Technical Factsheet on: SIMAZINE
List of Contaminants
As part of the Drinking Water and Health pages, this fact sheet is part of a larger publication:
National Primary Drinking Water Regulations
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 the following
health effects from acute exposures at levels above the MCL:
weight loss, changes in blood.
Drinking water levels which are considered "safe" for short-term
exposures: For a 10-kg (22 lb.) child consuming 1 liter of water
per day, up to a 7-year exposure to 0.07 mg/L.
Chronic: Simazine has the potential to cause the following
health effects from long-term exposures at levels above the MCL:
tremors; damage to testes, kidneys, liver and thyroid; gene
mutations.
Cancer: There is some evidence that simazine may have the
potential to cause cancer from a lifetime exposure at levels
above the MCL.
Usage Patterns
Simazine is a pre-emergence herbicide used for control of
broad-leaved and grassy weeds on a variety of deep-rooted crops
such as artichokes, asparagus, berry crops, broad beans, citrus,
pome and stone fruits orchards, and others. It is also used on
non-crop areas such as farm ponds, fish hatcheries, etc.
Its major use is on corn where it is often combined with AAtrex.
Other herbicides with which simazine is combined include:
paraquat, on apples, peaches; Roundup or Oust for noncrop use;
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.
Release Patterns
Simazine may be released into the environment via effluents at
manufacturing sites and at points of application where it is
employed as a herbicide.
Since simazine is not a listed chemical in the Toxics Release
Inventory, data on releases during its manufacture and handling
are not available.
Environmental Fate
If released to water, simazine is not expected to adsorb to
sediment and suspended particulate matter, or to volatilize.
Persistence depends upon many factors including degree of algae
and weed infestation. Simazine residues may persist up to 3 years
in soil under aquatic field conditions. Dissipation of simazine
in pond and lake water was variable, with half-lives ranging from
50 to 700 days. Slow biodegradation of simazine may occur in
water based upon the slow biodegradation observed in soil.
Simazine is fairly resistant to hydrolysis. However, chemical
hydrolysis of simazine may be more important environmentally than
biodegradation at low pH or when various catalysts are present.
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 groundwater; 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 (purportedly mainly soil
catalyzed hydrolysis) of simazine in two soil 45 and 100 days.
Simazine can be utilized by certain soil microorganisms as a
source of energy and mineralization. No degradation of simazine
was detected in a soil suspension 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.
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): Log Kow = 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 m/mole
Bioconcentration 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
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
Analysis:
| Reference Source |
Method Numbers |
| EPA 600/4-88-039 |
505; 507; 508.1; 525.2 |
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
List of Contaminants
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