Environmental and Health Impacts of Disposable E-Cigarette Waste: A Meta-Analysis of Chemical Exposures and Sustained Health Outcomes

Background: The increasing use of disposable e-cigarettes (DECs) has raised concerns regarding environmental pollution and public health risks due to their hazardous chemical components and improper disposal practices. Unlike rechargeable devices, DECs are discarded after a single use, generating substantial amounts of waste containing heavy metals, residual nicotine, volatile organic compounds (VOCs), and lithium-ion battery residues. The accumulation of such waste in landfills, waterways, and public spaces may adversely affect ecosystems and human health. Objectives: This meta-analysis aimed to evaluate the environmental and public health impacts associated with disposable e-cigarette waste by synthesizing evidence on chemical exposures and their ecological and health consequences. Methods: A systematic search was conducted to identify studies published between 2018 and 2024 that investigated the environmental and health effects of DEC waste. Studies were screened for relevance and methodological quality. Data were extracted on chemical constituents, exposure pathways, environmental contamination, human health outcomes, and mitigation measures. Quantitative data were pooled using a random-effects meta-analysis model. Results: Of 1.048 identified articles, 12 studies met the inclusion criteria and were included in the qualitative synthesis. Five studies examined heavy metal exposure, three investigated toxic effects on soil and aquatic environments, and four assessed human health outcomes, including respiratory disorders, oxidative stress, and cancer risk. A total sample of 3,426 exposure units or populations was analyzed. The pooled analysis demonstrated a significant association between DEC waste exposure and adverse environmental and health outcomes (OR = 1.72; 95% CI: 1.31–2.25; p < 0.001), with low heterogeneity among studies (I² = 18%). Conclusion: Disposable e-cigarette waste is significantly associated with environmental contamination and adverse human health effects. The non-sustainable design of DECs contributes to their emergence as a growing environmental pollutant. Strengthening regulatory frameworks, promoting public awareness, improving waste management systems, and encouraging environmentally sustainable product designs are essential to mitigate these risks.