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' ~ (.LS, E,NH/~Y!'~' /~~e-I~((o~.s ~':.II.CA~tiew,~ I ~h0.lysis <br />-9- <br />SA\11'1.1; 1'I21CSh.I2VA 11ON <br />Complete and u»eyuivucal prescn'aliun of s;unplcs, cllher dnnlcslic sewage, induslnal wastes, nr <br />natural waters, is a pr;tclicnl intpnssihlllly Kcga rdlcss nl the naunu of the "inl,lr, ulntplclc stability <br />for every cOnslilueni can never he arhtcrcd. AI hest. plcsclvalinn Icclunyurs wn nnl~ uuud the <br />chemical and biological changes Ih;u mcvil;lhly canliuuc all(•r 1 hr s;unplc Is rcnu,vcd Gnnl the parent <br />sourcc.'l he changes Iltal take pl:a'c iu a sample arc either chemical nl biological. In the fnrnlcr canc. <br />certain changes occur in the chemical structure of the constilucnls that arc a lunrlicm of physical <br />conditions. Metal cations nut}' prca pilatc as hyd rn.x «Ics ur loon cum pltxcs ,vith other rnnsUlucnts; <br />cations or anions may change ealence slates under cerulin reducutg or uxuliting conditions; other <br />i constilucnls may dissolve ur vulaulizc wish the passage of liutc. Mclal cauuns may also adsorb unto <br />surfaces (glass, plastic, yuartt, (c), wch as, Iran ^nd Irul. Hioln);ical change taking place in a <br />sample may change the valence of ^n elemeul nr ;t radical In a dilherent valence. Soluble cuosutuenis <br />I may be converted to organically hound neuerials in cell slrurlnres. ur crll Isis may result in rcl(•ase <br />' of cellular material into solution. The well known niungcn ;Ind phnsphonls e}cl(•s arc examples of <br />i biological influence un sample eompuslliou. I hcrcfurc, ;IS a gcncr;ll rule, it is hest lu ;utal}'i.c the <br />samples ;IS 50017 ;i$ pOSSl hll' allef CItIICell011. I IIIS IS l'tipCCI;III}' Irlll' (,'llC ll Illy 811;11 }'ll' C'l1llCClll ratl(111 Iti <br />I expected to be in the Imv ug/I r;ulge. <br />~ Methods of preservation arc Iclaliccly limited ;Ind arc intcudcd generally Ur (I) n'lard hiuinglcal <br />j action, (2) retard hydrolysis of chcmic,tl compounds and cln»plexcs, (~) reduce culalility of <br />i constilucnls, ;ut(I (4) reduce abscuptiun clfecl5. I'resen•:uinn nlclhnds ale genrr.Ill}' liutiled to pll <br />i <br />control, chemical ad(fition, refrigeration, and frcciing. <br />The recommended prescrvaln'c for (anuus cunsliulcnls is given in T;Ible I. These chnlccs arc based <br />on the accomp;mying rcfclences ;Ind un infnrntaiinn supplied he ,arious Olr,dily Assurance <br />Coordinalur5. As nutrc d:ua bccunle av,u table, Ihcsc rcrnnuncndr(I holding links will he adlusicd to <br />reflect new infurmalinn. Ulhcr infulm;tlinn prnnded iu the Iahlc Is an cstinriuun of the volume nl <br />58111p1e re(hllrl.'d fUr the :Illaytils, IIIC suggested type ul container, :fnd Ih(: nlaxinnun rernnuncndcd <br />holding lintcs fur samples puqu•Ily plcscrvc(I. <br /> <br /> <br />