Influence of temperature and salinity on toxicity of zinc oxide nanoparticles on the marine copepod Tigriopus japonicus

Abstract

Globally, there is no comprehensive regulation of nanomaterials (NMs) due to their diverse physicochemical properties and their complicated environmental interactions. In the marine environment, NMs are under the influences of various environmental factors, including temperature and salinity, while their influences are generally tested individually. Ranking as the 5th most produced and the 7th most prevalent NMs in commercial products, zinc oxide nanoparticles (ZnO-NP) are one of the priority NMs with environmental concern. This study found that aggregate size of ZnO-NP and zinc oxide bulk particles increased with increasing temperature and salinity, while their ion dissolution rate increased with decreasing temperature and increasing salinity. Salinity has minimal effect on the toxicity of test chemicals to the marine copepod Tigriopus japonicus while they are most toxic at the highest temperature, indicating that ion dissolution might not be the only contributor to their toxicity. Further histological and omic studies will be conducted to reveal its toxic mechanisms.