Yellowing, Weathering and Degradation of Marine Pellets and Their Influence on the Adsorption of Chemical Pollutants

Abstract

Marine microplastics (MPs) are exposed to environmental factors, which produce aging, weathering, surface cracking, yellowing, fragmentation and degradation, thereby changing the structure and behavior of the plastic. This degradation also has an influence on the adsorption of persistent organic pollutants over the microplastic surface, leading to increased concentration with aging. The degradation state affects the microplastic color over time; this is called yellowing, which can be quantified using the Yellowness Index (YI). Weathering and surface cracking is also related with the microplastic yellowing, which can be identified by Fourier transform infrared spectroscopy (FTIR). In this study, the degradation state of marine microplastic polyethylene pellets with different aging stages is evaluated and quantified with YI determination and the analysis of FTIR spectrums. A color palette, which relates to the microplastic color and YI, was developed to obtain a visual percentage of this index. The relation with the adsorption rate of persistent organic pollutant over the microplastic surface was also determined.

Ageing Affects the Mechanical Interaction between Microplastics and Lipid Bilayers

“…Aged pellets are easy to identify as they have turned from white to yellow. 36 This change in yellowing index becomes more pronounced with age and weathering. 36 Hence, this simple technique is used to sort the pellets based on their age, provided the changes in the yellowing index are substantial.…”

“…36 This change in yellowing index becomes more pronounced with age and weathering. 36 Hence, this simple technique is used to sort the pellets based on their age, provided the changes in the yellowing index are substantial. 36 Otherwise, combining the yellowing index with Fouriertransform infrared microscopy is required, which is not necessary here because we consider only groups of pellets that present a consequent change in the yellowing index.…”

“…35,36 Thus, this simple technique can be used to sort the pellets as a function of their age, provided the changes in the yellowing index are significant. 35,36 Alternatively, one could complement the yellowing index measurement with Fourier-transform infrared microscopy, but this is not necessary for environmental plastic pellets that exhibit a substantial change in the yellowing index. 36 In this study, we utilize plastic pellets to produce microplastics through grinding and filtering the pellets.…”

“…35,36 Alternatively, one could complement the yellowing index measurement with Fourier-transform infrared microscopy, but this is not necessary for environmental plastic pellets that exhibit a substantial change in the yellowing index. 36 In this study, we utilize plastic pellets to produce microplastics through grinding and filtering the pellets. We then investigate the impact of aging on the physical interaction between microplastics and a model lipid membrane, which is the final barrier that protects cells from the environment.…”

Adsorption of PAHs and PCDD/Fs in Microplastics: A Review

“…Abaroa et al [82] showed an increase in adsorption with aging, and proposed that the use of an indicator, the yellowness index (YI), related to the color change that microplastics present over time. This YI is estimated visually based on the color of the MPs and is related to the speed at which the POPs are adsorbed on the particles.…”