Application Of Homing Pigeons As A Biological Sampler For The Monitoring Of Atmospheric POPs In Datong City

Environmental pollution has become more and more serious in recent years,especially in urban areas with large populations,as a result of over-extraction of natural resources and uncontrolled discharge of pollutants.Urban air pollution is closely related to human health and has attracted increasing attention.Many persistent organic pollutants(POPs)have been frequently detected in the atmosphere.Because of their environmental persistence,bioaccumulation potential and possible health hazards,POPs have received extensive attention.Therefore,studying the bioaccumulation of POPs in atmosphere of typical cities is significance for understanding the risk of air pollution on human health.Traditional atmospheric monitoring can only provide the concentrations of pollutants in gas phase or particulate matters.Alternatively,using homing pigeons as biological monitors could gain pollution information with considerations of chemical bioavailability and toxicity.In addition,homing pigeons are merely exposed to the contaminants through the inhalation route and tend to fly in a certain area,thus they are considered a great biomonitor for urban atmospheric pollution.The main objectives of this thesis are to investigate the occurrence of POPs in the atmosphere and their potential health effects in Datong,Shanxi by using homing pigeons as biomonitors.Firstly,in order to save time and labor for sample preparation,we planned to develop a selective pressurized liquid extraction(SPLE)method to incorporate extraction and purification of biological samples at the same time.A set of three-factor and three-level optimization experiment with 17 treatments using the response surface method was designed,and the impacts of adsorbent type,the ratio of mixture adsorbents and fat weight on the efficiency of lipid removal by the developed SPLE method were studied.Upon the acceptable recovery of the target compounds,the extraction and purification were conducted simultaneously using an accelerated solvent extraction instrument.Silica gel and Florisil were selected as adsorbents and the extraction and purification conditions were optimized.The results showed that when the proportion of silica gel increased,the lipid removal efficiency increased,which indicated the relatively high affinity of silica gel to the fat than Florisil.However,none of the 17 treatments achieved good lipid removal efficiency,with less than 20% of lipid being removed.As a result,the sample could not be directly analyzed on the instrument after the sample preparation process,suggesting that the newly developed SPLE method could not be used for purifying the pigeon samples which contained high lipid contents.Therefore,the homing pigeon samples in the current study were extracted by solvents using vortex shaking and ultra-sonic extraction,and then cleaned with a combination of gel permeation chromatography and solid phase extraction.Then,we selected homing pigeon as the atmospheric biomonitoring species to study the pollution of POPs in atmosphere in urban and mining areas of a typical coal industrial city(Datong).The concentrations and distribution profiles of polycyclic aromatic hydrocarbons(PAHs),organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs)and polybrominated diphenyl ethers(PBDEs)in the lung,liver and fat tissues of the homing pigeons collected in different regions were analyzed,which provided information on atmospheric POPs(data were shown as lipid normalized concentrations)in Datong City with a consideration of bioavailability.Results showed that PBDEs had the highest concentrations in fat tissue,while the lowest in liver.On the other hand,the other three POPs had the highest concentrations in lung and the lowest concentrations in fat.Unexpectedly,the concentrations of PAHs in the homing pigeons from the urban area was higher than those from the mining area.Higher population,motor vehicle exhaust and cooking fumes in urban area may be the reasons for higher PAH concentrations.On the contrary,tissue concentrations of PBDEs were higher in the pigeons from the mining area,and this may be due to the fact that the mining area was mainly engaged in coal mining and subsequent treatments which used more flame retardants than that in urban areas.The other two POPs(OCPs and PCBs)had been banned for a long time,and their concentrations were similar in both areas.Moreover,the concentrations of PAH,PCBs and PBDEs in the homing pigeons collected in Datong were higher than those in Guangzhou while OCPs concentrations in Datong were relatively lower.The concentrations of PAHs in the pigeons from Datong were lower than those from Beijing,and were similar to those from Chengdu.At last,pathological data of the lung and liver tissues of the homing pigeons in Datong City were analyzed.It was found that the exposure to airborne pollutants would impair the pigeons' lung and liver,leading to the deposition of carbon,inflammatory cell infiltration and capillary tracheal barrier widening and breaking,liver cell edema,portal fibrosis and borderline inflammation.In addition,the analysis of the HSI of pigeons from Datong showed that there were no hepatomegaly or weight loss in the pigeons as a consequence of air pollution.The noted damages in the lung and liver of the pigeons in the mining area were significantly higher than those from the urban area.The main reason of lung damage might be the inhalable particulate matters,while POPs had little impact on the tissue damage.In summary,the use of pigeon as a biomonitor for urban atmosphere can provide bioavailability-based pollution and toxicity data,and can provide reference information for the health risks of urban residents.