Effects Of Silver Nanoparticle With Different Dosing Regimens And Exposure Media On Artificial Ecosystem

Silver nanoparticles(AgNPs)are one of the most popular nanomaterials in consumer products on the market,due to their s terilization activity,photoelectric,catalytic superconductivity and low manufacturing cost.The large amount of AgNPs production and extensive application of AgNP s inevitably released AgNPs into environment.Therefore,silver nanoparticles gave rise to a continuously increasing worldwide concern for their toxicological impacts on various biological and ecological systemsZebrafish is an ideal model animal with fas t reproduction speeds,low feeding cost and small sample size.Plants are primary producers in the ecosystem.When plants absorb nutrients,they also absorb pollutants in the environment.Plants absorb and accumulate pollutants in the tissue,which can cause harm to plants and animals and even humans if they enter into the food chain.Due to the wide use of silver nanoparticles(AgNPs)in various fields,it is crucial to explore the potential negative impacts on the aquatic environment with different way of AgNPs entering into the environment.There are two main kinds of ways for AgNPs to enter the environment:accidental(uncontrolled leaching from consumer products or textiles)or direct access(untreated runoff or treated sewage containing AgN Ps)releasing into environment.In this study,comparative experiments were conducted to investigate the toxicological impacts of polyvinylpyrrolidone coated silver nanoparticles(PVP-AgNPs)with two kinds of dosing regimens:the continuous and one-time pulsed dosing regimen,in different exposure media(deionized water and XiangJiang River water).There were a number of quite different experimental results(including the 100%mortality of zebrafish,the decline of enzymes activity and the least number and length of adventitious root of Egeria densa in one-time pulsed dosing regimen at high PVP-AgNPs concentration exposure(HOE)compared to other three treatments(continuous dosing regimen at high PVP-AgNPs concentration exposure,low concentration of PVP-AgNPs in deionized water and river water).Those results showed that HOE led to a range of dramatic ecosystem impacts which were more destructive than those of other treatments.Moreover,compared with continuous dosing regimen,despite higher toxicity was observed in HOE,there were few differences on the removal of total silver from the aquatic environment with different dosing regimen s.No obvious differences of ecological impacts were observed between different water columns under low concentration exposure.In an aquatic environment,AgNPs can release Ag~+.Meanwhile,we examined that the concentratio n of leached silver ions from PVP-AgNPs was too low to play a role in zebrafish death.Overall,this work highlighted that the toxicity of AgNPs was impacted by different dosing regimens in different exposure media,which may be helpful for the assessments of ecological impacts on aquatic environments.