Laserfiche WebLink
<br /> <br />,"ecfeation. The BurP'lU of Land M,1nagement also leases i,-rigated agricultural <br />land above the tt"speclive ll<itinnal vildliff! lefuges 0I10llg tllP Colorado Rivel-; <br />~ and (4) the U.S. Fish arId ....'jld1ife ServicE' manaRes tile 1l.1vasll. CiboJa. anri <br />(.f'" Imperial Xational h'ildlife Refuges fOI n,igliltolyand end.ll1gered vildlife <br />0) habitat. val-m vater fish babitilt. 'lnd public use recreatioll. <br />. . <br /> <br />Agricul tUfal praCl ices in this areCl are dominated hy product ion of <br />cotton and alfalfa, ...hich ale subject to frequent chemical treatments. All <br />the lefuges are located neilr intensively farmed aglicultllral areas and are <br />influenced chemically by illig:atioll return flovs. <br /> <br />The pUlpose of the iniliill study vas to determin~ from exi~linr. d<lta <br />and reconnaissance field silmplillg vhethpr ill-igatioll dtaill,1ge varers have <br />callsed or have the potentii'd to ca1l5P hdnnflll effects on human health. fish <br />and \lildlife. 01" other W'ater uses. The field scrE'pning detelmined vllether <br />cOI-rective action i~ needed and laid the groulldvork for mOle detailed <br />investigatiOl,s. if needed. to detC'lmine the extent, magnitude. alld causes of <br />the inigation drainage Quality probll."m. <br /> <br />Vater. bottom maleriid. and pl<'lnt ami ;m imo1. I tis~ue.s vel-I" collecred <br />and analyzed [or trace elpments and olR<lnic contaminant.<; in oldf:r to detel mine <br />existing or potential toxic E'tfects on IHlmans Ot fhh and vildlife. <br />Contaminilnts of palticuli1r concelll are selenium. lhi111illm, toxaphene. and DDT <br />ilnd its derivativps, All samples ....prp collected usinf, applo':ed collection <br />techniques. <br /> <br />Vatel., bottom milteli,li. and plant <lnrl i1tlim,11 ti:r;-SlH? samples and <br />field ouservations ....~Ie culleclt:>d <-It ]1 :-;ites alollg thE' LOV~l Colulado Rivel- <br />from O;'tvis Dam to belm.. L<tgulhl Dam. A ('once I ted eflol t ....as made to di:r;-trihute <br />sampling sites llpstn~i'lm .lnd d(l'~'nstrC'i1m from illigiltion distlicts and national <br />vildlife refug{"s. <br /> <br />Valel', bottom materi.11. i1nd p1.1nt and ,11dmal li~.<:ue samples and <br />field o!lsel-vations \o.'ere be> cllllt;'rtC'd only ol1ce <It the II ~iles" S.1mplillg W'as <br />accomplished at a time ...11('n in ig;'ttioll l'etlllns .lIt':' lIkelv to hilve a high <br />pe'"centage of tIo..' thill h:-HJ i};Jss~d thl-'HJ/.;h the soil hOli::ons. Because <br />irl"igatE'd ilRficultul'e is a 12 mOl1th-rer yeal artivity in The Lu....el" Cololildn <br />River valley and the Cololilrio River is so highly legulatrd. early to late <br />spring vas considered the best timp to samr1f'tol maximum impact. This <br />sampling schedule allo~ed lor optimtlm infol'malion fl)1 i1 minimum ('ost fo, a <br />reconnaissance (phase 1) stndy. This ,...,s eon<;ideled the minimum effort <br />necessary to evaluate ..:hether or nOI a problf'm exists. <br /> <br />The l-ecormaissance phase of the stud;- '~'as completed ann a l"eport <br />publ ishpd Pllt i lIed "ReCOllllrlis5.11H'P Invest igal ion 01 l.'ater {)llal i ty, Bot turn <br />Sediment, arllj Biotil Assrwla.t,f:'d vi III fll igilT iOJI Olilinagf' ill the Lover Color-ado <br />River V<llley. Arizona. Califollli'l. ilnr:l NeVoid.., ]Q86-87". ~ee U.S. Geological <br />Survey va ter Resolll-ces Inves t iga t i OilS Repol t H8-L.rJ22. <br /> <br />In the Lo'~'el Cololildn River '/illley alPa. sampling locations ....ere <br />fOllnd (I) be relatively tlPI? of hir:h t'Ollrel1tl'-lliol1<; of srlectt:'d toxic innlganic <br />and synthetic organic trilee constituents thaI coulr:l he a thrroat to hum<l.1s. <br />fish. and vilrllife 'Jith the E>xceplioll of selenium anti DDT. Ilovever, accotding <br />to the leport. a,'ela,>:e self-Ilium concentrarions in fish <lppln:lch. and in some <br />instanc('s exceed, rotlcelltratiollS that could IPSlllt ill If:'prndllcti'.'e impairment <br />in cel tain fish. <br /> <br />II! 3 <br />