Electronic waste exposure and DNA damage: a systematic review and meta-analysis

E-waste recycling in an optimized way for copper recovery by leaching and a case study on E-waste generation and management in Dhaka city

The widespread adoption of electronic devices has enhanced living standards but has also led to a surge in electronic waste (e-waste), creating serious environmental and health challenges. Although various methods exist to recover valuable metals from e-waste, each has notable drawbacks. Among these, chemical leaching with aqua regia is widely used but is both highly corrosive and hazardous. This study introduces a safer, more environmentally friendly approach to copper recovery from e-waste using an iron-based leaching solution. A combination of experimental procedures and computational modeling was employed to optimize copper extraction from printed circuit boards (PCBs). The experiments involved treating PCBs with iron-based solutions of different concentrations and testing the effectiveness over two distinct time periods. The most effective recovery rate, 72.69 % over five days, was achieved using a 50:50 mixture of ferrous and ferric sulfate. Computational analysis with Python's SciPy library further identified 5.92 g of PCB as the ideal input quantity for the process. In addition to the lab-based work, a survey of Dhaka's primary e-waste recycling hubs, Nimtoli and Elephant Road, revealed that approximately 1173 tons of e-waste are processed in these areas each year. Based on experimental findings, the survey findings have a projection to generate over 35 million BDT annually through copper recovery. However, despite government initiatives to regulate e-waste management, unsafe handling practices remain widespread. These practices not only endanger workers and the environment but also hinder regulatory efforts. The study emphasizes the urgent need for stricter regulations, greater public awareness, and the adoption of eco-friendly methods, like the proposed iron-based solution, to ensure safer and more effective copper recovery.

Comprehensive Blood Metabolome and Exposome Analysis, Annotation, and Interpretation in E-Waste Workers

Background: Electronic and electrical waste (e-waste) production has emerged to be of global environmental public health concern. E-waste workers, who are frequently exposed to hazardous chemicals through occupational activities, face considerable health risks. Methods: To investigate the metabolic and exposomic changes in these workers, we analyzed whole blood samples from 100 male e-waste workers and 49 controls from the GEOHealth II project (2017-2018 in Accra, Ghana) using LC-MS/MS. A specialized computational workflow was established for exposomics data analysis, incorporating two curated reference libraries for metabolome and exposome profiling. Two feature detection algorithms, asari and centWave, were applied. Results: In comparison to centWave, asari showed better sensitivity in detecting MS features, particularly at trace levels. Principal component analysis demonstrated distinct metabolic profiles between e-waste workers and controls, revealing significant disruptions in key metabolic pathways, including steroid hormone biosynthesis, drug metabolism, bile acid biosynthesis, vitamin metabolism, and prostaglandin biosynthesis. Correlation analyses linked metal exposures to alterations in hundreds to thousands of metabolic features. Functional enrichment analysis highlighted significant perturbations in pathways related to liver function, vitamin metabolism, linoleate metabolism, and dynorphin signaling, with the latter being observed for the first time in e-waste workers. Conclusions: This study provides new insights into the biological impact of prolonged metal exposure in e-waste workers.

E-waste: mechanisms of toxicity and safety testing

Currently, information on the toxicity profile of the majority of the identified e-waste chemicals, while extensive and growing, is admittedly fragmentary, particularly at the cellular and molecular levels. Furthermore, the toxicity of the chemical mixtures likely to be encountered by humans during and after informal e-waste recycling, as well as their underlying mechanisms of action, is largely unknown. This review paper summarizes state-of-the-art knowledge of the potential underlying toxicity mechanisms associated with e-waste exposures, with a focus on toxic responses connected to specific organs, organ systems, and overall effects on the organism. To overcome the complexities associated with assessing the possible adverse outcomes from exposure to chemicals, a growing number of new approach methodologies have emerged in recent years, with the long-term objective of providing a human-based and animal-free system that is scientifically superior to animal testing, more effective, and acceptable. This encompasses a variety of techniques, typically regarded as alternative approaches for determining chemical-induced toxicities and holds greater promise for a better understanding of key events in the metabolic pathways that mediate known adverse health outcomes in e-waste exposure scenarios. This is crucial to establishing accurate scientific knowledge on mixed e-waste chemical exposures in shorter time frames and with greater efficacy, as well as supporting the need for safe management of hazardous chemicals. The present review paper discusses important gaps in knowledge and shows promising directions for mechanistically anchored effect-based monitoring strategies that will contribute to the advancement of the methods currently used in characterizing and monitoring e-waste-impacted ecosystems.

Micronuclei frequency and exposure to chemical mixtures in three Colombian mining populations

The Colombian mining industry has witnessed significant growth. Depending on the scale and mineral extracted, complex chemical mixtures are generated, impacting the health of occupationally exposed populations and communities near mining projects. Increasing evidence suggests that chromosomal instability (CIN) is an important link between the development of certain diseases and exposure to complex mixtures. To better understand the effects of exposure to complex mixtures we performed a biomonitoring study on 407 healthy individuals from four areas: three located in municipalities exploiting different-scale mining systems and a reference area with no mining activity. Large, medium, and small-scale mining systems were analyzed in Montelibano (Córdoba), artisanal and small-scale mining (ASGM) in Nechí (Antioquia), and a closed mining system in Aranzazu (Caldas). The reference area with no mining activity was established in Montería (Córdoba). ICP-MS measured multi-elemental exposure in hair, and CIN was evaluated using the cytokinesis-block micronucleus technique (MNBN). Exposure to mixtures of chemical elements was comparable in workers and residents of the mining areas but significantly higher compared to reference individuals. In Montelibano, increased MNBN frequencies were associated with combined exposure to Se, Hg, Mn, Pb, and Mg. This distinct pattern significantly differed from other areas. Specifically, in Nechí, Cr, Ni, Hg, Se, and Mg emerged as the primary contributors to elevated frequencies of MNBN. In contrast, a combination of Hg and Ni played a role in increasing MNBN in Aranzazu. Interestingly, Se consistently correlated with increased MNBN frequencies across all active mining areas. Chemical elements in Montelibano exhibit a broader range compared to other mining zones, reflecting the characteristics of the high-impact and large-scale mining in the area. This research provides valuable insights into the effects of exposure to chemical mixtures, underscoring the importance of employing this approach in the risk assessment of communities, especially those from residential areas.

Male Germ Cell Telomeres and Chemical Pollutants

In recent decades, male infertility has been correlated with the shortening of sperm telomeres. Telomeres regulate the reproductive lifespan by mediating the synapsis and homologous recombination of chromosomes during gametogenesis. They are composed of thousands of hexanucleotide DNA repeats (TTAGGG) that are coupled to specialized shelterin complex proteins and non-coding RNAs. Telomerase activity in male germ cells ensures that the telomere length is maintained at maximum levels during spermatogenesis, despite telomere shortening due to DNA replication or other genotoxic factors such as environmental pollutants. An emerging body of evidence has associated an exposure to pollutants with male infertility. Although telomeric DNA may be one of the important targets of environmental pollutants, only a few authors have considered it as a conventional parameter for sperm function. The aim of this review is to provide comprehensive and up-to-date data on the research carried out so far on the structure/function of telomeres in spermatogenesis and the influence of environmental pollutants on their functionality. The link between pollutant-induced oxidative stress and telomere length in germ cells is discussed.

Global research into the relationship between electronic waste and health over the last 10 years: A scientometric analysis

Introduction

The aims of this research were to conduct the first holistic and deep scientometric analysis of electronic waste and health and provide with the prediction of research trends and hot topics.

Method

A comprehensive literature search was conducted via the Web of Science Core collection databases on 26 August 2022 to identify all articles related to electronic waste and health. A total of 652 records have been extracted from the Web of Science after applying inclusion and exclusion criteria and were analyzed using bibliometrix software of R-package, VOSviewer, and CiteSpace, visualized by tables and diagrams.

Result

The number of publications and total citations had shown a general growth trend from 2012 to 2021, with an average annual growth rate of 23.74%. Mainland China was the significant nation with the greatest number of publications, citations, and international links. The journal publishing the most was "Science of the Total Environment" (n = 56). Huo X and Hu XJ were the top two author contributing to this field with the highest h-index (23). Over time, the focus in this field shifted to exposure to heavy metal, polychlorinated biphenyls, polybrominated biphenyl ethers, and poly- and perfluorinated alkyl substances from electronic waste, and managements, such as hydrometallurgy.

Discussion

By this scientometric analysis, we found that the most active country, journal, organization and author contributing to this filed, as well as high impact documents and references and research hotspots. Also, we found that the hotspots might be exposure to toxic substances from electronic waste procession, its impact on human health and relevant managements. And evironmentally friendly materials to replace heavy metal mate rials, and environmentally friendly and effective recycling methods of electronic waste need to be further studied.

Health Risks Associated with Informal Electronic Waste Recycling in Africa: A Systematic Review

Informal electronic waste (e-waste) recycling in Africa has become a major public health concern. This review examined studies that report on the association between e-waste exposure and adverse human health outcomes in Africa. The review was conducted following the updated version of the Preferred Items for Systematic Review and Meta-analysis (PRISMA 2020) statement checklist. We included papers that were original peer-reviewed epidemiological studies and conference papers, written in English, and reported on e-waste exposure among human populations and any health-related outcome in the context of Africa. Our results from the evaluation of 17 studies found an association between informal e-waste recycling methods and musculoskeletal disease (MSD) symptoms and physical injuries such as back pains, lacerations, eye problems, skin burns, and noise-induced hearing loss (NIHL). In addition, the generation and release of particulate matter (PM) of various sizes, and toxic and essential metals such as cadmium (Cd), lead (Pb), zinc (Zn), etc., during the recycling process are associated with adverse systemic intermediate health outcomes including cardiopulmonary function and DNA damage. This systematic review concludes that the methods used by e-waste recyclers in Africa expose them to increased risk of adverse health outcomes. However, there is a need for more rigorous research that moves past single pollutant analysis.

Mitochondrial dysfunctions elicited by solid waste leachates provide insights into mechanisms of leachates induced cell death and pathophysiological disorders

Emissions (mainly leachates and landfill gases) from solid waste facilities are laden with mixtures of dangerous xenobiotics implicated with significant increase in various pathophysiological disorders including cancer, and eventual mortality of exposed wildlife and humans. However, the molecular mechanisms of solid waste leachates induce pathophysiological disorders and cell death are still largely unknown. Although, evolving evidence implicated generation of reactive oxygen species and oxidative stress as the possible mechanism. Recent scientific reports are linking reactive oxygen species and mitochondrial dysfunctions as the player mechanism in pathophysiological disorder and apoptosis induced by xenobiotics in solid waste leachates. This systematic review presents an explicit discussion of recent scientific findings on the structural and functional alterations in mitochondria induced by solid waste leachates as the molecular mechanisms plausibly responsible for the pathophysiological disorders, cancer and cell death reported in landfill toxicology and epidemiological studies. This review aims to increase scientific understanding on solid waste leachate induced mitochondria dysfunctions as the key player in molecular mechanisms of solid waste induced toxicity. The findings in this review were mainly from using primary cells, cell lines, Drosophila and fish. Whether the findings will similarly be observed in mammalian test systems in vivo and particularly in exposed humans, remained to be investigated. Improvement in technological advancements, enforcement of legislation and regulations, and creation of sophisticated health surveillance against exposure to solid waste leachates, will expectedly mitigate human exposure to solid waste emissions and contamination of the environment.

The Impact of Oxidative Stress of Environmental Origin on the Onset of Placental Diseases

Oxidative stress (OS) plays a pivotal role in placental development; however, abnormal loads in oxidative stress molecules may overwhelm the placental defense mechanisms and cause pathological situations. The environment in which the mother evolves triggers an exposure of the placental tissue to chemical, physical, and biological agents of OS, with potential pathological consequences. Here we shortly review the physiological and developmental functions of OS in the placenta, and present a series of environmental pollutants inducing placental oxidative stress, for which some insights regarding the underlying mechanisms have been proposed, leading to a recapitulation of the noxious effects of OS of environmental origin upon the human placenta.