Maximum Concentration of Constituents for Groundwater Protection

Constituent concentration 1 Maximum Arsenic 0.05 Barium 1.0 Cadmium 0.01 Chromium 0.05 Lead 0.05 Mercury 0.002 Selenium 0.01 Silver 0.05 Nitrate (as N) 10. Molybdenum 0.1 Combined radium-226 and radium-228 5 pCi/liter Combined uranium-234 and uranium-238 2 30 pCi/liter Gross alpha-particle activity (excluding radon and uranium) 15 pCi/liter Endrin (1,2,3,4,10,10-hexachloro-6,7-exposy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo,endo-5,8-dimethanonaphthalene) 0.0002 Lindane (1,2,3,4,5,6-hexachlorocyclohexane, gamma insomer) 0.004 Methoxychlor (1,1,1-trichloro-2,2′-bis(p-methoxyphenylethane)) 0.1 Toxaphene (C 10 H 10 Cl 6 , technical chlorinated camphene, 67-69 percent chlorine) 0.005 2,4-D (2,4-dichlorophenoxyacetic acid) 0.1 2,4,5-TP Silvex (2,4,5-trichlorophenoxypropionic acid) 0.01 1 Milligrams per liter, unless stated otherwise. 2 Where secular equilibrium obtains, this criterion will be satisfied by a concentration of 0.044 milligrams per liter (0.044 mg/l). For conditions of other than secular equilibrium, a corresponding value may be derived and applied, based on the measured site-specific ratio of the two isotopes of uranium. [60 FR 2866, Jan. 11, 1995]