简介：ＣｈａｎｇｅｓｏｆｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｎｐｏｐｕｌａｔｉｏｎａｎｄｅｎｖｉｒｏｎｍｅｎｔｉｎｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＶａｌｅｙｉｎｈｉｓｔｏｒｙＺＨＡＮＧＤｉｘｉａｎｇＳＵＮＰｉｎｇＴｈｅＰｏｐｕｌａｔｉｏｎＲｅｓｅａｒｃｈ...

简介：BasedonhistoricaldocumentsandrecordsthispaperanalyzesthecharacteristicsoffrequencyanddistributionofmajordisastersthattookplaceinthehistoryofChina.Thefindingsshowthatoccurrencesofdifferenttypesofdisastersvariedandspatialpatternatprovinciallevelaresignificantlydifferentaswell.Theresultsalsoindicatethatthereisastrongrelationshipbetweentypeofdisastersandspatialdistributionandthatthespatialpatternoflosseswasnotthesameasthatofthefrequency.Thereasonsare:(1)thehazard-formativeenvironmentswhich,toalargeextent,determinethespatialpatternofthedisastersaresignificantlydifferent;(2)thelossescausedbynaturaldisasterswerecloselyrelatedtotheconcentrationofeconomyandpopulation.Numberofdeathswasusuallylargeinareaswhereagriculture,cultureandbusinesswererelativelydeveloped.ThespatialpatternofdisasterlossesisanevitableresultofuneveneconomicdevelopmentinthehistoryofChina.

简介：Themercurycontentin158fishesand28musselsintheSecondSonghuariverweredetected.Therangeofmercuryconcentrationsinfishesandmusselswas0.02-0.66mg/kgand0.002-0.056mg/kg,respectively.Thehistorychangeofmercurycontentinfisheswasanalyzedinthispaper.Fromupstreamtodownstream,theaveragemercuryconcentrationsinfishesincreasedwiththeincreaseofthedistancetotheheadstream,thendecreasedinthedownstreamofWujiazhantown(samplingsite).Thefactilluminatedthatthesourceofmercurycontaminationwasmercuryinsediment.Inthedifferentspeciesoffishes,themercuryconcentrationinParasiburusasvtuswasthehighestandtheorderofmercurydistributioninfisheswas:themercuryvalueinfishesintheriverbottom>thatinfishesinthesurfaceandthatinpredaciousfishes>thatinherbivorousfishes.Intheinvestigation,therewereamountoffisheswhosemercuryvalueexceededthecriterionforthatinfishesthatsuggestedthatthemercurycontaminationintheSecondSonghuaRiverhavenotcompletelybeeneliminateduntilnow.

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