Identification, origin and characteristics of bio-bead microplastics from beaches in western Europe

Abstract

Primary microplastics have been collected from 17 beaches along the Atlantic, English Channel and southern North Sea coasts of western Europe. Based on visual characteristics, these plastics were differentiated as either relatively smooth, lentil-or disc-shaped pre-production pellets (or nurdles), which were usually a few mm in diameter and were mainly white to off-white, or rougher and more irregular pellets that were slightly larger and usually black. The latter appeared to be bio-beads, or plastics that are specifically manufactured for use as biomedia in certain sewage water treatment (SWT) plants, and possibly in other industrial wastewater treatment applications. Identification of bio-beads was confirmed following the acquisition of identical samples from a SWT plant in southwest England and a French supplier of bio-beads. Infrared and x-ray fluorescence analysis revealed that bio-beads have, at least historically, been constructed of plasticised polyethylene and, unlike pre-production pellets, contained variable quantities of potentially toxic elements: Br, Cd, Cr, Hg, Pb and Sb; with a distinctive Br to Sb ratio indicative of brominated flame retardants and antimony-based retardant synergists. It is asserted that bio-beads have been manufactured from a heterogeneous mix of recycled polyethylene and end-of-life electrical and electronic plastic, with concentrations of Br, Cd, Cr or Pb in about 50 bio-beads (out of 500 analysed) non-compliant or potentially non-compliant with respect to current regulations on hazardous plastic waste. Concentrations of Br, Cd, Cr, Pb and Sb extracted from individual bio-beads by a simulated avian digestive fluid were variable, with maximum values of about 14, 0.8, 1.3, 20 and 1.4 g g-1 , respectively. The presence and, in many cases, dominance of bio-beads among beached primary microplastics is discussed with regard to the classification of microplastics and potential impacts on wildlife.

A Global Perspective on Microplastics

“…These bio‐beads may be similar in size to preproduction pellets (nurdles) used to manufacture plastic products. Turner et al () suggested that the release of bio‐beads contributed to the plastic litter observed on western European beaches. They further hypothesized, based on elemental analyses (e.g., Br, Sb, and Pb), that some of the bio‐beads might be derived from recycled e‐waste plastics containing toxic additives such as flame retardants.…”

Critical Assessment of Analytical Methods for the Harmonized and Cost-Efficient Analysis of Microplastics

“…In the reviewed studies, FT-IR was performed either by measuring single particles, 16,54,59,81–150 via handheld FT-IR, 137,…”

Remediation of Contaminated Waters with Microplastics

“…In this way, water reduced in organic load, ammonia, and suspended solids are obtained. Turner et al (2019) describe the use of polyethylene (made from recycled plastics from electronic industry) in local wastewater treatment plants. The PE used as a filter in this process has a high surface area where a layer of microorganisms is deposited that decomposes ammonia compounds present in the water.…”

“…It should be mentioned that according to Turner et al (2019), these polar polymers will not only capture organic matter but also metal ions. When, as they report, these MPs containing relevant amounts of metals such as Cr, Cd, Hg, and Pb are lost from the treatment reactors, they can come into contact with natural waters becoming potential contaminants due to the leaching of the sorbed contaminants.…”