Studies On Mosses's Physiological And Biochemical Response To Typical PBDEs And Pb And Surveys In The E-waste Recycling Sites

Mosses have a special physiological structure and the nutrition and water they need to grow mainly come from air where heavy metal and organic pollutant accumulate in the mosses through dry and wet deposition.Therefore,mosses have been widely used to monitor the heavy metal and organic pollutant in the air by domestic and foreign scholars.Although some achievements of monitoring the heavy metal and organic pollutant in the air have been obtained in China,the research is largely confined to aspects like the content and physiology as well as morphology changes of heavy metal and organic(pesticide and PAHs).As a result of the fast development of information technology,we are entering into an era that is dominated by electric products and information.The pollution of heavy metal and PBDEs during dismantlement of e-waste has become a new environmental problem.Yet,it is still unclear about the toxication mechanism that heavy metal and PBEDs bring to mosses and the monitor that mosses have reacted to such air pollution.The thesis focuses on the three mosses,Hypnum plumaeforme,Thuidium cymbifolium,and Plagiomnium cuspidofum,under the circumstance of single and multiple pollution of Pb,and PBDEs(BDE-47,BDE-209).The thesis investigates the accumulation and depletion of radical oxygen species,the injured situation of membrane system and photosynthetic system,and the changes of antioxidative enzymes,aiming to reflect the physiological response difference and toxication mechanism of those three mosses and select moss-bag materials and the valid physiological parameters in the moss.The thesis can offer scientific and theoretical foundations of heavy metal and PBDEs pollution monitored by the mosses in typical e-waste sites.Meanwhile,with Wenling and other e-waste sites as inspection place,the thesis monitors the concentration of heavy metal and PBDEs in the air,dust and samples of Hypnum plumaeforme.After primarily researching the connection between mosses and heavy metal and PBDEs in different environmental medium(air,dust),and trying to monitor and evaluate the pollution in the recycling sites through the moss-bag method and the moss physiological method,the thesis offers a simple and sensible way to monitor and warn the air pollution of heavy metal and PBDEs in the Recycling sites.The main results are showed as followed:(1)The toxication caused by single pollution of Pb,PBE-47,and BDE209 to mosses:the Chl synthetises from up to down;H2O2,·O2-raises consistently and the content of Pro raises constantly;the peroxidation of membrane lipid intensifies,reflecting as the increasing content of MDA;In the antioxidant system,the activity of POD raises consistently,the activity of SOD goes from up to down,CAT reduces constantly,and POD plays an important role in clearing H2O2;Due the MDA,Pro,POD and CAD depend on the density of pollution,they can be treated as subsidiary physiology parameter to monitor the air pollution caused by heavy metal and PBDEs in the typical recycling sites.(2)The three Mosses's responses to single and combined pollution caused by Pb and PBDEs:under the circumstance of single and combined pollution caused by Pb and BDE-209,the activity of the content of Chl in Plagiomnium cuspidofum is evidently lower than in Hypnum plumaeforme and Thuidium cymbifolium,while the content of MDA and ·O2-in Plagiomnium cuspidofum is obviously higher than in Hypnum plumaeforme,Thuidium cymbifolium;The content of Pro and the activity of SOD,POD and CAT in Hypnum plumaeforme is evidently lower than in Thuidium cymbifolium,and the content of MDA and ·O2-in Hypnum plumaeforme is evidently higher than in Thuidium cymbifolium;The sensitivities of the three mosses to single and combined pollution caused by Pb and PBDEs are ordered as:Thuidium cymbifolium>Hypnum plumaeforme>Plagiomnium cuspidofum;Hence,Hypnum plumaeforme and Thuidium cymbifolium are the most suitable mosses in the moss-bag method inspection,while Hypnum plumaeforme and Plagiomnium cuspidofum are the most suitable mosses in the sensitivities of physiology inspection parameter.(3)The time effect of single pollution or combined pollution of Pb and PBDEs on HP is manifested as follows:when the pollution exposure time is between 0-4 d,Chl,Chla/b,SOD,POD,CAT will have a slight fluctuation while MDA,·O2-,H2O2,Pro will rise dramatically.In addition,when the pollution exposure time is between 4-8 d,Chl,Chla/b,SOD,POD,CAT will witness a big drop while MDA,·O2-,H2O2,Pro will keep going up but tend to be stable.The magnitude of harm caused by different pollution treatment methods on HP is given below:Pb+BDE-47+BDE-209>Pb>BDE-47>BDE-209.(4)A detection of the PBDEs and heavy metals in the moss-bag,sample plot HP,air and dust in the typical e-wastes recycling sites of Wenlin City shows that its concentration of PBDEs is 1 or 2 orders of magnitude higher than that of non-recycling sites,with BDE-209 as its main homolog and a strong correlation existing between its homologs.It also shows that its concentration of heavy metals is 2 to 4 times higher than that of non-recycling sites(Zn as an exception),with Zn,Cu,Mn,Pb,Cr as its main elements,and moreover,there is a strongly significant correlation between Cu and Pb in dust,and significant correlation between Cr and Pb in moss bags.Why their sources are the same could probably be explained by the recycling activities of PCBs.(5)A spearman correlation analysis of the homologs of PBDEs,and heavy metal elements between moss-bag and dust,moss-bag and air shows that there exists a relevantly strong relationship between most PBDEs and heavy metals in different media,most of which turns out a quite significant correlation and significant correlation.It means that most PBDEs and heavy metals of the moss-bag come from the air and the dust,and most from the air in the indoor environment.(6)Linear analysis of content of PBDEs homologues of ten kinds and that of heavy metal of thirteen kinds between moss-bag and atmosphere,and those between moss-bag and dust suggests there is close linearity between PBDEs and heavy metals of moss-bag and atmosphere(P<0.05?R2=0.686-0.965;P<0.01?R2=0.765-0.994),and relatively close linearity between PBDEs(six kinds)and heavy metals(five kinds)of moss-bag and dust(P<0.05?R2=0.409-0.728;P<0.05,R2=0.407-0.992).It shows that content of PBDEs and heavy metals,monitored with moss-bag method,in typical electronic waste recycling sites can reveal pollution of PBDEs and heavy metals in atmosphere of this sites,but cannot reveal of that of PBDEs and heavy metals in dust of this sites.(7)Testing on and comparative analysis of PBDEs,heavy metals and four physiological indicators(MDA,Pro,POD,CAT)of Hypnum plumaeforme in case field shows PBDEs and heavy metals of Hypnum plumaeforme in case field have the same trend.Meanwhile,four physiological indicators can indicate pollution of PBDEs and heavy metal in atmosphere.Compared to moss-bag method,both methods have merits and disadvantages with moss bag method reflecting total pollution while physiological indicator method reflecting physiological effects,sensitivity degree of which can be employed as biomarkers of PBDEs pollution of atmosphere.