HYDROGEOCHEMISTRY
In recent years, advances in analytical technology have allowed hydrogeochemical surveys to become a very powerful exploration technique.
The high-resolution method Actlabs has developed has become the new benchmark in exploring for gold, base metals, uranium, REE and other metals using water. Actlabs is unique in that we are the only commercial lab in the world serving the mineral industry with this Technology.
The conventional method of preservation of water for analysis is 0.2% (2 mL/L) of concentrated ultra-pure nitric acid for inorganic parameters. This may be inadequate in alkaline environments. The acid should be added only after the sample has been collected, and not as pre-charged acid in bottles which may leach metals from the bottle. When filling the bottle, it should be rinsed with the sample water twice before retaining the sample. It should then be acidified. A test of pH using pH paper will indicate if the pH after acidification is adequate (pH 2). Depending on the sample composition, preservation with nitric may invalidate Ag, As, Br and I analyses. Preservation with acetic acid should be used in that case; however, acetic acid can invalidate results for Cr. Some customers do not add any stabilizing agents, since this has the potential for adding trace contaminants to the samples and causing analytical problems. A study conducted by the Geological Survey of Canada (GSC) has indicated that low cost, high-density screw cap polyethylene bottles (rinsed with water) are best. We require 30 mL of water for analysis for inorganic parameters. Conventional wisdom recommends storage at 4ºC. Studies by the GSC indicate that this may not be necessary where samples are acidified < pH 2. Do not freeze water as it will cause precipitation of some elements. Samples should be shipped to the lab as soon as possible for analysis. Stability tests indicate most samples are stable for at least 30 days and can be stable for a year or more (British Columbia Geological Survey) even when stored at room temperature. Gold unfortunately is not stable and will be adsorbed onto the sides of the bottle within a short period of time (hours). Addition of activated charcoal sachets can collect the gold which can then be analyzed by INAA. Further information is available from Actlabs on request. Code 6 HR-ICP/MS method removes these metals from the plastic bottle and puts it back into solution for analysis directly by HR-ICP/MS. For hydrogeochemical samples being analyzed by ICP-MS or by Ion Chromatography, please include TDS/conductivity measurements if available.
Samples must be acidified prior to analysis. Water samples are analyzed by Perkin Elmer Sciex ELAN 9000 ICP/MS, Perkin Elmer Nexion, Thermo icapQ or Agilent 7700. A blank and two water standards are run at the beginning and end of each group of 32 samples. A reagent blank is run at the beginning of the group and every 10th sample is run in duplicate. If instrument suppression occurs, sample(s) affected are re-run at appropriate dilutions until response is normal. Dilution factors will increase by the same factor that samples were diluted.
For analysis of marine waters or brines, detection limits will be correspondingly elevated depending on the dilution necessary to run the water samples.
If % RSDs are required, choose option Code 6 EXPER (detection limits listed below) for 1-4 elements only.
Elements and Detection Limits (µg/L)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Ag | 0.2 | 5,000 |
| Al | 2 | 100,000 |
| As | 0.03 | 5000 |
| Ba | 0.1 | 5000 |
| Be | 0.1 | 5000 |
| Bi | 0.3 | 2,000 |
| Ca | 700 | 200,000 |
| Cd | 0.01 | 5000 |
| Ce | 0.001 | 5000 |
| Co | 0.005 | 5000 |
| Cr | 0.5 | 5000 |
| Cs | 0.001 | 5000 |
| Cu | 0.2 | 5000 |
| Dy | 0.001 | 100 |
| Er | 0.001 | 100 |
| Eu | 0.001 | 100 |
| Fe | 10 | 50,000 |
| Ga | 0.01 | 2000 |
| Gd | 0.001 | 100 |
| Ge | 0.01 | 5000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Hf | 0.001 | 1000 |
| Hg | 0.2 | |
| Ho | 0.001 | 100 |
| In | 0.001 | 5000 |
| K | 30 | 200,000 |
| La | 0.001 | 5000 |
| Li | 1 | 5000 |
| Lu | 0.001 | 100 |
| Mg | 2 | 200,000 |
| Mn | 0.1 | 5000 |
| Mo | 0.1 | 5000 |
| Na | 5 | 100,000 |
| Nb | 0.005 | 5000 |
| Nd | 0.001 | 5000 |
| Ni | 0.3 | 5000 |
| Pb | 0.01 | 2000 |
| Pr | 0.001 | 5000 |
| Rb | 0.005 | 5000 |
| Sb | 0.01 | 5000 |
| Sc | 1 | 5,000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Se | 0.2 | 5000 |
| Si | 200 | 200,000 |
| Sm | 0.001 | 100 |
| Sn | 0.1 | 5000 |
| Sr | 0.04 | 5000 |
| Ta | 0.001 | 1000 |
| Tb | 0.001 | 1000 |
| Te | 0.1 | 5,000 |
| Th | 0.001 | 100 |
| Ti | 0.1 | 5000 |
| Tl | 0.001 | 5000 |
| Tm | 0.001 | 100 |
| U | 0.001 | 100 |
| V | 0.1 | 2000 |
| W | 0.02 | 1000 |
| Y | 0.003 | 5000 |
| Yb | 0.001 | 100 |
| Zn | 0.5 | 5000 |
| Zr | 0.01 | 5000 |
6 ICP-MS options:
6 Hg (Hg on a separate sample)
| Element | Detection Limit ( ng/L ) |
|---|---|
| Hg | 6 |
6 B (Boron Add-On)
| Element | Detection Limit ( µg/L ) |
|---|---|
| B | 3 |
6 EXPER Elements and Detection Limits (µg/L)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Ag | 0.2 | 2,000 |
| Al | 2 | 2,000 |
| As | 0.03 | 200 |
| Au | 0.002 | - |
| B | 3 | - |
| Hf | 0.001 | 20 |
| Ho | 0.001 | 100 |
| I | 1 | 4,000 |
| In | 0.001 | 200 |
| Ir | 0.002 | - |
| Rh | 0.02 | - |
| Ru | 0.01 | - |
| Sb | 0.01 | 100 |
| Sc | 1 | 20,000 |
| Se | 0.2 | 250 |
6 ICP-MS-Exper proposed Elements and Detection Limits (µg/L)
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Ag | 0.2 | 5,000 |
| Al | 2 | 100,000 |
| As | 0.03 | 5000 |
| B | 3 | 5000 |
| Ba | 0.1 | 5000 |
| Be | 0.1 | 5000 |
| Bi | 0.3 | 2,000 |
| Ca | 700 | 200,000 |
| Cd | 0.01 | 5000 |
| Ce | 0.001 | 5000 |
| Co | 0.005 | 5000 |
| Cr | 0.5 | 5000 |
| Cs | 0.001 | 5000 |
| Cu | 0.2 | 5000 |
| Dy | 0.001 | 100 |
| Er | 0.001 | 100 |
| Eu | 0.001 | 100 |
| Fe | 10 | 50,000 |
| Ga | 0.01 | 2000 |
| Gd | 0.001 | 100 |
| Ge | 0.01 | 5000 |
| Element | Detection Limit | Upper Limit |
|---|---|---|
| Se | 0.2 | 5000 |
| Si | 200 | 200,000 |
| Sm | 0.001 | 100 |
| Sn | 0.1 | 5000 |
| Sr | 0.04 | 5000 |
| Ta | 0.001 | 1000 |
| Tb | 0.001 | 1000 |
| Te | 0.1 | 5,000 |
| Th | 0.001 | 100 |
| Ti | 0.1 | 5000 |
| Tl | 0.001 | 5000 |
| Tm | 0.001 | 100 |
| U | 0.001 | 200 |
| V | 0.1 | 2000 |
| W | 0.02 | 1000 |
| Y | 0.003 | 5000 |
| Yb | 0.001 | 100 |
| Zn | 0.5 | 5000 |
| Zr | 0.01 | 5000 |
Our research activities over the last few years have allowed us to link the capillary electrophoresis and HPLC techniques to conventional ICP/MS or High Resolution ICP/MS. Using as little as 5 µg/L of solution, we can conveniently speciate a number of metals for their inorganic or organic metal species. This allows determination of a number of metal species sequentially. ACTLABS can consult on the best ways to preserve samples for speciation analysis.
- Pore Water Extraction (from sediment core)
- As speciation (As3+, As5+, MMA, DMA)
- Sn speciation (Tripropylpentyl; Tributylpentyl; Dibutyldipentyl; Monobutyl,tripentyl; Monophenyl,tripentyl; Diphenyl,tripentyl;
- Triphenyl,tripentyl)
- Fe Speciation (Fe3+, Fe2+)
- Se Speciation (Se6+, Se4+, Se-Methionine, Se-Cystine)
- Cr Speciation (Cr3+, Cr6+)
Note – Minimum of 10 samples
Samples must be preserved with AR. Water samples are analyzed using a High Resolution Magnetic Sector ICP-MS (Finnegan Mat ELEMENT 2).
6 Au HR-ICP-MS Elements and Detection Limits (ng/L)
| Element | Detection Limit |
|---|---|
| Au | 0.1 |
Samples must be acidified prior to analysis. Water samples are analyzed using a High Resolution Magnetic Sector ICP-MS (Finnegan Mat ELEMENT 2). A blank and two water standards are run at the beginning and end of each group of 32 samples. A reagent blank is run at the beginning of the group and every 10th sample is run in duplicate. If instrument suppression occurs, sample(s) affected are re-run at appropriate dilutions until response is normal. Dilution factors will increase by the same factor that samples were diluted.
Elements and Detection Limits (µg/L)
| Element | Detection Limit |
|---|---|
| Ag | 0.002 |
| Al | 0.5 |
| As | 0.02 |
| B | 0.1 |
| Ba | 0.01 |
| Be | 0.001 |
| Bi | 0.001 |
| Ca | 5 |
| Cd | 0.001 |
| Ce | 0.001 |
| Co | 0.001 |
| Cr | 0.01 |
| Cs | 0.001 |
| Cu | 0.05 |
| Dy | 0.0005 |
| Er | 0.00005 |
| Eu | 0.00005 |
| Fe | 1 |
| Ga | 0.001 |
| Gd | 0.00005 |
| Element | Detection Limit |
|---|---|
| Ge | 0.001 |
| Hf | 0.0005 |
| Hg | 0.05 |
| Ho | 0.0001 |
| In | 0.0001 |
| K | 1 |
| La | 0.001 |
| Li | 0.05 |
| Lu | 0.00005 |
| Mg | 0.2 |
| Mn | 0.05 |
| Mo | 0.005 |
| Na | 5 |
| Nb | 0.0001 |
| Nd | 0.0001 |
| Ni | 0.05 |
| Pb | 0.005 |
| Pr | 0.00005 |
| Rb | 0.005 |
| Re | 0.0001 |
| Element | Detection Limit |
|---|---|
| Sb | 0.001 |
| Sc | 0.01 |
| Se | 5 |
| Sm | 0.005 |
| Sn | 0.01 |
| Sr | 0.01 |
| Ta | 0.0005 |
| Tb | 0.00002 |
| Te | 0.001 |
| Th | 0.00002 |
| Ti | 0.01 |
| Tl | 0.0001 |
| Tm | 0.0001 |
| U | 0.0001 |
| V | 0.001 |
| W | 0.001 |
| Y | 0.0005 |
| Yb | 0.00005 |
| Zn | 0.5 |
| Zr | 0.001 |
Water samples are analyzed using ICP-OES (Agilent Axial 730-ES) for the 36 element suite.
Elements and Detection Limits (µg/L)
| Element | Detection Limit |
|---|---|
| Ag | 5 |
| Al | 0.1 mg/L |
| As | 30 |
| Ba | 20 |
| Be | 2 |
| Bi | 20 |
| Ca | 0.1 mg/L |
| Cd | 2 |
| Ce | 30 |
| Co | 2 |
| Cr | 20 |
| Cu | 2 |
| Element | Detection Limit |
|---|---|
| Fe | 0.01 mg/L |
| K | 0.1 mg/L |
| Li | 0.05 mg/L |
| Mg | 0.1 mg/L |
| Mn | 0.01 mg/L |
| Mo | 5 |
| Na | 0.1 mg/L |
| Ni | 5 |
| P | 0.02 mg/L |
| Pb | 10 |
| S | 1 mg/L |
| Sb | 10 |
| Element | Detection Limit |
|---|---|
| Se | 20 |
| Si | 0.1 mg/L |
| Sn | 10 |
| Sr | 10 |
| Te | 10 |
| Ti | 10 |
| Tl | 10 |
| U | 0.05 mg/L |
| V | 10 |
| W | 10 |
| Y | 10 |
| Zn | 5 |
Water samples are analyzed using a High Resolution Magnetic Sector ICP-MS (Finnegan Mat ELEMENT 2).
Elements and Detection Limits (ng/L)
| Element | Detection Limit |
|---|---|
| Au | 0.1 |
| Ir | 1 |
| Pd | 1 |
| Pt | 0.5 |
| Rh | 0.5 |
| Ru | 3 µg/L |
Un-acidified water samples are analyzed using the DIONEX DX-120 Ion Chromatography System to determine and quantify a group of seven anions. This analysis is applicable to concentrations less than 75 mg/L for Cl, NO2 and NO3; less than 50 mg/L for F; less than 125 mg/L for PO4; less than 250 mg/L for Br and less than 375 mg/L for SO4. Samples exceeding this range (with high total dissolved solids) must be diluted to avoid over-saturation. Measurement uncertainty is evaluated and controlled by an appropriate quality assurance program, including the use of regular laboratory duplicates of samples and verification of the precision/calibration of the instrument through regular runs of various primary dilution standard solutions
Ion Chromatography
| Anion | Detection Limit (mg/L) |
|---|---|
| Fluoride (F) | 0.01 |
| Chloride (Cl) | 0.03 |
| Bromide (Br) | 0.03 |
| Nitrite (NO2 ) | 0.01 |
| Nitrate (NO3 ) | 0.01 |
| Phosphate (PO4 ) | 0.02 |
| Sulphate (SO4 ) | 0.03 |
Reference:
EPA Method 300.0
Analysis and Reporting Limits
| Analysis | Method | Reference | Reporting Limit |
|---|---|---|---|
| Acidity | Titrimetry | EPA 305.2 | 10 mg/L CaCO3 |
| Alkalinity (CaCO3) Includes: Carbonate (CO32-), Bicarbonate (HCO32-) | Titrimetry | AOAC 11.1.05 | 2 mg/L CaCO3 |
| NH3 + NH4 | ISE | SM 4500-ammonia | 0.02 mg/L NH3 0.01 mg/L NH4 |
| Bi214 | Detector | 0.1 Bq/L | |
| Bisphenol A (BPA) | Organics (GC/MS) | 1 µg/L | |
| BTEX | Organics (GC/MS) | 0.25-0.97 µg/L | |
| Cyanide (SAD CN) | Analyzer | 0.15 µg/L | |
| Cyanide (Weak Acid Dissociable - WAD CN) | SKALAR automated analyzer | 0.8 µg/L | |
| Cyanide (Free CN) | SKALAR automated analyzer | 0.8 µg/L | |
| Cyanide (Total CN) | SKALAR automated analyzer | 0.8 µg/L | |
| Colour | Colour | 1 – 500 | |
| Conductivity | ISE | 0.01 µS | |
| Dissolved Oxygen (DO) | Analyzer | 0.01 mg/L | |
| DOC | Analyzer | 0.01 mg/L | |
| Glycols (Proplyene & Ethylene) | Organics (GC/FID) | 0.01% | |
| H2S | TITR | 0.1 mg/L | |
| Hardness | ICP/OES | mg/L CaCO3 | |
| Microbiology (E.coli, Total Coliforms, Fecal Coliforms, Heterotrophic Plate Count) | MF | > 0 | |
| Oil & Grease (Total) | GRAV | mg/L | |
| P | ICP/OES | > 0.02 mg/L | |
| Pb210 | Detector | 0.01 Bq/L | |
| Pb214 | Detector | 0.1 Bq/L | |
| PBB/PBDE | Organics (GC/MS) | 1 mg/g | |
| PCBs (Total) | Organics (GC/MS) | 1 µg/L | |
| pH | pH | > 0.1 pH units | |
| Phthalates | Organics (GC/MS) | 5 µg/L | |
| Polyaromatic Hydrocarbons (PAHs or PNAs - 16 compounds) | Organics (GC/MS) | 0.42-0.99 µg/L | |
| Ra226 | Detector | 0.005 Bq/L | |
| Salinity | SAL | > 2.00 g/L | |
| Silica | SP | 1 mg/L | |
| Sulphur (Elemental) | Organics (GC/MS) | 0.5 mg/kg | |
| Total Dissolved Solids (TDS) | ISE | ASTM | 0.01 mg/L |
| Total Dissolved Solids (TDS) | Gravimetric | Standard methods for the examination of Water and Wastewater | 2.5 mg/L |
| Total Suspended Solids (TSS) | Gravimetric | EPA 160.2 | 4 mg/L |
| Total Volatile Solids (TVS) | Gravimetric | 4 mg/L | |
| Total Kjeldahl Nitrogen (TKN) | Analyzer | 0.03 – 25 mg/L | |
| Total Organic Carbon (TOC) | Analyzer | 0.01 mg/L | |
| Total Petroleum Hydrocarbon (TPH) (gas/diesel) | Organics (GC/FID) | 0.5 mg/L | |
| Trihalomethanes | Organics (GC/MS) | 0.33-0.71 µg/L | |
| Turbidity | Turbidimetric | 0.1 – 10,000 NTU | |
| Water Density | GRAV | g/ml |
