E-waste in the environment: Unveiling the sources, carcinogenic links, and sustainable management strategies

Abstract

E-waste refers to electrical and electronic equipment discarded without the intent of reuse by choice or at the end of its functional lifespan. In 2022, approximately 62 billion kilograms of e-waste, equivalent to 7.8 kilograms per capita, was generated globally. With an alarming annual growth of approximately 2 million metric tonnes, e-waste production may exceed 82 billion kilograms by 2030. Improper disposal of e-waste can be detrimental to human health and the entire biosphere. E-waste encompasses a wide range of chemicals, including heavy metals, Polychlorinated Biphenyls (PCBs), Per- and Polyfluoroalkyl Substances (PFAS), Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Dibenzo-dioxins and -furans (PCDD/Fs), Polybrominated Diphenyl Ethers (PBDEs), and radioactive elements. Improper disposal of e-waste equipment can directly contaminate the aquatic and terrestrial environment, leading to human exposure through ingestion, inhalation, dermal absorption, and trans-placental transfer. These contaminants can directly enter the human body from the environment, potentially fueling carcinogenesis by modulating cell cycle proteins, inducing oxidative stress, and mutations. Heavy metals such as cadmium, mercury, arsenic, lead, chromium, and nickel along with organic pollutants like PAHs, PCBs, PBDEs, PFAS, and radioactive elements, play a crucial role in inducing malignancy in humans. Effective collection, sorting, proper recycling, and appropriate disposal techniques are essential in reducing environmental contamination by e-waste-derived chemicals. Hence, this comprehensive review aims to uncover the global environmental burden of e-waste and its links to carcinogenesis in humans. Furthermore, it provides an inclusive discussion on potential treatment approaches to minimize environmental e-waste contamination.