Presence of microplastics in the groundwater of volcanic islands, El Hierro and La Palma (Canary Islands)

The increasing amount of plastic litter worldwide is a serious problem for the environment and its biodiversity,
ecosystems, animal and human welfare and the economy. The degradation of these plastics leads to microplastics
(MPs), which have been reported for the first time in groundwater in the Canary archipelago. This research
investigates the presence of MPs at nine different points on La Palma and El Hierro, where samples were collected
in galleries, wells and springs during the month of December 2022. Six different polymers were found with
Fourier transform infrared spectroscopy (FTIR) – polypropylene (PP), polyethylene (PE), cellulose (CEL), polyethylene
terephthalate (PET), polystyrene (PS) and polymethyl methacrylate (PMMA). The particle concentrations
found ranged from 1 to 23 n/L, with a maximum particle size of 1900 μm, the smallest being 35 μm. PP and
PE were the most common polymers found in the analysis, associated with the use of packaging, disposable
products, textiles and water pipes, related to poorly maintained sewerage networks where leaks occur, allowing
these MPs to escape into the environment and end up in groundwater. The detection of microplastic pollution in
groundwater emphasises environmental hazards, including biodiversity disruption and water source contamination.
Additionally, it presents potential risks to human health by transferring contaminants into the food chain
and through respiratory exposure.