|Chemical Abstract Number (CAS #)||
|Synonyms||Chlorpropham||Carbamic acid, (3-chlorophenyl)-, 1-methylethyl ester||CIPC||Isopropyl 3-chlorocarbanilate||Chloro-IPC||Furloe||Metoxon||Preventol
||EPA Method 632|
Link to the National Library of Medicine's Hazardous Substances
Database for more details
on this compound.
|Use|| CHLORPROPHAM ACTS AS HIGHLY SELECTIVE PREEMERGENCE & EARLY
POSTEMERGENCE HERBICIDE; IT EFFECTIVELY CONTROLS MANY ANNUAL
GRASSY & BROADLEAF WEEDS; APPLICATION DURING LATE FALL & WINTER FOR
CONTROL OF SOME PERENNIAL WEEDS.
FOR CONTROL OF WEEDS IN ALFALFA, LIMA & SNAP BEANS, BLUEBERRIES, CANE
BERRIES, CRANBERRIES, CARROTS, LADINO CLOVER, GARLIC, SEED GRASS,
PEAS, ONIONS, SPINACH, SUGAR BEETS, TOMATOES, SAFFLOWER, SOYBEANS,
GLADIOLI, WOODY NURSERY STOCK. ALSO FOR INHIBITING POTATO SPROUTING
AND SYSTEMIC SUCKER CONTROL IN TOBACCO.
|Consumption Patterns|| HERBICIDE, OF WHICH APPROXIMATELY 82% IS USED ON SOYBEANS AND
18% ON VEGETABLES (1975)
|Apparent Color|| HONEY COLOR ; LIQUID @ ROOM TEMP ; LIGHT BROWN CRYSTALLINE
SOLID ; Light tan powder ; Faint characteristic odor
|Odor|| VERY LITTLE ODOR
|Boiling Point|| 149 DEG C AT 2 MM HG
|Melting Point|| 40.7-41.1 DEG C
|Molecular Weight|| 213.68
|Density|| 1.180 @ 30 DEG C
|Sensitivity Data|| Mild irritant.
|Environmental Impact|| Chlorpropham is a herbicide used on several crops to control annual grasses and many
broad-leaved weeds. The release of chlorpropham in the environment occurs during its
manufacture and particularly from its use in the field. Chlorpropham adsorbs strongly to soil and
clays and will exhibit low mobility in soil. In soil, chlorpropham is transformed primarily by
biodegradation. The half-life of chlorpropham from field soil is about 30 days. If released in water,
chlorpropham will adsorb strongly to sediment and particulate matter in the water column.
Although a slow process, biodegradation should be the major pathway for degradation. Loss of
chlorpropham due to hydrolysis, photolysis and volatilization should not be important loss
processes. Chlorpropham will not bioconcentrate in aquatic organisms. In the atmosphere,
chlorpropham will react with hydroxyl radicals with an estimated half-life of 5.5 hrs. Partial
removal of atmospheric chlorpropham will also occur by dry and wet deposition. Chlorpropham
has been infrequently detected in groundwater around sprayed farmlands. Workers who apply
chlorpropham are the most likely people to be exposed to chlorpropham. Exposure would be
expected by inhalation and dermal contact. The general population may be exposed to low levels
of chlorpropham in food.
|Environmental Fate|| TERRESTRIAL FATE: Biodegradation via enzymatic hydrolysis will be the major
process by which chlorpropham will be lost from most soils . The loss of chlorpropham from
soil due to photolysis on soil surface may not be important . Vaporization loss of chlorpropham
from dry soil should be negligible, but increases with increase in temperature, moisture content
and air flow rate . The leaching of chlorpropham from three types of soil was low and more
than 90% of chlorpropham was found in the upper inch of the soil after 4 cm of rain .
Depending on the nature of soil and climatic conditions, the field half-life of chlorpropham in soil
range from less than 30 days to 65 days with an average half-life of 30 days .
AQUATIC FATE: Based on a mean rate constant of 2.6X10-14 l/organism-hr and a bacterial
concn of 5X10 8 organisms/l in water, the half-life of chlorpropham has been estimated to be
2208 days . Therefore, biodegradation of chlorpropham should not be important in clear bodies
of water. However, biodegradation may become important if the bacterial population in
water is several orders of magnitude higher than 10 8 organisms . The hydrolysis half-life of
chlorpropham in the pH range 5-9 has been estimated to be greater than 10000 days . The
estimated minimum half-life for the direct sunlight photolysis of chlorpropham in clear surface
layers of water is 121 days . Based on the available data , it is concluded that biodegradation
may be the dominant degradation pathway for chlorpropham in polluted waters, but photolysis
may become the dominant degradative pathway in unpolluted waters. Based upon the
moderate water solubility (89 ppm) and the low vapor pressure (7.5X10-6 mmHg) ,
chlorpropam should not volatilize from water or bioconcentrate in aquatic organisms(5,SRC).
ATMOSPHERIC FATE: From its estimated vapor pressure of 7.5X10-6 mm Hg at 25 deg
C(1,4), chlorpropham is expected to be present partially in the vapor phase and partially in the
particulate form in air(2,SRC). Based on an estimation method(3,5), vapor phase chlorpropham
should be removed from the atmosphere with an estimated half-life of 5.5 hrs due to reaction with
photochemically produced hydroxyl radicals. Partial removal of particulate chlorpropham
from the air may occur by dry deposition. Chlorpropham may also be washed out of the air
MOIST SOIL TREATED WITH CHLOROPROPHAM TO GIVE CONCN OF 100 PPM AI
WAS INCUBATED IN POLYETHYLENE BAGS @ 23 DEG C FOR 30 WK. CO2
EVOLUTION WAS DETERMINED WEEKLY. CHLOROPHAM WAS DEGRADED
RAPIDLY IN FIRST 6WK & 5% OF ORIGINAL AMT COULD BE DETECTED 30 WK
|Drinking Water Impact|| GROUNDWATER: Chlorpropham has been detected in one groundwater sample from
28 of California's 58 counties at a concn of 8.0 ug/l(1-3).