Solid waste: An overlooked source of microplastics to the environment

We present the first ever global account of the production, use, and end-of-life fate of all plastics ever made by humankind.

Microplastics are a pollutant of environmental concern. Their presence in food destined for human consumption and in air samples has been reported. Thus, microplastic exposure via diet or inhalation could occur, the human health effects of which are unknown. The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research. Key literature up to September 2016 relating to bioaccumulation, particle toxicity, and chemical and microbial contaminants were critically examined. Whilst this is an emerging field, complimentary existing fields indicate potential particle, chemical and microbial hazards. If inhaled or ingested, microplastics may bioaccumulate and exert localised particle toxicity by inducing or enhancing an immune response. Chemical toxicity could occur due to the localised leaching of component monomers, endogenous additives, and adsorbed environmental pollutants. Chronic exposure is anticipated to be of greater concern due to the accumulative effect which could occur. This is expected to be dose-dependent, and a robust evidence-base of exposure levels is currently lacking. Whilst there is potential for microplastics to impact human health, assessing current exposure levels and burdens is key. This information will guide future research into the potential mechanisms of toxicity and hence therein possible health effects. Show more

Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies. Show more