| Nanomaterials often exhibit unique characteristics of light,electricity,magnetism,heat,and mechanics due to their small unit size.This makes nanomaterials have broader application prospects than general materials.Although the application prospects of nanotechnology are very promising,the potential harm of nanomaterials to the environment and human health is not well understood.How to effectively and accurately evaluate the biotoxicity of nanomaterials is a hot topic in current research.Acute toxicity experiment is an important method to evaluate the biological toxicity of pollutants.Acute toxicity experiment can be used to evaluate the possible harm of nanomaterials to organisms.Artemia is small,sensitive to environmental changes,and rich in nutrients.It is the excellent animal feed for aquaculture.Therefore,in this paper,Artemia was selected as the test organism to study the acute toxicity experiment of nano metal oxides.In this study,nano-metal oxides widely used in the fields of chemical engineering,biomedicine and other fields are the main research objects.Artemia is used as the test organism to design the four nano-scales of Nano-CuO,Nano-NiO,Nano-ZnO,Nano-Cr2O3 The acute toxicity experiment of metal oxides on Artemia,explore the impact of nano metal oxides on organisms through the indicators of the mortality of tested Artemia.Design the adsorption experiment of Chaetoceros on nano-metal oxide,and feed the Artemia with the tested Chaetoceros,observe the residual of nano-metal oxide in Artemia,and explore the transfer of nano-metal oxide in the food chain.Specifically,this paper draws the following conclusions:(1)The 24-hour toxicity test results show that these four nano-metal oxides have a certain toxic effect on Artemia.The 24-hour half lethal concentrations ofNano-CuO,Nano-NiO,Nano-ZnO,Nano-Cr2O3 are:1.92g·L-1,3.62g·L-1,1.1g·L-1,1.76g·L-1.The toxicity is Nano-Cr2O3>Nano-ZnO>Nano-CuO>Nano-NiO.(2)The 48-hour toxicity test results show that these four nano-metal oxides have obvious toxicity to Artemia.The half-lethal concentrations of the four nano-metal oxides are:0.27g·L-1,0.42g·L-1,0.29g·L-1,0.13g·L-1.The toxicity is Nano-Cr2O3>Nano-CuO>Nano-ZnO>Nano-NiO.The 48-hour LC50 of four kinds of nano-metal oxides on Artemia was much less than its 24-hour LC50 on Artemia.Prolonging the test time of the biological toxicity test can significantly reduce the LC50 and increase its exposure to the test The toxic effect of the organism,the tested organism is more sensitive to the poison in the toxic environment for a longer period of time,and the general aquatic toxicity experiment fish,algae,etc.are also the results of the 48-hour experiment.It can be seen that the 48-hour toxicity is selected Experimental results are meaningful.(3)The toxicity effects of four metal ions on Artemia were higher than their corresponding nano metal oxides in the same treatment time.The 24-hour half-lethal concentrations of Cu2+,Ni2+,Zn2+,and Cr3+Were:3.85mg·L-1,10.01mg·L-1,114.0Omg·L-1,68.88mg·L-1.The toxicity is Cu2+>Ni2+>Cr3+>Zn2+.Metal ions have a faster and more toxic effect on Artemia than nanometal oxides of the same metal element.Studies have shown that nanometal oxides can dissociate metal ions in Artemia.One of the reasons for the toxic effect may be that the nano metal oxide dissociates metal ions in Artemia and causes toxic effects on Artemia.(4)Chaetoceros have good absorption/adsorption effect on nano metal oxides and can play a media role in the food chain delivery.Over time,the amount of Chaetoceros cells adsorbing nano-metal oxides will decrease slightly.As shown by the experimental results of the adsorption and absorption of Nano-CuO by Chaetoceros,during the increase of Nano-CuO dosage from 0.40mg to 3.20mg,the adsorption of Nano-CuO by Chaetoceros increased from 0.31mg to 3.06mg,this indicates that the 3.20mg Nano-CuO dosage range of Chaetoceros is not saturated in the dosage range.At 24 hours of contact time,the adsorption of Chaetoceros on copper oxide was 3.18mg,and the adsorption rate was 99%.With the increase of the contact time,the adsorption of Nano-CuO from Chaetoceros decreased,and when the contact time was 120 hours,the adsorption amount of Chaetoceros vulgaris on Nano-CuO is 3.06mg,and the adsorption rate is 95%.(5)Transmission electron microscopy observation showed that there were nano oxides transferred through the food chain in Artemia.Taking Nano-CuO as an example,it can be seen through transmission electron microscopy that after feeding Chaetoceros that adsorbed Nano-CuO,Nano-CuO particles aggregated in Artemia and mainly deposited on the belly of Artemia.Taking Nano-CuO data as an example,using atomic absorption spectroscopy to detect Artemia in vivo,the environmental content is 0.04 mg,the intake of Artemia Nano-CuO is 0.10 μg accounting for 0.26%of the total Nano-CuO in the environment.Existing nano-metal oxides will remain in Artemia with the delivery process ofthe food chain,which has a toxic effect on Artemia,while also revealing that nano-metal oxides will pass along the food chain and ultimately endanger human environmental risks. |
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