Dissolved Organic Matter Modulates Algal Oxidative Stress and Membrane System Responses to Binary Mixtures of Nano-Metal-Oxides (nCeO2, nMgO and nFe3O4) and Sulfadiazine.

Fan Zhang,Nan Ye,Hao Fang,Yue Meng,Se Wang,De-Gao Wang,Zhuang Wang

doi:10.3390/nano9050712

Abstract

Joint biomarker responses, oxidative stress and membrane systems, were determined for nano-metal-oxides (nMeO, i.e., nCeO2, nMgO, and nFe3O4) and sulfadiazine (SDZ) exposed at relevant low concentrations to two freshwater microalgae Scenedesmus obliquus and Chlorella pyrenoidosa. The impacts of dissolved organic matter (DOM) on the joint biomarker responses were also investigated. Results indicated that the presence of SDZ significantly decreased the level of intercellular reactive oxygen species (ROS) in the algal cells exposed to each nMeO. Reduction of cell membrane permeability (CMP) and mitochondrial membrane potential (MMP) in the algal cells was observed when the algae were exposed to the mixture of SDZ and the nMeO. The degree of reduction of the ROS level, CMP, and MMP significantly went down with the addition of DOM to a certain extent. Changes in cellular oxidative stress and membrane function depended on the types of both nMeO and algal species. This contribution provides an insight into the hazard assessment of a mixture consisting of emerging contaminants and DOM, as they can coexist in the aquatic environment.

Highlights

Environmental contaminants in the form of mixtures commonly exist in field-relevant conditions [1,2]
We found that SDZ displayed a protective effect on the algal cells against oxidative stress induced by the particles
The presence of SDZ significantly decreased the level of intercellular reactive oxygen species (ROS) in S. obliquus and C. pyrenoidosa induced by the three nMeO

Summary

Introduction

Environmental contaminants in the form of mixtures commonly exist in field-relevant conditions [1,2]. The interaction between emerging pollutants, such as engineered nanoparticles (ENPs) [3,4,5] and antibiotics [6,7], have drawn a lot of attention due to their potential ecological toxicity. ENPs may interact with antibiotics in the environment, potentially resulting in a co-exposure of organisms and the occurrence of mixture effects [8,9,10]. Dissolved organic matter (DOM), a ubiquitous abiotic factor, has been demonstrated to play a vital role in the behavior and effect of ENPs in the aquatic environment [11,12,13,14,15,16]. It is important to take into account the presence of DOM when co-exposure of ENPs and antibiotics is being studied

Objectives

Methods

Results

Conclusion