Environmental assessment request letter, February 2002

NYC 9/11 Public Portal Document 02/20/2002 09:03 FAX Q 021 .,.,, . JLC ENV RONMEHTPL N0.8n P.IR

Maze Croup LI.0 (104 John Street) JLC Project # C1,2D94aOf pagre 2

I'ntruductfon Pdarlzed light dispersion Is the asbestos In bulk method far s. it s n t method {JLC lab d~rgbulkdi tori'alanalyses. MethQdasbrgy A ctain of custody is kept for each sanpIe to ensure proper handling awtysts. To avoid any possible eontemtrtotlon, all same and slide and delivery to the JLC tab prior to ventpa HEPA-filter hood with corrtirnOu8 airflow. Sample anaemiapreparation Is perbrmed is carried out in a using PLM-DS In accordance with the USEPA ,'Method for is DstemiInatlon of Asbestos In EPA S00 8.83115, July 1983, and NiYQQH-EI.AP certlPic atIon Sulk Su€tdng Mataadals," manual, Methods for ld#sntifylnp and tuarstitating Asbestos in Bulk $samples," "Polarized Light Microscope ELAP 198.1, October 1993. ern&ytic i Procedtsms • All sanpies are subject to preliminary visual stememlcroscopc ,AN id camiria#fon. Observation of homogeneity, cation, and semiqusntltation of c nst3tusnts can be triads at this point Samples lacdng uniformity of composition endlnr distribution of component rnats,fals then undergo non-friable organically bound (NOB) fi les such as floor tiles and hcmogeniz tion. Some steps to dislodge problem matrices O,e. ashina. +e*ractians, and TLM). roofing matertais may require additional

ldantiflcatJan of suspect fibers in made by PIJM analysis of subsamples. polarising flitera enables cis to observe speciltc opti i oh otedatkos A mic mscape equipped With dual of asbestos requires d termination of the foU lraQ of esdt sample. Positive Identification opeal propertias; rsfracflvs lockers, birefringerice, axdndion rJ,eracwleljcs, end morphology, color and pieochroiam, signs of 6iorlgs floe. ~, Asbestos quen Caron is performed by point-counting procedctrs► dearmin the reiadve areas ocr upland by separate minerals a standard technique in petrography for or points Aver the micrceoope-s field of view. Then bar of inants rack. An ocular reticle superimposes mimes a point pa~ras ~ fiber Is neaordaat. A total of 400 Pants must fro positioned thready above each kind of ~ be counted over at heat eight different representative subsarlor to r~rr►pit% analysis.

Polasrasd Ught Mlarasoapy JLC uses an Wyrnpus l3HT.p Polarizing Mi scapccrnpiae with polarizer, analyzer, port for wave r tardatten plat 380 9i rot rQ stage, stage condenser, lamp end lamp i~a$, eyepiece ratio degree Roint you t fight aaailowaa for the determination of refraction indices relative to sp ' c cremations, Morphology and color can also be observed plane polarized fight Obssrvatien of particles or fibers under while oriented between polarletng filters whose privileged vibrrnton directions are perpendIc r allows exanctlon dxracteriaifics of snisatroplc paartideg, 5n4 for dets> m inon of isotroplsmt aanis'COplsm, be placed in the polarized light paste for verification maculation of bireftingarns'. A retardation plate may of signs of Notation.

Ma lytegi Results The "Summery Of Analytical Results* rapr*santa the results of analysis, Positive results mean die sample is aaabeatc or contains more than one percent asbestos ldintlfl tj and quantftetiorl of major ooncentre1Jc a Of by weight The rsaujts are generally suPtdent for atdIt onai techniques may be necessary. Pisses b8 aware autos, However,, It may be found that that PLM is not aonslsterdy reeable in detecting asbeatca in floor coverings and simnilar NOD materials, trued as wort.asbestos containing. confirmation must be maw Def rs ttla material can os considered or Microscopy (TEM), by quantitative TransmIston 81ectrcn

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