預(yù)防醫(yī)學(xué)英文版課件：Introduction

PREVENTIVEMEDICINE

DepartmentofEnvironmentalHealthSchoolofPublicHealthChinaMedicalUniversityIntroduction(一).HealthandDisease

1.Health

Healthisastateofcompletephysical,mentalandsocialwellbeingandnotmerelytheabsenceofdiseaseorinfirmity.WorldHealthOrganization(WHO)putforwardaproposal:“Healthforallbytheyear2000”.Medicalmodel:biomedical→bio-psycho-socialmedicalmodel

2.DiseaseOppositetohealth,diseaseisin-adaptation,in-coordinationoforganismcausedbyenvironmentalstimulation,disequilibriumoforganismandinternalandexternalenvironment,destructionofhomeostasisandoccurrenceofdamageinsystemic,localororganicfunctionandstructure.3.Preventivemedicine

StudyrangeObjectBasicMedicineLaboratoryExperimentalFindingsClinicalMedicineHospitalIndividualPreventiveMedicineCommunityPopulation1).Definition

Preventivemedicinestudiestheenvironmentalfactorsandtheireffectsonhumanhealth,basedonwhichmancantakemeasurementsinordertoimproveenvironmentalquality,establishenvironmentalstandards,andprotecthumanhealthandpreventthedisease.

2).Objectofstudyenvironmentalfactorhealtheffectimprovementofenvironment

3).Purposeofstudy:

preventthediseaseprotectandpromotehumanhealth4).DepartmentofPreventiveMedicine:

Statistics,HealthToxicology,HealthChemistry,HealthMicroorganism,Epidemiology,EnvironmentalHealth,IndustrialHealthandOccupationalDisease,Nutritionandfoodhealthandsoon.

(二).Threelevelpreventionofthedisease

1.Primaryprevention—etiologicalpreventionPrimarypreventionispreventionofthediseasebyalteringsusceptibilityorreducingexposureforsusceptibleindividuals.

2.Secondaryprevention----preclinicalpreventionSecondarypreventionistheearlydetection,diagnosisandtreatmentofdisease.3.Tertiaryprevention----clinicalpreventionTertiarypreventionisthealleviationofdisabilityresultingfromdiseaseandattemptstorestoreeffectivefunctioning.

補(bǔ)充：全球環(huán)境問(wèn)題溫室效應(yīng)臭氧層耗竭酸沉降環(huán)境內(nèi)分泌干擾物持久性有機(jī)污染物生物多樣性銳減抗生素濫用人類健康質(zhì)量下降溫室效應(yīng)（green-houseeffect，globalwarming）溫室氣體大量排放——全球表面T↑ContributiontoglobalwarmingCarbondioxide55%Methane15%Nitrousoxides6%Chlorofluorocarbons(CFCs)24%危害：極地冰雪融化，海平面上升。全球降雨模式改變。自然疫源性疾病、不明原因疾病增多人類壽命的影響酸沉降（aciddeposition；acidprecipitation）包括酸雨(pH<5.6)、酸霧、酸雪、酸云等。被稱為“現(xiàn)代空中死神”。導(dǎo)致土壤酸化，肥力降低；腐蝕建筑物、金屬、橡膠等；破壞動(dòng)物生息地（急劇減少和滅絕的青蛙已達(dá)30種）；危害人類健康.臭氧層空洞（耗竭）

stratosphericozonedepletion,

ozone-layerdepletionThestratosphericozonelayershieldstheearthfromultravioletradiation.CFCs（Chloroflurocarbons–e.g.freons）arestable,driftupwardsUVradiationbreaksdownCFCsintochlorineatoms,Chlorineatomsreactwithanddestroyozone.Chlorinewillpersistover100yearsinstratosphereA1%decreaseinozonelayer

increaseUVradiationreachingearthby2%2-10%increaseincellcarcinomas

increasesinskinmelanomas氯氟烴——ClOClO+O3——Cl+O2+O2Cl+O3

——ClO+O2+O2MontrealProtocol1987:29nationsagreedtophaseoutuseofCFCsDevelopedcountriesbannedCFCsuseandproductionin1996DevelopingcountriesmaystilluseandproduceCFCsuntil2010環(huán)境內(nèi)分泌干擾物

environmentalendocrinedisruptors定義（USEPA）：能干擾機(jī)體天然激素合成、分泌、轉(zhuǎn)運(yùn)、結(jié)合或清除的各種外源性物質(zhì)。來(lái)源：自然界（如某些植物激素）人工合成（環(huán)境污染的主要來(lái)源）名稱衍變環(huán)境雌激素（Environmentalestrogens,EEs）外源性雌激素（Xenoestrogens,XEs）內(nèi)分泌干擾物（Endocrinedisruptingchemicals，EDCs）內(nèi)分泌活性化合物（Endocrineactivecompounds,EACs)環(huán)境內(nèi)分泌干擾物（Environmentalendocrinedisruptors,EEDs）機(jī)制：模擬(mimicking)。在結(jié)構(gòu)及性質(zhì)上均類似天然激素；拮抗(antagonizing)。結(jié)構(gòu)上類似但性質(zhì)上不同，從而作為競(jìng)爭(zhēng)者，阻滯或拮抗天然激素與受體的結(jié)合；改變（altering）激素的代謝。影響體內(nèi)激素的合成、儲(chǔ)存、釋放、轉(zhuǎn)運(yùn)、清除等多個(gè)過(guò)程；弱化（modifying）受體水平。如調(diào)低受體數(shù)量，或降低受體與正常激素結(jié)合的敏感度等。危害及后果：人類及動(dòng)物生殖能力下降：精子平均數(shù)從1940年1.13億/ml下降到1990年的0.66億/ml，不育癥患者越來(lái)越多。生殖系統(tǒng)腫瘤發(fā)病率增加：乳腺癌、前列腺癌等兒童性發(fā)育異常.美國(guó)USEPA公布的第一批環(huán)境內(nèi)分泌干擾物質(zhì)（67種（類））Dioxinsandfurans二惡英及其多氯代苯并呋喃類（1）高溫焚燒含氯有機(jī)物后形成；（2）農(nóng)藥中的雜質(zhì)或副產(chǎn)品；（3）紙漿的氯化漂白過(guò)程中形成 Polychlorinatedbiphenyl(PCBs)多氯聯(lián)苯熱媒、無(wú)碳復(fù)寫(xiě)紙、電容器變壓器絕緣Polybromobiphenyl(PPB)多溴聯(lián)苯防火材料Hexachlorobenzene(HCB)六氯苯殺菌劑Pentachlorophenol(PCP)五氯苯酚殺菌消毒劑、除草劑、防腐劑2,4,5-Trichlorophenoxyaceticacid2,4,5-三氯苯氧基乙酸（2,4,5-滴）除草劑 2,4-Dichlorophenoxyaceticacid2,4-二氯苯氧基乙酸（2,4-滴）除草劑Amitrole殺草強(qiáng)除草劑、樹(shù)脂硬化劑Atrazine莠去凈除草劑 Alachlor草不氯除草劑Simazine(CAT) 西瑪津除草劑HexachlorocyclohenaneEthylParathion六氯環(huán)己烷乙基對(duì)硫磷殺蟲(chóng)劑Carbaryl 西維因殺蟲(chóng)劑Chlordane 氯丹殺蟲(chóng)劑Oxychlordane氧化氯丹 氯丹的代謝中間產(chǎn)物Trans-Nonachlor 反式-九氯 殺蟲(chóng)劑1,2-dibromo-3-chloropropane1,2-二溴-3-氯丙烷殺蟲(chóng)劑DDT滴滴涕殺蟲(chóng)劑DDEandDDD滴滴伊和滴滴滴 殺蟲(chóng)劑（DDT的代謝中間產(chǎn)物）Kelthane(Dicofol) 三氯殺螨醇 殺蟲(chóng)劑 Aldrin 艾氏劑 殺蟲(chóng)劑 Endrin 異狄氏劑 殺蟲(chóng)劑 Dieldrin 狄氏劑 殺蟲(chóng)劑 Endosulfan(Benzoepin) 硫丹 殺蟲(chóng)劑 Heptachlor 七氯 殺蟲(chóng)劑 Heptachlorepoxide 環(huán)氧七氯 七氯的代謝中間產(chǎn)Malathion 馬拉硫磷 殺蟲(chóng)劑 Methomyl 滅索威 殺蟲(chóng)劑 Methoxychlor 甲氧滴滴涕 殺蟲(chóng)劑 Mirex 滅蟻靈 殺蟲(chóng)劑持久性有機(jī)污染物

(PersistentOrganicPollutants，POPs)定義：符合以下四個(gè)特性的環(huán)境污染物環(huán)境持久性（長(zhǎng)期殘留）；生物蓄積性（可在食物鏈中蓄積并放大）；半揮發(fā)性（能夠在大氣環(huán)境中長(zhǎng)距離遷移），高毒性（在環(huán)境濃度下就有毒性）的天然或人工合成的有機(jī)污染物。符合上述定義的POPs物質(zhì)有數(shù)千種之多。斯德哥爾摩國(guó)際公約提出首批控制12種：艾氏劑、狄氏劑、異狄氏劑、DDT、氯丹、六氯苯、滅蟻靈、毒殺芬、七氯、多氯聯(lián)苯(PCBs)、二惡英和苯并呋喃(PCDD／Fs)。生物多樣性（biodiversity）銳減生物多樣性包括三個(gè)層次生態(tài)系統(tǒng)多樣性：如“地球之肺”熱帶雨林，“地球之腎”天然濕地等。物種多樣性：地球上每天有100種生物絕種。種內(nèi)基因多樣性：不同的人種、鳥(niǎo)種、微生物種類等多樣性銳減主要為人類活動(dòng)所致無(wú)限制采伐、掠奪性開(kāi)采、過(guò)度捕撈狩獵、嚴(yán)重污染對(duì)人類前途構(gòu)成致命威脅（生態(tài)平衡失調(diào)）猶如缺了零件的飛機(jī)?？股貫E用（antibioticabuse）1928年弗萊明發(fā)明青霉素，1940年用于臨床，使人類平均壽命從40歲提高到了65歲。目前許多毀滅性新舊傳染疾病正在逐漸出現(xiàn)。如目前全球已有17億人感染了結(jié)核桿菌，約有2000萬(wàn)結(jié)核病病人，每年死亡300萬(wàn)人。在抗生素投入使用至今的60年間，很多細(xì)菌就對(duì)抗生素產(chǎn)生了嚴(yán)重的耐藥，有的甚至產(chǎn)生了多重耐藥。20世紀(jì)50年代在歐美首先發(fā)生了耐甲氧西林金黃色葡萄球菌的感染，很快席卷全球，有5000萬(wàn)人被感染,50多萬(wàn)人死亡。細(xì)菌產(chǎn)生耐藥性的速度遠(yuǎn)遠(yuǎn)快于人類新藥開(kāi)發(fā)的速度，如不遏止，人類將進(jìn)入“后抗生素時(shí)代”，也即回到抗生素發(fā)現(xiàn)之前的人們面對(duì)細(xì)菌性感染束手無(wú)策的黑暗時(shí)代。

人類健康及生活質(zhì)量下降亞健康狀態(tài)者增加嚴(yán)重危害健康的慢性疾病糖尿病、高血壓、心腦血管疾病等發(fā)病率增加、高發(fā)年齡提前癌癥發(fā)病率上升、高發(fā)年齡提前不育癥患者增加新型、不明原因傳染病增多：SARS、禽流感等耐藥性疾病增多心理疾患增多、自殺率增加青少年發(fā)育、行為問(wèn)題及犯罪率增加更年期提前……EnvironmentFactorsandDisease

Chapter1:MankindandEnvironment

Section1.HumanEnvironment1.Definitionofenvironment

(1)Environment

Theimplicationofenvironmentisthewholethingsofoutsideworldthatismainlycomposedofhumanbeingsociety.Itincludesnaturalenvironmentandsocialenvironment.①NaturalenvironmentNaturalenvironmentreferstototalthingsofmaterialsandenergyformednaturally,whichdirectlyorindirectlyaffectslivingandproductionofhumanbeingsurroundingthespaceofthecrowd.環(huán)境自然環(huán)境社會(huì)環(huán)境（大氣圈、巖石圈、水圈、生物圈）原生環(huán)境primaryenvironment次生環(huán)境secondaryenvironmentprimaryenvironment原生環(huán)境：天然形成的,未受或少受人為因素影響的環(huán)境有利健康因素不利健康因素促進(jìn)健康地方病“正?！笨諝?水,土壤,陽(yáng)光,微小氣候,風(fēng)光secondaryenvironment次生環(huán)境：人類活動(dòng)下形成的環(huán)境，環(huán)境污染是主要問(wèn)題

破壞生態(tài)平衡:次生環(huán)境質(zhì)量惡化

保持生態(tài)平衡:次生環(huán)境優(yōu)于原生環(huán)境促進(jìn)健康引起疾?、赟ocialenvironmentalSocialenvironmentreferstotheartificialenvironmentcreatedbysociallaborconsciouslyforalongtimeonthebasisofnaturalenvironment.(2).LivingenvironmentLivingenvironmentreferstoavarietyofnaturalandartificialconditions,whichcloselyapproachandrelatetosociallifeofmankind.(3).Ecologicalenvironment

Ecologicalenvironmentreferstogeneralizednaturalenvironment,whichisapartalittlefarfromthesociallifeofmankindandiscomposedofavarietyoftypesandlevelsofecologicalsystem.2.EnvironmentalFactors(1)BiologicalfactorPathogenicmicroorganism

微生物寄生蟲(chóng)支原體原蟲(chóng)環(huán)境中能引起傳染病和寄生蟲(chóng)病的生物病原因子

(2)ChemicalfactorDuetoartificialornaturalreasonchemicalcompositioninair,water,soilandfoodmayvarygreatly.ForexamplelargeamountoffuelisburnedwhichdischargeSO2intotheair.

人為原因(環(huán)境污染)自然原因:洪水、地震、風(fēng)景、火山爆發(fā)燃料燃燒工業(yè)廢水污染或灌溉農(nóng)田

(汞;鎘;砷)空氣

水

土壤

食物化學(xué)組成變化(3)

Physicalfactor

Physicfactorrefertoairtemperature,humidity,aircurrent,radiationandairpressure,whichareknownasclimaticconditions.Radioactivesubstance,highfrequencyelectromagneticfield,microwave,laser,noiseandvibrationmayalsocontaminateourenvironmentcausehazardtohumanbeing.

氣象因素(微小氣候)放射元素——電離輻射

生活、生產(chǎn)環(huán)境

陽(yáng)光電磁輻射

人為原因自然原因：異常氣象

物理因素變化(4)Social-psychologicalfactorInhabitinsocialcommunity,economicstatus,politicalstatus,educationalandculturallevel,livingstandard,medicalservice,behaviorandhabitetcarealsohavetheirinfluenceonhumanbeing.Studytheeffectofthesefactorareanewfieldofpreventivemedicine.3.Ecosystemandecologicalequilibrium(1).BiosphereAlllivingthingsinhabitontheearthsurface.Thesurfacelayeroftheearthinthepresenceoflivingthingsiscalledbiosphere.Itrangesfrom12kmdepthoftheearthcrustorocean,toapproximately15kmthicknessofairlayer.Thereareair,sunlight,water,soil,rockinthebiosphere,whichprovidethenecessitiesfororganisms.Biosphereisthecombinationoforganismsandtheirenvironment.

生物圈：生物生存的地球表層。范圍：12km深地殼、海洋及15km以內(nèi)的地表大氣層(2).EcosystemEcosystemiscomposedoflivingthingsandtheirenvironment,air,water,andsoil.Livingthingsarecloselylinkedtotheirexternalenvironment.

Structureofecosystem:producer,consumer,decomposerandnon-livingthingsenvironment.

Functionofecosystem:energyflowthroughecosystem,materialcyclesinecosystemandinformationtransferinecosystem.

(3).EcologicalequilibriumThroughenergyandnourishmentcirculation,ecosystemkeepsitsbalance.Itiscalledecologicalequilibrium,inwhicheachlinkkeepsstableinqualityandinquantities,andadaptstoeachother.

(4).EcologicaldisturbanceDuetoman-madecausessometimeenvironmentfactormaychangegreatly,causedisruptionofecologicalequilibrium.Forexamplepesticidewhichisnotintrinsiccomingintoenvironment,killinsects,reducethenumberofbirds,owingtodiminishpollination,plantbloom,blossomandbearnofruit,residuepesticidecomeintoanimalandhumantissueposepotentialhazardtohumanbeing.Section2.Therelationshipof

environmentandhealth1.Theunityofhumanandenvironment2.Theadaptabilityofhumantoenvironment3.Theinteractionofhumanandenvironment1.Theunityofhumanandenvironment

Aswementionedearlier,livingthingsarecloselyrelatedtoitsexternalenvironment.Throughtakingfood,waterfromenvironmenthumanobtainsenergyandthematerialtobuiltitsbodytissue.Accordingtoanalysiselementarycontentofhumanbodyandrockofearthcrust,theelementalabundancearequitesimilarbetweenhumananditsenvironment.Thoseelementswhicharerichinexternalenvironment,arefoundplentyinhumanbody,onthecontraryitisalsotrue,rareelementarescarceinhumanbody.Theabovefactindicatesthecloserelationbetweenhumananditsenvironment.人體血液中和地殼中元素含量的相關(guān)性2.Theadaptabilityofhumantoenvironment

3.TheinteractionofhumanandenvironmentSection3Environmentalpollution

andHealtheffects

一.Outlineofenvironmentalpollution

1.Definitionofenvironmentalpollution:Owingtomen-madeornaturalcause,thealterationinenvironmentalconstituentandcondition,resultsindisturbanceanddisruptionofecologicalequilibriumandnormalenvironmentforhumanlivingandproducing,leadsdirect,indirectorpotentialdamagetohumanhealthisdefinedasenvironmentalpollution.

2.Typesofenvironmentalpollution①.ChemicalcontaminationPoisonousgas:SO2,NO2,Cl2,COHeavymetal:Hg,Cd,Pb,Cr,NiOrganiccompounds:organophosphoruspesticide,organochlorinepesticidehigh-molecularcompounds②.Physicalcontaminationnoise,microwaveradiationandradioactivesubstancescontamination③.BiologicalcontaminationPathogenicmicroorganismParasiticovum

3.SourceofenvironmentalpollutionItmaybeclassifiedasproductive,domesticandmiscellaneous.Sourceofenvironmentalpollutionisasfollows.(1).ProductivepollutionWastegas,wastewater,wasteresidue(threewaste)fromindustrialprocess,withoutpropertreatmentpourintoexternalenvironmentmaycausecontaminationofair,water,soilandfood.(2).Domesticsourcepollution(3).MiscellaneoussourceApartfromproductiveanddomesticsourcethereareothersourcesuchastransportation:train,ship,airplane,automobile.TheyburncoalorgasolineandemitSO2,hydrocarbonandincompletecombustionproduct.Soilwithoutcoveredwithlawnortree,soilparticlesmaybeblownintotheair.Insomedistrict,soilparticleaccountfor50%ofairdust.

廢水

生產(chǎn)性污染

廢氣

工業(yè)性“三廢”

廢渣

污水

生活性污染

糞尿

生活性“三廢”

垃圾其它污染：噪聲等環(huán)境內(nèi)分泌干擾物（EEDs）持久性有機(jī)污染物（POPs）

(一)生產(chǎn)性污染（Productivepollutant）

1.能源大規(guī)模使用；

2.資源大規(guī)模的開(kāi)發(fā)；

3.新物質(zhì)的大規(guī)模合成：現(xiàn)有960萬(wàn)種新的化學(xué)物質(zhì)，人工合成200萬(wàn)種，增加1000種/

年。三大合成（塑料、纖維、橡膠）。特點(diǎn)：有組織排放、量大、毒性強(qiáng)、易治理工廠大量廢氣的排放工廠廢水未經(jīng)處理大量排放排污口長(zhǎng)江水污染資源大規(guī)模的開(kāi)發(fā)(二)生活性污染（Domesticpollutant）污水：醫(yī)院污水、生活污水垃圾：成分復(fù)雜，含致突變致癌物糞尿：主要是生物性污染

煤煙：產(chǎn)生大量有害氣體和灰塵。1999年九屆人大11

次會(huì)議提案：在大城市禁止燒煤。特點(diǎn)：片污染、無(wú)組織排放、難治理生活性三廢隨意亂倒的生活垃圾堆積如山(三)其他污染（Otherpollutant

）交通污染噪聲污染光污染放射性污染農(nóng)藥化肥交通性污染4.Spreadandtransportationofchemicalpollutantintheenvironment(1).Migrationofchemicalpollutants①Bio-concentration

Inbiosphere,thetransferofenvironmentalpollutantismorecomplex,onenteringlivingthings,somepollutantsmaycombinetightlywithprotein,andsulfhydrylgroupsthenexcrete,oreliminateless.Asaresulttheygraduallyaccumulateandconcentrateinbodytissue.Thephenomenonthattheconcentrationofpollutantinbiologicalbodysurpassestheconcentrationinenvironmentiscalledbio-concentration.Theratioofchemicalconcentrationinbiologicalsubstanceversustheconcentrationinenvironmentcalledcoefficientofbio-concentration.②Bio-magnificationApartfromaccumulationinonebiologicalspecies,theprocessmayfurtheramplifythroughfoodchainandeventuallyreachessuchahighlevelastocauseintoxicationinhigheranimalsandthisprocessiscalledbio-magnification.環(huán)境污染物發(fā)生生物放大的條件:①環(huán)境化學(xué)物質(zhì)易為各種生物體吸收②進(jìn)入生物體的環(huán)境化學(xué)物質(zhì)較難分解和排泄③污染物在生物體內(nèi)富集和逐漸積累時(shí)，尚不會(huì)對(duì)該生物造成致命性的損害④在生物放大過(guò)程中是通過(guò)食物鏈進(jìn)行Fortunatelyfoodchainaccumulationisnotnecessaryprocessformostpollutant.Onthecontrary,throughspreadandtransportationgenerallytheconcentrationsofthepollutantgraduallydeclineordisappearaswellasdetoxify.Thecommonorganicsuchashydrocarbonproteinsthroughbiochemicaloxidationmicroorganismsplayamajorrule,decomposetonitrite,carbonate,sulfate.Thesearestablesimpleinorganic,whichnolongerputrid,andsafe.(2)TransformationofchemicalpollutantsItsphysic-chemicalpropertyandenvironmentalconditiondeterminethebehaviorofpollutantafterdischargingintotheenvironment.Ininorganicsphere,usuallythroughdilution,dissolutionandsedimentationtheconcentrationofpollutantgraduallydeclined.Apartfromthephysicalprocess,oxidation,reduction,hydrationalsooccurs,throughwhichpollutantsdegradedecomposethendetoxify.Duringdegradationmicroorganismsplayamajorrule.

①PrimarypollutantThechemicalpollutants,whichcomefrompollutionsourcedirectlyanddon’tchangetheirphysic-chemicalpropertiesinenvironment,arecalledprimarypollutants.②SecondarypollutantThenewcompounds,whichareformedfromoriginalpollutantsafterdischargefrompollutionsourcebyphysical,chemicalorbiologicalreaction,arecalledsecondarypollutant.

(3)Environmentalself-purificationTheprocessofself-purification(biodegradation)includesasfollows.PhysicalactionChemicalactionBiologicalaction自凈方式

物理凈化：稀釋、混合、擴(kuò)散、沉降、揮發(fā)、逸散、凝聚化學(xué)凈化：氧化、還原、水解及中和、光解生物凈化：吸收、分解或降解、轉(zhuǎn)化、氧化、拮抗等影響因素環(huán)境物理?xiàng)l件(溫度、流量、流速、風(fēng)速)污染物的物理特性(比重、形態(tài)、粒度)影響因素環(huán)境化學(xué)條件(pH值、化學(xué)組分、氧化還原電勢(shì))污染物的化學(xué)性質(zhì)環(huán)境污染物的吸收、分布與排泄(一)環(huán)境污染物的吸收

肺泡總表觀面積大，壁薄，毛細(xì)血管豐富：吸收迅速不經(jīng)肝，直接進(jìn)入大循環(huán)肺泡/血液濃度(分壓)差大，吸收快血/氣分配系數(shù)大，易吸收入血顆粒大小、分散度、溶解度活動(dòng)強(qiáng)度、肺通氣量環(huán)境氣象因素1.呼吸道：氣體、蒸氣、氣溶膠特點(diǎn)影響因素2.消化道吸收：水與食物中的有害物質(zhì)消化道吸收：水與食物中的有害物質(zhì)特點(diǎn)主要經(jīng)小腸吸收絨毛增加吸收面積600倍擴(kuò)散方式為主，也可經(jīng)載體可在腸肝循環(huán)過(guò)程中反復(fù)被吸收影響因素pH值胃腸道內(nèi)容物多少、排空時(shí)間、蠕動(dòng)狀況3.皮膚吸收：水溶性同時(shí)具脂溶性環(huán)境毒物特點(diǎn)主要經(jīng)表皮，少量經(jīng)毛囊、汗腺、皮脂腺透過(guò)三層屏障

——表皮角質(zhì)層：阻止分子量>300的物質(zhì)

——連接角質(zhì)層：阻止水、電解質(zhì)、水溶性物質(zhì)通過(guò)脂溶性物質(zhì)

——基膜(表皮與真皮間)：阻止少數(shù)物質(zhì)不進(jìn)入肝臟，直接進(jìn)入大循環(huán)影響因素脂/水分配系數(shù)易溶于脂、難溶于水、易揮發(fā)：吸收少，如苯易溶于脂、水、不易揮發(fā)：吸收多，如有機(jī)磷皮膚完整性(二)環(huán)境污染物在體內(nèi)的分布與貯存

1.分布：環(huán)境污染物通過(guò)吸收后，隨血液和淋巴液分散到全身各組織的過(guò)程非均勻分布器官或組織血流量大，灌注速率高，如肝臟化學(xué)物與器官親和力：90%鉛鹽沉積在骨骼屏障作用(血腦、胎盤(pán)、血眼、血睪)：甲基汞易通過(guò)血腦和胎盤(pán)屏障2.貯存(storage)靶器官：多數(shù)情況下污染物貯存的部位就是毒物直接作用部位，稱為靶部位（靶組織或靶器官）貯存庫(kù)：化學(xué)物含量高，但不顯示明顯毒作用的部位

—血漿蛋白(白蛋白為主)是暫時(shí)貯存庫(kù)

—肝、腎、脂肪組織是多數(shù)污染物的貯存庫(kù)硫蛋白(metallothionein)蓄積

物質(zhì)蓄積：進(jìn)入機(jī)體的污染物或其代謝產(chǎn)物，不能完全排出而逐漸蓄積于體內(nèi)

功能蓄積：毒物進(jìn)入體內(nèi)后，用現(xiàn)代檢測(cè)技術(shù)不能發(fā)現(xiàn)其在體內(nèi)有明顯貯留，但由該物質(zhì)引起的功能改變卻逐漸累積，導(dǎo)致機(jī)體對(duì)該毒物的反應(yīng)性增強(qiáng)(三)環(huán)境污染物在體內(nèi)的轉(zhuǎn)化

生物轉(zhuǎn)化：進(jìn)入機(jī)體的環(huán)境化學(xué)物，在體液或組織內(nèi)參與機(jī)體固有的復(fù)雜生化過(guò)程，使其本身的化學(xué)結(jié)構(gòu)發(fā)生一系列變化。污染物第一階段反應(yīng)(降解反應(yīng)):氧化、還原、水解第二階段反應(yīng)(II相反應(yīng))：結(jié)合反應(yīng)生物解毒作用(detoxication)經(jīng)過(guò)體內(nèi)的轉(zhuǎn)化，環(huán)境污染物毒性降低，如大多數(shù)毒物。生物活化作用(bioactivation)經(jīng)過(guò)生物轉(zhuǎn)化，環(huán)境污染物毒物增加，如對(duì)硫磷，樂(lè)果；苯并(a)芘、芳香胺(四)環(huán)境污染物的排泄1.經(jīng)腎隨尿排出：主要途徑污染物或其代謝物腎小球被動(dòng)過(guò)濾腎小管解離.水溶性未解離.脂溶性被動(dòng)擴(kuò)散尿重吸收入血不易排除2.經(jīng)肝、膽通過(guò)腸道隨糞便排出肝臟生物轉(zhuǎn)化代謝物肝細(xì)胞膽汁腸道隨糞排出腸肝循環(huán)3.經(jīng)呼吸道排出

氣態(tài)或揮發(fā)性物質(zhì)(CO、SO2、HS、C4H6)可經(jīng)肺呼出以下因素可加速排出——血中溶解度低——肺泡分壓?。阂浦量諝庑迈r環(huán)境——肺通氣量大4.其他排除途徑

毛發(fā)、唾液、乳汁、月經(jīng)生物監(jiān)測(cè)指標(biāo)(生物標(biāo)記物)：血液、尿液、呼出氣、毛發(fā)及脂肪組織等生物樣品中某些化學(xué)物或其代謝產(chǎn)物的含量，可作為評(píng)價(jià)體內(nèi)該化學(xué)物量的生物檢測(cè)指標(biāo)，即生物標(biāo)記物5.Publicnuisance

Itreferstoharmfulsituation,whichpollutedanddestroyedenvironment,endangeredthepublichealth,safety,andlifeaswellascommonorprivateproperty.6.Publicnuisanceevent

Itreferstotheincidentthatresultedinobviouslyincreaseofdiseaseanddeathinashortperiodofthetimebysevereenvironmentalpollution.Inthehistory,thepublicnuisanceexperiencedthreeperiods:

①theemergingperiodofpublicnuisance(Theendof19centurytothebeginningof20century)②thedevelopingperiodofpublicnuisance(Twentiestofortiesof20century)③theoverflowingperiodofpublicnuisance(FiftiestoSeventiesof20century)7.Publicnuisancedisease

Thepatientswerelocatedinsomeregionwheresevereenvironmentpollutionhadhappenedinsomeperiodofthetime.Thiskindofthediseasewascalledthepublicnuisancedisease.8.Toxicityindexofenvironmentalpollutants1).ToxicityOnecoulddefineapoisonasanyagentcapableofproducingadeleteriousresponseinabiologicalsystem,seriouslyinjuringfunctionorproducingdeath.Thisisnot,however,ausefulworkingdefinitionfortheverysimplereasonthatvirtuallyeveryknownchemicalhasthepotentialtoproduceinjuryordeathifitispresentinasufficientamount.

Paracelsus(1493-1541),phrasedthiswellwhenhenoted“Whatistherethatisnotpoison?Allthingsarepoisonandnothingiswithoutpoison.Solelythedoesdeterminesthatathingisnotapoison”.Toxicityisameasuretothedegreetowhichsomethingistoxicorpoisonous.2).Lethaldose

(1).Absolutelethaldose(LD100)Absolutelethaldoseisthelowestdoseorconcentrationofachemicalthatcanbeexpectedtocausedeathinalloftheanimalstested.(2).Medianlethaldose(LD50)Medianlethaldoseisthestatisticallyderivedsingledoseofasubstancethatcanbeexpectedtocausedeathin50percentoftheanimalstested.TheLD50valueisthestandardforcomparisonofacutetoxicitybetweentoxicantsandbetweenspecies.Determinationofthemedianlethaldoseisusuallythefirstexperimentperformedwithanewchemical.(3).Minimallethaldose(MLD/LD01)Minimallethaldoseisthelowestdoseofachemicalthathadeverbeenobservedtoresultindeath.(4).Maximaltolerancedose(MTD/LD0)Maximaltolerancedoseisthehighestdoseofachemicalthatcannotcausedeathintheanimalstested.3).Maximalno-effectdose(ED0)

Maximalno-effectdoseishighestdoseofachemicalthatcannotproduceanyadverseeffectsuchasmortality,clinicalsignsoftoxicity,orpathologiclesionsthatwouldbepredictedtoshortentheanimals’naturallifespan.4).Minimaleffectdose(MEL/ED01)

Minimaleffectdoseisthedosebelowwhichnoresponseoccurs.Itevokesastatedall-or-noneresponse.Wecanalsocallit“thresholddose”Fortheinter-individualvariabilityinresponseandqualitativechangesinresponsepatternwithdosemakeitdifficulttoestablishatrueED0/ED01foranychemical.Sointhetoxicexperimentweuseno-observedadverseeffectlevel(NOAEL)/lowestobservedadverseeffectlevel(LOAEL)instead.二.Healtheffectofenvironmentalpollution

（一）Theeffectofenvironmentalpollutiononhealthinfluenceofpopulation1.Dose-effectrelationshipanddose-responserelationship①Dose-effectrelationship

Doseeffectrelationshipistherelation-shipofdifferentdoseandeffectsindiffer-entintensity,rangingfromundetectable,pre-clinicaltoclinicaloreventodeath.Asweknow,theeffectofanychemicalsorphysicalagentisdose-related.

ThecurveofdoseeffectrelationgenerallyappearsasStypefortoxicagentorastraightlineforcarcinogens.Foressentialtraceelementthesituationismorecomplicated.Atverylowdosephysiologicalrequirementcannotbesatisfiedwith,diseasemayoccur,athighdoselevel,intoxicationappears.Onlyatproperdosepeoplecankeephealthy.Forexample,insufficientoffluorine,dentalcariesoccurs;however,excessiveamountoffluorinemaycausefluorosis.②Dose-responserelationshipItistherelationbetweendifferentdosageandincidenceofdamage,intoxication,orotherclinicalsymptom.2.Populationhealtheffectspectrumandhigh-riskgroupThehealthspectrumusuallyisexpressedbyafigure1-1.Itlookslikeapyramid.Thetopofpyramidexpressthestrongesteffect,buttherateislowest,thebottomexpressestheslightesteffect(pre-clinicalphase),peopletherearethemajority.Inthepollutedareatheconcentrationoftoxicagentatdifferentsitearedifferent,personsexposedtodifferentleveloftheagent,ontheotherhandthesensitivityofindividualsarealsodifferent,consequentlytheresponseamongindividualsarevarious.Scientistvividlydescribesthehealtheffectspectrumasanicebergfloatingontheocean.Fromremoteonlythetopoficebergcanbeseenbutthemajorpartareundertheocean,ifthispartistobeneglectedandtakenomeasureofprevention,theshipofhumanhealthwillinevitablyrunoniceberg.（二）Characteristicsofhealtheffectsofenvironmentalpollutants

1)Extensiveinfluencetopopulation2)Long-termeffectoflowdoseaction3)Complexityofmultiplefactors4)Multipletypesofaction(三).Healthhazardofenvironmentalpollution

1.Specificinjury(1).AcuteeffectAcuteintoxicationmayoccuraftersingleorshortperiodexposuretohighdoseofenvironmentalpollutant.Inthiscasegenerallyappearasdisaster,suchasLondonsmog,orLosAngelesepisode,thelaterisconsequenceofphotochemicalsmog.

(2).ChroniceffectChronicintoxication:Chronicintoxicationismorecommon,suchasMinamatadiseaseandIti-itidisease,duetomethylHgorCdintoxication.(3).Remoteeffects

①.CarcinogenesisThemechanismofcarcinogenesisisnotperfectlyidentified.Itisknownthatmutationofoncogenortumorsuppressorgenemayinitiatecarcinogenesis.OncogenandtumorsuppressorgenesarethegenesthatregulatereproductionofDNA.TheactivationoftheoncogenorinactivationofthetumorsuppressorgenethroughmutationwouldcauseexcessiveduplicationofDNA.Theuncontrolledgrowthofcellwouldresultintheformationoftumor.Carcinogensareclassifiedasphysicalfactor,suchasradioactivesubstance,UVR,chemicalfactor,suchasbenzo(a)pyrene,

-naphylamine,arsenic,aflatoxin-B,asbestosandbiologicalfactorsuchasnasolaryngealcancer,whichcanbeinducedbyvirus.

化學(xué)致癌物的分類

按對(duì)人的危險(xiǎn)性分 按活化的需要分按是否具有誘變性分按化學(xué)結(jié)構(gòu)分根據(jù)致癌物對(duì)人類和動(dòng)物的致癌作用分類國(guó)際癌癥研究機(jī)構(gòu)（IARC2002年）根據(jù)證據(jù)的強(qiáng)度將化學(xué)物質(zhì)分為四組（878種）：1類：確證的人類致癌物，是指在流行病學(xué)及動(dòng)物致癌試驗(yàn)均有充分證據(jù)的致癌物有87種。2類：對(duì)人很可能或可能致癌物，分為組2A和組2B兩組。2A類：對(duì)人類很可能致癌，指有充分動(dòng)物試驗(yàn)結(jié)果證明，但對(duì)人類證據(jù)有限，有63種。2B類：對(duì)人類可能致癌，指對(duì)人類致癌性證據(jù)有限，對(duì)動(dòng)物致癌性證據(jù)并不充分，有243種。3類：現(xiàn)有的證據(jù)不能對(duì)人類致癌性進(jìn)行分類，即動(dòng)物試驗(yàn)及流行病學(xué)調(diào)查有一定結(jié)果，但均未能確證其有致癌性的物質(zhì)，有493種。4類：對(duì)人類可能是非致癌物，即按目前的試驗(yàn)結(jié)果，未見(jiàn)有致癌性的物質(zhì)，有1種。按活化的需要分類直接致癌物（directcarcinogens)各種烷化劑，大多為親電子反應(yīng)物間接致癌物（indirectcarcinogens)多環(huán)芳烴、芳香胺類化合物按是否具有誘變性分類誘變性致癌物——遺傳毒性致癌物(genotoxiccarcinogen)。非誘變性致癌物——非遺傳毒性致癌物(nogenotoxiccrcinogen)，或稱DNA活性外或基因外致癌物（epigeneticcarcinogen)。②.MutagenesisMutagenesisgenerallyistheappearanceofevolution,resultsintheadaptationofchangingenvironmentbutmutationinducedbyenvironmentalpollutantisharmfultohumanhealth.Mutationofbodilycellwillresultincarcinogenesis,andmutationinreproductivecellwillresultinteratogenesis.Mutationiscloselyrelatedtocarcinogenesis,mostmutagensarealsocarcinogens.

③.

TeratogenesisSomeagentthroughmaternalplacentaduringpregnancymaydisturbthedevelopmentofembryoandcausesterility,abortion,stillbornandmalformation.Thedelayeddevelopmentofwitiscalledteratogen.Thiseffectisnothereditary,suchasthalidomide,urticariavirus.Somemutageninducedmutationofreproductivecellresultsinmalformation,whichisheritable.5.生育毒性和發(fā)育毒性

反應(yīng)停事件(4).

Effectonimmunefunction①Sensitization:Someenvironmentalpollutantactasallergen,isabletocauseallergicdiseasesuchaspollencausehayfever.②Immunosuppression:Someenvironmentalpollutantcancauseimmunesuppression,disturboneorafewstepsofimmuneprocesssuchasalkylatingagent,anti-metabolicdrug,ionization,UVR,somepesticide.2.Non-specificinjuryApartfromspecificeffect,environmentalpollutantmaycausenon-specificinjury,suchasincreaseprevalenceofcommondiseases,frequentlyoccurringdiseases,respiratoryinfection,commoncoldandraisebloodpressure.Themechanismofthisisnotf