Section 11-20-3 - Maximum contaminant levels for inorganic chemicals(a) The MCL for nitrate, nitrite, and total nitrate and nitrite is applicable to all public water systems except as provided by subsection (d) and (e). The MCL for fluoride apply only to community water systems. The MCLs for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, mercury, selenium, and thallium apply to community water systems and non-transient non-community water systems. Compliance with MCLs for inorganic chemicals is calculated pursuant to section 11-20-11.(b) The following are the MCLs for inorganic chemicals: Contaminant | MCL, Milligrams Per Liter (mg/L) | Chemical Abstract Source Registry Number (CAS #) |
(1) Arsenic | 0.010 | 7440-38-2 |
(2) Asbestos | 7 million fibers/liter(longer than 10 µm) | |
(3) Barium | 2 | 7440-39-3 |
(4) Cadmium | 0.005 | 7440-43-9 |
(5) Chromium | 0.1 | 7440-47-3 |
(6) Mercury | 0.002 | 7439-97-6 |
(7) Nitrate | 10 (as Nitrogen) | 14797-55-8 |
(8) Nitrite | 1 (as Nitrogen) | |
(9) Total Nitrate and Nitrite | 10 (as Nitrogen) | |
(10) Selenium | 0.05 | 7882-49-2 |
(11) Antimony | 0.006 | 7440-36-0 |
(12) Beryllium | 0.004 | 7440-41-7 |
(13) Cyanide | 0.2 (as free Cyanide) | |
(14)(reserved) | | |
(15) Thallium | 0.002 | 7440-28-0 |
(16) Fluoride | 4.0 | 16984-48-8 |
The MCL of 0.01 mg/l for arsenic is effective January 23, 2006. Prior to January 23, 2006, the MCL for arsenic is 0.05 mg/L.
(c) At the discretion of the director, nitrate levels not to exceed twenty milligrams per liter or mg/l may be allowed in a non-community water system if the supplier of water demonstrates to the satisfaction of the director that: (1) Such water will not be available to children under six months of age;(2) The non-community water system is meeting the public notification requirements under section 11-20-18(i), including continuous posting of the fact that nitrate levels exceed 10 mg/L and the potential health effects of exposure; (3) Local and state public health authorities will be notified annually of nitrate levels that exceed ten milligrams per liter or mg/l; and(4) No adverse health effects shall result.(d) The best available technologies (BATs) for treating inorganic chemicals to achieve compliance with their MCLs are found in 40 C.F.R. § 141.62(c).(e) Small system compliance technologies for the treatment of arsenic are identified in 40 C.F.R. section 141.62(d) for systems serving 10,000 persons or fewer.[Eff 12/26/81; am and comp 3/7/92; am and comp 1/2/93; am and comp 12/15/94; am and comp 10/13/97; am and comp 9/7/99; am and comp 11/30/02; am and comp 12/16/05; comp 11/28/11; comp MAY 02 2014] (Auth: HRS §§ 340E-2, 340E-9) (Imp: HRS §§ 340E-2, 340E-9; 42 U.S.C. §§ 300g-1, 300g-2; 40 C.F.R. Parts 141, 142, § 141.11, § 141.62, § 142.10 )