A recent investigation conducted by the Applied Analytical Chemistry Research Group (AChem) at the University of La Laguna has uncovered the existence of pyroplastics on three beaches in Tenerife: Playa Grande, Bocinegro, and Almáciga. Although these formations were identified for the first time in 2019 along the shores of the United Kingdom, they had not been recognised in the Canary Islands until now.
Pyroplastics are fragments of incinerated plastic that bear a resemblance to rocks and can easily be mistaken for them along the shoreline. The primary distinction is that due to their low density, they float in seawater, whilst also possessing a creamy texture.
The research team involved in this study, recently published in the journal Marine Pollution Bulletin, discovered a total of 300 of these fragments during sampling conducted from 2021 to 2024 on the aforementioned beaches in Tenerife, despite examining a significantly larger number of beaches. The pyroplastics identified are predominantly grey and dark in colour, with an average mass of 6.8 grams and dimensions measuring between 34 millimetres in length, 24 millimetres in width, and 14 millimetres in height. Many of these pieces contain various embedded materials such as wood, paper, charcoal, or sand. Although the exact origin remains uncertain, various studies suggest that they may stem from the incineration of plastic waste in coastal regions.
A diverse array of marine organisms has also been discovered attached to the surface of these formations, including algae, bryozoans, annelids, and foraminifera, among others, which may indicate that these formations serve as a means of transport for marine life.
Concerning the composition of pyroplastics, Fourier-transform infrared spectroscopy (FTIR-ATR) has revealed that polyethylene and polypropylene constitute the primary components, accounting for 61% and 33%, respectively.
Moreover, analysis through X-ray fluorescence spectroscopy (XRF) has detected a range of metals, notably highlighting elevated concentrations of certain heavy metals such as lead (Pb) and chromium (Cr), with average concentration values of 205.3 ± 6.3 mg·kg-1 (parts per million) and 51.1 ± 8.9 mg·kg-1, respectively.
A strong correlation was also established for these two metals across a total of 22 pyroplastics, which could suggest the presence of PbCrO4 as an additive, widely used in the plastics industry for its vivid yellow pigment, but is now regulated due to its detrimental effects on human health and the environment.
This research forms part of the doctoral thesis of Christopher Dominguez Hernandez, a doctoral candidate in the Chemistry and Chemical Engineering Doctoral Programme at the University of La Laguna.
