Adsorption and Desorption Behaviour of Polychlorinated Biphenyls onto Microplastics’ Surfaces in Water/Sediment Systems

Abstract

The potential of microplastics (MPLs) in marine ecosystems to adsorb and transport other micropollutants to biota, contributing to their entry in the food chain, is a primary cause of concern. However, these interactions remain poorly understood. Here, we have evaluated the adsorption/desorption behaviour of marker polychlorinated biphenyls (PCBs), onto MPL surfaces of three widely used polymers—polystyrene (PS), polyethylene (PE), and polyethylene terephthalate (PET). The range of MPL sizes ranged from 1 to 600 μm. The adsorption/desorption was evaluated in sediment/water systems in marine microcosms emulating realistic environmental conditions for 21 days. The adsorption percentages ranged from 20 to 60%. PCBs with a lower degree of chlorination showed higher adsorption percentages because of conformational impediments of PCBs with high-degree chlorination, and also by their affinity to be adsorbed in sediments. Glassy plastic polymers as PET and PS showed a superior affinity for PCBs than rubbery polymers, such as PE. The polymers that can bond PCBs by π-π interactions, rather than van der Waals forces showed better adsorption percentages, as expected. Finally, the adsorption/desorption behaviour of selected PCBs onto MPLs was fitted to a Freundlich isotherm model, with correlations higher than 0.8 in most of the cases.

Interactions Between Microplastics and Heavy Metals in Aquatic Environments: A Review

“…As simple non-polar crystalline polymers, PE and PP have no functional groups and can only adsorb contaminants in a single layer with van der Waals forces, so the adsorption capacity is relatively small (Chen et al, 2019). For PS and PET, the polarity is increased due to the presence of phenyl and ester groups, and the adsorption capacity can be increased through the interaction of π-π bonds with pollutants (Llorca et al, 2020;Loncarski et al, 2020). PVC, because it contains polar atomic chlorine, is a strong polar polymer, so it has very large adsorption capacity (Brennecke et al, 2016).…”

Organic Contaminants and Interactions with Micro- and Nano-Plastics in the Aqueous Environment: Review of Analytical Methods

“…Table 1 shows the phase that is analyzed to obtain the concentrations of TOrCs. For this purpose, the trace organic chemical can be extracted from the particle, for instance by means of soxhlet extraction [ 65 ]. The TOrCs are washed off the particle with a solvent (e.g., dichloromethane), concentrated, purified, and finally analyzed.…”

“…Measurement by liquid scintillation counting is another method for analyzing sorbed TOrCs in laboratory experiments [ 6 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ...…”

Spatial Distribution and Location of Natural Organic Matter on Sediment Particles by Scanning Electron Microscopic Analysis and the Development of a New Persistent Organic Pollutant–Sediment Kinetic Desorption Model

“…Soubaneh et al (2015) found that 2 toxaphene congeners with low partitioning to marine sediments were more readily available for uptake by marine biota. Recently, research attention has turned to the ability of microplastics to store and later release POPs in marine environments (Llorca et al 2020). Research has not shied away from studying NOM and POPs, but the literature has not explored the specific physical relationship, which is vital for understanding the mechanism for sorption and desorption.…”