science and technology to assess, mitigate, or lessen these adverse impacts have emerged (i.e., environmental impact assessment (EIA) methodologies). The involvement of EIA in sustainable development has become a prevalent topic in research in either developed and developing countries. The present work investigated the research status, development trends, and hotspots of EIA in a region with massive environmental challenges; the Arab world. Bibliometric analysis and visualization mapping were utilized with an objective of revealing and evaluating the developments in knowledge on EIA from the Arab world. A sum of 595 documents was the productivity of the Arab world on EIA (2.1% of total global productivity). Most of the studies were performed by scholars in Egypt (143 documents; 24.0%), followed by Saudi Arabia (96 documents; 16.1%), and Tunisia (68 documents; 11.4%). France, the USA, and the UK were, respectively, the most collaborated countries with the Arab world on EIA. Most of the publications on EIA were in prestigious journals in relation to environmental sciences. King Abdulaziz University, Saudi Arabia and University of Kuwait were the most productive institutions (24 documents/institution). Topics in relation to assessing different environmental impacts on the quality and quantity of water will continue to be vital themes of research. While, the utilization of remote sensing, geographic information systems, risk assessment, life cycle assessment, bioaccumulation, and biomarkers techniques in assessing environmental impacts will continue to be dominant as efficient tools in conducting EIA related research. The outcomes displayed, in general, a rapidly and steadily rising interests on EIA. However, the development of regional experience, increasing of funds and advancing of competencies will further promote research activities on EIA.

Coronavirus disease-19 in environmental fields: a bibliometric and visualization mapping analysis

A coronavirus disease-19 (COVID-19) caused by a novel coronavirus has appeared in China by the end of 2019 and later recognized as a global pandemic. This pandemic has evolved as a global public health menace. It has affected every aspect of human life. In line with these concerns, governments and the scientific community react promptly to the outbreak of this pandemic. These efforts are devoted to develop vaccine and curative medicines. Further efforts are dedicated to assessing the impacts of the pandemic in relation to socioeconomic, psychological, and environmental dimensions. In this regard, it is important to follow up developments and research activities on this global issue. The present work intended to tracking the current hotspots and research trends on COVID-19 in environmental fields. Bibliometric analysis and visualization mapping were utilized with the objective of revealing and evaluating the developments in knowledge on COVID-2019 and its impacts based on a collection of environmental sources. A sum of 729 documents were collected from Scopus database limiting to environmental sources only. Of all these publications, 563 (77.2%) were articles, 56 (7.7%) were reviews, and 110 (15.0%) were others. China has the highest share of publications (163; 22.4%). It is followed by the USA (139; 19.15), and Italy (110; 15.1%). Most publications on COVID-19 were in prestigious journals. The most productive institution at global level was Chinese Academy of Sciences, China (24 documents; 3.3%). The most prevalent topics are in relation to impacts of the pandemic on air quality, mental health, psychological, and economic aspects. The development of these topics is based on cross-sectional studies, evidence-based tools, remote sensing, satellite mapping, geographic information systems, market analysis and sampling. The progress of environmental research on COVID-19 will guide the development of global environmental strategies to control future global environmental risks.

Energy, Economy, and Environment: A Worldwide Research Update

This paper has reviewed the international research on the interactions between the Economy, Energy, and Environment (3E) in the 21st century. For this purpose, a bibliometric and cluster analysis by fractional accounting has been carried out based on the two most important databases: Web of Science (WoS) and Scopus. The research found and studied 2230 documents from the WoS Core Collection and 3,149 from Scopus. The results show a continuous increase in the number of articles that were published and citations during the whole period. They also showed that China and the United States (U.S.) were the most productive countries and there was a predominance of Asian organizations supporting and fostering researches. The main contribution of this article is the analysis of keywords from 2001 to 2018. The trends show that the main common elements are sustainable development and sustainability and they also include CO2 emissions and consumption. Future research in this field should address the energy transition issue in the area of sustainable development by adapting it to the restrictions of this economic model.

Review of global sanitation development

The implementation of the United Nations (UN) Millennium Development Goals (MDGs) and Sustainable Development Goals (SDGs) has resulted in an increased focus on developing innovative, sustainable sanitation techniques to address the demand for adequate and equitable sanitation in low-income areas. We examined the background, current situation, challenges, and perspectives of global sanitation. We used bibliometric analysis and word cluster analysis to evaluate sanitation research from 1992 to 2016 based on the Science Citation Index EXPANDED (SCI-EXPANDED) and Social Sciences Citation Index (SSCI) databases. Our results show that sanitation is a comprehensive field connected with multiple categories, and the increasing number of publications reflects a strong interest in this research area. Most of the research took place in developed countries, especially the USA, although sanitation problems are more serious in developing countries. Innovations in sanitation techniques may keep susceptible populations from contracting diseases caused by various kinds of contaminants and microorganisms. Hence, the hygienization of human excreta, resource recovery, and removal of micro-pollutants from excreta can serve as effective sustainable solutions. Commercialized technologies, like composting, anaerobic digestion, and storage, are reliable but still face challenges in addressing the links between the political, social, institutional, cultural, and educational aspects of sanitation. Innovative technologies, such as Microbial Fuel Cells (MFCs), Microbial Electrolysis Cells (MECs), and struvite precipitation, are at the TRL (Technology readiness levels) 8 level, meaning that they qualify as "actual systems completed and qualified through test and demonstration." Solutions that take into consideration economic feasibility and all the different aspects of sanitation are required. There is an urgent demand for holistic solutions considering government support, social acceptability, as well as technological reliability that can be effectively adapted to local conditions.

The way forward confronting eco-environmental challenges during land-use practices: a bibliometric analysis

With rapid urbanisation and industrialisation, land-use practice, while satisfying the ever-increasing desires of our material civilisation in the short term, may undermine natural ecosystems on a local, regional and global scale in the long run. Innovative and sustainable land-use practices should be developed in response, so that eco-environmental problems can assessed and dealt with during the whole process of land-use planning, construction, operation, maintenance and management. Using a bibliometric analysis, this study has traced global trends in land-use research from 1992 to 2016, as indexed in the Science Citation Index EXPANDED (SCI-EXPANDED) and the Social Sciences Citation Index (SSCI). A novel method called 'word cluster analysis' has revealed that hotspot analysis is one of the emerging techniques, tools and strategies used to respond to, improve, and protect deteriorating ecosystems during land use. Based on involving various elements, the emerging analytical techniques and tools, including geographical information systems (GIS) and remote sensing, have attracted attention for their ability to assess and solve increasingly serious eco-environmental problems, such as climate change, deforestation, soil erosion, greenhouse gas (GHG) emissions and eutrophication. Ecosystem services, biodiversity conservation, protected areas, and sustainable development are also potential resilience strategies used to confront eco-environmental destruction. The maximum benefits that can be derived from natural ecosystems should be pursued to achieve environmentally sustainable land-use development, strengthening the socio-economy and eco-environment, as well as enhancing the well-being of people and nature.

State of the art on granular sludge by using bibliometric analysis

With rapid industrialization and urbanization in the nineteenth century, the activated sludge process (ASP) has experienced significant steps forward in the face of greater awareness of and sensitivity toward water-related environmental problems. Compared with conventional flocculent ASP, the major advantages of granular sludge are characterized by space saving and resource recovery, where the methane and hydrogen recovery in anaerobic granular and 50% more space saving, 30-50% of energy consumption reduction, 75% of footprint cutting, and even alginate recovery in aerobic granular. Numerous engineers and scientists have made great efforts to explore the superiority over the last 40 years. Therefore, a bibliometric analysis was desired to trace the global trends of granular sludge research from 1992 to 2016 indexed in the SCI-EXPANDED. Articles were published in 276 journals across 44 subject categories spanning 1420 institutes across 68 countries. Bioresource Technology (293, 11.9%), Water Research (235, 9.6%), and Applied Microbiology and Biotechnology (127, 5.2%) dominated in top three journals. The Engineering (991, 40.3%), China (906, 36.9%), and Harbin Inst Technol, China (114, 4.6%) were the most productive subject category, country, and institution, respectively. The hotspot is the emerging techniques depended on granular reactors in response to the desired removal requirements and bio-energy production (primarily in anaerobic granular sludge). In view of advanced and novel bio-analytical methods, the characteristics, functions, and mechanisms for microbial granular were further revealed in improving and innovating the granulation techniques. Therefore, a promising technique armed with strengthened treatment efficiency and efficient resource and bio-energy recovery can be achieved.