Uptake of Polychlorinated Biphenyls (PCBs) from an Aqueous Medium by Polyethylene, Polyvinyl Chloride, and Polystyrene Films

Abstract

The sorption of selected polychlorinated biphenyl (PCB) congeners (from tri to deca chlorinated) by three food-packaging plastic films [polyethylene, polyvinyl chloride (PVC), and polystyrene] from an aqueous solution was investigated. From the data generated, PCB uptake, partition, and diffusion coefficients were calculated for the various films. Polyethylene exhibited the highest PCB uptake, diffusion, and partition coefficients when compared to the other materials. Although PVC indicated larger sorption diffusion and partition coefficients for the lower chlorinated congeners than polystyrene, a reversal of this trend was observed for the higher congeners. For polyethylene and PVC, the PCB uptake decreased as the chlorine numbers in the congeners increased, confirming the correlation between increasing chlorination and increasing cohesive density within the PCB molecules. For polystyrene, the uptake decreased from tri to penta congeners, but showed an increase for the hexa, and then a decreased uptake until the deca chlorination. A comparison of the molecular sizes of the PCB congeners showed that the partition (Ke) and sorption diffusion (Ds) coefficients generally decreased with their increasing molar volumes. The resulting Ke values were used to determine the extent of sorption because these values indicate the affinity of PCBs for the plastic films. Results from this study can be of practical importance for cases of product quality related to the transfer of contaminants from the product to the packaging materials.

The Complex Mixture, Fate and Toxicity of Chemicals Associated with Plastic Debris in the Marine Environment

“…The physical and chemical properties of each type of plastic [e.g. surface area (Teuten et al 2007), diffusivity (Karapanagiot and Klontza 2008;Pascall et al 2005;Rusina et al 2007;Mato et al 2001) and crystallinity (Karapanagioti and Klontza 2008;Mato et al 2001)] influence the accumulation of chemicals to plastic debris (Pascall et al 2005;Rusina et al 2007) and accumulation patterns will be compound-specific (e.g. increasing in affinity to the polymer with greater hydrophobicity; Smedes et al 2009).…”

“…increasing in affinity to the polymer with greater hydrophobicity; Smedes et al 2009). For organic chemicals, several studies show that polyethylene, polypropylene and polystyrene sorb greater concentrations of organic contaminants than PVC and polyethylene terephthalate (PET; Pascall et al 2005;Teuten et al 2007;Karapagioti and Klontza 2008;Rochman et al 2013c, d). For some chemicals (i.e.…”

“…PCBs) there is no detectable difference (Rochman et al 2013c). Rubbery polymers, such as polyethylene and polypropylene are expected to demonstrate greater diffusion than the glassy polymers, PET and PVC, which may explain their greater sorptive capacity (Pascall et al 2005). Polyethylene has a greater sorptive capacity than polypropylene (Teuten et al 2007), probably due to its greater surface area (Teuten et al 2007) and free volume (Pascall et al 2005).…”

“…Rubbery polymers, such as polyethylene and polypropylene are expected to demonstrate greater diffusion than the glassy polymers, PET and PVC, which may explain their greater sorptive capacity (Pascall et al 2005). Polyethylene has a greater sorptive capacity than polypropylene (Teuten et al 2007), probably due to its greater surface area (Teuten et al 2007) and free volume (Pascall et al 2005). Moreover, diffusion into the polymer has been observed in polyethylene pellets, but not in polypropylene (Karapanagioti and Klontza 2008).…”

“…This is likely the reason that polyethylene has a large affinity for a wide range of organic contaminants varying in hydrophobicity (Müller et al 2001) and is often used as a passive-sampling device (Lohmann 2012;Pascall et al 2005). For polystyrene, the presence of benzene increases the distance between adjacent polymeric chains, which can make it easier for a chemical to diffuse into the polymer (Pascall et al 2005), and may explain why contaminants sorb similarly to polystyrene as they do to polyethylene, despite being a glassy polymer (Pascall et al 2005).…”