R18-11-406. Numeric Aquifer Water Quality Standards: Drinking Water Protected Use

A. The aquifer water quality standards in this Section apply to aquifers that are classified for drinking water protected use. B. The following are the aquifer water quality standards for inorganic chemicals: Pollutant (mg/L) Antimony 0.006 Arsenic 0.010 Asbestos 7 million fibers/liter (longer than 10 mm) Barium 2 Bromate 0.010 Beryllium 0.004 Cadmium 0.005 Chlorite 1.0 Chromium 0.1 Cyanide (As Free Cyanide) 0.2 Fluoride 4.0 Lead 0.05 Mercury 0.002 Nickel 0.1 Nitrate (as N) 10 Nitrite (as N) 1 Nitrate and nitrite (as N) 10 Selenium 0.05 Thallium 0.002 Uranium 0.030 C. The following are the aquifer water quality standards for organic chemicals: Pollutant (mg/L) Benzene 0.005 Benzo (a) pyrene 0.0002 Carbon Tetrachloride 0.005 o-Dichlorobenzene 0.6 para-Dichlorobenzene 0.075 1,2-Dichloroethane 0.005 1,1-Dichloroethylene 0.007 cis-1,2-Dichloroethylene 0.07 trans-1,2-Dichloroethylene 0.1 1,2-Dichloropropane 0.005 Dichloromethane 0.005 Di (2-ethylhexyl) adipate 0.4 Di (2-ethylhexyl) pthalate 0.006 Ethylbenzene 0.7 Haloacetic Acids 0.060 Hexachlorobenzene 0.001 Hexachlorocyclopentadiene 0.05 Monochlorobenzene 0.1 Pentachlorophenol 0.001 Styrene 0.1 2,3,7,8-TCDD (Dioxin) 0.00000003 Tetrachloroethylene 0.005 Toluene 1 Trihalomethanes (Total) 0.080 1,2,4-Trichlorobenzene 0.07 1,1,1-Trichloroethane 0.20 1,1,2-Trichloroethane 0.005 Trichloroethylene 0.005 Vinyl Chloride 0.002 Xylenes (Total) 10 D. The following are the aquifer water quality standards for pesticides and polychlorinated biphenyls (PCBs): Pollutant (mg/L) Alachlor 0.002 Atrazine 0.003 Carbofuran 0.04 Chlordane 0.002 Dalapon 0.2 1,2-Dibromo-3-Chloropropane (DBCP) 0.0002 2,4,-Dichlorophenoxyacetic Acid(2,4-D) 0.07 Dinoseb 0.007 Diquat 0.02 Endothall 0.1 Endrin 0.002 Ethylene Dibromide (EDB) 0.00005 Glyphosate 0.7 Heptachlor 0.0004 Heptachlor Epoxide 0.0002 Lindane 0.0002 Methoxychlor 0.04 Oxamyl 0.2 Picloram 0.5 Polychlorinated Biphenols (PCBs) 0.0005 Simazine 0.004 Toxaphene 0.003 2,4,5-Trichlorophenoxypropionic Acid (2,4,5-TP or Silvex) 0.05 E. The following are the aquifer water quality standards for radionuclides: 1. The maximum concentration for gross alpha particle activity, including Radium-226 but excluding radon and uranium, shall not exceed 15 pCi/l. 2. The maximum concentration for combined Radium-226 and Radium-228 shall not exceed 5 pCi/l. 3. The average annual concentration of beta particle and photon radioactivity from man-made radionuclides shall not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year. 4. Except for the radionuclides listed in this subsection, the concentration of man-made radionuclides causing 4 millirem total body or organ dose equivalents shall be calculated on the basis of a 2-liter-per-day drinking water intake using the 168-hour data listed in “Maximum Permissible Body Burdens and Maximum Permissible Concentration of Radionuclides in Air or Water for Occupational Exposure,” National Bureau of Standards Handbook 69, National Bureau of Commerce, as amended August 1963 (and no future editions), incorporated herein by reference and on file with the Office of the Secretary of State and with the Department. If two or more radionuclides are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed 4 millirem/year. The following average annual concentrations are assumed to produce a total body or organ dose of 4 millirem/year: Radionuclide Critical Organ pCi/l Tritium Total body 20,000 Strontium-90 Bone Marrow 8 F. Aquifer water quality standard for microbiological contaminants. The aquifer water quality standard for microbiological contaminants is based upon the detection or non-detection of either Fecal Coliform or E.coli in a 100-milliliter sample, depending on the requirement in the permit. 1. If a routine sample for Fecal Coliform results in a detection, a 100-milliliter repeat sample of either Fecal Coliform or E.coli shall be taken within five days of becoming aware of the detection. A repeat sample for Fecal Coliform or for E.coli resulting in a detection following a routine Fecal Coliform sample that resulted in a detection constitutes a violation of the aquifer water quality standard for microbiological contaminants. 2. If a routine sample for E.coli results in a detection, a 100- milliliter repeat sample for E.coli shall be taken within five days of becoming aware of the detection. A repeat sample for E.coli resulting in a detection following a routine E.coli sample that resulted in a detection constitutes a violation of the aquifer water quality standard for microbiological contaminants. G. The following are the aquifer water quality standards for turbidity: 1. One nephelometric turbidity unit as determined by a monthly average except that five or fewer nephelometric turbidity units may be allowed if it can be determined that the higher turbidity does not interfere with disinfection, prevent maintenance of effective disinfectant agents in water supply distribution systems, or interfere with microbiological determinations. 2. Five nephelometric turbidity units based on an average of two consecutive days.