Data Series 283

U.S. GEOLOGICAL SURVEY
Data Series 283

Appendix A. Water-quality Terminology and Parameter Definitions

Long-Term Method Detection Level (LT-MDL) is a detection level derived by determining the standard deviation of 20 or more MDL spike-sample measurements over an extended period of time. LT-MDL data are collected on a continuous basis to assess year-to-year variations in the LT-MDL (Childress and others, 1999). The LT-MDL controls false positive error (reporting an analyte present when it is not in the sample at a concentration equal to or greater than the reporting level). The chance of falsely reporting a concentration greater than or equal to the LT-MDL for a sample that did not contain the analyte is predicted to be less than or equal to 1 percent. The USGS National Water Quality Laboratory collects quality-control data from selected analytical methods on a continuing basis to determine LT-MDL and establish laboratory reporting levels (LRL). These concentrations are reevaluated annually based on the most current quality-control data and may therefore change. In cases where there is not sufficient quality-control data for a given analytical method, the LT-MDL is the LRL (Childress and others, 1999).

Reporting Level (RL) generally is equal to twice the yearly determined LT-MDL (Childress and others, 1999). The LRL controls false negative error (stating the analyte is not detected when present at or greater than the detection level). The probability of falsely reporting a nondetection for a sample that contained an analyte at a concentration equal to or greater than the RL is predicted to be less than or equal to 1 percent. The value of the RL will be reported with a “less than” (<) remark code for samples in which the analyte was not detected (Childress and others, 1999).

Dissolved Oxygen—field

1. Parameter name: Dissolved oxygen is molecular oxygen (oxygen gas) dissolved in water.

2. Sample fraction: Dissolved oxygen samples were taken from a sample cup by immediate transfer into an ampoule to minimize aeration or other sources of contamination.

3. Measurement units: Dissolved oxygen is reported as milligrams per liter (mg/L).

4. Field or lab measurement: Dissolved oxygen measurements were conducted in the field.

5. Value type: Actual

6. Description of sample preparation procedure: CHEMet ampoules were filled from a 25-mL sample cup, the ampoule was inverted several times to mix its contents, after 2 minutes the ampoule was held up to the color comparator beneath a bright source of light. The concentration of dissolved oxygen is determined by color matching the test ampoule to the color comparator.

7. Description of sample transport/preservation: Dissolved oxygen measurements were made in the field. Preservation and transportation of water sampled were not necessary.

8. Lab analytical method/procedure name, source citation, and ID: Indigo Carmine—ASTM D 888-87, Colorimetric Indigo Carmine, Test Method A (Gilbert and others, 1982).

9. Name and model number of field equipment: CHEMetrics, CHEMets Kit K-7512 was used in this field study.

10. Maximum and minimum quantification limits for the method or procedure:

a. Range: 1–12 mg/L

b. Resolution: 0.5 mg/L

pH—field

1. Parameter name: pH is a measure representing the negative base-10 logarithm of hydrogen-ion activity of a solution in moles per liter: pH= –log₁₀(a_H+)

2. Sample fraction: pH for this study was measured on unfiltered water samples.

3. Measurement units: pH is reported on a scale that ranges from 0 to 14 and is directly related to the ratio of hydrogen (H⁺) and hydroxyl (OH^-) ion activity at a given temperature.

4. Field or lab measurement: pH measurements were made in the field.

5. Value type: Actual.

6. Description of sample preparation procedure: The pH meter was checked and calibrated twice daily in the field using pH buffers (pH 7 and pH 10 or pH 4). Buffers were allowed to equilibrate to approximate sample temperatures prior to calibration of the instrument. pH was measured either directly in the source or, when water depth was inadequate, from a beaker of sample water. The electrode was allowed to equilibrate until the pH reading was stable. The probe was rinsed with deionized water and stored upright in electrode storage solution.

7. Description of sample transport/preservation: pH measurements of sample water were conducted in the field. Preservation and transportation of sample water was not necessary.

8. Lab analytical method/procedure name, source citation, and ID: pH measurement procedures were followed according to the NFM, chapter A6, section 6.4 (U.S. Geological Survey, 1998).

9. Name and model number of field equipment: Orion model 250A temperature-compensated pH meter with gel-filled ATC combination electrode.

10. Maximum and minimum quantification limits for the method/procedure: pH measurement

a. Range: –2.00 to 19.99

b. Resolution: 0.01/0.1

c. Relative accuracy: ±0.02

d. Slope: 80 to 120 percent

e. Temperature measurement

f. Range: -5.00 to 105.0°C

g. Resolution: 0.1°C

h. Relative accuracy: ±1.0°C

Specific [Electrical] Conductance (SC)—field

1. Parameter name: Specific [electrical] conductance is a measure of the capacity of water (or other media) to conduct an electrical current. Electrical conductance of water is a function of the types and quantities of dissolved substances in water.

2. Sample fraction: Specific conductance for this study was measured in unfiltered water samples.

3. Measurement units: Specific conductance is reported in microsiemens per centimeter (µS/cm) at 25°C.

4. Field or Lab Measurements: Specific conductance for this study was measured in the field.

5. Value type: Actual.

6. Description of sample preparation procedure: The specific conductance instrument was calibrated prior to sample measurements with standards that bracket the expected sample conductance. Standards were equilibrated to the approximate sample temperature. Measurements were made either directly from the source or when water depth was inadequate, from a beaker of sample water. The conductivity probe was immersed in sample water until it equilibrated to sample temperature. The probe was stored in a bottle containing deionized water.

7. Description of sample transport/preservation: Specific conductance of sample water was measured in the field. Preservation and transportation of sample water was not necessary.

8. Lab analytical method/procedure name, source citation, and ID: Specific conductance measurement procedures were followed according to the NFM, chapter A6, section 6.3 (U.S. Geological Survey, 1998).

9. Name and model number of field equipment: Cole-Parmer model 1481-61 temperature-compensated specific-conductance meter with probe model 01481-64, platinum dip-type sensor.

10. Maximum and minimum quantification limits for the method/procedure:

Conductivity range: 0–200,000 µS/cm (microsiemens per centimeter)

Temperature compensation:

Temperature coefficient: 2 percent per degree Celsius

Reference temperature: 25°C

Compensation range: 5–45°C

Temperature range: 5–45°C

Alkalinity—field

1. Parameter name: Alkalinity refers to the acid-neutralizing capacity of solutes in a water sample. Alkalinity, thus, consists of the sum of titratable carbonate and noncarbonate chemical species in a filtered sample. In most aqueous systems, alkalinity is controlled by carbonate chemistry and is mainly attributed to bicarbonate (HCO₃) ion, with lesser contributions by carbonate (CO₃) and hydroxide (OH) ions.

2. Sample fraction: Alkalinity (CaCO₃) was measured from filtered water samples.

3. Measurement units: Alkalinity is reported in milligrams per liter (mg/L) as CaCO₃.

4. Field or lab measurement: Alkalinity concentrations were determined in the field.

5. Value type: Actual

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 500-mL polyethylene bottle and tightly capped without headspace. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity). Sample bottles previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water.

7. Description of sample transport/preservation: Samples were stored on ice in an insulated container and transported by backpack from the collection sites to an ice filled cooler in a field vehicle at the trailhead. Prior to titration the samples were transferred to a refrigerator. Samples were titrated on the evening of their collection at field technicians’ lodging usually within 5 or 6 hours of sample collection. Samples were allowed to equilibrate to room temperature before titration.

8. Lab analytical method/procedure name, source citation, and ID: Alkalinity measurement procedures were followed according to the NFM, chapter A6, section 6.6 (U.S. Geological Survey, 1998).

9. Name and model number of field equipment: Hach Digital Titrator, Model 16900-01.

10. Maximum and minimum quantification limits for the method or procedure: This method is suitable for water containing alkalinity regardless of concentration; however, if the Hach Digital Titrator is used with 0.16 N sulfuric acid solution, as was done for this study, the minimum quantification limit is 1 mg/L.

11. Method/procedure detection limit: The current long-term method detection limit for alkalinity determined at the USGS NWQL is 1 mg/L.

Calcium

1. Parameter name: Calcium (calcium as Ca).

2. Sample fraction: Calcium analyses are performed on filtered water samples.

3. Measurement units: Calcium concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of calcium concentrations was conducted at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) in Lakewood, Colorado.

5. Value type: Actual.

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 250-mL polyethylene, acid-rinsed bottle. The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity).

7. Description of sample transport/preservation: After collection, the sample was acidified with nitric acid (HNO₃) to a pH of less than 2. The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Schedule 2750: Major Ions; Lab code 659: Calcium, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water containing from 0.01 to 25 mg/L of calcium for water that has a measured specific conductance of less than 2,000 µS/cm. Samples containing analyte concentrations greater than the maximum concentration limit can be analyzed for calcium if the sample is diluted, and if after dilution the specific conductance is less than 2,000 µS/cm.

10. Method/procedure detection limit: At the time of this study, the long-term method detection limit (LT-MDL) for calcium was 0.01 mg/L. The reporting level (RL) was 0.02 mg/L.

Magnesium

1. Parameter name: Magnesium (magnesium as Mg).

2. Sample fraction: Magnesium analyses are performed on filtered water samples.

3. Measurement units: Magnesium concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of magnesium concentrations was analyzed at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Schedule 2750: Major Ions; Lab code 663: Magnesium, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water containing from 0.004 to 5 mg/L of magnesium for water that has a measured specific conductance of less than 2,000 µS/cm. Samples containing analyte concentrations greater than the maximum concentration limit can be analyzed for magnesium if the sample is diluted, and if after dilution the specific conductance is less than 2,000 µS/cm.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for magnesium was 0.004 mg/L. The reporting level (RL) was 0.008 mg/L.

Potassium

1. Parameter name: Potassium (potassium as K).

2. Sample fraction: Potassium analyses are performed on filtered water samples.

3. Measurement units: Potassium concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of potassium was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

7. Description of sample transport/preservation: After collection, the sample was acidified with nitric acid (HNO₃) to a pH of less than 2. The bottle was packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Schedule 2750: Major Ions; Lab code 2773: Potassium, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze atmospheric precipitation, water, brines, and water-suspended sediment. The analytical ranges for potassium are from 0.08 to 10 mg/L. Sample solutions containing potassium concentrations greater than 10 mg/L need to be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for potassium was 0.08 mg/L. The reporting level (RL) was 0.16 mg/L.

Sodium

1. Parameter name: Sodium (sodium as Na).

2. Sample fraction: Sodium analyses are performed on filtered water samples.

3. Measurement units: Sodium concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of sodium was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Schedule 2750: Major Ions; Lab code 675: Sodium, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water containing from 0.10 to 50 mg/L sodium for water that has a measured specific conductance of less than 2,000 µS/cm. Samples containing analyte concentrations greater than the maximum concentration limit can be analyzed for sodium if the sample is diluted and if after dilution the specific conductance is less than 2,000 µS/cm.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for sodium was 0.10 mg/L. The reporting level (RL) was 0.20 mg/L.

Bromide

1. Parameter name: Bromide (bromide as Br)

2. Sample fraction: Bromide analyses are performed on filtered water samples.

3. Measurement units: Bromide concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of bromide was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 250-mL polyethylene bottle. The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity).

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-2057-85, Schedule 2750: Major Ions; Lab code 3166: Bromide, using ion chromatography.

9. Maximum and minimum quantification limits for the method or procedure: The analytical range for this procedure is 0.02 to 0.4 mg/L. Concentrations greater than 0.4 mg/L must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for bromide was 0.01 mg/L. The reporting level (RL) was 0.02 mg/L.

Chloride

1. Parameter name: Chloride (chloride as Cl).

2. Sample fraction: Chloride analyses are performed on filtered water samples.

3. Measurement units: Chloride concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of chloride was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-205785, Schedule 2750: Major Ions; Lab code 1571: Chloride, using ion chromatography (Fishman and Friedman, 1989).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to analyze most samples of water, wastewater, and brines containing from 0.10 to 50 mg/L chloride. Concentrations greater than 50 mg/L must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for chloride was 0.10 mg/L. The reporting level (RL) was 0.20 mg/L.

Fluoride

1. Parameter name: Fluoride (fluoride as Fl).

2. Sample fraction: Fluoride analyses are performed on filtered water samples.

3. Measurement units: Fluoride concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of fluoride was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 250-mL polyethylene bottle. The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity).

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-232785, Schedule 2750: Major Ions; Lab code 31: Fluoride, using colorimetry, electrometric, ion-selective electrode, automated-segmented flow (Fishman and Friedman, 1989).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water and water-suspended sediment containing from 0.05 to 3.0 mg/L of fluoride with specific conductivities less than 20,000 µS/cm.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for fluoride was 0.05 mg/L. The reporting level (RL) was 0.10 mg/L.

Iodide

1. Parameter name: Iodide (iodide as I).

2. Sample fraction: Iodide analyses are performed on filtered water samples.

3. Measurement units: Iodide concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of iodide was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-237189, Lab code 1202: Iodide, using colorimetry, automated-segmented flow, ceric-arsenious (Fishman and Friedman, 1989).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to determine iodide in fresh water and brines containing from 0.001 to 0.060 mg/L of iodide. Greater concentrations need to be reduced by dilution.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for iodide was 0.001 mg/L. The reporting level (RL) was 0.002 mg/L.

Silica

1. Parameter name: Silica as silica dioxide (silica as SiO₂).

2. Sample fraction: Silica analyses are performed on filtered water samples.

3. Measurement units: Silica concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of silica was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 250-mL polyethylene, acid-rinsed bottle. The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity).

7. Description of sample transport/preservation: After collection, the sample was acidified with nitric acid (HNO₃) to a pH of less than 2. The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Schedule 2750: Major Ions; Lab code 667, Silica, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water containing from 0.01 to 100 mg/L of silica for water that has a measured specific conductance of less than 2,000 µS/cm. Samples containing analyte concentrations greater than the maximum concentration limit can be analyzed for silica if the sample is diluted, and if after dilution the specific conductance is less than 2,000 µS/cm.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for silica was 0.02 mg/L. The reporting level (RL) was 0.04 mg/L.

Sulfate

1. Parameter name: Sulfate (sulfate as SO₄).

2. Sample fraction: Sulfate analyses are performed on filtered water samples.

3. Measurement units: Sulfate concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of sulfate was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-205785, Schedule 2750: Major Ions; Lab code 1572: Sulfate, using ion chromatography (Fishman and Friedman, 1989).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to analyze most samples of water, wastewater, and brines containing from 0.09 to 100 mg/L sulfate. Concentrations greater than 100 mg/L must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for sulfate was 0.09 mg/L. The reporting level (RL) was 0.18 mg/L.

Residue on Evaporation (ROE) at 180°C

1. Parameter name: Residue on evaporation (total dissolved solids).

2. Sample fraction: ROE analyses are performed on filtered water samples.

3. Measurement units: ROE concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of ROE was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-175089, Schedule 2750: Major Ions; Lab code 27: ROE, gravimetric (Fishman and Friedman, 1989).

9. Maximum and minimum quantification limits for the method or procedure: The residue-on-evaporation method is applicable to all water regardless of concentration, provided that the residue layer in the evaporation dish is kept sufficiently thin.

10. Method/procedure detection level: At the time of this study, the long-term method detection level was residue on evaporation was 10 mg/L. At the time of this study, the reporting level (RL) was 10 mg/L.

Ammonia

1. Parameter name: Ammonia (ammonia as N).

2. Sample fraction: Ammonia as nitrogen analyses are performed on filtered water samples.

3. Measurement units: Ammonia as nitrogen concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of ammonia as nitrogen was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

6. Description of sample preparation procedure: Sample water was syringe filtered through a disposable 0.45-micron pore disk filter into a 125-mL brown polyethylene bottle. The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with filtered sample water. (At Superintendent’s Spring, USGS Site ID 362856121103801 and Chalone Bridge Spring, USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity).

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, with ice (in order to maintain a temperature of 4°C), for prompt shipment to the NWQL.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-2522-90, I-2525-89; Lab Schedule 318: Nutrients, Lab code 3116, ammonia as nitrogen, using colorimetry, DA, salicylate-hypochlorite (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to analyze samples of surface, domestic, and industrial water, and brines containing from 0.01 to 1.5 mg/L of ammonia-nitrogen. Greater concentrations must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for ammonia as nitrogen was 0.005 mg/L. The reporting level (RL) was 0.010 mg/L.

Nitrite + Nitrate

1. Parameter name: Nitrite + nitrate (nitrite + nitrate, as N).

2. Sample fraction: Nitrite + nitrate as nitrogen analyses are performed on filtered water samples.

3. Measurement units: Nitrite + nitrate as nitrogen concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of nitrite + nitrate as nitrogen was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Calculated.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-254590; Lab Schedule 318: Nutrients, Lab code 1975, Nitrite + nitrate as nitrogen, using colorimetry, automated-segmented flow, cadmium reduction – diazotization (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to analyze samples of surface, domestic, and industrial water and brines containing from 0.1 to 5.0 mg/L of nitrite + nitrate-nitrogen.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for nitrite + nitrate (as N) was 0.030 mg/L. The reporting level (RL) was 0.060 mg/L.

Nitrite

1. Parameter name: Nitrite (nitrite as N).

2. Sample fraction: Nitrite as nitrogen analyses are performed on filtered water samples.

3. Measurement units: Nitrite as nitrogen concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of nitrite as nitrogen was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

8. Lab analytical method/procedure name, source citation, and ID: NWQL Methods I- 2540-90, I-2542-89; Lab Schedule 318: Nutrients, Lab code 3117, Nitrite as nitrogen, using colorimetry, DA (Fishman and Friedman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: These methods are used to analyze samples of precipitation or natural water containing from 0.001 to 1.0 mg/L of nitrite-nitrogen. Concentrations greater than 1.0 mg/L must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for nitrite (as N) was 0.001 mg/L. The reporting level (RL) was 0.002 mg/L.

Total Nitrogen

1. Parameter name: Total dissolved nitrogen (NO₂+NO₃+NH₃+organic nitrogen, as N)

2. Sample fraction: Total dissolved nitrogen analyses are performed on filtered water samples.

3. Measurement units: Total dissolved nitrogen concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of total dissolved nitrogen was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-265003; Lab code 2754, Total dissolved nitrogen, using alkaline persulfate digest (Patton and Kryskalla, 2003).

9. Maximum and minimum quantification limits for the method or procedure: The analytical range for this method is 0.03 to 5.00 mg/L. Greater concentrations must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for total dissolved nitrogen (as N) was 0.03 mg/L. The reporting level (RL) was 0.06 mg/L.

Orthophosphate

1. Parameter name: Orthophosphate as phosphorus (orthophosphate as P)

2. Sample fraction: Orthophosphate as phosphorus analyses are performed on filtered water samples.

3. Measurement units: Orthophosphate as phosphorus concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of Orthophosphate as phosphorus was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-2601-90 Lab Schedule 318; Lab code 3118, orthophosphate as phosphorus, using colorimetry, DA, phosphomolybdate (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to analyze most samples of water, wastewater, and brines containing from 0.01 to 1.0 mg/L of orthophosphate-phosphorus. Concentrations greater than 1.0 mg/L must be diluted.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for total dissolved orthophosphate (as P) was 0.003 mg/L. The reporting level (RL) was 0.006 mg/L.

Phosphorus

1. Parameter name: Phosphorus (phosphorus as P)

2. Sample fraction: Phosphorus analyses are performed on filtered water samples.

3. Measurement units: Phosphorus concentrations are reported in milligrams per liter (mg/L).

4. Field or lab measurement: Measurement of concentrations of phosphorus was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-2610-99; Lab Schedule 318; Lab code 1983, phosphorus, using colorimetry, automated-segmented flow, Microkjeldahl Digestion (Patton and Truitt, 1992).

9. Maximum and minimum quantification limits for the method or procedure: This method is used to determine total phosphorus in water, wastewater, brines, and water-suspended sediment. The analytical range of this method is 0.01 to 2.00 mg/L of phosphorus.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for phosphorus (as P) was 0.02 mg/L. The reporting Level (RL) was 0.04 mg/L.

Aluminum

1. Parameter name: Aluminum (aluminum as Al).

2. Sample fraction: Aluminum analyses are performed on filtered water samples.

3. Measurement units: Aluminum concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of aluminum concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1784: Aluminum, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for aluminum analysis by the ICP-MS method is 2,500 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for aluminum was 0.8 µg/L. The reporting level (RL) was 1.6 µg/L.

Antimony

1. Parameter name: Antimony (antimony as Sb).

2. Sample fraction: Antimony analyses are performed on filtered water samples.

3. Measurement units: Antimony concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of antimony concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1785: Aluminum, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for antimony analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for antimony was 0.1 µg/L. The reporting level (RL) was 0.2 µg/L.

Arsenic

1. Parameter name: Arsenic (arsenic as As).

2. Sample fraction: Arsenic analyses are performed on filtered water samples.

3. Measurement units: Arsenic concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of arsenic concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3122: Arsenic, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for arsenic analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for arsenic was 0.06 µg/L. The reporting level (RL) was 0.12 µg/L.

Barium

1. Parameter name: Barium (barium as Ba).

2. Sample fraction: Barium analyses are performed on filtered water samples.

3. Measurement units: Barium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of barium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1786: Barium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for barium analysis by the ICP-MS method is 2,500 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for barium was 0.1 µg/L. The reporting level (RL) was 0.2 µg/L.

Beryllium

1. Parameter name: Beryllium (beryllium as Be).

2. Sample fraction: Beryllium analyses are performed on filtered water samples.

3. Measurement units: Beryllium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of beryllium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1787: Beryllium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for beryllium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for beryllium was 0.03 µg/L. The reporting level (RL) was 0.06 µg/L.

Boron

1. Parameter name: Boron (boron as B).

2. Sample fraction: Boron analyses are performed on filtered water samples.

3. Measurement units: Boron concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of boron concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 2504: Boron, using inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino, 1999).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for boron analysis by the ICP-MS method is 1,000 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for boron was 4 µg/L. The reporting level (RL) was 8 µg/L.

Cadmium

1. Parameter name: Cadmium (cadmium as Cd).

2. Sample fraction: Cadmium analyses are performed on filtered water samples.

3. Measurement units: Cadmium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of cadmium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1788: Cadmium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for cadmium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for cadmium was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Chromium

1. Parameter name: Chromium (chromium as Cr).

2. Sample fraction: Chromium analyses are performed on filtered water samples.

3. Measurement units: Chromium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of chromium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3126: Chromium, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for chromium analysis by the ICP-MS method is 100 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for chromium was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Cobalt

1. Parameter name: Cobalt (cobalt as Co).

2. Sample fraction: Cobalt analyses are performed on filtered water samples.

3. Measurement units: Cobalt concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of cobalt concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3124: Cobalt, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for cobalt analysis by the ICP-MS method is 100 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for cobalt was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Copper

1. Parameter name: Copper (copper as Cu).

2. Sample fraction: Copper analyses are performed on filtered water samples.

3. Measurement units: Copper concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of copper concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3128: Copper, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for copper analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for copper was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Iron

1. Parameter name: Iron (iron as Fe).

2. Sample fraction: Iron analyses are performed on filtered water samples.

3. Measurement units: Iron concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of iron concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-147287, Lab Schedule 2750, Lab code 645: Iron, using inductively coupled plasma (ICP), atomic emission spectrometry (Fishman, 1993).

9. Maximum and minimum quantification limits for the method or procedure: This method may be used to analyze water containing from 5 to 10,000 µg/L of iron for water that has a measured specific conductance of less than 2,000 µS/cm. Iron also can be determined after appropriate dilution in samples that have a measured specific conductance greater than 2,000 µS/cm; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for iron was 3 µg/L. The reporting level (RL) was 6 µg/L.

Lead

1. Parameter name: Lead (lead as Pb).

2. Sample fraction: Lead analyses are performed on filtered water samples.

3. Measurement units: Lead concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of lead concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1792: Lead, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for lead analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for lead was 0.04 µg/L. The reporting level (RL) was 0.08 µg/L.

Lithium

1. Parameter name: Lithium (lithium as Li).

2. Sample fraction: Lithium analyses are performed on filtered water samples.

3. Measurement units: Lithium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of lithium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 2505: Lithium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for lithium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for lithium was 0.3 µg/L. The reporting level (RL) was 0.6 µg/L.

Manganese

1. Parameter name: Manganese (manganese as Mn).

2. Sample fraction: Manganese analyses are performed on filtered water samples.

3. Measurement units: Manganese concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of manganese concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1793: Manganese, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for manganese analysis by the ICP-MS method is 2,500 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for manganese was 0.1 µg/L. The reporting level (RL) was 0.2 µg/L.

Molybdenum

1. Parameter name: Molybdenum (molybdenum as Mo).

2. Sample fraction: Molybdenum analyses are performed on filtered water samples.

3. Measurement units: Molybdenum concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of molybdenum concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1794: Molybdenum, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for molybdenum analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm, the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for molybdenum was 0.2 µg/L. The reporting level (RL) was 0.4 µg/L.

Nickel

1. Parameter name: Nickel (nickel as Ni).

2. Sample fraction: Nickel analyses are performed on filtered water samples.

3. Measurement units: Nickel concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of nickel concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3130: Nickel, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for nickel analysis by the ICP-MS method is 100 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm, the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for nickel was 0.03 µg/L. The reporting level (RL) was 0.06 µg/L.

Selenium

1. Parameter name: Selenium (selenium as Se).

2. Sample fraction: Selenium analyses are performed on filtered water samples.

3. Measurement units: Selenium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of selenium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3132: Selenium, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for selenium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for selenium was 0.04 µg/L. The reporting level (RL) was 0.08 µg/L.

Silver

1. Parameter name: Silver (silver as Ag).

2. Sample fraction: Silver analyses are performed on filtered water samples.

3. Measurement units: Silver concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of silver concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1796: Silver, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for silver analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for silver was 0.1 µg/L. The reporting level (RL) was 0.20 µg/L.

Strontium

1. Parameter name: Strontium (strontium as Sr).

2. Sample fraction: Strontium analyses are performed on filtered water samples.

3. Measurement units: Strontium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of strontium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 2507: Strontium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino, 1999).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for strontium analysis by the ICP-MS method is 2,500 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm, the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for strontium was 0.2 µg/L. The reporting level (RL) was 0.4 µg/L.

Thallium

1. Parameter name: Thallium (thallium as Tl).

2. Sample fraction: Thallium analyses are performed on filtered water samples.

3. Measurement units: Thallium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of thallium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 2508: Thallium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino, 1999).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for thallium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm, the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for thallium was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Uranium, natural

1. Parameter name: Uranium, natural (uranium as U).

2. Sample fraction: Uranium analyses are performed on filtered water samples.

3. Measurement units: Uranium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of uranium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-247792, Schedule 2710: Trace elements; Lab code 1797: Uranium, using inductively coupled plasma (ICP), mass spectrometry (MS) (Faires, 1993).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for uranium analysis by the ICP-MS method is 250 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for uranium was 0.02 µg/L. The reporting level (RL) was 0.04 µg/L.

Vanadium

1. Parameter name: Vanadium (vanadium as V).

2. Sample fraction: Vanadium analyses are performed on filtered water samples.

3. Measurement units: Vanadium concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of vanadium concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3134: vanadium, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for vanadium analysis by the ICP-MS method is 100 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for vanadium was 0.05 µg/L. The reporting level (RL) was 0.10 µg/L.

Zinc

1. Parameter name: Zinc (zinc as Zn).

2. Sample fraction: Zinc analyses are performed on filtered water samples.

3. Measurement units: Zinc concentrations are reported in micrograms per liter (µg/L).

4. Field or lab measurement: Measurement of zinc concentrations was conducted at the USGS NWQL in Lakewood, Colorado.

5. Value type: Actual.

8. Lab analytical method/procedure name, source citation, and ID: NWQL Method I-202005, Schedule 2710: Trace elements; Lab code 3138: Zinc, using collision/reaction cell inductively coupled plasma (ICP), mass spectrometry (MS) (Garbarino and others, 2006).

9. Maximum and minimum quantification limits for the method or procedure: The upper calibration limit for zinc analysis by the ICP-MS method is 1,000 µg/L for samples with specific conductance less than 2,500 µS/cm. If the specific conductance of the sample is greater than 2,500 µS/cm the sample must be diluted; however, detection levels and sensitivity will change proportionally.

10. Method/procedure detection level: At the time of this study, the long-term method detection level (LT-MDL) for zinc was 0.3 µg/L. The reporting level (RL) was 0.6 µg/L.

Deuterium/Protium Ratio

1. Parameter name: Deuterium/protium ratio (²H/¹H)

2. Sample fraction: Deuterium/protium ratio analyses are performed on unfiltered water samples, except for two samples (listed in Item 6 below).

3. Measurement units: Deuterium/protium ratios are reported in per mil (indicates parts deuterium per thousand parts protium; δ²H/δ¹H), relative to Vienna Standard Mean Ocean Water.

4. Field or lab measurement: Measurement of deuterium/protium ratios was conducted at the USGS Reston Stable Isotope Laboratory in Reston, Virginia.

5. Value type: Actual.

6. Description of sample preparation procedure: Unfiltered sample water was collected into a 60-mL glass bottle with a polyseal cap. (At Superintendent’s Spring-USGS Site ID 362856121103801 and Chalone Bridge Spring-USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity). Samples were allowed to overflow the bottle, and then part of the sample was discarded to provide headspace in the bottle. Bottles were not field rinsed.

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to USGS Reston, Virginia, Isotope Lab.

8. Lab analytical method/procedure name, source citation, and ID: Lab Schedule 1142; Lab Code 1574: deuterium/protium ratio, using mass spectrometry (Revesz and Coplen, 2003a).

9. Maximum and minimum quantification limits for the method or procedure: Not applicable.

10. Method/procedure detection level: The 2-sigma uncertainty of hydrogen isotopic results is 2 per mil. This means that if the same sample were resubmitted for isotopic analysis, the newly measured value would lay within the uncertainty bounds 95 percent of the time.

Oxygen-18/Oxygen-16 Ratio

1. Parameter name: Oxygen-18/oxygen-16 ratio (¹⁸O/¹⁶O)

2. Sample fraction: Oxygen-18/oxygen-16 ratio analyses are performed on unfiltered water samples, except for two samples (listed in Item 6 below).

3. Measurement units: Oxygen-18/oxygen-16 ratios are reported in per mil (indicates parts oxygen-18 per thousand parts oxygen-16; δ¹⁸O/δ¹⁶O), relative to Vienna Standard Mean Ocean Water.

4. Field or lab measurement: Measurement of oxygen-18/oxygen-16 ratios was conducted at the USGS Reston Stable Isotope Laboratory in Reston, Virginia.

5. Value type: Actual.

6. Description of sample preparation procedure: Unfiltered sample water was collected into a 60-mL glass bottle with a polyseal cap. (At Superintendent’s Spring-USGS Site ID 362856121103801 and Chalone Bridge Spring-USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity). Samples were allowed to overflow the bottle, and then part of the sample was discarded to provide headspace in the bottle. Bottles were not field rinsed.

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to USGS Reston, Virginia, Isotope Lab.

8. Lab analytical method/procedure name, source citation, and ID: Lab Schedule 1142; Lab Code 489: oxygen-18/oxygen-16 ratio, using mass spectrometry (Revesz and Coplen, 2003b).

9. Maximum and minimum quantification limits for the method or procedure: Not applicable.

10. Method/procedure detection level: The 2-sigma uncertainty of oxygen isotopic results is 0.2 per mil. This means that if the same sample were resubmitted for isotopic analysis, the newly measured value would lay within the uncertainty bounds 95 percent of the time.

Tritium

1. Parameter name: Tritium (³H) (tritium in water molecules)

2. Sample fraction: Tritium analyses are performed on unfiltered water samples, except for at the two sample sites listed in Item 6 below.

3. Measurement units: Tritium is reported in picocuries per liter (pCi/L).

4. Field or lab measurement: Measurement of tritium concentrations was conducted at the University of Miami, Tritium Laboratory, Miami, Florida.

5. Value type: Actual.

6. Description of sample preparation procedure: Unfiltered sample water was collected into a 1L polyethylene bottle with a Polyseal cap. (At Superintendent’s Spring-USGS Site ID 362856121103801 and Chalone Bridge Spring-USGS Site ID 362912121101101—disposable 0.45-micron pore capsule filters were used due to excess turbidity). The bottle previously had been lab-rinsed with distilled water and transported to the field half filled with distilled water. In the field, the bottle was emptied and then rinsed once with unfiltered sample water. Samples were allowed to overflow the bottle, and part of the sample was discarded to provide headspace in the bottle.

7. Description of sample transport/preservation: The bottle was sealed in a plastic bag and packed into a cooler, without ice, for shipment to the University of Miami, Tritium Laboratory.

8. Lab analytical method/procedure name, source citation, and ID: Lab Code 1043: Tritium, by electrolytic enrichment and gas counting (Östlund, 1987).

9. Maximum and minimum quantification limits for the method or procedure: The limit of detection for tritium is 0.1 TU (tritium units—1TU = 3.19 pCi/L).

10. Method/procedure detection level: At the time of this study, the reporting level (RL) for tritium was 0.300 pCi/L.

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