United States
Environmental Protection
Agency.
Office of Water
4601
EPA811-F-95-003bb-T
October 1995
**EPA
Primary Drinking
Water Regulations
Simazine
CHEMICAL/ PHYSICAL PROPERTIES
CAS NUMBER: 122-34-9
COLOR/ FORM/ODOR:
White powder
M.P.: 225° C B.P.: N/A
VAPOR PRESSURE: 6.1x10"9
OCTANOL/WATER PARTITION (Kow):
LogKow = 2.18
DENSITY/SPEC..GRAV.: 1.3g/ml at 20° C
SOLUBILITY: 5 mg/L of water at 20° C;
Soluble in water
ODOR/TASTE THRESHOLDS: N/A
SOIL SORPTION COEFFICIENT:
Koc =135 (measured); slight to high
mobility in soil, depending upon other
factors
HENRY'S LAW COEFFICIENT:
4.63x10"10 atm-cu rn/mole
EtlOCONCENTRATION FACTOR:
BCF <10 in fish; not expected to
bioconcentrate in aquatic organisms.
TRADE NAMES/SYNONYMS:
Aktinit; Batazina; Bitemol;
CAT(Herbicide); CDT; Cekuzina-S;
Geigy 27,692; Gesatop; Herbazin;
Herbex; Hungazin; Premazine; Primatol
S; Pricep; Printop; Radocon; Simadex;
Tafazine; Zeapur; 2-chloro-4,6-
bis(ethylamino)-1,3,5-Triazine
Its major use is on com where it is often combined with
AAtrex. Other herbicides with which simazine is com-
bined include: paraquat, on apples, peaches; Roundup
orOustfornoncropuse; Surflan on Christmas trees; Dual
on corn and ornamentals.
The amount of simazine used annually in the USA was
estimated in 1985 to be 4.8 billion pounds.
DRINKING WATER STANDARDS
MCLG: 0.004 mg/L
MCL: 0.004 mg/L
HAL(child): 1-to 10-day: 0.07 mg/L
Longer-term: 0.07 mg/L
HEALTH EFFECTS SUMMARY
Acute: EPA has found simazine to potentially cause RELEASE PATTERNS
the following health effects from acute exposures at simazine may be released into the environment via
levels above the MCL: weight loss, changes in blood. eff|uents at manufacturing sites and at points of applica-
Drinking water levels which are considered "safe" for tion where it is employed as a herbicide.
short-term exposures: For a 10-kg (22 Ib.) child consum- Since simazjne is not a listed chemical in the Toxics
ing 1 liter ofwater per day, up to a 7-year exposure to 0.07 Re|ease Inventory, data on releases during its manufac-
m9/L. . ture and handling are not available.
Chronic: Simazine has the potential to cause the
following health effects from long-term exposures at ENVIRONMENTAL FATE
levels above the MCL: tremors; damage to testes, kid- If released to water, simazine is not expected to adsorb
neys, liver and thyroid; gene mutations. to sediment and suspended particulate matter, or to
Cancer: There is some evidence that simazine may volatilize. Persistence depends upon many factors in-
have the potential to cause cancer from a lifetime expo- eluding degree of algae and weed infestation. Simazine
sure at levels above the MCL. residues may persist up to 3 years in soil under aquatic
field conditions. Dissipation of simazine in pond and lake
USAGE P rr water was variable, with half-lives ranging from 50 to 700
days. Slow biodegradation of simazine may occur in
Simazine is a pre-emergence herbicide used for con- water based upon the slow biodegradation observed in
rol of broad-leaved and grassy weeds on a variety of soi| simazine is fairly resistant to hydrolysis. However,
deep-rooted crops such as artichokes, asparagus, berry chemical hydrolysis of simazine may be more important
:rops, broad beans, citrus, pome and stone fruits or- environmentally than biodegradation at low pH or when
shards, and others. It is also used on non-crop areas various catalysts are present
such as farm ponds, fish hatcheries, etc.
October 1995
Technical Version
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If released to soil, the mobility of simazine will be
expected to vary from slight to high in soil-types ranging
from clay soils to sandy loams soils, respectively, based
upon soil column, soil thin-layer chromatography, and
Koc experiments. Therefore, it may leach to groundwa-
ter; adsorption of simazine in soil has been observed to
increase as titratable acidity, organic matter and, to a
lesser extent, clay content of the soil increased..
Simazine may be susceptible to slow hydrolysis in soil
based upon reported half-lives for degradation (purport-
edly mainly soil catalyzed hydrolysis) of simazine in two
soil 45 and 100 days.
Simazine can be utilized by certain soil microorgan-
isms as a source of energy and mineralization. No
degradation of simazine was detected in a soil suspen-
sion test without the addition of glucose as an energy
source suggesting that degradation of simazine in these
soil experiments was due to co-metabolism.. Reported
persistence of simazine in soil varies from a half-life of <1
month to no degradation being observed in 3.5 months.
Simazine is not expected to volatilize from near surface
soils or surfaces under normal environmental conditions.
If released to the atmosphere, simazine is expected to
exist almost entirely in the particulate phase. Vapor
phase reactions with photochemically produced hydroxyl
radicals in the atmosphere may be important (estimated
half-life of about 2.8 hr). Photolysis may be an important
removal mechanism in the atmosphere.
Simazine has a low potential to bioaccumulate in fish.
BCFs: 0.76-0.95, green sunfish ; <1, bluegill sunfish; 5,
bluegill sunfish; 2, catfish. Other BCF values up to 55
have been reported in the literature.
The most probable exposure should be occupational
exposure which may occur through dermal contact or
inhalation at places where simazine is produced or used
as a herbicide.
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 > 0.00007 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
* 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
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