Microplastics and Their Effects: Environmental Distribution, Analytical Characterization, and Ecological and Human Health Implications

Microplastic pollution has become a widespread environmental concern due to the extensive use of plastic materials and their persistence in environment and possible interaction with biota. Microplastics are generally considered to be small pieces of plastic particles with a size less than 5 mm and they can originate either from fragmentation of larger plastic debris or from direct emissions from industrial, waste and consumer products. Microplastics have been detected in aquatic systems, terrestrial soils, atmospheric particles, indoor dust, food and the human body. This review critically covers the sources, environmental occurrences, analytical characterisation, pathways of exposure, and ecological and human health effects of microplastics. Attention was paid to recent advances in three innovative analytical techniques: FTIR, Raman spectroscopy and pyrolysis-GC/MS, while contamination and quality controls were considered as well. Experimental evidences suggest that some microplastics are able to produce oxidative stress, inflammation and physiological effects in some biological systems. However, the existing differences in particle properties, experimental conditions, methods and endpoints, prevent comparisons and direct application of results to human exposure. This review points out urgent methodological and toxicological issues, priorities in pollution monitoring, exposure assessment, pollution abatement and risk management.