Friday, July 24, 2009

Searching for the Perfect Water Filter - EPA Drinking Water Regulations

What I learned from browsing the EPA water drinking regulations?

Here's what you will know and what you won't know from your water agency report:

The Environmental Protection Agency (EPA) is regulating more than 90 contaminants found in the drinking water, although there are many more that keep on seeping in -- pun intended. For short, there are three types of standards or guidelines that needs to be followed:

National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water. There is a full list of the regulated contaminants including the maximum allowed levels, potential health effects, and sources of the contaminants. The list include:Microorganisms, Disinfectants, Disinfection Byproducts, Inorganic Chemicals, Organic Chemicals, and Radionuclides.

National Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards. Problems are starting to arise with this list, depending on the water district. I decided to include the whole table with these contaminants as most of them are the ones I would like to completely reduce from the water I drink. The table is adapted from the Secondary Drinking Water Regulation: Guidance for Nuisance Chemicals released in July 1998. Well, since 1998 the scientific community added more proof about health effects of some of these contaminants which should call EPA to more strict standards or at least to enforce these to all public water systems.

Contaminant Secondary MCL Noticeable Effects above the Secondary MCL
Aluminum 0.05 to 0.2 mg/L* colored water
Chloride 250 mg/L salty taste
Color 15 color units visible tint
Copper 1.0 mg/L metallic taste; blue-green staining
Corrosivity Non-corrosive metallic taste; corroded pipes/ fixtures staining
Fluoride 2.0 mg/L tooth discoloration
Foaming agents 0.5 mg/L frothy, cloudy; bitter taste; odor
Iron 0.3 mg/L rusty color; sediment; metallic taste; reddish or orange staining
Manganese 0.05 mg/L black to brown color; black staining; bitter metallic taste
Odor 3 TON (threshold odor number) "rotten-egg", musty or chemical smell
pH 6.5 - 8.5 low pH: bitter metallic taste; corrosion
high pH:
slippery feel; soda taste; deposits
Silver 0.1 mg/L skin discoloration; graying of the white part of the eye
Sulfate 250 mg/L salty taste
Total Dissolved Solids (TDS) 500 mg/L hardness; deposits; colored water; staining; salty taste
Zinc 5 mg/L metallic taste
* mg/L is milligrams of substance per liter of water

Unregulated Contaminants are contaminants which are not subject to any proposed or promulgated national primary drinking water regulation (NPDWR), are known or anticipated to occur in public water systems. For more information check out the list,This list include Methyl-t-butyl ether (MTBE), Triazines & degradation products of triazines and others. This lists perchlorate for which in January 2009, EPA issued an interim health advisory level of 15 micrograms per liter (µg/L) to assist state and local officials in addressing local contamination of perchlorate in drinking water. Again, this is advisory, not enforced or reported.

For more information about contaminants you can visit the Drinking Water Standards page. In addition you can look over an article I wrote earlier about perfluorochemicals and other chemicals found in the water of some states.

Next step is to understand the water report and to find out which of the secondary standards are tested by my public water system.

1 comment:

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