Physiological Toxicity and Antioxidant Mechanism of Photoaging Microplastics on Pisum sativum L. Seedlings

Abstract

Recent studies have confirmed that changes in the physical properties of microplastics (MPs) trigger toxicological effects and ecological risks. To explore the toxicity of different types of MPs on plants, and the influence of MP photoaging, this study investigated the toxicity mechanisms of pristine, 7 and 14 d photoaged polystyrene (PS), polyamide (PA), polyethylene (PE), and polyethylene terephthalate (PET) MPs on seed germination, root growth, nutrient fraction, oxidative stress, and antioxidant systems of Pisum sativum L. (pea) seedlings. The results showed that pristine PS and 14 d photoaged PET inhibited seed germination. Compared to the pristine MPs, photoaged MPs had negative effects on root elongation. Moreover, photoaged PA and PE impeded the nutrient transport of soluble sugars from roots to stems. Notably, the production of superoxide anion radicals (•O2−) and hydroxyl radicals (•OH) through the photoaging of MPs exacerbated oxidative stress and reactive oxygen species formation in roots. Antioxidant enzyme data revealed that the activities of superoxide dismutase and catalase were significantly activated in photoaged PS and PE, respectively, in order to scavenge •O2− and hydrogen peroxide (H2O2) accumulation and alleviate lipid peroxidation levels in cells. These findings provide a new research perspective on the phytotoxicity and ecological risk of photoaged MPs.

Toxicity and tolerance mechanism of binary zinc oxide nanoparticles and tetrabromobisphenol A regulated by humic acid in Chlorella vulgaris

“…The increasing trend in the enzyme activity was similar to the increasing concentration of TBBPA in the binary system, which revealed that the toxicity of TBBPA was relatively obvious at concentrations between 0.5 and 8 mg L −1 . As an initial protection line against ROS accumulation and membrane lipid peroxidation, SOD primarily converts the acutely toxic ˙O 2 − to less toxic H 2 O 2 , 43 as evidenced by the levels of ˙O 2 − and H 2 O 2 in the algal cells. Previous studies have confirmed that an increase in SOD activity is associated with the activation of repair functions and is a sign of elevated antioxidant status, 44 implying that the activation of the antioxidant system enhanced the plant tolerance and resistance to binary ZnO NPs.…”

Preliminary assessment of nursery workers’ exposure to applied pesticides

“…Due to large amount of pesticides handled, close contact with pesticides or the treated crops, agricultural workers have a greater risk of being exposed to pesticides and associated health effects than the general public [1]. Despite the inherent toxicity of pesticides, nurseries often rely on the heavy use of pesticides for high-quality flowers, fruits and vegetables, leading to various health risks towards non-target organisms [2].…”