高二英语Unit13Thewaterplanet教案背景知识:WaterPollutionWhatisnecessarytolifeonearth
Allorganismscontainit;someliveinit;somedrinkit
Plantsandanimalsrequirewaterthatismoderatelypure,andtheycannotsurviveiftheirwaterisloadedwithtoxicchemicalsorharmfulmicroorganisms
Ifsevere,waterpollutioncankilllargenumbersoffish,birds,andotheranimals,insomecaseskillingallmembersofaspeciesinanaffectedarea
Pollutionmakesstreams,lakes,andcoastalwatersunpleasanttolookat,tosmell,andtoswimin
Fishandshellfishharvestedfrompollutedwatersmaybeunsafetoeat
Peoplewhoingestpollutedwatercanbecomeill,and,withprolongedexposure,maydevelopcancersorbearchildrenwithbirthdefects
Themajorwaterpollutantsarechemical,biological,orphysicalmaterialsthatdegradewaterquality
Pollutantscanbeclassedintoeightcategories—petroleumproducts;pesticidesandhe