Work

Size-dependent toxic interaction between polystyrene beads and mercury on the mercury accumulation and multixenobiotic resistance (MXR) of brackish water flea Diaphanosoma celebensis

Year: 2024

Type: article

Abstract: Due to their worldwide distribution and persistence, mercury, and nano- and microplastics (NMPs) pose major threats to global ocean ecosystems. Hg and NMPs co-exist in the ocean and can interact with each other. However, information on the toxicity of this interaction to marine biota remains limited. Thus, we investigated the toxicological interaction between HgCl2 (Hg) and NMPs by studying the influence of different sizes of polystyrene beads (0.05-, 0.5-, and 6-μm) on Hg accumulation in the brackish water flea Diaphanosoma celebensis. The Hg adsorption capacity of NPs (0.05-μm) was higher than that of MPs (0.5- and 6-μm). Only the group co-exposed to both Hg and NPs showed increased Hg content in D. celebensis. Multixenobiotic resistance (MXR) activity and transcriptional modulation of transporter genes (ABCBs and ABCCs) were decreased by NMP exposure, particularly by NPs, suggesting MXR disruption by NPs. However, the activity of multidrug resistance-associated proteins (MRPs; ABCCs) was increased by Hg exposure alone and decreased upon NP co-exposure. Furthermore, in vivo toxicity tests showed a synergistic toxic interaction between Hg and NPs on the reproduction of D. celebensis. Our findings suggest that NPs have the potential to enhance the toxicity of Hg, increasing Hg accumulation not only by serving Hg as a carrier but also by disrupting MXR.

Source: Ecotoxicology and Environmental Safety

DOI: 10.1016/j.ecoenv.2024.117131