Influence Of Coal Fly Ash On The Secretion Of Micro-nano Particulate Matter Of Daphnia Magna

Fly ash is one of the largest annual solid wastes in my country.Studies have shown that fly ash has varying degrees of toxicity to organisms of the first,second and third trophic levels.However,current research mainly focuses on the toxicity of fly ash leachate,and there is still a lack of research on the toxicity of fly ash particles of different sizes.In this thesis,by studying the effects of different particle grades of fly ash on the amount of micro-nano particles produced by a potential and new type of toxic response of Daphnia magna,it is the first time to use gel chromatography to extract micro-nano particles secreted by Daphnia magna.The nanoparticle tracking analyzer（NTA）was used to characterize the size and concentration of the extracted micro and nano particles,and the relationship between the amount of micro and nano particles produced and the toxicity of different particle sizes of fly ash,and the generation of micro and nano particles were analyzed.s reason.The main research conclusions are as follows:（1）Try to use gel permeation chromatography column method to extract the micro-nano particles secreted by Daphnia magna,and use NTA to measure the size distribution and number concentration.The results showed that after the M7 medium（H₃BO₄、Mn Cl₂·4H₂O、Li Cl·H₂O、Rb Cl、Sr Cl₂·6H₂O、Na Br、Na₂Mo O₄·2H₂O、Cu Cl₂·2H₂O、Zn Cl₂、Co Cl₂·6H₂O、Zn Cl₂、Co Cl₂·2H₂O、KI、Na₂Se O₃、NH₄VO₃、Ca Cl₂·2H₂O、Mg SO₄·7H₂O、KCl、Na HCO₃、Na₂Si O₃·9H₂O、Na NO₃、KH₂PO₄、K₂HPO₄、Vitamin B1、Vitamin B12、Vitamin H）was added to Daphnia magna,the amount of micro-nano particles produced increased significantly from the second day（p<0.05）,and it increased to 6.88×10⁷±2.22×10⁷ particles/ml on the seventh day,indicating a healthy Daphnia magna secretes micro-nano particles,which increase over time.（2）After adding the toxic substances potassium dichromate and fly ash to the culture solution of Daphnia magna,the production of micro-nano particles increased significantly（p<0.05）,indicating that exposure to toxic substances would stimulate Daphnia magna’s secretion of a large number of micro-nano particles.The main reason may be that toxicity inhibition induces an immune response,which leads to an increase in the production of micro-nano particles.（3）The experimental results of the acute toxicity of fly ash with different particle sizes on the large-sized fly ash show that the fine-particle（<28μm）fly ash particles are slightly more toxic（p>0.05）,followed by the large-particle（>150μm）fly ash.Unsieved fly ash is slightly less toxic.The results of the chronic toxicity experiment showed that,at the concentration of 0.125 g/L and 0.2 g/L fly ash,the large moss had decreased litter size,increased mortality,decreased body length,and decreased intrinsic growth rate（r）.However,there was no significant difference in the acute and chronic toxicity results between different particle sizes of fly ash（p>0.05）.（4）Under the same exposure conditions,comparing the two toxic response amounts of the number of flies produced and the amount of micro-nano particles produced by the mother flies,the results show that:under the toxic effects of different particle sizes of fly ash,there is no significant difference in the number of flies produced（p>0.05）;however,there are significant differences in the amount of micro-nano particles produced by the mother Daphnia magna exposed to different particle sizes（p<0.05）.The smaller the particle size of the fly ash,the micro-nano particles produced The more the amount of particles.It shows that micro-nanoparticles as a new toxicity response are more sensitive than chronic toxicity indicators（the number of feta）.（5）Compared with chronic toxicity experiments,the extraction and characterization experiment period of micro-nano particles secreted by Daphnia magna is shorter,and the extraction method is faster and more convenient.The use of micro-nano particles as a new biological response quantity is very important for the rapid detection of the biological toxicity of pollutants.potential.The paper has 26 figures,23 tables,and 156 references.