HYDRO28632

• Permit No: M1980233
• IBM Index Class Name: Hydrology
• Doc Date: 4/12/1996
• Doc Name: COSTILLA LANDFILL PIT COSTILLA CNTY COLO
• From: GREYSTONE
• To: DMG
• Media Type: D
• Archive: No

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April 11, 1996

Mr. James C. Stevens
' State of Colorado
Division of Minerals and Geology
' Department of Natural Resources
1313 Sherman Street, Room 215
Denver, Colorado 80203
RE: Costilla Landfill Pit, Costilla County, Colorado
' Dear Mr. Stevens:
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Greystone is submitting this letter on behalf of Costilla County to provide you with analytical
' results associated with March 19, 1996 groundwater sampling at the aforementioned location.
Groundwater samples were obtained from four monitor wells (MWl through MW4) on
March 19, 1996. The groundwater samples were submitted for laboratory analysis. The
samples were analyzed for volatile organics using EPA Method 624, semi-volatile organics
using EPA Method 625, pesticides using EPA Method 608 and herbicides using EPA
' Method 8150. Additionally, the samples were analyzed for Human Health Standards, less
asbestos, and Secondary Drinking Water Standards listed in the Colorado Department of
Health, Water Quality Control Commission, The Basic Standards for Ground Water.
' Samples were collected using a teflon sampler. The sampler was decontaminated with a
phosphate-free detergent and distilled water before each use. Samples were placed in
laboratory supplied containers with the appropriate preservative and placed on ice until
delivery to the laboratory for analyses. The samples analyzed for phenols, odor,
radiochemistry, cyanide, foaming agents, metals, nitrates, nitrites, fluoride, alkalinity, chloride,
' color, TDS, sulfides and pH were filtered in the field (.45 microns). Chain-of-custody forms
accompanied the samples throughout the shipment and are included with the analytical
report.
' Total Dissolved Solids (TDS) and pH were within the acceptable range for ground water as
prescribed within The Basic Standards for Ground Water. Manganese concentrations were
slightly elevated above the Secondary Drinking Water Standards in MW1 and MW2. The
Secondary Drinking Water Standard is an aesthetic standard related to the odor and taste
of the water. The manganese concentrations of 0.069 and 0.131 mg{L in MWl and MW2,
' respectively are only slightly above the Secondary Drinking Water Standard of 0.050 mg/L.
Additionally, MWl is located upgradient from the landfill and MW2 is located crossgradient.
LE2.484041] 612:53 m
5990 Greenwood Plaza Blvd. Suite 250 Englewood, CO 80111
(303?850-0930 • .Raxf303?721-9298