Microplastic is a new kind of pollutant.It exists widely in the aquatic environment and seriously endangers the aquatic ecosystem.In this study,the coagulating sedimentation method was used to remove microplastics in ...Microplastic is a new kind of pollutant.It exists widely in the aquatic environment and seriously endangers the aquatic ecosystem.In this study,the coagulating sedimentation method was used to remove microplastics in water.Polyethylene(PE)was selected as the representative of microplastics,polyferric sulfate(PFS),polyaluminum chloride(PAC)and aluminum sulfate(AS)were used as coagulant,and polyacrylamide(PAM)was used as coagulant aid to study the effects of pH,coagulant concentration and sedimentation time on the removal of PE by single and composite coagulant.The results showed that when the dosage of PFS was 0.5 g/L and pH was 5.0,the removal rate could reach 82.14%,which was better than PAC and AS,indicating that PFS had better coagulation and sedimentation performance for PE;the composite coagulant of PFS+PAC+AS(1 g/L+0.2 g/L+0.2 g/L,pH was 5.0)had the highest removal rate of PE,reaching 96.06%;the removal rate of PE increased with the increase in sedimentation time,but considering that the longer sedimentation time has less contribution to the improvement of removal rate,it is recommended that 4 h is appropriate.展开更多
Polyethylene microplastics(PE-MPs)have toxicity to ecological environment,including animals and plants.This study investigated the toxicity of photodegraded PE-MPs on Brassica rapa,which is a typical model plant and o...Polyethylene microplastics(PE-MPs)have toxicity to ecological environment,including animals and plants.This study investigated the toxicity of photodegraded PE-MPs on Brassica rapa,which is a typical model plant and only have around a 30-day life cycle.It is noted that the presence of photodegraded PEMPs inhibited Brassica rapa growth since the stem length decreased by 11.94%-51.11%while the fresh weight and dry weight decreased by 18.56%e27.46%and 1.90%-6.91%respectively,compared to the blank group.PE-MPs receiving more light radiation became more hydrophobic.This inhibited PE-MPs entering the plant body along with the process of plant absorbing water.Furthermore,when PE-MPs were located in the lower soil layers,Brassica rapa reaching them needs a longer time,hence showing lower toxicity effect than the case of PE-MPs located in the upper soil layer.The research outcomes also indicated that malondialdehyde(MDA)contents in photodegraded PE-MPs exposure group increased by 1.37%-7.28%while the catalase activity(CAT)increased by 60.11%.This means that PE-MPs caused oxidative stress response in plants,inducing plants to resist external stress.Transcriptomic analysis results showed that Brassica rapa,which was affected by PE-MPs,significantly up-regulated genes related to the plant-pathogen interaction pathway while the ribosome pathway genes were significantly downregulated.This led to a decrease in growth rate and a decrease in the homeostatic level of the ribosomal subunit and hence resulting in abnormal leaf vein development.These conclusions indicated the toxic effect and damage mechanism of photodegraded PE-MPs on Brassica rapa.The novelty of this study was to use both univariate analysis and transcriptomic analysis to investigate how photodegraded PE-MPs exert toxicity on Brassica rapa.The results can provide a theoretical basis for revealing the influence of MPs on plant growth.展开更多
基金Supported by Innovation and Entrepreneurship Training Program for College Students(202210580015).
文摘Microplastic is a new kind of pollutant.It exists widely in the aquatic environment and seriously endangers the aquatic ecosystem.In this study,the coagulating sedimentation method was used to remove microplastics in water.Polyethylene(PE)was selected as the representative of microplastics,polyferric sulfate(PFS),polyaluminum chloride(PAC)and aluminum sulfate(AS)were used as coagulant,and polyacrylamide(PAM)was used as coagulant aid to study the effects of pH,coagulant concentration and sedimentation time on the removal of PE by single and composite coagulant.The results showed that when the dosage of PFS was 0.5 g/L and pH was 5.0,the removal rate could reach 82.14%,which was better than PAC and AS,indicating that PFS had better coagulation and sedimentation performance for PE;the composite coagulant of PFS+PAC+AS(1 g/L+0.2 g/L+0.2 g/L,pH was 5.0)had the highest removal rate of PE,reaching 96.06%;the removal rate of PE increased with the increase in sedimentation time,but considering that the longer sedimentation time has less contribution to the improvement of removal rate,it is recommended that 4 h is appropriate.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2024A1515010371)National Natural Science Foundation of China(52170100,U21A2036).
文摘Polyethylene microplastics(PE-MPs)have toxicity to ecological environment,including animals and plants.This study investigated the toxicity of photodegraded PE-MPs on Brassica rapa,which is a typical model plant and only have around a 30-day life cycle.It is noted that the presence of photodegraded PEMPs inhibited Brassica rapa growth since the stem length decreased by 11.94%-51.11%while the fresh weight and dry weight decreased by 18.56%e27.46%and 1.90%-6.91%respectively,compared to the blank group.PE-MPs receiving more light radiation became more hydrophobic.This inhibited PE-MPs entering the plant body along with the process of plant absorbing water.Furthermore,when PE-MPs were located in the lower soil layers,Brassica rapa reaching them needs a longer time,hence showing lower toxicity effect than the case of PE-MPs located in the upper soil layer.The research outcomes also indicated that malondialdehyde(MDA)contents in photodegraded PE-MPs exposure group increased by 1.37%-7.28%while the catalase activity(CAT)increased by 60.11%.This means that PE-MPs caused oxidative stress response in plants,inducing plants to resist external stress.Transcriptomic analysis results showed that Brassica rapa,which was affected by PE-MPs,significantly up-regulated genes related to the plant-pathogen interaction pathway while the ribosome pathway genes were significantly downregulated.This led to a decrease in growth rate and a decrease in the homeostatic level of the ribosomal subunit and hence resulting in abnormal leaf vein development.These conclusions indicated the toxic effect and damage mechanism of photodegraded PE-MPs on Brassica rapa.The novelty of this study was to use both univariate analysis and transcriptomic analysis to investigate how photodegraded PE-MPs exert toxicity on Brassica rapa.The results can provide a theoretical basis for revealing the influence of MPs on plant growth.
