United States
                             Environmental Protection
                             Agency
                                                      Office of Water
                                                      4601
            EPA811-F-95-003V-T
                   October 1995
                             National Primary  Drinking
                             Water Regulations
                             Methoxychlor
  CHEMICAL/ PHYSICAL PROPERTIES

  CAS NUMBER: 72-43-5

  COLOR/ FORM/ODOR:
    Colorless crystals with slightly fruity
    odor; available as: wettable powder;
    emulsifiable, dust and aerosol concen-
    trates; oil solutions

  M.P.:.89C    B.P.: N/A

  VAPOR PRESSURE: very low

  DENSITY/SPEC. GRAV.: 1.41 at 25 C
                                 OCTANOL/WATER PARTITION (Kow):
                                   Log Kow = 4.83,4.91 and 5.08

                                 SOLUBILITY: 0.10 mg/L of water at 25 C;
                                   Slightly soluble in water

                                 HENRY'S LAW COEFFICIENT:
                                   1.6x10-5 atm-cu m/mole at 25 C

                                 ODOR/TASTE THRESHOLDS:  odor threshold
                                   is 4.7 mg/L in water

                                 SOIL SORPTION COEFFICIENT:
                                   measured Koc ranges from 9700 to
                                   41,000 in sand to 80,000 to 100,000
   in fine silt; low mobility in soil

BlOCONCENTRATION FACTOR:
   BCFs of 1500 to 8500 in shellfish and
   algae, much lower in fish; expected to
   bioconcentrate in aquatic organisms.

TRADE NAMES/SYNONYMS:
   2,2-bis(p-methoxyphenyl)-1,1,1-
   trichloroethane, dianisyl trichloroethane,
   Dimethoxy-DDT, Methoxy-DDT,
   Chemform, Maralate, Methoxo,
   Methoxcide, Metox, Moxie
                                                toxic to others. It has been used extensively in Canada for
                                                the control of biting flies, and is also effective against
                                                mosquitoes and houseflies.
                                                  Available information indicates production of methoxy-
                                                chlor has decreased: from 3.7 million Ibs. in 1978 to
                                                700,000 Ibs in  1982. In 1982 it  was estimated that
                                                industries consumed methoxychlor as follows: 43 per-
                                                cent as an insecticide for livestock and poultry, 29 per-
                                                cent on alfalfa crops and 29 percent on citrus.

                                                RELEASE PATTERNS
                                                  Release of methoxychlor to the environment occurs
                                                due to its use as an insecticide for home .and garden
                                                applications, livestock and poultry, alfalfa, soya beans,
                                                forests (Dutch Elm disease), ornamental shrubs, decidu-
                                                ous fruits and nuts, and vegetables Other sources of
                                                release may include loss during the manufacture, formu-
                                                lation, packaging, and disposal of methoxychlor.
                                                  From  1987 to 1993, according to EPA's Toxic Chemi-
                                                cal Release Inventory, methoxychlor releases to land
                                                and water totalled only about 2000 Ibs.

                                                ENVIRONMENTAL FATE
USAGE PATTERNS                                    Methoxychlor does not tend to persist when released
  Methoxychlor is preferred to DDT for use on animals, to soil or water- and does not accumulate in fish.
in animal feed, and on  DDT-sensitive  crops such as   If released to soil, methoxychlor is expected to remain
squash, melons, etc. Since methoxychlor is  more un- immobilized primarily in the upper layer of soil although a
stable than DDT, it has less residual effect. Compared to small percentage may migrate to lower depths, possibly
DDT, methoxychlor, is more toxic to some insects & less into groundwater as suggested by the detection of me-
DRINKING WATER STANDARDS
  MCLG:      0.04 mg/L
  MCL:       0.04 mg/L
  HAL(child):  1 day: 0.05 mg/L.
             Longer-term: 0.05 mg/L

HEALTH EFFECTS SUMMARY
  Acute:  EPA has found methoxychlor to potentially
cause central nervous system depression, diarrhea, and
damage to liver, kidney and heart tissue from short-term
exposures at levels above the MCL.
  Drinking water levels which are considered "safe" for
short-term exposures! For a 10-kg (22 Ib.) child consum-
ing 1 liter of water per day, upto a 7-year exposure to 0.05
mg/L.
  Chronic:  Methoxychlor has the potential to damage
liver, kidney and heart tissue and to retard growth from
long-term exposure at levels above the MCL.
  Cancer: There is no evidence that methoxychlor has
the potential to cause cancer from lifetime exposures in
drinking water.
October 1995
                                          Technical Version
             Printed on Recycled Paper

-------
thoxychlor in some groundwater samples.
  Measured soil sorption coefficient (Koc) values  in
various soil are as follows: 9700 to 41,000 in sand, 80,000
to 86,000 in coarse silt, 73,000 to 100,000 in medium silt,
80,000 to 100,000 in fine silt and 73,000 to 92,000 in clay.
In another study, a Koc of 620 was found in  a water-
sediment system.
  This range of Koc values suggests that methoxychlor
would  be  moderately mobile to immobile in  soil and
adsorb significantly to suspended solids and sediments
in water. Methoxychlor was found to migrate as much as
100 cm  under conditions in which 95 to 97% of the
residues remained  in the top 10 cm of soil.
  Under anaerobic soil/sediment conditions, biodegra-
dation  appears to be the dominant removal mechanism.
In sediments, methoxychlor was found to have a half-life
of >100 days under relatively aerobic conditions and < 28
days under anaerobic conditions. Half-lives in anaerobic
soils are about 3 months. Methoxychlor may  undergo
indirect "sensitized" photolysis on the soil surfaces and
it may undergo chemical hydrolysis in moist soils (half-life
> 1 year).
  If released to water, methoxychlor may be removed or
transported by several different mechanisms. Methoxy-
chlor may adsorb to suspended solids and sediments. It
may undergo  direct photolysis (half-life 4.5 months)  or
indirect "sensitized" photolysis (half-life <5 hours) de-
pending  upon the presence of photosensitizers. Based
on the Henry's law constant, volatilization of methoxy-
chlor may be significant (half-life 4.5 days from a shallow
river).
  Methoxychlor may also biodegrade in sediments, as
mentioned above, but oxidation and chemical hydrolysis
are not expected to be significant fate processes.
  If released to the atmosphere, methoxychlor may exist
in either vapor or particulate form. Methoxychlor may
undergo reaction with  photochemically generated hy-
droxyl radicals (estimated vapor phase half-life 3.7 hours)
or physical removal  by settling out or washing  out  in
precipitation.
  Significant bioconcentration has been measured  in
certain shellfish, insects, algae and fish, although fish are
generally reported to metabolize methoxychlorfairly rap-
idly and do not accumulate it.
  The  most probable route of exposure to methoxychlor
would be inhalation  or dermal contact during home use of
this insecticide, inhalation of airborne particulate matter
containing methoxychlor or ingestion of food or drinking
water contaminated with methoxychlor.
         OTHER REGULATORY INFORMATION
         MONITORING:
         FOR GROUND/SURFACE WATER SOURCES:
           INITIAL FREQUENCY-  4 quarterly samples every 3 years
           REPEAT FREQUENCY- If no detections during initial round:
                         2 quarterly per year if serving >3300 persons;
                         1 sample per 3 years for smaller systems
         TRIGGERS - Return to Initial Freq. if detect at> 0.0001 mg/L
                                  METHOD NUMBERS
                                  505; 508; 508.1; 525.2
ANALYSIS:
REFERENCE SOURCE
EPA 600/4-88-039


TREATMENT:
BEST AVAILABLE TECHNOLOGIES
Granular Activated Charcoal
         FOR ADDITIONAL INFORMATION:
         * EPA can provide further regulatory and other general information:
          EPA Safe Drinking Water Hotline - 800/426-4791


         * Other sources of toxicological and environmental fate data include:
          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
          National Pesticide Hotline - 800/858-7378
 October 1995
Technical Version
                                             Page 2

-------