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5-7 MEMO ."•i" ?• ° 3 'any r ..�-giT„` - '�'-.tax_.. _ ^.^r .�.'$'".s£ NAR Ra. D Aufi{J+t�t, �d✓t f,ds :tint FdA ler: Prrga 4 0232U 1407 3.4 1doNIT0RING WELL.INSTALLATION Orta monitoring well(F.dWDI was inst;rtlrct in tt�e ao-1 tiArintj The monitoring weft w.ts constnrcled ie well of 4-Inch diamcler,scIlMute 40 PVC C,jsing with I,,us tds. l ol well il ` scroun wa$installed from a depth of G8 feet to a depth ir 53 aet bcitrw grade, A ;arxlirtter wa rAacOd 10 a height of approxtrnalely 2 1(%,, above the ton of the screen. The wall was around the wall screen oa ell completed with a bentonit©setal nod ct)mont grout,cO mainated SAW-i teembox h awa ct trglit bottrdlid W be wellhead was protected try a locking cap and construction details are presented In the dNI log(Apmndsx C)• 3,5 GROUNDWATER MONITORING The nevAyinsfallod monitoring wet'was dcr'-60PM wing a truGk•mounled surg¢•sYstem before the well was sealed.and hand-baaed and surged In fr.e gallpn intervals,Of 55 gallons o1 water to remrne fFno- grained sedirrtonts from the well and f4ter pack, The devetWment waler was retained on site in a DOT- approved 55-0,lon drum pending proper disposal. On Duty 24,1991 the water table in moniloring weal MV1.9 was mondyM to grade to determine the static level and thickness of any separate•phase hyd[Wrbon5(SP). The water table levet was measured using an QRS Emironmentat Erpu=pment INTERFACT PI'OSE``r V.ell t.onitoring System.consisting of a dual optical sensor and electrical coMuctWy probe,that disaingu:shes between water and petroleum products. No SP was present. Sinco monitoring wet!LjW9 is the only well that extends into the groundwaier during the current drought conditions,the groundwater flaw direction for the silo cannot be determined. Howrrver, previous data rovca'•ed a groundwater How di:Ktiq:t of north•nonhenst. 3.6 GROUNDWATER SAMPLING Subsequent to monitoring.the watt was purged of approximately six well Casing volumes p to sampling. In addition.the well was monitored for a second tirro to assure tKlt the water level In the well had recovered to at least So percent of the static 1,-v& The groundwater collection were corrected using a Tenon sampler cleaned with an industrial•streVh detergent and distiled water. Immediately prior to the collection o!the water sairple from MW-9.a distilledf water e.r*ate blank was collected from the Teflon sampler as a Quality control check on the eleartfrraess of coratrd. Each sample was ae..id;fied,...labeled.aract ...._..._ the sampler. A trip blank was also c eCcd for sXualit}r The samOes war placed en Ice in an insOated container for dr--livery Io a S131Q-cen1I*d iabomtory. Ctrrri`.-trtvv1•t:tt 3 t:Cu�r at.r K.1: INC,