Electronic waste (e-waste) contains numerous chemicals harmful to human and ecological health. To update a 2013 review assessing adverse human health consequences of exposure to e-waste, we systematically reviewed studies reporting effects on humans related to e-waste exposure. We searched EMBASE, PsycNET, Web of Science, CINAHL, and PubMed for articles published between Dec 18, 2012, and Jan 28, 2020, restricting our search to publications in English. Of the 5645 records identified, we included 70 studies that met the preset criteria. People living in e-waste exposed regions had significantly elevated levels of heavy metals and persistent organic pollutants. Children and pregnant women were especially susceptible during the critical periods of exposure that detrimentally affect diverse biological systems and organs. Elevated toxic chemicals negatively impact on neonatal growth indices and hormone level alterations in e-waste exposed populations. We recorded possible connections between chronic exposure to e-waste and DNA lesions, telomere attrition, inhibited vaccine responsiveness, elevated oxidative stress, and altered immune function. The existence of various toxic chemicals in e-waste recycling areas impose plausible adverse health outcomes. Novel cost-effective methods for safe recycling operations need to be employed in e-waste sites to ensure the health and safety of vulnerable populations.

Environmental context: Recent developments in nanotechnology have focussed towards innovation and usage of multifunctional and superior hybrid nanomaterials. Possible exposure of these novel nanohybrids can lead to unpredicted environmental fate, transport, transformation and toxicity scenarios. Environmentally relevant emerging properties and potential environmental implications of these newer materials need to be systematically studied to prevent harmful effects towards the aquatic environment and ecology. Nanomaterial synthesis and modification for applications have progressed to a great extent in the last decades. Manipulation of the physicochemical properties of a material at the nanoscale has been extensively performed to produce materials for novel applications. Controlling the size, shape, surface functionality, etc. has been key to successful implementation of nanomaterials in multidimensional usage for electronics, optics, biomedicine, drug delivery and green fuel technology. Recently, a focus has been on the conjugation of two or more nanomaterials to achieve increased multifunctionality as well as creating opportunities for next generation materials with enhanced performance. With incremental production and potential usage of such nanohybrids come the concerns about their ecological and environmental effects, which will be dictated by their not-yet-understood physicochemical properties. While environmental implication studies concerning the single materials are yet to give an integrated mechanistic understanding and predictability of their environmental fate and transport, the importance of studying the novel nanohybrids with their multi-dimensional and complex behaviour in environmental and biological exposure systems are immense. This article critically reviews the literature of nanohybrids and identifies potential environmental uncertainties of these emerging ‘horizon materials’.