Study On The Composition Characteristics Of Seasonal PM_2.5 And PM₁ In Lin'an And Their Multi-generational Toxic Effects On Caenorhabditis Elegan

In recent years,ambient air quality has been significantly improved,but the problem of air pollution has remained very serious,and the health hazards it has caused not only affect human health,but also caused adverse effects on offsprings,however,the exact extent of the impact needed to be explored through scientific research.In this study,the Lin’an atmospheric background station was selected as the sampling site,which was located in the center of the Yangtze River Delta region,and the collected samples could effectively reflect the background condition of atmospheric pollution in the Yangtze River Delta region.The study investigated the compositional properties of atmospheric particulate matter at this site and also explored the toxic effects caused by its exposure.Based on the advantage of the short generation time of Caenorhabditis elegans（C.elegans）,the effects of atmospheric particulate matter（PM）on maternal and offspring health were studied through parental exposure.By analyzing the correlation between chemical composition and toxicity indexes in particulate samples,the key toxicogenic components and cross-generational inheritance patterns of particulate matter toxicity effects were investigated.PM_2.5 and PM₁ samples from different seasons were selected and collected by the group from April 2019 to January 2020 in Lin’an,China.The average daily mass concentrations of PM_2.5 and PM₁ showed a trend of highest in winter and lowest in summer,and the composition analysis（Inorganic ions,Metals,PAHs,OCEC）was performed on particulate matter samples from all seasons.A higher proportion of organic carbon components（34.3%,35.9%）and PAHs（0.014%,0.020%）were occupied in the PM_2.5and PM₁ samples in winter,respectively.PM₁in summer was enriched with some metal elements（2.7%）.And the percentage of organic matter（OM）in PM₁ in Lin’an area is higher than in PM_2.5.Exposure to PM led to slowed development,motility behavior and increased number of germ cell apoptosis points.in C.elegans,as well as induced intestinal autofluorescence or reactive oxygen species（ROS）production.And lower particle size PM₁caused stronger toxic effects than PM_2.5.The correlation between PM chemical components and F0 generation toxicity index was analyzed.Body length,germ cell apoptosis and lipofuscin level were all highly correlated with Cu,As,Pb,OC and PAHs,and most strongly with PAHs.The highest correlation coefficients between ROS and each component were SO₄^2-（R=0.743）,Cd（R=0.816）and OC（R=0.716）.The results implied that OC,PAHs and some transition metals played an important role in the toxicity of fine PM to C.elegans,where the organic fraction may be the key toxicogenic component.The multigenerational studies showed that PM toxicity could be passed from parent to its offspring,and gradually returned to control levels in the F3-F4 generation,with germ cell apoptosis being restored in the F4 generation.Therefore,the adverse effects of PM on reproductive damage were more profound.In summary,the key toxicogenic components of atmospheric PM in Lin’an area and the transmission pattern of toxic effects between offspring were investigated through in vivo exposure experiments in this study.It promoted the progress of research on the attributed risk of atmospheric particulate matter and provided a scientific basis for regional long-term health risk evaluation.