Water Test Interpretation Mike Kizer OSU Extension Irrigation Specialist Ca ++ Na + Na + Cl - Cl - SO 4 = K + Mg ++ HCO 3 - CO 3 = NO 3 -

Measures of Water Quality Electrical Conductivity (EC)Electrical Conductivity (EC) Total Dissolved Solids (TDS)Total Dissolved Solids (TDS) Individual mineral concentrationsIndividual mineral concentrations Calculated salinity products (Hardness, SAR, Na%, etc.)Calculated salinity products (Hardness, SAR, Na%, etc.)

Electrical Conductivity (EC) Pure water is a poor conductor of electricityPure water is a poor conductor of electricity The more minerals dissolved in water, the more current it conductsThe more minerals dissolved in water, the more current it conducts EC is a good estimator of total mineral content (TSS)EC is a good estimator of total mineral content (TSS)

Units - EC mmho/cm = (millimho per centimeter)mmho/cm = (millimho per centimeter)   mho/cm = (micromho per centimeter) dS/m = (deciSiemen/meter)dS/m = (deciSiemen/meter) mS/cm = (milliSiemen per centimeter)mS/cm = (milliSiemen per centimeter) 1 mmho/cm = 1 dS/m = 1mS/cm1 mmho/cm = 1 dS/m = 1mS/cm 1 mmho/cm = 1000  mho/cm1 mmho/cm = 1000  mho/cm

Total Dissolved Solids (TDS) TDS is calculated by totaling all measured mineral concentrations as determined by chemical analysesTDS is calculated by totaling all measured mineral concentrations as determined by chemical analyses TSS is an estimate of TDS based on ECTSS is an estimate of TDS based on EC EC (mmho/cm) x 640  TSS mg/lEC (mmho/cm) x 640  TSS mg/l This equivalence is approximate and depends on the ions causing the salinityThis equivalence is approximate and depends on the ions causing the salinity

Units - TDS / TSS mg/l = milligrams/liter ppm = parts per million  g/l = micrograms/liter ppb = parts per billion 1 mg/l = 1 ppm in water chemistry (1 liter of water weighs 1,000,000 mg)1 mg/l = 1 ppm in water chemistry (1 liter of water weighs 1,000,000 mg) 1 mg/l = 1000  g /l1 mg/l = 1000  g /l 1  g /l = 1 ppb in water chemistry1  g /l = 1 ppb in water chemistry

SW&FAL Water Quality Tests The OSU Soil Water & Forage Analytical Laboratory (Room 048 Ag. Hall) offers three water tests: Livestock Water TestLivestock Water Test Household Water TestHousehold Water Test Irrigation Water TestIrrigation Water Test (All tests require a 1 pint water sample)

Livestock Water Test Price:$6.00Price:$6.00 Analytes:Analytes: pHpH Total Soluble Salts (TSS)Total Soluble Salts (TSS) Electrical Conductivity (EC)Electrical Conductivity (EC) Nitrate-Nitrogen (NO 3 -N)Nitrate-Nitrogen (NO 3 -N)

Livestock Water Quality Total Soluble Salts -TSS Livestock Water Quality Total Soluble Salts - TSS TSS (ppm)Interpretation Less than 1000: Excellent Less than 1000: Excellent 1000 – 3000: Satisfactory for all animals1000 – 3000: Satisfactory for all animals 3000 – 5000: Unsatisfactory for poultry3000 – 5000: Unsatisfactory for poultry 5000 – 7000: Can be used except for pregnant, lactating or immature livestock5000 – 7000: Can be used except for pregnant, lactating or immature livestock Over 10,000: Unsatisfactory for all animalsOver 10,000: Unsatisfactory for all animals

Livestock Water Quality Nitrate- Nitrogen –NO 3 -N Livestock Water Quality Nitrate- Nitrogen – NO 3 -N NO 3 -N (ppm)Interpretation Less than 100: Satisfactory for all animalsLess than 100: Satisfactory for all animals 100 – 290: Use with care when given in combination with high nitrate feeds (especially certain forages in times of drought)100 – 290: Use with care when given in combination with high nitrate feeds (especially certain forages in times of drought) Over 290: Unsatisfactory for all animalsOver 290: Unsatisfactory for all animals

Livestock Water Quality Sulfate (SO 4 )Sulfate (SO 4 ) –If most of the TSS are sulfates the acceptable TSS level is reduced because of scouring concerns –Polioencephalomalasia (PEM) is a nervous system disease in cattle caused by thiamine deficiency. High dietary sulfate has been linked to thiamine deficiency by research and case studies. pHpH –The preferred range is Animals can tolerate water outside this range, but some species may perform poorly.

Household Water Test Price:$15.00Price:$15.00 Analytes:Analytes: Sodium (Na)  Nitrate-Nitrogen (NO 3 -NSodium (Na)  Nitrate-Nitrogen (NO 3 -N Calcium (Ca)  Iron (Fe)Calcium (Ca)  Iron (Fe) Magnesium(Mg)  Manganese (Mn)Magnesium(Mg)  Manganese (Mn) Potassium (K)  ZnPotassium (K)  Zn Boron (B)  Electrical Conductivity (EC)Boron (B)  Electrical Conductivity (EC) Hardness  Total soluble Salts (TSS)Hardness  Total soluble Salts (TSS) Chloride (Cl)  Sodium PercentageChloride (Cl)  Sodium Percentage Sulfate (SO 4 )  pHSulfate (SO 4 )  pH

Household Water Test Nitrate-Nitrogen – (NO 3 -N) NO 3 -N is the only analyte on the test with a Federal SDWA StandardNO 3 -N is the only analyte on the test with a Federal SDWA Standard The NO 3 -N standard is 10 mg/lThe NO 3 -N standard is 10 mg/l Newborn infants (less than 9 months) and pregnant women are “at-risk” consumersNewborn infants (less than 9 months) and pregnant women are “at-risk” consumers NO 3 -N affects the blood’s ability to carry oxygen, causing methemoglobenemiaNO 3 -N affects the blood’s ability to carry oxygen, causing methemoglobenemia

Household Water Test Secondary Contaminants Other regulated analytes on the Household Water Test are Secondary Contaminants that have Federal SDWA GuidelinesOther regulated analytes on the Household Water Test are Secondary Contaminants that have Federal SDWA Guidelines Exceeding SDWA Guidelines is not a primary health riskExceeding SDWA Guidelines is not a primary health risk Secondary contaminants affect aesthetic quality of water (taste, odor, etc.) or damage the water system (hardness, corrosion, etc.)Secondary contaminants affect aesthetic quality of water (taste, odor, etc.) or damage the water system (hardness, corrosion, etc.)

Household Water Test Secondary Contaminants Secondary contaminants can indirectly affect health: –High sulfates can cause diarrhea which could result in dehydration –Corrosion due to low pH and low alkalinity can leach lead and copper from plumbing fixtures which could cause lead toxicity

Corrosiveness of Water pH – Alkalinity Balance

Household Water Test Hardness Hardness Class CaCO 3 Equivalent Hardness (mg/l) Soft Soft 0 – 60 0 – 60 Moderately Hard Moderately Hard 60 – – 120 Hard Hard 120 – – 180 Very Hard Very Hard Hardness is caused by calcium and magnesium (iron also contributes to hardness)

Irrigation Water Test Price:$15.00Price:$15.00 Analytes:Analytes: –Sodium (Na) — Chloride (Cl) –Calcium (Ca) — Sulfate (SO4) –Magnesium (Mg) — Nitrate-Nitrogen (NO 3 -N) –Potassium (K) — Carbonate (CO 3 ) –Boron (B) — Bicarbonate (HCO 3 ) –pH — Electrical Conductivity (EC) –Hardness — Total Soluble Salts (TSS) –Residual Carbonates — Sodium Adsorption Ratio (SAR)

Irrigation Water Quality Important Analytes EC (or TSS): determines soil osmotic potential EC (or TSS): determines soil osmotic potential SAR (or Na%): rates infiltration problem potential SAR (or Na%): rates infiltration problem potential Boron: toxic at very low concentrations Boron: toxic at very low concentrations Residual Carbonates (RSC): raises effective SAR/Na% Residual Carbonates (RSC): raises effective SAR/Na%

The Effect of Salinity of Soil Water Availability Salt Concentrations 0.4% = 4000 mg/l 0.4% = 4000 mg/l 0.2% = 2000 mg/l 0.2% = 2000 mg/l 0.1% = 1000 mg/l 0.1% = 1000 mg/l

Irrigation Water Quality Sodium (Na) Hazard Na generally creates soil infiltration problems before becoming toxic to plantsNa generally creates soil infiltration problems before becoming toxic to plants In hot, dry weather conditions sprinkling can lead to leaf burning due to Na toxicityIn hot, dry weather conditions sprinkling can lead to leaf burning due to Na toxicity Na reduces soil permeability by dispersing clay particles which seal larger pore spacesNa reduces soil permeability by dispersing clay particles which seal larger pore spaces Na hazard is greater high clay content soilsNa hazard is greater high clay content soils Na hazard is greater in expanding clays than in non-expanding claysNa hazard is greater in expanding clays than in non-expanding clays

Potential for infiltration problems due to high Na + water. Potential for infiltration problems due to high Na + water.

Water Suitability Based on Total Salinity and Sodium Content (Example: EC = 1.7 dS/m = 1700  mho/cm and Na%= 35)

Irrigation Water Quality Boron (B) Crops are very sensitive to boronCrops are very sensitive to boron Threshold soil concentration for yield reduction: 0.3 – 5 mg/lThreshold soil concentration for yield reduction: 0.3 – 5 mg/l Toxic to all vegetation:  mg/lToxic to all vegetation:  mg/l Typical boron toxicity symptoms are spotting, yellowing and/or drying at tips and edges of older leavesTypical boron toxicity symptoms are spotting, yellowing and/or drying at tips and edges of older leaves

Irrigation Water Quality Residual Carbonates (RSC) Excessive bicarbonate and carbonate in irrigation water will combine with calcium and magnesium ions in soilExcessive bicarbonate and carbonate in irrigation water will combine with calcium and magnesium ions in soil This effectively increases the SAR and leads to greater risk of infiltration problemsThis effectively increases the SAR and leads to greater risk of infiltration problems Residual carbonates ≥ 2.5 are usually a problemResidual carbonates ≥ 2.5 are usually a problem RSC = (CO 3 + HCO 3 ) - (Ca + Mg)

Nitrate Nitrogen NO 3 -N in irrigation water should be accounted for in nutrient managementNO 3 -N in irrigation water should be accounted for in nutrient management 1 mg/L of NO 3 -N in irrigation water applies 0.23 lb/acre of N per 1 inch of irrigation water applied1 mg/L of NO 3 -N in irrigation water applies 0.23 lb/acre of N per 1 inch of irrigation water applied

Water Quality Units and Terms (Concentrations) 1 mg/l = 1 ppm = 1000  g/l ppb 1 mg/l = 1 ppm = 1000  g/l = 1000 ppb TSS = Total Soluble Salts TSS = Total Soluble Salts TDS = Total Dissolved Solids TDS = Total Dissolved Solids TSS  TDS TSS  TDS TSS, (mg/l)  640 x EC, (mmho/cm) TSS, (mg/l)  640 x EC, (mmho/cm) (Electrical Conductivity) 1 mmho/cm = 1 dS/m = 1 mS/cm= 1000  mho/cm 1 mmho/cm = 1 dS/m = 1 mS/cm = 1000  mho/cm EC = electrical conductivity of water EC = electrical conductivity of water EC e = electrical conductivity of saturated soil extract EC e = electrical conductivity of saturated soil extract

Water Quality Units and Terms (Concentrations) meq/l = milliequivalents per liter epm = equivalents per million 1 meq/l = 1 epm Ionppm per meq/lIonppm per meq/l Ca 20CO 3 30 Mg 12HCO 3 61 Na 23SO 4 48 K 39Cl 35.5

Derived Water Quality Terms SAR = Sodium Adsorption Ratio SAR = Na (Ca+Mg)/2 Na% = Sodium Percentage Na% = (Na x 100) (Ca+Mg+K+Na) RSC = Residual Sodium Carbonates RSC = (CO 3 + HCO 3 ) - (Ca + Mg) (the 3 calculations on this page are in meq/l)

OSU Publications L-256 Understanding Your Livestock Water Test ReportL-256 Understanding Your Livestock Water Test Report L-296 Understanding Your Household Water Test ReportL-296 Understanding Your Household Water Test Report L-323 Understanding Your Irrigation Water Test ReportL-323 Understanding Your Irrigation Water Test Report F-2401 Classification of Irrigation Water QualityF-2401 Classification of Irrigation Water Quality To download a copy of this presentation go to: (