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iJ * we Sampson <br /> i <br /> Mr . Geox9e Costao Chairman <br /> f <br /> Y <br /> Se t e;iibe r 27 , 1989 <br /> Page Two <br /> water sal ty s rtip1ing conducted y our office n <br /> ]_ . The er <br /> September 33, 1g confirms that first water sinps <br /> throughout <br /> the building contain oncenLi-at ions of 10a(l ill <br /> excess of the present feral and stare drinking watei- <br /> standard of 50 parts per billion F • <br /> Resi. <br /> l i is of the aria lyse�* of i�rs�F. lush concentrations C <br /> le i Lhe water r a va r .i <br /> a .. ous o ut leLs. vary s gni f cart l <br /> between Sampling rounds , The attached Labl , which Is <br /> summary of all available leac sampling resulLs, showS this <br /> lu tuat ' <br /> In a) l instances, except one (sample CB on 9/1/89 1 HE t <br /> lead concentrations in t fie drinkingwater were greatly <br /> reduced uc d f llo in running the water fur two r �ilute at the <br /> This implies that the source of lead contamillatiun <br /> may be at or very near the fixture from which the water <br /> r <br /> ri► l was drawn, I also impl i that corrosion c� <br /> f a <br /> sample <br /> substance containing lead at or near the fixture inky be <br /> raising theconcentration of lead in the first drEtw s ni lo . <br /> . v"irst: draw water samples obtained within the uilding have <br /> Shown significantly higher lead c ori nLra i ns than t1ju ; <br /> the i conic sup ply (astested t the Hydrant prior t Lhe <br /> g F' <br /> i_j ]c i n . <br /> 5 . Lead concentrations in the first draw samples have decreased <br /> s nif is t ly since the . r t sampling period, First taw <br /> concentrations on the days following system f lu hi 119 , <br /> however , have shows, an increase in lead concentrations . <br /> 6 . Plumbing s stent construction, based on materials tesLiny <br /> • � � le�; with <br /> field inspections, ars shop drawing review, <br /> the ilitelit of the systems s design and the tipplicable buildi'1�4 <br /> codes with respect to the use of , lead--free" ina er i a . . <br /> The findings of our investigation imply t.hdt the eleval.cisd <br /> lead concentrations in the first dr.aw samples a Lhe E'leinerx b r <br /> School may he a result: - .) corrosion of plumbic:c aiateri is <br /> coritaininq lead. T material , are I ike,I t0 be the <br /> �� utilized fcr' t sstettxs <br /> ��- ree so le r- and f i t L i ng s <br /> Construction . 13l definition, ", lead-free" wolder can contain tip <br /> to 2 percent lead and lead free fit i.n9s can cion 'a n up to <br /> percent lean. Although these perientagos ", are :love, in %-I Y-1 <br /> environment which is corrosive, new p umb ngy stews can release <br /> lead into the water in the% sy Steal. First draw Sa rple an b <br /> order guitu a higher than samples ohtr iri of Ler a shQ? t <br /> p <br /> riod o lushin � tie system, ie to Icer the coLc- <br />