| Chemical Abstract Number (CAS #) |
333415
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| Synonyms | Diazinon |
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Spectracide | Phosphorodithioic acid, O,O-diethyl O-(2-isopropyl-6-methyl-4-pyrimidinyl) ester | Dipofene | Diazitol | Basudin |
| Analytical Method |
EPA Method 8141A |
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| Molecular Formula | C12H21N2O3PS |
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| Use | INSECTICIDE FOR NON-AGRICULTURAL USE (EG, HOME & GARDEN) & FOR
AGRICULTURAL USE (EG, ALFALFA & CORN).
ACARICIDE
Insecticide (use against fire ants permitted by EPA).
A non-systemic insecticide, its main applications are in fruit trees, horticultural crops, maize,
potatoes, rice, sugarcane, tobacco and vineyards for a wide range of sucking and leaf-eating
insects. Also, used against flies in glasshouses, mushroom houses.
TO CONTROL TICKS & OTHER INSECTS ON ANIMALS & PREMISES CONTROLLING
FACE FLY LARVAE IN MANURE.
VET: Used against flies and ticks in veterinary practice.
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| Consumption Patterns | NON-AGRICULTURAL USE-EG, IN HOME, GARDEN & LAWN PRODUCTS, 43%;
ALFALFA, 12%; CORN, 5%; SOYBEANS, 5%; VEGETABLES, 5%; DECIDUOUS FRUITS
& NUTS, 3%; WHEAT, 2%; COTTON, 2%; SORGHUM, 2%; OTHER FIELD CROPS-EG,
PEANUTS, RICE, SUGARCANE, SMALL GRAINS, & CITRUS, 21% (1982 INSECTICIDE
USE).
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| Apparent Color | COLORLESS LIQUID
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| Odor | FAINT ESTER-LIKE ODOR
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| Boiling Point | 83-84 DEG C AT 2X10-3 MM HG
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| Molecular Weight | 304.36
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| Density | SP GR: 1.116-1.118 @ 20 DEG C/4 DEG C
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| Environmental Impact | Diazinon's release to the environment will result from its manufacture and use as a
non-systemic insecticide used principally on rice, fruit trees, vineyards, sugarcane, corn, tobacco,
potatoes and horticultural crops and in pest control strips. If it is released to soil it will not
strongly bind to the soil and will be expected to exhibit moderate mobility in the soil. Hydrolysis
has been reported to be slow at pH >6, but may be significant in some soils. Biodegradation will
be expected to be a major fate process in soils with reported half-lives of <1,2, and 5 weeks in
non-sterile soils. Photolysis may be significant on the surface of soils, but evaporation from the
surface of soils is not expected to be a significant transport process. If it is released to water it
may sorb to sediments moderately but it will not bioconcentrate in aquatic organisms. Hydrolysis
may be a significant fate process with reported half-lives of 31 days (pH 5), 185 days (pH 7.4),
and 136 days (pH 9.0) at 20 deg C and 2-3 weeks in distilled water at pH 6 at room temperature;
major products of hydrolysis are 2-isopropyl-4-methyl-6-hydroxypyrimidine and diethyl
thiophosphoric acid or diethyl phosphoric acid. Biodegradation and photolysis may be significant
fate processes in natural waters. Evaporation may be significant with a half-life of 46 days
predicted for evaporation from a river 1 m deep, flowing at 1 m/sec with a wind velocity of 3
m/sec. If diazinon is released to the atmosphere it may be subject to direct photolysis since it
adsorbs light >290 nm. The estimated vapor phase half-life in the atmosphere is 4.83 hrs as a
result of reaction with photochemically produced hydroxyl radicals. Exposure to diazinon will
occur through the ingestion of contaminated water and food and the inhalation of contaminated
air. Exposure will also occur through occupational exposure.
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| Environmental Fate | DIAZINON IS RELATIVELY NONPERSISTENT IN SOIL. MOST DIAZINON
APPLIED IS LOST FROM SOIL THROUGH CHEMICAL & BIOLOGIC DEGRADATION
WITHIN ABOUT 2 MO OF APPLICATION. ABOUT 46% OF DIAZINON ADDED TO
NEUTRAL AQ SOLN REMAINED AFTER 2 WK.
TERRESTRIAL FATE: If diazinon is released to soil, it will not be expected to strongly bind to
the soil and will be expected to exhibit moderate mobility in the soil. Hydrolysis has been reported
to be slow at pH >6, but may be significant in some soils. Biodegradation will be expected to be a
major fate process in soils with reported half-lives of <1, 2, and 5 weeks in non-sterile soils
compared to half-lives of 6, 6.5, and 12.5 weeks in sterile soils(1,2). Overall persistence in soils
has been reported to be 3-14 weeks . Photolysis may be significant on the surface of soils.
Evaporation from the surface of soils is not expected to be a significant transport process.
AQUATIC FATE: If diazinon is released to water it may sorb to sediments moderately but will
not bioconcentrate in aquatic organisms. Hydrolysis may be a significant fate process with
reported half-lives of 31 days (pH 5), 185 days (pH 7.4), and 136 days (pH 9) at 20 deg C and
2-3 weeks in distilled water at pH 6 at room temperature ; major products of hydrolysis were
2-isopropyl-4-methyl-6-hydroxypyrimidine and diethyl thiophosphoric acid or diethyl phosphoric
acid . Biodegradation may be a significant fate process in natural waters. Photolysis may be an
important fate process based on 36% photolysis in pH 7 buffer solution exposed to light >290 nm
in 24 hrs . Evaporation may be significant with a half-life of 46 days predicted for evaporation
from a river 1 m deep, flowing at 1 m/sec with a wind velocity of 3 m/sec .
ATMOSPHERIC FATE: If diazinon is released to the atmosphere it may be subject to direct
photolysis since it adsorbs light >290 nm. The estimated vapor phase half-life in the atmosphere is
4.83 hrs as a result of reaction with photochemically produced hydroxyl radicals.
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| Drinking Water Impact | DRINKING WATER: California, 54 wells, detected, not quantified . Ottawa, in
Ontario, Canada, tap water, not detected (<1 parts per trillion ) . Japan tap water, 0.9-4.7
ppt .
SURFACE WATER: USEPA STORET database, 21,978 whole water samples, 0-33.4 ppm, avg
1.7 ppb, 359 filtered water samples, 0-1.0 ppb, avg 0.031 ppb . National surface water
monitoring program, 1976-80, 1.2% pos samples, max concn 2.38 ppb . US selected streams,
1968-71, 448 samples, 1.6% pos, 0.01-0.10 ppb, avg of pos, 0.04 ppb . Beaver River, Beaver
Falls, PA, 0.09 ppb . Ontario, Canada, 1975-77, 11 agricultural watersheds, 0.1% pos samples,
not detected-0.15 parts per trillion, max individual avg, <0.01 parts per trillion, overall avg <0.01
parts per trillion . Diazion was not detected (detection limit = 1 ppb) in a 1985-1987 study of
drainage ditch water on farms in British Columbia, Canada in an area where the pesticide is
known to be used even though the pesticide was sporadically found in the sediments of the
ditches(6).
EFFL: Effluent from wastewater treatment plants, 10 plants, 10% pos .
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