Evaluation of the different possible managements of plastic wastes: a focus on human health.

Aims of the work: Waste management is a problem of considerable importance, not only at the environmental level but also for what are the repercussions on public health. Microplastics (MPs) are the result of the uncorrected management of plastic wastes, both solid and wastewaters. No rules or guidelines are present at today to prevent the releases of MPs. The very low size of the plastic debris seems to favor their penetration into animal tissues and cells, causing alterations in the physiological process. The human body is continuously exposed to MPs through oral, inhalation or dermal route. Populations residing near to waste management areas have always expressed growing concerns about the possible link between the presence of the waste treatment plants and the hypothesis of the onset of various diseases. We carried out a systematic review to provide a concise overview of current knowledge about the different modalities of plastic waste treatments and related health risk for humans. Methods: The method applied for the analysis of literature is the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Landfill, incinerating, mechanic treatments (including wastewaters and sludges) and recycling were researched on the subject, to clarify and highlight the strengths and negative effects that allow for a possible correct management of these specific wastes. The articles included are published on 1990-2020 period. The literature search showed 22403 articles based on categories of treatments, those chosen as eligible as sum were 61. Results: No health effects are reported for waste energy plants managed according the EU BAT emission levels, these plants are the better choice for eliminate plastic wastes due to, also, a minor release of MPs. Instead, the landfill poses some risk for residents with possible loss of leachates and dust rich in MPs for old plants that received undifferentiated wastes. Composting is the major route of dispersion of MPs together to reuse of wastewater's sludges for their reuse in soil and, some health risks are recognized such as lung inflammation often coupled also to lung and gut infections. Finally, recycling poses some risk both for plastic and electronic wastes bounded to an heterogenicity on health risks. Between the wastewater’s treatments, only the plants with a secondary treatment are able to reduce the releases of MPs also if this is again related to the size of the MPs. Conclusion: The recycling of plastic it is not always possible, in fact only about 30% of the plastic is destined for recycling, therefore, it is necessary to choose systems that technologically allow savings for environmental and human health. We believe that incinerating is the better choice both for the reduction of plastic wastes and MPs releases. However, a complete network of treatment’s systems, by implementing the circular economy, also through industrial symbiosis, will it allow us to reduce exposures to MPs and therefore, will allow us to better prevent and reduce related health outcomes.