United States
        Environmental Protection  Office of Water                EPA 811'F 94-OO6

        Aoencv               463                        November 1994

An Innovative  Approach to Regulating

a  Naturally-Occurring  Contaminant

What is sulfate?

     Sulfate is a naturally occurring ion found in combination with metals in the
form of salts.  Sulfate salts with lower molecular weight metals such as sodium
potassium, and magnesium are very water soluble and are often found in natural
waters. Salts of higher molecular weight metals such as barium, iron or lead have
very low water solubility.

Why is sulfate proposed for regulation?

     In 1974, Congress passed the Safe Drinking Water Act (SDWA), whose goal
is to ensure that aH Americans can enjoy healthy and palatable drinking water  The
SDWA requires EPA to set Maximum Contaminant Levels (MCLs) or specify
treatment techniques for contaminants that "may have any adverse effect on the
health of persons and which are known or anticipated to occur in public water
systems."  These are called  National Primary Drinking Water Regulations (NPDWRs)
for contaminants in public drinking water supplies. EPA may specify treatment
techniques when it is not "economically or technologically feasible" to derive
MCLs. The 1986 amendments to the SDWA required EPA to issue a proposed and
final standard for sulfate because of its known adverse health effects.

What are the health effects?

     There are no known chronic adverse health effects from exposure to sulfate
The acute effects from exposure to high levels of sulfate range from soft stools to
diarrhea.  Sulfate salts, such as magnesium sulfate, are used as medicinal
laxatives. The effect is temporary, and lasts approximately two weeks while the
intestinal system acclimates. People who are accustomed to the high-sulfate water
experience no ill effects. The target population susceptible to the effect consists of
newborn infants, travelers and new residents in areas of the country with high
sulfate levels.  Infants consume more water on a body weight basis than adults
and consequently ingest a higher dose of sulfate (per body weight) in drinking h'lgh-
sulfate water.  In infants, the greatest risk is from dehydration and electrolyte
imbalance that may result from diarrhea.

 What are the sources of sulfate?

  a JU!J3t? 1S f?Und ln SH sediments and rocks, and occurs in the environment
 as a result of both natural processes and human activities, such as mining.

 How is sulfate used?

       Sulfate is used for a variety of commercial purposes, including pickle liquor
 (sulfuric acid) for steel and metal industries, and as a reagent in manufacturing o
 products such as copper sulfate (a fungicide/algicide).

 Has sulfate been released to the environment?

       Specific data on the total production of all sulfates are not available but
 production is expected to be thousands of tons per year.  Sulfate may enter
 surface and ground water as a  result of discharge or disposal of sulfate-containing
 wastes.  In addition, sulfur oxides produced during the combustion of fossil fuels
 are transformed to sulfuric acid in the atmosphere. Through precipitation (i.e., acid
 ram , sulfuric acid can enter surface waters, lowering the pH and raising sulfate

 What happens to sulfate when it is released  to the environment?

      Sulfate exists naturally in water and in human bodily fluids.  In soil  sulfate
 may re-enter water and move downward into ground water.  Sulfate compounds do
 not readily evaporate from surface waters  and soils.

 What are the proposed means of compliance?

  -i  T^6.,rule prPses a unl<*ue means of compliance intended to provide relief
 and flexibility to small systems.  A combination of public education/notification and
 the provision of alternative water in the form of bottled water which has been
 monitored or certified to be in compliance with EPA MCLs, or water treated bv a
 filtering device, is proposed as an alternative to central treatment.  Central
 treatment options are reverse osmosis, ion exchange and electrodialysis reversal.

What are the proposed monitoring requirements?

      Monitoring requirements for nondetecting systems or systems with best
available  technology (BAT) installed are shown in the table below  Systems
adopting  the proposed method of compliance, alterative water and public
notification/education, would  not be required to monitor after the initial monitoring
because they would be orovidina the taraat nnrmia*; ,.,:*u .*. *i_^	.,    *'
     he                                                      that

Water Source
Ground Water
Initial Frequency
One sample once
every 3 years
One sample annually
One sample every 9
years after 3 rounds
of non-detection
One sample every 9
years after 3 rounds
of non-detection
> 500 mg/L
> 500 mg/L
Is additional information available?

      Yes, additional information regarding sulfate in drinking water is available
from numerous sources, including those listed below.

*     EPA's toll-free numbers for further information on drinking water quality,
      treatment technologies, health advisories and other regulatory information.
        Safe Drinking Water Hotline - 800/426-4791
        National Pesticides Hotline - 800/858-7378
      *  Toxic Substance Control Act Information Line - 202/554-1404
      >  Toxics Release Inventory, National Library of Medicine - 301/496-6531
*     Agency for Toxic Substances and Disease Registry - 404/639-6000