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<br />.. '.-" '. /i, ,,~ <br /> <br />SENT BY: BOR-WCAOS SDj <br /> <br />8.16-96 4:47PMj 970 385 6539 -> <br /> <br />303 866 4474j <br /> <br />#8/22 <br /> <br />. .._...r...... .n". .,"" <br /> <br />SWQB/NMED Sumawy <br />August 12, 1996 <br />PIKe 12 <br /> <br />from 12 to 36 pereent, This allo",.. a rough estimate of total vlllues to be calculated from dissolved <br />values. <br /> <br />Table 13 (page B-21) Thie table lists the: number ofaxceedanc:es of water quality standDrds a[ the <br />various La Plata River SlariOllS elMg with the total Dumber of samples collcclfld for the selected trace <br />elements, As di~ussed earlier, the table does not indicate whether the samples are for total or <br />dissolved and it must be acc:c:pted on faith that the values were oompared to the comet numeric <br />standards. We nod such an assumption difficult [0 accept since the water quality 5taDdards used <br />were incom:ct. 'Chis lable only Mn1~ the saJijple: results from IIKl La Plata RiVeT a1 the ~...'"' line <br />to the: Colorado water aualitv standard.~ ",,-hile tn~ shoulrt ,wo be cODlJ)ared to the New Mn:;CD <br />wat.... <[""lilY 'ItJIndvds. Fotlrleell s.trtple, Ollt 11160 (13") ~()U.r;t,rJ lor me'l:lITY from dte foil' <br />La PID", RiveT sfllfl_ NpOrretlly acwldld ,,,. cllrolrk II_it: ,1iuIMs,d. F orty4bc SG"'PW Ollt <br />0163 (73") c~rJlor $ClaP_from tlIeloUl' La PhI", River SI4&III reportftly aceded tire <br />Cl'Dllic lIhu1tlrml, This table also complltes the selenium sample rEsults to the EP A aquatic life <br />chronic criterion (5 ~gfL). Tv.lIIlty-5ix of the 63 (41 %) slUIlples collected reportedly exceeded this <br />less stringent standard. The total number of observations at the various stations on this table does <br />not agree with the tctaI. number of o~r\'ations shown in tabli:5 10 and 11. Since the number of <br />samples compared to the New Mexico water quality standald (total recoverable) and the EP A aquatic <br />life chronic criterion (usumed to be dissol...ed in this report) in this table: ace the same, the issue of <br />whether the samples Wlft properly compared to appropriate dissolved, total or total teCOverable <br />standards must again be raised, <br /> <br />Tables GW-l and OW-2 (pqcs B-83 and B-86) The!'e tables show the results of groundwater <br />samplina in 1992 and IIgain in 1994-95 in the La Plata :River basin, The sampling was conducted <br />to give some indication of the quality offuturc irriiation return flows. The 1992 samples (Table <br />OW-I) show that many of the wells, seeps and springs are below the detection level for selenium <br />and mercuzy, The 1994-93 samples collected from different sources (Table: OW-2) show that <br />selenium level! ~ very hiih, IlIJIging liP to 116 /l.g!L; 580"10 of the Stll'te's ~ water quality <br />criterion. Apparently the return flo'\\'S, while variable in quality. would frequently be very high in <br />selenium, addina to the selenium load aI~ady prOMl1t in the La Plata River. Some samples also <br />yielded very high level! of copper, lIfSOJIio, anc and lead, well in elICCSS of New Mexiw surface <br />water standards, Since flow in the La Plata River under the Project will consist primarily of <br />lniption ~tum flow, there is reason to be concerned about water quality for all of these pollutants <br />in this river far into the f'utuR, <br /> <br />Table GW.3 (page B.87) This I:\ble summarizes data collected on the quality of the present retwn <br />flows to the La Plata River. This table, like many of the others, does not liS! units or the water <br />fraction analyzed. Assumini 1ha1 the sample units are ~WL. then levels ofarsemc, copper, mercury, <br />iWlenium and zinc are in excess of New Mexico suri'ace water standards, It is interesting to note that <br />lead is not im;l\lded in this table, although included in other tables. In botb stretches of the La Plata <br />River examined,the minimum levels ofsclcniwn foW1d (6 and 8 J.l'glL) are well in CXcellS ofth" <br /> <br />'%.3 <br />