Characterization of pyroplastics from the North Atlantic.

This work describes for the first time the presence of pyroplastics in the Canary Islands (Spain). A total of 300 pyroplastics, identified between 2021 and 2024 in three beaches of the island of Tenerife, present mainly grey and dark colors, a mean weight of 6.8 ± 13.4 g and mean dimensions of 34.2 ± 17.0 mm (X), 24.5 ± 12.2 mm (Y) and 14.4 ± 6.4 (Z). A wide variety of encapsulated and semi-encapsulated materials were also found in the pyroplastics matrix, such as rocks, wood, charcoal and unmelted plastic inclusions. Fourier-transform infrared spectroscopy analysis revealed that polyethylene and polypropylene were the main types of plastic found, 61.3 % and 33.6 %, respectively. However, an important number of pyroplastics composed of more than one polymer were also found, coexisting even mixtures of polyester and polyethylene or polyethylene and styrene-ethylene-butylene-styrene in the same matrix. X-ray fluorescence spectroscopy analysis revealed the presence of a wide range of elements, being remarkable the high concentration of some heavy metals such as Pb and Cr, registering mean concentration values of 205.3 ± 6.3 mg·kg-1 and 51.1 ± 8.9 mg·kg-1, respectively. A good correlation was also found for these two metals in a total of 22 pyroplastics, which could be indicative of the presence of PbCrO4 as additive, widely used in the plastic industry for its bright yellow color, but currently regulated and restricted due to its harmful effects on human and environment health. Also noteworthy is the large variety of remains of marine organisms identified attached to the surface of the pyroplastics, such as algae, bryozoans, arthropods and molluscs, among others, which could indicate that these formations may act as a transport vector for such marine organisms.

Microplastic pollution in sublittoral coastal sediments of a North Atlantic island: The case of La Palma (Canary Islands, Spain).

In this work, the microplastic content of sediments collected in July 2020 between 5 and 7 m depth was studied in four locations of La Palma island (Canary Islands, Spain). At each sampling location, three samples were taken parallel to the shoreline. The microplastic content in each sampling corer was studied every 2.5 cm depth after digestion with a H2O2 solution followed by flotation in a saturated NaCl solution. Visualization of the final filtrates under a stereomicroscope revealed that all the sediment samples evaluated contained mostly microfibers (98.3%) which were mainly white/colorless (86.0%) and blue (9.8%), with an average length of 2423 ± 2235 (SD) mm and an average concentration of 2682 ± 827 items per kg of dry weight, being the total number of items found 1,019. Fourier Transform Infrared microscopy analysis of 13.9% (n = 139) of the microfibers also showed that they were mainly cellulosic (81.3%). No significant differences were found between the depths of the sediment. However, significant differences were found between the number of fibers from the sampling sites at the east and west of the island. Such variability could be driven by the winds and ocean mesoscale dynamics in the area. This study confirms the wide distribution of microfibers in sediments from an oceanic island like La Palma, providing their first report in marine sediments of the Canary Islands.

Use of polyoxyethylene surfactants for the extraction of organochlorine pesticides from agricultural soils.

Two non-ionic surfactant mixtures (POLE and Polyoxyethylene 10 Cetyl ether, POLE and Polyoxyethylene 10 Stearyl ether) have been used for microwave-assisted extraction of six organochlorine pesticides from agricultural soils prior to being determined by HPLC-UV. An experimental design was applied for the determination of variables which affect to recovery and to optimize the extraction parameters, surfactant concentration and volume, microwave time and power. Under the optimized conditions, the method was applied to different soil samples in order to analyze the influence of soil characteristics on the pesticides extraction. The results obtained indicate that most of these compounds can be recovered in good yields with RSD lower than 10% and detection limit ranged between 80 and 800 ng g(-1) for the pesticides studied. The proposed method was applied to a reference soil sample and to aged soils.