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<br />APPENDIX-WATER-QUALlTY DATA FROM THE UPPER COLORADO
<br />RIVER BASIN IN A NATIONAL CONTEXT
<br />
<br />For a complete view of Upper Colorado River Basin data and for additional information about specific benchmarks used, visit our Web site at
<br />hltp:llwater.usgs.gov/nawqa/. Also visit the NAWOA Data Warehouse for access to NAWOA data sets at hltp:llinfotrek.er.usgs.gov/wdbctxlnawqa/nawqa.home.
<br />
<br />This appendix is a summary of chemical concentrations
<br />and biological indicators assessed in the Upper Colorado
<br />River Basin. Selected results for this Basin are graphically
<br />compared to results from as many as 36 NAWQA Study
<br />Units investigated from 1991 to 1998 and to national
<br />water-quality benchmarks for human health, aquatic life, or
<br />fish-eating wildlife. The chemical and biological indicators
<br />shown were selected on the basis of frequent detection,
<br />detection at concentrations above a national benchmark,
<br />or regulatory or scientific importance. The graphs illustrate
<br />how conditions associated with each land use sampled in
<br />the Upper Colorado River Basin compare to results from
<br />across the Nation, and how conditions compare among
<br />the several land uses. Graphs for chemicals show only
<br />detected concentrations and, thus, care must be taken to
<br />evaluate detection frequencies in addition to concen-
<br />trations when comparing study-unit and national results.
<br />For example, simazine concentrations in Upper Colorado
<br />River Basin agricultural streams were similar to the
<br />national distribution, but the detection frequency was much
<br />higher (72 percent compared to 18 percent).
<br />
<br />CHEMICALS IN WATER
<br />
<br />Concentrations and detection frequencies, Upper Colorado River
<br />Basin, 1996-98-Detection sensitivity varies among chemicals and,
<br />thus, frequencies are not directly comparable among chemicals
<br />
<br />. Detected concentration in Study Unit
<br />
<br />66 38 Frequencies of detection, in percent. Detection frequencies
<br />were not censored at any common reporting limit. The left-
<br />hand column is the study-unit frequency and the right-hand
<br />column is the national frequency
<br />
<br />Not measured or sample size less than two
<br />
<br />12 Study-unit sample size. For ground water, the number of
<br />samples is equal to the number of wells sampled
<br />
<br />National ranges of detected concentrations, by land use, in 36
<br />NAWQA Study Units, 1991-98-Ranges include only samples
<br />in which a chemical was detected
<br />
<br />Streams in agricultural areas
<br />Streams in urban areas
<br />Streams and rivers draining mixed land uses
<br />
<br />Shallow ground water in agricultural areas
<br />Shallow ground water in urban areas
<br />Major aquifers
<br />
<br />.- - _:-
<br />
<br />Lowest Middle Highest
<br />25 50 25
<br />percent percent percent
<br />
<br />National water-quality benchmarks
<br />
<br />National benchmarks include standards and guidelines related to
<br />drinking-water quality, criteria for protecting the health of aquatic life, and
<br />a goal for preventing stream eutrophication due to phosphorus. Sources
<br />include the U.S. Environmental Protection Agency and the Canadian
<br />Council of Ministers of the Environment
<br />
<br />Drinking-water quality (applies to ground water and surface water)
<br />Protection of aquatic life (applies to surface water only)
<br />Prevention of eutrophication in streams not flowing directly into
<br />lakes or impoundments
<br />No benchmark for drinking-water quality
<br />No benchmark for protection of aquatic life
<br />
<br />28 Water Quality in the Upper Colorado River Basin
<br />
<br />Pesticides in water-Herbicides
<br />
<br />Study-unit frequency of detection. in percent
<br />11Nat:ona, freQUelncy 01 dete~tiOn, in per~ent I Study-unit sample ISilze
<br />
<br />Alachlor (Lasso, Bronco, Lariat, Bullet) ..
<br />
<br />~~ a ~~" ~
<br />d _ I
<br />1 .......
<br />
<br />85 88
<br />86
<br />78 87
<br />40
<br />16 30
<br />o 18
<br />
<br />Atrazine (AAtrex, Atrex, Atred, Gesaprim)
<br />
<br />'-==_: ~.~ r
<br />... -1~
<br />
<br />38 15
<br />18
<br />44 11
<br /><1
<br />1
<br /><1
<br />
<br />2,4-D (Aqua-Kleen, Lawn-Keep, Weed-B-Gone)
<br />
<br />~...n r
<br />-
<br />-
<br />
<br />72 18
<br />30
<br />78 20
<br />1
<br />12 1
<br />o <1
<br />
<br />DCPA (Dacthal, chlorthal-dimethyl) . ..
<br />_.'
<br />-
<br />... .-;.
<br />an
<br />C!"
<br />
<br />72
<br />33
<br />
<br />Deethylatrazine (Atrazine breakdown product) . ..
<br />
<br />75 . I .. ......_.._
<br />62
<br />75 "1 "',-
<br />
<br />39
<br />28 _
<br />19 .
<br />
<br />54 81
<br />64
<br />78 83
<br />18
<br />9
<br />5
<br />
<br />Metolachlor (Dual, Pennant)
<br />:'~" .--..
<br />
<br />~
<br />I
<br />
<br />0.0001
<br />
<br />0.001
<br />
<br />0.01
<br />
<br />0.1
<br />
<br />10
<br />
<br />100
<br />
<br />CONCENTRATION, IN MICROGRAMS PER LITER
<br />
<br />Other herbicides detected
<br />Acetochlor (Harness Plus, Surpass) . ..
<br />Benfluralin (Balan, Benefin, Bonalan) . ..
<br />Bentazon (Basagran, Bentazone) ..
<br />Bromacil (Hyvar X, Urox B, Bromax)
<br />Cyanazine (Bladex, Fortrol)
<br />2,4-DB (Butyrac, Butoxone, Embutox Plus, Embutone) . ..
<br />Dicamba (Banvel, Dianat, Scolts Proturf)
<br />EPTC (Eptam, Farmarox, Alirox) . ..
<br />Ethalfluralin (Sonalan, Curbit) . ..
<br />Oryzalin (Surflan, Dirimal) . ..
<br />Prometon (Pramitol, Princep) ..
<br />Simazine (Princep, Caliber 90)
<br />Tebuthiuron (Spike, Tebusan)
<br />Trifluralin (Treflan, Gowan, Tri-4, Trific)
<br />
<br />Herbicides not detected
<br />Acifluorfen (Blazer, Tackle 2S) ..
<br />Bromoxynil (Buctril, Brominal) .
<br />Butylate (Sutan +, Genate Plus, Butilate)
<br />Chloramben (Amiben, Amilon-WP, Vegiben) ..
<br />Clopyralid (Stinger, Lontrel, Transline) . ..
<br />Dacthal mono-acid (Dacthal breakdown product) . ..
<br />Dichlorprop (2,4-DP, Seritox 50, Lentemul) . ..
<br />2,6-Diethylaniline (Alachlor breakdown product) . ..
<br />Dinoseb (Dinosebe)
<br />Diuron (Crisuron, Karmex, Diurex) ..
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />32
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />32
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />o
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />32
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />32
<br />
<br />39
<br />o
<br />9
<br />o
<br />25
<br />32
<br />
<br />1,000
<br />
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