A bibliometric analysis of investigations of polybrominated diphenyl ethers (PBDEs) in biological and environmental matrices from 1992 - 2018

Occurrence and ecotoxicological impacts of polybrominated diphenyl ethers (PBDEs) in electronic waste (e-waste) in Africa: Options for sustainable and eco-friendly management strategies

Polybrominated diphenyl ethers (PBDEs) are persistent contaminants used as flame retardants in electronic products. PBDEs are contaminants of concern due to leaching and recalcitrance conferred by the stable and hydrophobic bromide residues. The near absence of legislatures and conscious initiatives to tackle the challenges of PBDEs in Africa has allowed for the indiscriminate use and consequent environmental degradation. Presently, the incidence, ecotoxicity, and remediation of PBDEs in Africa are poorly elucidated. Here, we present a position on the level of contamination, ecotoxicity, and management strategies for PBDEs with regard to Africa. Our review shows that Africa is inundated with PBDEs from the proliferation of e-waste due to factors like the increasing growth in the IT sector worsened by the procurement of second-hand gadgets. An evaluation of the fate of PBDEs in the African environment reveals that the environment is adequately contaminated, although reported in only a few countries like Nigeria and Ghana. Ultrasound-assisted extraction, microwave-assisted extraction, and Soxhlet extraction coupled with specific chromatographic techniques are used in the detection and quantification of PBDEs. Enormous exposure pathways in humans were highlighted with health implications. In terms of the removal of PBDEs, we found a gap in efforts in this direction, as not much success has been reported in Africa. However, we outline eco-friendly methods used elsewhere, including microbial degradation, zerovalent iron, supercritical fluid, and reduce, reuse, recycle, and recovery methods. The need for Africa to make and implement legislatures against PBDEs holds the key to reduced effect on the continent.

A data-driven analysis of global research trends on dirty-dozen persistent organic pollutants

The occurrence, distribution, and fate of persistent organic pollutants (POPs) have been extensively studied worldwide; however, the patterns and dynamics of scientific publications on POPs are still unclear. In this study, the research trends on dirty dozen POPs, which are identified under the Stockholm Convention (SC) for immediate action were investigated and evaluated in a broad context to obtain up-to-date information. For this purpose, bibliometric analysis was carried out between 1945 and 2021 using the Web of Science (WoS) database. A total of 197,029 publications were analyzed. "Environmental Sciences" was the most popular research category and the USA was the leading country in dirty dozen POPs studies. The research hotspots are related to the most used keywords such as "Polychlorinated Biphenyls", "Dioxin" and "Persistent Organic Pollutants". In the evaluation of keyword clusters with highlighted research points, 7 clusters were obtained from the publications, which are related to the chemical properties, synthesis, structures, health effects, and analysis methods of dirty dozen POPs. The number of publications and, accordingly, the scientific interest in dirty dozen POPs listed under the SC has not reached equilibrium and continues regardless of the level of development of countries in the world.

Sequestration of steroidal estrogen in aqueous samples using an adsorption mechanism: a systemic scientometric review

Steroidal estrogens (SEs) remain one of the notable endocrine disrupting chemicals (EDCs) that pose a significant threat to the aquatic environment in this era owing to their interference with the normal metabolic functions of the human body systems. They are currently identified as emerging contaminants of water sources. The sources of SEs are either natural or synthetic active ingredients in oral contraceptive and hormonal replacement therapy drugs and enter the environment primarily from excretes in the form of active free conjugate radicals, resulting in numerous effects on organisms in aquatic habitats and humans. The removal of SEs from water sources is of great importance because of their potential adverse effects on aquatic ecosystems and human health. Adsorption techniques have gained considerable attention as effective methods for the removal of these contaminants. A systemic review and bibliometric analysis of the application of adsorption for sequestration were carried out. Metadata for publications on SE removal utilizing adsorbents were obtained from the Web of Science (WoS) from January 1, 1990, to November 5, 2022 (107 documents) and Scopus databases from January 1, 1949, to November 5, 2022 (77 documents). In total, 137 documents (134 research and 4 review articles) were used to systematically map bibliometric indicators, such as the number of articles, most prolific countries, most productive scholars, and most cited articles, confirming this to be a growing research area. The use of different adsorbents, include activated carbon graphene-based materials, single and multi-walled carbon nanotubes, biochar, zeolite, and nanocomposites. The adsorption mechanism and factors affecting the removal efficiency, such as pH, temperature, initial concentration, contact time and adsorbent properties, were investigated in this review. This review discusses the advantages and limitations of different adsorbents, including their adsorption capacities, regenerative potential, and cost-effectiveness. Recent advances and innovations in adsorption technology, such as functionalized materials and hybrid systems, have also been highlighted. Overall, the bibliographic analysis provides a comprehensive overview of the adsorption technique for the removal of SEs from other sources, serving as a valuable resource for researchers and policymakers involved in the development of efficient and sustainable strategies to mitigate the effects of these emerging contaminants.

Hydrogel Applicability for the Industrial Effluent Treatment: A Systematic Review and Bibliometric Analysis

In recent decades, hydrogels, as adsorption materials, have received important attention due to their characteristics and properties, such as mechanical strength, biocompatibility, biodegradability, swellability, and stimuli sensitivity. In the actual framework of sustainable development, it has been imperative to develop practical studies of hydrogels in the treatment of actual industrial effluents. Accordingly, the current work has, as its objective, to make evident hydrogels' applicability in the treatment of actual industrial effluents. For this purpose, a bibliometric analysis and systematic review based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method were conducted. The relevant articles were selected from the Scopus and Web of Science databases. Some important findings were that: (1) China is the leading country when it comes to hydrogel application in actual industrial effluents, (2) the motor studies are focalized on the treatment of wastewater by hydrogels, (3) the fixed-bed columns are suitable unit equipment for the treatment of industrial effluents of using hydrogels, and (4) the hydrogels show excellent adsorption capacities of ion and dye contaminants present in industrial effluents. In summary, since the implementation of sustainable development in 2015, the progress of practical hydrogel applications in the treatment of industrial effluent has been receiving more attention, and the selected studies demonstrate the implementation viability of these materials.

A systematic assessment of research trends on polycyclic aromatic hydrocarbons in different environmental compartments using bibliometric parameters

Polycyclic aromatic hydrocarbons (PAHs) are a large group of diverse hazardous organic compounds that are relatively stable and widely distributed throughout the world's ecosystems due to various anthropogenic activities. They are generally less soluble in water and have a low vapour pressure, but dissolve easily in adipose tissues; and they bioaccumulate into high concentrations in aquatic animals, thereby exerting a variety of hazardous and lethal effects. Despite the plethora of research studies on these pollutants, only few bibliometric reviews on the subject have been documented in the literature. As a result, the present study aimed to assess the research growth on PAHs-related studies across different ecosystems. Science Citation Index-Expanded of Web of Science was explored to obtain the research studies that were conducted between 1991 and 2020, and RStudio was utilized for the data analysis. Annual productivity increased arithmetically over the years, with a 9.2% annual growth rate and a collaboration index of 2.52. Foremost among the trend topics in this field of study include soil, sediments, biodegradation, bioremediation, bioavailability, and source apportionment. China, USA, Spain, France and Germany were the five top-ranked countries in terms of publications and citations over the three decades investigated; however, Korea, Japan, United Kingdom, Germany, and Canada were ranked as the five leading countries in terms of collaboration per published article (MCP ratio). Therefore, efforts to strengthen international collaboration in this field of study especially among the less participating countries and continents are thus encouraged. The findings of this study are expected to provide future direction for the upcoming researchers in identifying the hot spots in this field of study as well as research leaders whom to seek collaboration in their future research plan.

Prenatal exposure to polybrominated diphenyl ethers and birth outcomes

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) were used as flame retardants and from their end-use products they can be released to accumulate within indoor environments. This may result in exposures to pregnant women with potential adverse effects on the developing fetus. While studies have shown associations between prenatal PBDE exposure and poor birth outcomes, research has mainly focused on birth weight and gestational age and may miss important indicators of newborn size.

METHODS

The sample included a cohort of Dominican and African American mother-child pairs from New York City recruited from 1998 to 2006. PBDE congeners (BDE-47, BDE-99, BDE-100, and BDE-153) were measured in cord serum at birth and dichotomized into low (<80th percentile) and high (>80th percentile) categories. Weight, length, head circumference, and gestational age were measured at birth and the ponderal index (birth weight/length x 100), size for gestational age, and population-based z-scores were calculated (n = 305). Separate regression analyses were conducted to estimate associations between PBDEs or PBDE sum (ng/g lipid) and birth outcomes. Quantile g-computation was performed to estimate the effect of total PBDE mixture. We also assessed effect modification by sex and ethnicity.

RESULTS

Adjusting for relevant covariates, the high exposure category of BDE-153 was associated with lower birth weight z-score (-0.25, 95% CI: -0.5, 0.0) and longer gestation (0.43 weeks, 95% CI: 0.07, 0.79). The high exposure category of BDE-99 was associated with lower birth length z-score (-0.55, 95% CI: -0.98, -0.12). There was a negative association between the overall PBDE mixture and birth length z-score (-0.10, 95% CI: -0.21, 0.00) per 1 quintile increase in PBDEs. There was no effect modification by sex or ethnicity.

CONCLUSIONS

These results suggest that prenatal exposures to BDE-153, BDE-99, and total PBDE mixture are associated with birth outcomes in a cohort of Dominican and African American newborns.

A Global Perspective of Vibrio Species and Associated Diseases: Three-Decade Meta-Synthesis of Research Advancement

Outbreaks of Vibrio infections have a long history of global public health concern and threat to the aquaculture industry. This 3-decade (1990-2019) meta-synthesis of global research progress in Vibrio species and associated disease outbreaks was undertaken to generate the knowledge needed to design effective interventions with policy implications. Using PRISMA protocol, we obtained data on the online version of the Institute for Scientific Information (ISI), Web of Science (WOS), and Scopus from January 1990 to September 2021 by title search of the keywords "Vibrio species OR Vibrio spp. OR vibriosis." On the 3-decade survey, the result has shown that a total of 776 publications document types were published on the subject, with an average of 24.25 ± 13.6 published documents per year with an annual growth rate of 4.71%. The year 2020 recorded the highest output of 52 published documents accounting for 6.70% of the total. The most prolific author, Blanch A., published 12 articles on the subject and has received citations of 1003 with an h-index of 10. While the most global cited paper author is the journal of J. Bacteriol (Bassler et al), receiving total citation (TC) (550) and per Year (22). The top active corresponding authors country is the United States of America with (92) articles, freq. 12.40%; TC of 3103. The observations in this study, such as the collaborations network map, and index, which have outlined a big difference between countries based on economic status, have underscored the need for a sustained research mentorship program that can define future policies.

Global research production in neonatal abstinence syndrome: A bibliometric analysis

BACKGROUND

Recently, neonatal abstinence syndrome (NAS) emerged as a significant global concern with a dramatic increase in healthcare expenditures. The incidence of the NAS has increased notably in the past decade and emergence as a global public health problem.

AIM

To evaluate the development and trend of global NAS research from 1958 to 2019 by bibliometric analysis.

METHODS

Analyzed aspects included publication output per year, language, document types, journals, countries/territories, h-index, authors, and top research priorities. The VOSviewer was used to determine the top research priorities, and trends, and to present bibliometric networks concerning various dimensions, such as co-authorship, authors, and countries.

RESULTS

A total of 1738 articles were retrieved in the Scopus database from 1958 to 2019. It was found that the great majority of the total NAS documents (n = 1295) were original articles followed by reviews (n = 268) and letters (n = 48). The most productive countries in the NAS field were the United States (n = 833), Canada (n = 112), the United Kingdom (n = 111), and Germany (n = 77). Treatment and hospital outcomes in NAS, evidence-based nurse-driven interventions for the care of newborns with NAS, and a systematic reviews and network meta-analysis for therapeutic approaches of NAS were found in recent years (after 2010), compared with terms such as pathophysiology, mechanisms of NAS, and signs and symptoms in the early years.

CONCLUSION

Treatment and pediatric outcomes and the effectiveness of pharmacological treatment may be frontiers in the NAS field, and continued efforts from researchers are needed in those topics.

Global research production in neonatal abstinence syndrome: A bibliometric analysis

BACKGROUND

Recently, neonatal abstinence syndrome (NAS) emerged as a significant global concern with a dramatic increase in healthcare expenditures. The incidence of the NAS has increased notably in the past decade and emergence as a global public health problem.

AIM

To evaluate the development and trend of global NAS research from 1958 to 2019 by bibliometric analysis.

METHODS

Analyzed aspects included publication output per year, language, document types, journals, countries/territories, h-index, authors, and top research priorities. The VOSviewer was used to determine the top research priorities, and trends, and to present bibliometric networks concerning various dimensions, such as co-authorship, authors, and countries.

RESULTS

A total of 1738 articles were retrieved in the Scopus database from 1958 to 2019. It was found that the great majority of the total NAS documents (n = 1295) were original articles followed by reviews (n = 268) and letters (n = 48). The most productive countries in the NAS field were the United States (n = 833), Canada (n = 112), the United Kingdom (n = 111), and Germany (n = 77). Treatment and hospital outcomes in NAS, evidence-based nurse-driven interventions for the care of newborns with NAS, and a systematic reviews and network meta-analysis for therapeutic approaches of NAS were found in recent years (after 2010), compared with terms such as pathophysiology, mechanisms of NAS, and signs and symptoms in the early years.

CONCLUSION

Treatment and pediatric outcomes and the effectiveness of pharmacological treatment may be frontiers in the NAS field, and continued efforts from researchers are needed in those topics.

Systematic mapping of DNAzymes research from 1995 to 2019

DNAzymes (catalytic DNA) have gained significant diagnostic and therapeutic applications with increasing research output over the years. Functional oligonucleotides are used as molecular recognition elements within biosensors for detection of analytes and viral infections such as SARS-CoV-2. DNAzymes are also applied for silencing and regulating cancer specific genes. However, there has not been any report on systematic analysis to track research status, reveal hotspots, and map knowledge in this field. Therefore, in the present study, research articles on DNAzymes from 1995 to 2019 were extracted from Web of Science (SCI-Expanded) after which, 1037 articles were imported into Rstudio (version 3.6.2) and analysed accordingly. The highest number of articles was published in 2019 (n = 138), while the least was in 1995 (n = 1). The articles were published across 216 journals by 2344 authors with 2337 multi-author and 7 single authors. The most prolific authors were Li Y (n = 47), Liu J (n = 46), Wang L (n = 33), Willner I (n = 33) and Zhang L (n = 33). The top three most productive countries were China (n = 2018), USA (n = 447) and Canada (n = 251). The most productive institutions were Hunan University, China (n = 141), University of Illinois, USA (n = 139) and Fuzhou University, China (n = 101). Despite the increasing interest in this field, international collaborations between institutions were very low which requires immediate attention to mitigate challenges such as limited funding, access to facilities, and existing knowledge gap.

Inevitable human exposure to emissions of polybrominated diphenyl ethers: A perspective on potential health risks

Polybrominated diphenyl ethers (PBDEs) serve as flame retardants in many household materials such as electrical and electronic devices, furniture, textiles, plastics, and baby products. Though the use of PBDEs like penta-, octa- and deca-BDE greatly reduces the fire damage, indoor pollution by these toxic emissions is ever-growing. In fact, a boom in the global market projections of PBDEs threatens human health security. Therefore, efforts are made to minimize PBDEs pollution in USA and Europe by encouraging voluntary phasing out of the production or imposing compelled regulations through Stockholm Convention, but >500 kilotons of PBDEs still exist globally. Both 'environmental persistence' and 'bioaccumulation tendencies' are the hallmarks of PBDE toxicities; however, both these issues concerning household emissions of PBDEs have been least addressed theoretically or practically. Critical physiological functions, lipophilicity and toxicity, trophic transfer and tissue specificities are of utmost importance in the benefit/risk assessments of PBDEs. Since indoor debromination of deca-BDE often yields many products, a better understanding on their sorption propensity, environmental fate and human toxicities is critical in taking rigorous measures on the ever-growing global deca-BDE market. The data available in the literature on human toxicities of PBDEs have been validated following meta-analysis. In this direction, the intent of the present review was to provide a critical evaluation of the key aspects like compositional patterns/isomer ratios of PBDEs implicated in bioaccumulation, indoor PBDE emissions versus human exposure, secured technologies to deal with the toxic emissions, and human toxicity of PBDEs in relation to the number of bromine atoms. Finally, an emphasis has been made on the knowledge gaps and future research directions related to endurable flame retardants which could fit well into the benefit/risk strategy.

Systematic mapping of organophosphate contaminant (OPC) research trends between 1990 and 2018

Since the addition of polybrominated diphenyls and organochlorine pesticides (OCPs) to the world banned list, toxic organophosphate contaminants (OPCs) such as organophosphate flame retardants and organophosphate pesticides have been, respectively, used as substitutes. These chemicals are reported to be more toxic than their halogenated counterparts. It is rare to find a study that focuses on visualising the publication trends of these chemical classes. In this study, we employed a bibliometric model to systematically map research activities between 1990 and 2018 using OPC articles retrieved from the WoS and Scopus databases. A total of 1090 articles were retrieved from the hybrid databases with an article/author and author/article ratio of 0.33 and 3.02, respectively. Articles on OPC studies were positively correlated with the number of years (r² = 0.96; y = 0.23x² - 3.82x + 27.90) suggesting an increase in the number of articles on this subject in future. The USA ranked first in terms of articles (n = 245) and citations (n = 12,922) followed by China and India (203 and 89 articles, respectively). Articles from China and the USA had strong collaboration with other countries. Research priorities and top author keywords included pesticides (n = 112), organophosphate (n = 83) and acetylcholinesterase (n = 60) and were also well represented in keywords-plus. Developed countries had higher outputs compared to developing countries. It was observed that from our thematic literature classifications, human toxicity, ecotoxicological impacts, and environmental monitoring of OPCs were of greater importance to scholars, thus indicating the direction of future research. Futuristic studies need to foster partnership with policymakers, journalists, consultants, farmers, artisans and community workers on OPC research. This will not only enhance scientific communication and community engagement but will also increase the awareness of these pollutants to the general public.

Global scientific trends on aflatoxin research during 1998-2017: a bibliometric and visualized study

BACKGROUND

Aflatoxins are fungal metabolites associated with contaminated food products. Intake of aflatoxin-contaminated food results in serious health hazards and even death. Therefore, the aim of this study is to evaluate the global scientific output of research of aflatoxin by using bibliometric techniques.

METHODS

This bibliometric study was conducted using Scopus database and classified the retrieved publications were classified from different aspects, including the countries/region of focus, journals, authors, institutes, citations, and content analysis to discover any hot and emerging topics. In addition, the bibliometric analysis of the international collaborative network and hot research topics were generated by VOSviewer© software version 1.6.10. The publication period was restricted in the search for two decades (1998-2017).

RESULTS

The search engine of the Scopus database found 9845 documents published in the field of aflatoxin. The USA is the top publishing source in the world (22.85%), followed by China (11.85%), India (9.32%), and Italy (5.25%). In earlier years, researchers focused on terms related to the topics of "sources and biosynthesis of aflatoxin", "health effects by aflatoxin", and "detoxification and treatment of aflatoxin". However, in recent years, researchers pay more attention to the topic of detection and quantification of aflatoxin.

CONCLUSIONS

The quantity of research in global aflatoxin has substantially increased over the past two decades. The evaluation of the historical status and development trend in aflatoxin scientific research can guide future research, and ultimately provide the basis for improving management procedures for governmental decisions, healthcare, industries, and educational institutions.