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<br />............ w.... ....., ..... . ""'.. <br /> <br />8-16-96 4:50PM; 970 385 6539 -> <br />.~ IOR.WCAQ8 8D: '13 <br /> <br />303 866 4474; <br /> <br />#14/22 <br /> <br />SENT 8Y: BOR-WCAOS SOj <br /> <br />SWQBINMED Summaxy <br />August 12, 1996 <br />Pase 10 <br /> <br />responses in an aquatic ecosystem," We do "olll"'~, <br /> <br />Table 2 (paae 27) lirls the total numbers of samples and the maximum concentrations of dissolved <br />trace elements in the Alliu1iIIi River 8IId compares these: to the EP A aqW1lic life criteria. The <br />maximum concentration of disoolved selenium ".,...s 20 #.vL.rqpal to. the New Mexico acute Wlter <br />quality standard for total reooverllhl", ~lm1ium and 10 times the NC5W Mexico chronic!1andard. This <br />concentration is also 10 times the level determined to be harmful by the U,S. Fish and Wildlife <br />Service. It is not possible to estimate the level of total selenium at the time this slIIDple was <br />collected, since ranges of percentages of trace metal. in the dissolved fraction are given only for tbe <br />La Plata River. The maximum CODl:enlration of dissolved mercUJY was 0.5 ,ugIL, 42 times the New <br />Mexico chronic water quality stll:ldard for total mercury. No other dissolved trace elements <br />repodtJdly exceeded the EP A aquatic life aiteria in the Animas River. Here 1I8ain, howevcl', IIQ raw <br />data are included, so no comparisons by NMED can be made, <br /> <br />Table 3 (page 28) This table',lists the geometric IMIU15 of dissolved clementi in samples from the <br />Animu River. The geometric means of di!lSolved mercury for the Animu River at Cedar Hill and <br />at A%tec are 0.12 and 0.11 J.l.2IL. an order ofmagnimde above the l:!PA aquatic life criterion for <br />~ 8IId 811 ord.w of magnitud; above tb; New Mexico water quality 31:lmdard. for S5l1lll memJ[}', <br />The Assl!s.ml!Jlt lltates that ''it is likely that selenium will mitigate the toxicity of mercury" (paz... <br />37); W, tlfJ 1101 agru, The Assessment wso determined that "(b]uard quotients for the geometric <br />meanconoentratioDll ofclia8olved elements (in the Animas River) lIldi.cated tM.t -.imi\llI1, copper, <br />lead. and selenium were low baza~ suggestins that some poteDtilll for subletblll effects should be <br />consida:ed, Mercury was calegorized as a moderate hazard Indicatin& that adYm.~ effects ~~"^"iAl M <br />wilh this element are likelv." [Emphasis adeled] These metC1.11j' levels "~resent a hA7"rr1 to fish. <br />....tin; hink Ilnd m","mals in the area," pxesumably including bwnans, [Emphasis added] We again <br />note that this 8IUlIysis did not consider the effects of individual pulses of toxicants nor did it <br />seemingly consider the synergistic effects of dlronic exposure6 to a number of different ponutants, <br /> <br />"The highest dissolved concentration of selenium (20 ,uglL) met the EPA acute water quality <br />criterion. However. no monality is e:lqlCCled. to re5lllt from these short-lenn exposures." "In ieneral, <br />concentIatiOllS of selenium in 5aIl1ples oC water, sediment, and biota from the Animas Rh'er do not <br />reprellel'lt a threat to the biological community-" This statement contradicts the previous statement <br />that the potential for sublethal effects should be considered. Lf!veIs Df ~ "d~,.ill."" whltlr <br />lIT' "",,"tltarivdy .qua/'o .h, New Maico ,"u~ murdt",l wltltlr II based 011 lO.1ll ,'cQ\lf!rII61f! <br />s,l",iII.. would (11'1'(1' to I'I'pl'Ulltt IJ ",ry,ul tlll'ltII 10 Ill, Sltlie's fISh, ilacludi1lg .lIdiu1g,,,d <br />'1'"16& Mor1lllity would be a possibility at the total recoverable levels probably encountered at the <br />same time, and sublethal effects would be certain. <br /> <br />/ ~IzJ <br />