Journal Article

Oxidative stress, energy metabolism and molecular responses of earthworms (Eisenia fetida) exposed to low-density polyethylene microplastics

da Costa, João P., Rocha-Santos, Teresa, Pereira, Ruth, Rodríguez-Seijo, Andrés, Duarte, Armando C.

2018

Overview

Soils are both a sink and a pathway of plastic wastes, but there is a great lack of knowledge regarding their impacts on soil biota. To tackle the mechanisms of toxicity of these contaminants to soil invertebrates, earthworms ( Eisenia fetida Savigny, 1826) were exposed during 28 days to different concentrations of low-density polyethylene microplastics (62, 125, 250, 500 and 1000 mg MPs kg −1 soil dw ) with sizes ranging between 250 and 1000 μm, in an artificial soil. The ecotoxicological responses were evaluated by analysing various oxidative stress biomarkers (catalase, glutathione S-transferase and thiobarbituric acid reactive substances), a biomarker of energy metabolism (lactate dehydrogenase) and overall organism molecular changes by Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance (NMR) analyses. Significant effects resulting from an unbalanced oxidative stress system, expressed in terms of thiobarbituric acid reactive substances levels were recorded on earthworms exposed at the three highest concentrations tested. Despite that, no significant changes were recorded on the molecular profiles of earthworms by FTIR-ATR. NMR analysis pointed out for differences from the control, only for earthworms exposed to the lowest concentration of MPs. Considering that stress responses are complex, and involve multiple mechanisms, a cluster analysis taking into account all the parameters assessed, clearly identified two groups of earthworms separated by the concentration of 250 mg MPs kg −1 soil dw , above each meaningful effects were recorded.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Animals / Aquatic Pollution / Atmospheric Protection/Air Quality Control/Air Pollution / Biomarkers / Biomarkers - metabolism / Biota / Catalase / Catalase - metabolism / Cluster analysis / Contaminants / Density / Earth and Environmental Science / earthworms / Ecotoxicology / Eisenia fetida / Energy metabolism / Energy Metabolism - drug effects / Environment / Environmental Chemistry / Environmental Health / Environmental science / Exposure / Fourier transform infrared spectroscopy / Fourier transforms / Glutathione / Glutathione transferase / Glutathione Transferase - metabolism / Infrared analysis / Infrared spectroscopy / Invertebrates / L-Lactate dehydrogenase / Lactate dehydrogenase / Lactic acid / Low density polyethylenes / Metabolism / Microplastics / NMR / Nuclear magnetic resonance / nuclear magnetic resonance spectroscopy / Oligochaeta / Oligochaeta - drug effects / Oligochaeta - metabolism / Oxidative metabolism / Oxidative stress / Oxidative Stress - drug effects / Parameter identification / Plastic debris / Plastic pollution / Polyethylene / Polyethylene - toxicity / Research Article / soil / Soil - chemistry / Soil contamination / Soil invertebrates / Soil Pollutants - toxicity / Soil pollution / Soils / Spectrometry / stress response / Thiobarbituric acid / thiobarbituric acid-reactive substances / Toxicity / Waste Water Technology / wastes / Water Management / Water Pollution Control / Worms