Microplastics and plastic additives as contaminants of emerging concern: a multi-biomarker approach using Rhinella arenarum tadpoles

MAXIMILIANO ATTADEMO; LUCILA CURI; ANA PAULA CUZZIOL BOCCIONI; CARLOS BARRIOS; PAOLA PELTZER; MARÍA F SIMONIELLO; RAFAEL LAJMANOVICH; MELINA MICHLIG; MARÍA REPETTI; JUAN MANUEL RÍOS

Environmental Advances

Elsevier

Lugar: Londres (UK); Año: 2023 vol. 14

2666-7657

Plastic products and their residuals are emerging contaminants of environmental concern due to its global ubiquity. Polyethylene, a whitish thermoplastic polymer with numerous applications, is one of the materials most widely used in the industrial sector, whereas tetrabromobisphenol A (TBBPA) is a brominated flame retardant. Our aim was to analyze the effects of polyethylene MPs and TBBPA on Rhinella arenarum tadpoles at the laboratory scale. Tadpoles were chronically exposed (30 days) to four treatments: MP (60 mg L-1), TBBPA (10 µg L-1), their mixture (MP+TBBPA), and dechlorinated water as negative control (CO). The activity of B-esterases (acetylcholinesterase; AChE and carboxylesterase; CbE) and oxidative stress enzymes (Glutathione-S-Transferase–GST– and glutathione reductase, GR) was studied in the treated tadpoles. Alkaline phosphatase (ALP), thyroid hormone (T4) and cholesterol (CHOL) levels were also assessed. In addition, intestine and liver were histomorphologically evaluated to analyze the potential treatment effects. AChE activity of tadpoles was significantly inhibited after the single MP and TBBPA exposure with respect to CO. T4 levels increased significantly in all treatments with respect to CO. In addition, ALP and CHOL showed higher values in the mixture of MP+TBBPA treatment and in MP+TBBPA and TBBPA treatments, respectively, than is to CO. The intestinal structure of tadpoles after single exposure with MP or MP+TBBPA showed signs of mechanical damage. The intestinal wall of tadpoles under MP, TBBPA and MP+TBBPA treatments was thicker than that of CO individuals. The analysis of liver histology also demonstrated the hepatotoxicity caused by MP+TBBPA. This study provides quantitative evidence of the harmful effects of polyethylene MPs and TBBPA on enzymatic and hormonal activities, and histological evidence of intestinal wall hypertrophy and liver damage.