Michigan Administrative Code › Department - Environmental Quality › Drinking Water And Municipal Assistance Division › Supplying Water to the Public › Part 6 - STATE DRINKING WATER STANDARDS AND ANALYTICAL › Section R. 325.10604c - MCL for inorganic chemicals

Current through Vol. 24-12, July 15, 2024
Rule 604c.
(1)
				  Except as specified, the maximum contaminant levels and effective dates for
				  inorganic chemicals in table 1 of this rule apply to community and nontransient
				  noncommunity water supplies. These public water supplies are considered "water
				  supplies" or "supplies" in this rule.
Table 1 MCLs for inorganic chemicals
Contaminant
Maximum Contaminant Level in mg/l
Effective Date
Antimony
0.006
January 17, 1994.
Arsenic
0.010
April 6, 2005.
Asbestos
7 million fibers per liter (longer than 10 um)
July 30, 1992.
Barium
2
January 1, 1993.
Beryllium
0.004
January 17, 1994.
Cadmium
0.005
July 30, 1992.
Chromium
0.1
July 30, 1992.
Cyanide (as free
0.2
January 17, 1994.
cyanide)
Fluoride1
4.0
[effective date of this rule]
Mercury
0.002
July 30, 1992.
Nickel
MCL withdrawn
May 30, 2002
Nitrate (as
10
July 30, 1992.
Nitrogen)2
Nitrite (as
1
July 30, 1992.
Nitrogen)2
Total Nitrate and
10
July 30, 1992.
Nitrite (as Nitrogen)3
Selenium
0.05
July 30, 1992.
Thallium
0.002
January 17, 1994.
1 The MCL and effective date
					 apply to only community water supplies.
2 The MCLs and effective dates
					 apply to community and noncommunity water supplies.
(2) Compliance with the MCL requirements of
				  this rule shall be determined based on the analytical results that are obtained
				  at each sampling point as specified in R 325.10710. If 1 sampling point is in
				  violation of an MCL, then the water supply is in violation of the MCL. All of
				  the following provisions apply:
(a) For
				  supplies monitoring more than once per year, compliance with the MCL for
				  antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide,
				  fluoride, mercury, nickel, selenium, or thallium is determined by a running
				  annual average at each sampling point.
(b) Supplies monitoring annually or less
				  frequently whose sample result exceeds the MCL for antimony, arsenic, asbestos,
				  barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel,
				  selenium, or thallium shall begin quarterly sampling. Compliance with the MCL
				  shall be based on the running annual average. For the purpose of calculating
				  the running annual average, the initial exceedance shall be considered the
				  result for the first quarter. If the department requires a confirmation sample
				  under R 325.10710(9), then the average of the initial exceedance and the
				  confirmation sample shall be considered the result for the first quarter. The
				  supply shall not be considered in violation of the MCL until it has completed 1
				  year of quarterly sampling.
(c) If
				  any sample result causes the running annual average to exceed the MCL at any
				  sampling point, then the supply is out of compliance with the MCL
				  immediately.
(d) If a supply fails
				  to collect the required number of samples, then compliance shall be based on
				  the total number of samples collected.
(e) If a sample result is less than the
				  detection limit, then zero shall be used to calculate the annual
				  average.
(f) Compliance with the
				  MCLs for nitrate and nitrite is determined based on 1 sample if the levels of
				  these contaminants are below the MCLs. If the level of nitrate or nitrite or
				  the combination of nitrate and nitrite is more than the MCLs in the initial
				  sample, then a confirmation sample is required under R 325.10710 (9) (b) and
				  (c), and compliance shall be determined based on the average of the initial and
				  confirmation samples.