vvEPA
                       United State*
                       Environmental Protection
                                          Office of Water
                                          (MC-4304)
EPA-822-F-93-002
   October, 1993
            Fact Sheet
                       Ambient Aquatic Life Water Quality  Criteria
                       for 2,4-Dimethylphenol
           AUTHORITY

           Ambient water quality criteria are published pursuant to Section 304(a) of the Clean Water
           Act and may form the basis for enforceable standards if adopted by a State into water quality
           standards.  The criteria reflect the latest scientific knowledge on the identifiable effects of
           pollutants on public health and welfare, aquatic life and recreation. They are developed
           using a process described in the "Guidelines for Deriving Numerical National Water Quality
           Criteria for the Protection of Aquatic Organisms and Their Uses" (Stephan fiLaL, 1985).

           BACKGROUND

                 2,4-Dimethylphenol (2,4-DMP) is a naturally occurring, substituted phenol derived
           from petroleum or coal tars. 2,4-DMP (l-hydroxy-2,2-dimethylbenzene, m-xylenol, 2,4-
           xylenol or m-4-xylenol) is used in the manufacture of phenolic antioxidants, disinfectants,
           solvents, pharmaceuticals, insecticides, fungicides, plasitcizers, rubber chemicals
           polyphenylene oxide, wetting agents, and dyestuffs. 2,4-DMP is also an additive of
           lubricants, gasolines, and cresylic acid.  2,4-Dimethylphenol is classified by EPA's Office of
           Water as a priority pollutant (Section 307(a) of the Clean Water Act).

                 Acute and Chronic Criteria for 2,4-dimethylphenol in this draft document will   .
           supersede guidance given in the previous Ambient Water Quality Criteria for 2.4-
           dimethvlphenol (U.S.  EPA, 1980).   These new criteria were derived using  improved
           procedures and additional (more  current) information.
                                                             concentration (i.e., acute exposure)
                                                             does not exceed 1,300 ugA more
                                                             than once every three years on the
                                                             average, and

                                                             saltwater aquatic organisms and
                                                             their uses should not be affected
                                                             unacceptably if the four-day
                                                             average concentration (i.e., chronic
                                                             exposure) of 2,4-Dimethylphenol
                                                             does not exceed  110 ug/1 more than
                                                             once every three years on the
Except where locally important species are
very sensitive.

*     freshwater aquatic organisms and
      their uses should not be affected
      unacceptably if the four-day
      average concentration (i.e., chronic
      exposure) of 2,4-Dimethylphenol
      does not exceed 530 ug/1 more than
      once ever/ three years on the
      average and if the one-hour average

-------
      average and if the one-hour average
      concentration  (i.e., acute exposure)
      does not exceed 270 ug/1 more than
      once every three years on the
      average.

IMPLEMENTATION INTO STATE
STANDARDS

Ambient water quality criteria may form
the basis for enforceable standards if
adopted by a State into water quality
standards.  States may opt to develop site
specific criteria (Water Quality Standards
Handbook, December, 1983, EPA#:
440/5-83-011).  Replacement of national
criteria with site specific criteria may
include site specific  criterion
concentrations, mixing zone considerations
(Water Quality Standards Handbook,
December, 1983, EPA#:  440/5-83-011),
averaging periods and site-specific
frequencies of allowed exceedences
 (Guidelines for Deriving Numerical
 National Water Quality Criteria for the
 Protection of Aquatic Organisms and Their
 Uses, Stephan fl aL. 1985). When the
 basis for site specific criteria relate  to the
 averaging period, there should be a
 justification for why variability
 assumptions underlying national criteria
 are inappropriate.
AVAILABILITY OF DOCUMENT

Copies of the proposed criteria document,
and other referenced documents, may be
obtained from the address below.

2,4-Dimethylphenol Proposal
Water Resource Center, (RC-4100)
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C., 20460

For further information please contact:

Mrs.  Amy L. Leaberry
U.S.  Environmental Protection Agency
Office of Water
Water Quality Criteria Section
 (Mail Code - 4304)
 401 M Street, SW
 Washington, DC 20460

-------