United States
Environmental Protection
Agency
Office of Water
4601
EPA811-F-95-003d-T
, October 1995
National Primary Drinking
Water Regulations
Atrazine
CHEMICAL/ PHYSICAL PROPERTIES
CAS NUMBER: 1912-24-9
COLOR/ FORM/ODOR:
Available as suspension concentrate;
wettable powder; water-dispersible
granules.
M.P.: 171-174° C B.P.: N/A
VAPOR PRESSURE: 3x1 Q-7 mm Hg at 20° C
DENSITY/SPEC. GRAV.: 1.19 g/mL at 20° C
OCTANOL/WATER PARTITION (Kow):
Log Kow = 2.75
SOLUBILITY: 0.03 g/L of water at 20° C
ODOR/TASTE THRESHOLDS: N/A
SOIL SORPTION COEFFICIENT:
Koc average is 122; medium to high
mobility in soil
BlOCONCENTRATION FACTOR:
Log BCF ranges from 0.3 to 2.0 in
fish; low bioconcentration potential
HENRY'S LAW COEFFICIENT:
2.63x10"9 atm-cu m/mole (calculated);
TRADE NAMES/SYNONYMS: Aatrex; Actinite PK;
Akticon; Argezin; Atazinax; Atranex;
Atrataf; Atred; Candex; Cekuzina-T;
Chromozin; Crisatrina; Cyazin;
Fenamin; Fenatrol; Gesaprim; Griffex;
Hungazin; Inakor; Pitezin; Primatol;
Radazin; Strazine; Vectal; Weedex A;
Wonuk; Zeapos; Zeazine
and roses. It also was used until 1993 for control of
vegetation in fallow and in noncrop land.
Atrazine was estimated to be the most heavily used
herbicide in the United States in 1987/89, with its most
extensive use for com and soybeans in Illinois, Indiana,
Iowa, Kansas, Missouri, Nebraska, Ohio, Texas, and
Wisconsin.
Effective in 1993, use for non-crop vegetation control
was eliminated, and use was restricted by a requirement
for a buffer zone between application sites and surface
water.
RELEASE PATTERNS
Atrazine may be released to the environment through
effluents from manufacturing facilities and through its use
as a herbicide. Atrazine was the second most frequently
detected pesticide in EPA's National Survey of Pesti-
cides in Drinking Water Wells. EPA's Pesticides in
Ground Water Database indicates numerous detections
of atrazine at concentrations above the MCL in ground
water in several States, including Delaware, Illinois,
Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri,
Nebraska and New York.
ENVIRONMENTAL FATE
USAGE PATTERNS Microbial activity possibly accounts for significant deg-
Atrazine is a widely used herbicide for control of radation of atrazine in soil. The effect of atrazine on these
broadleaf and grassy weeds in com, sorghum, range- °rgan.sms seems to be negligible. Photodegradation
land, sugarcane, macadamia orchards, pineapple, turf and volatilization are of little significance under most field
grass sod, aspap»^js-faresin/_arasslands_arass crops, cor)ditions.
DRINKING WATER STANDARDS
MCLG: 0.003 mg/L
MCL: 0.003 mg/L
HAL(child): 1 - to 10-day: 0.1 mg/L
Longer-term: 0.05 mg/L
HEALTH EFFECTS SUMMARY
Acute: EPA has found atrazine to potentially cause a
variety of acute health effects from acute exposures at
levels above the MCL. These effects include: congestion
of heart, lungs and kidneys; hypotension; antidiuresis;
muscle spasms; weight loss; adrenal degeneration.
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, a one- to ten-day exposure to
0.1 mg/L or upto a 7-year exposure to 0.05 mg/L.
Chronic: Atrazine has the potential to cause weight
loss, cardiovascular damage, retinal and some muscle
degeneration, and mammary tumors from a lifetime ex-
posure at levels above the MCL.
Cancer: There is some evidence that atrazine may
have the potential to cause cancer from a lifetime expo-
sure at levels above the MCL.
October 1995
Technical Version
Printed on Recycled Paper
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Atrazine does not hydrolyze in soils when uncatalyzed
even at elevated temperatures. However, the rate of
hydrolysis was found to drastically increase upon small
additions of sterilized soil, humic acid, and fulvic acid,
indicating atrazine hydrolysis could be catalyzed. Atr-
azine was completely hydrolyzed within 3-4 days at
extreme pHs. Alkaline hydrolysis proceeds twice as rapid
as acidic hydrolysis.
The average Koc value for 4 soils was determined to
be 122. Based on the Koc values for soils, atrazine is
expected to maintain a high to medium mobility class in
soils. However atrazine may also strongly absorb to
colloidal materials in the water column. Atrazine is more
readily adsorbed on muck or clay soils than on soils of low
clay & organic content. The downward movement or
leaching is limited by its adsorption to certain soil con-
stituents. Adsorption is not irreversible, and desorption
often occurs readily, depending on such factors as tem-
perature, moisture, and pH.
Photolysis of atrazine did not occur in water at wave-
lengths > 300 nm. At wavelengths greater than or equal
to 290 nm, the photolysis half-life of atrazine at a concen-
tration of 10 mg/l in aqueous solution at 15 deg C was 25
hr as compared to a half-life of 4.9 hr for identical
conditions with an acetone sensitizer added at a concen-
tration of 1 ml/100 ml.
Based upon a water solubility of 30 mg/l at 20 deg C
and a vapor pressure of 2.78X10'7 mm Hg at 20 deg C, the
Henry's Law Constant for atrazine can be calculated to
be 2.63X10-9 atm-cu m/mole, which indicates volatiliza-
tion of atrazine from water will not be environmentally
important.
Reactions with photochemically produced hydroxyl
radicals in the atmosphere may be important, with reports
of an atmospheric half-life of about 2.6 hr at an atmo-
spheric concentration of 5X10+5 hydroxyl radicals per cu
cm. (
Experimental log BCF values of 2.0 to 0.3 have been
reported for atrazine in six fish species. Atrazine levels in
the tissues of Brook trout were below the detectable limit
after 44 weeks of exposure at a mean concentration of
0.74 mg/l. Based on these measures of BCF and uptake,
atrazine is not expected to bioconcentrate. The biocon-
centration factor predicted from water solubility = 86
(calculated); predicted from soil adsorption coefficient =
7 (calculated).
OTHER REGULATORY INFORMATION
^^^^^^I^^^^^^^^^^^M
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 > 0.001 mg/L
METHOD NUMBERS
505; 507; 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
4 Other sources of lexicological 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
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