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MINNESOTA DEPARTMENT OF NEALTH WATER QUALITY PARAMETERS VOLAT[LE ORGANIC CHEMdU�S (YOC's) are a large group of low boiling point, carbon-containing, predomi- nantly manmade substances. VOC's are contained in a wide variety of industrial. commercial, and resi- dential products including: cleaners, degreasers. paints, sotvents, inks, and petroleum distillates. VOC's do not normally occur in groundwater. Their presence usually signifies contamination from � improper use, storage. disposal , spillage or leakage of solvenis or petroleum products. VOC's vary widely in their toxicity anC drinking Nater conCentration standards. NITRATE AHO NITRITE MITROGEM is used as one of the principal indicators of water quality. Nitrate is the stable form of nitrogen in oxygenateG groundwater. Nitrite presents a particular health threat to infants. Sources of nitrogen include: municipal and industrial wastes. landfill leachate, animal and human wastes. nitrogen fertiliZers, decomposition of organic matter dnC dissolution of nitrogen- containing soil and rocks. BackgrounG concentrations* in Minnesota groundwaters range from less than 0.4 mi)iigrams per liter (my/1) to 140 mg/1 with a mean of 2.7 mg/l. A primary drinking water standard of 10 mg/1 has been established for public aater supplies. A�MOMIA. a compound of nitrogen and hydrogen, is generally found in low concentrations in groundwater due to oxidation to nitrate and adsorption to soil particles. High concentrations of artmonia may represent oxygen depleted water or rapid introduction of ammonia fertilizers. animal or human wastes, or leaching of solid wastes. CHLORIDE is one of the major inorganic anions in water. Chloride is very soluble and Nill move through groundwater with little attenuation. The presence of chloride in groundwater may be due to natural salts in soils or rocks. or leaching of chemical fertilizers. solid wastes or highway deicing salts. Background chloride concentrations in Minnesota groundwaters range from 0.3 mg/1 to 490 mg/1 , with a mean of 19.2 mg/1, The secondary drinking water standard (recommended guiGeline) for public water supplies is 250 mg/1. SUIPHATE occurs almost universally in groundwater, Rainfall may contain 10 mg/1 or more sulphate. Household wastes. includin9 d�tergents. may add 10 mg/1 or more sulphate to sewage. The usual source in groundwater is naturally occurring suiphates of gypsum or anhydrite. BackgrounC concentrations of sulphate in Minnesota groundwaters range from 0.5 mg/1 to 1300 mg/1 with a mean of 72 mg/l. The secondary drinking water standard for public water supplies is 250 mg/1, IROb is a commonly found constituent in groundwaters, primarily derived from ►�eathering of soil and rocks. High concentrations can be due to corrosive water or leaching of wastes. Background concen- trations in Min�esota groundwaters range from less than 0.03 mg/1 to 46 mg/1 with a mean of 1.3 mg/1. 7he secondary drinking water standard for public water supplies is 0.3 mg/1. SPECIFIC CONDUCTANCE is a measure of the ability of water to conduct an electric cur�ent. This ability depends on the presence, concentration, and chemical state of ions. Nastewater and leachate typically have high concentrations of dissolved material (ions) and therefore high specific conductance. Back- ground specific ConductanCe in Minnesota groundwaters ranges from 50 to 2500 micromhos per Centimeter (umho/cm) with a mean of 630 µmho/cm. Specific conductance is often uSeG to estimate total dissolveG � sotids (TOS) by multiplying specific conductance by .6. The secondary drinking water standard for public water supplies is 500 mg/1 TDS. pH is a measure of the hydrogen ion activity of water, pH less than 7 represen[s acid conditions, pH greater than 1 represents alkaline or basic tonditions. Background pH levels in Minnesota grounG- wa[ers range from 5.9 to 9.4 with a mean of 7.5. The secondary Arinking water 5[andard for public water supplies is 6.5 Co 8.5. *Background co�centrations represent water quality values from 410 welis and springs sampled throughout Minnesota in the Minnesota Pollution Control Agency'S Ground Nater Quality Monit.orinq Proqram. MHD 210 LM 19R6