MULTIPLE ENDPOINTS OF POLYETHYLENE MICROPLASTICS TOXICITY IN VASCULAR PLANTS OF FRESHWATER ECOSYSTEMS: A STUDY INVOLVING Salvinia auriculata (SALVINIACEAE)

GOMES, ALEX RODRIGUES; FREITAS, ÍTALO NASCIMENTO; DA LUZ, THIARLEN MARINHO; GUIMARÃES, ABRAÃO TIAGO BATISTA; ARAÚJO, AMANDA PEREIRA DA COSTA; KAMARAJ, CHINNAPERUMAL; RAHMAN, MD. MOSTAFIZUR; ISLAM, ABU REZA MD. TOWFIQUL; ARIAS, ANDRÉS HUGO; BARBOSA DA SILVA, FÁBIA; KARTHI, SENGODAN; CRUZ-SANTIAGO, OMAR; SILVA, FABIANO GUIMARÃES; MALAFAIA, GUILHERME

JOURNAL OF HAZARDOUS MATERIALS.

ELSEVIER SCIENCE BV

Año: 2023

0304-3894

More recently, the number of studies on the impacts of microplastics (MPs) on plants has grown considerably. However, many of these studies focused on terrestrial plants, with vascular plants from freshwater ecosystems being little studied. Thus, we aimed to evaluate the possible effects of exposure of Salvinia auriculata, for 28 days, to different concentrations of polyethylene MPs (PE MPs – diameter: 35.46 ± 18.17 µm) (2.7 x 108 and 8.1 x 108 particles/m3), using different biomarkers. Our data indicated that exposure to MPs caused alterations in plant growth/development (inferred by the lower floating fronds number, “root” length, and the number of “root”), as well as lower dispersion of individuals in the experimental units. Plants exposed to PE MPs also showed lower epidermal thickness (abaxial leaf face) and longer length of the central leaf vein and vascular bundle area. Ultrastructural analyses of S. auriculata exposed to MPs revealed rupture of some epidermal cells and trichomes on the adaxial and abaxial, leaf necrosis, and chlorosis. In the “roots”, we observed dehydrated filamentous structures with evident deformations in plants exposed to the pollutants. Both on the abaxial leaf face and on the “roots” we observed the adherence of MPs. Furthermore, exposure to PE MPs induced lower chlorophyll content, cell membrane damage, and redox imbalance, marked by reduced catalase and superoxide dismutase activity and increased production of reactive oxygen and nitrogen species and malondialdehyde. However, in general, we did not observe the dose-response effect for the evaluated biomarkers. The values of the integrated biomarker response index and the results of the principal component analysis (PCA) and the hierarchical clustering analysis confirmed the similarity between the responses of plants exposed to different PE MPs concentrations. Therefore, our study sheds light on how PE MPs can impact S. auriculata and reinforce the ecotoxicological risk associated with the dispersion of these pollutants in freshwater environments.