Info

picocuries per Liter (pCi/L)

Increased risk of cancer

Erosion of natural deposits

as of

12/08/03: zero

Radionuclides

(mg/L)2

Potential Health Effects from Ingestion of Water

Sources of Contaminant in Drinking Water

Beta particles and photon emitters

none7

4 millirems per year

Increased risk of cancer

Decay of natural and man-made deposits

as of

12/08/03: zero

Radium 226 and Radium 228 (combined)

none7

5 pCi/L

Increased risk of cancer

Erosion of natural deposits

as of

12/08/03: zero

12/08/03: 30 ug/L

Increased risk of cancer, kidney toxicity

Erosion of natural deposits

The following footnotes apply to the above tables.

1 Definitions: Refer to the discussion box on page 12.

2 Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million.

3 EPA's surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels:

• Cryptosporidium: (as of January 1, 2002) 99% removal/inactivation

• Giardia lamblia: 99.9% removal/inactivation

• Viruses: 99.99% removal/inactivation

• Legionella: No limit, but EPA believes that if Giardia and viruses are removed/inactivated, Legionella will also be controlled.

• Turbidity: At no time can turbidity (cloudiness of water) go above 5 nephelometric turbidity units (NTU); systems that filter must ensure that the turbidity go no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples in any month. As of January 1, 2002, turbidity may never exceed 1 NTU, and must not exceed 0.3 NTU in 95% of daily samples in any month

• HPC: No more than 500 bacterial colonies per milliliter.

4 No more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform-positive). Every sample that has total coliforms must be analyzed for fecal coliforms. There may not be any fecal coliforms or E. coli.

5 Fecal coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and people with severely compromised immune systems.

6 Although there is no collective MCLG for this contaminant group, there are individual MCLGs for some of the individual contaminants:

9 Trihalomethanes: bromodichloromethane (zero); bromoform (zero);

dibromochloromethane (0.06 mg/L). Chloroform is regulated with this group but has no MCLG.

• Haloacetic acids: dichloroacetic acid (zero); trichloroacetic acid (0.3 mg/L). Monochloroacetic acid, bromoacetic acid, and dibromoacetic acid are regulated with this group but have no MCLGs.

7 MCLGs were not established before the 1986 Amendments to the Safe Drinking Water Act. Therefore, there is no MCLG for this contaminant.

8 Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L.

9 Each water system must certify, in writing, to the state (using third-party or manufacturer's certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified, as follows:

, Acrylamide = 0.05% dosed at 1 mg/L (or equivalent)

• Epichlorohydrin = 0.01 % dosed at 20 mg/L (or equivalent)

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