Histopathology of chironomids exposed to fly ash and microplastics as a new biomarker of ecotoxicological assessment

Jelena Stojanović; Dimitrija Savić-Zdravković; Boris Jovanović; Jelena Vitorović; Jelena Bašić; Ivana Stojanović; Andrea Žabar Popović; Hatice Duran; Margareta Kračun Kolarević; Đurađ Milošević

doi:10.1016/j.scitotenv.2023.166042

Histopathology of chironomids exposed to fly ash and microplastics as a new biomarker of ecotoxicological assessment

Sci Total Environ. 2023 Dec 10:903:166042. doi: 10.1016/j.scitotenv.2023.166042. Epub 2023 Aug 4.

Affiliations

¹ Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, Niš, Serbia. Electronic address: jelena.conic@pmf.edu.rs.
² Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, Niš, Serbia.
³ Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, USA.
⁴ Department of Biochemistry, Faculty of Medicine, University of Nis, Bulevar dr Zorana Đinđića 81, 18000 Nis, Serbia.
⁵ Department of Materials Science & Nanotechnology Engineering, TOBB University of Economics and Technology, Söğütözü Cad. 43, 06560 Ankara, Türkiye; UNAM - National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Türkiye.
⁶ Department of Hydroecology and water protection, Institute for Biological Research "Siniša Stanković", National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia.

PMID: 37543338
DOI: 10.1016/j.scitotenv.2023.166042

Abstract

In the last few decades, industrial pollution has gained extensive attention in terms of its effect on the aquatic environment. This imposes the need to develop sensitive biomarkers for early detection of pollutant toxicity in ecotoxicological assessment. The advantages of histopathological biomarkers are many, including quick reaction to the presence of contaminants, and the small number of individuals needed for efficient analysis. The present study analyzed the negative effect of lignite coal fly ash (LCFA) and microplastic particles (MPs) on Chironomus riparius, a suggested model organism by the Organization for Economic Cooperation and Development (OECD). This study aimed to perform histological analyses of larval tissues and target potential changes in treated groups that could serve as promising histopathological biomarkers of the contaminant's negative effects. Following that, other known sensitive sub-organismal biomarkers were analyzed and paired with the histopathological ones. Histological analysis of larvae showed a significantly decreased length of microvilli in midgut regions II and III in both treatments. Treatments with MPs affected oxidative stress parameters: thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPP), superoxide dismutase (SOD), and hemoglobin levels, while LCFA significantly affected all tested sub-organismal biomarkers (DNA damage, levels of AOPP, SOD, and hemoglobin), except catalase (CAT) and TBARS. When observing histological slides, a significant shortage of brush border length in the posterior parts of the midgut was detected in all treatments. In the case of LCFA, the appearance of intensive vacuolization of digestive cells with inclusions resembling apoptotic bodies, in mentioned regions was also detected. This study demonstrated high sensitivity of brush border length to the MPs and LCFA exposure, complementary to other tested sub-organismal biomarkers. Revealing the great potential of this histopathological biomarker in ecotoxicological studies contributes to the international standard ecotoxicology assessment of emerging pollutants.

Keywords: Biomarkers; Chironomidae; Fly ash; Histology; Microplastics.