| Chemical Abstract Number (CAS #) |
120365
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| Synonyms | Dichlorprop |
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Propanoic acid, 2-(2,4-dichlorophenoxy)- | 2,4-DP | Cornox RK | 2-(2,4-dichlorophenoxy)propionic acid | Hedonal DP |
| Analytical Methods |
EPA Method 515.1 |
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EPA Method 515.2 |
EPA Method 555 |
EPA Method 615 |
EPA Method 8150B |
EPA Method 8151 |
| Molecular Formula | C9H8Cl2O3 |
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| Use | When used as directed at 2.5 lb per acre controls Polygonum persicaria, Polygonum
lapathifolium, Polygonum convolvulus and Spergula arvensis in addition to many of the weeds
controlled by mecoprop.
HERBICIDE FOR BRUSH CONTROL ON RANGELAND, RIGHTS-OF-WAY, AQUATIC
WEEDS. IT ISUSED FOR CONTROL OF POLYGONUM SPECIES, CALIUM APARINE
(CLEAVERS), CHICKWEED, IN CEREALS, PASTURES, TURF, ALONE OR MIXED
WITH OTHER HORMONE TYPE PHENOXY HERBICIDES.
Control of broad-leaved aquatic weeds; and chemical maintenance of embankments and roadside
verges. Also used to prevent premature fruit fall in apples.
Particularly effective for the control of Bilderdykia convolvulus. It also controls Galium
aparine and Stellaria media but is not consistently effective against Polygonum aviculare. 267]
Selective pre- and post-emergence herbicide
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| Apparent Color | COLORLESS CRYSTALLINE SOLID; WHITE TO TAN, CRYSTALLINE SOLID
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| Odor | ODORLESS; Faint phenolic odor
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| Melting Point | 117.5-118.1 DEG C
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| Molecular Weight | 235.07
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| Density | ABOUT 1.42
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| Sensitivity Data | Affects the skin, eyes, and mucous membranes of the resp tract.
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| Environmental Impact | Dichloroprop is released directly to the environment through its use as an agricultural
herbicide. If released to soil, adsorption will not be an important fate process (experimental Kocs
of 50-62) and, therefore, dichloroprop is expected to leach. The half-life in soil typically ranges
from 8 to greater than 103 days; the US Dept of Agriculture's Pesticide Properties Database lists a
soil half-life of 10 days. Insufficient data are available to assess the importance of biodegradation
in soil and water. If released to water, volatilization and bioconcentration in fish will not be
important. In groundwater, half-lives of 196 to 1,286 days were observed; however, degradation
pathways were not specified. If released to the atmosphere, dichloroprop will exist in the vapor
and particulate phases; vapor phase dichloroprop degrades rapidly by reaction with
photochemically produced hydroxyl radicals (estimated half-life of 12 hours). Physical removal
from air may occur through dry deposition. Worker exposure to dichloroprop occurs through
dermal contact and inhalation of dust.
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| Environmental Fate | Terrestrial fate: In soil, metabolism involves degradation of the side-chain to
2,4-dichlorophenol, ring hydroxylation, and ring opening.
TERRESTRIAL FATE: Half-lives vary in soils. Dichloroprop was reported to persist for greater
than 103 days in soil . Half-lives in 3 forest soils ranged from 8-12 days . According to all
available data in the U.S. Department of Agriculture's Pesticide Properties Database, a
degradation half-life of 10 days was estimated for dichloroprop in soil . Furthermore,
biodegradation data are limited. One study suggests dichloroprop may not appreciably biodegrade
in soils(7). Experimental Kocs of 50-62 in 3 soils indicate that dichloroprop will have a low
potential to adsorb to soil. Detection in groundwater(5-6) indicates a leaching
potential.
AQUATIC FATE: Half-lives in groundwaters at 15 deg C were measured to be 1,235 and 824
days at initial concns of 1 and 5 ug/l dichloroprop, respectively, with a lag-period of several
months . Half-lives in groundwaters at 22 deg C were measured to be 1,286 and 196 days at
initial concns of 1 and 5 ug/l dichloroprop, respectively, with a lag-period of several months .
No hydrolysis data were located under environmental conditions. Experimental Kocs of 50-62 in
3 soils indicate that dichloroprop will have a low potential to adsorb from the water column to
sediments and suspended material. An estimated BCF value of 23 and Henry's Law
constant of 1.22X10-8 atm-cu m/mole at 25 deg C suggest that bioconcentration in fish and
volatilization from water will not be important.
A vapor pressure of about 1.4X10-5 mm Hg at 20-25 deg C can be estimated from an estimated
Henry's Law constant of 1.22X10-8 atm-cu m/mole at 25 deg C and a water solubility of 350
mg/l at 20 deg C . According to a suggested classification scheme , dichloroprop will exist in
the vapor and particulate phases in the ambient atmosphere. It will degrade in the vapor phase by
reaction with photochemically produced hydroxyl radicals with an estimated half-life of about 12
hrs(4,SRC). Physical removal from air by dry deposition will also occur.
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| Drinking Water Impact | SURFACE WATER: According to a survey carried out in 1987, dichloroprop was one
of the pesticides most frequently found in Norwegian surface waters ; no quantitative data were
reported. Between 1971-77, dichloroprop was detected at maximum concns of 0.007-7.15 ug/l in
surface water from 11 water quality districts in Western Canada . Dichloroprop was
qualitatively detected in the Trent and Saugeen Rivers, aquatic systems in the Lake Ontario and
Huron water basins, respectively . During a Jan 1981 to Dec 1985 water monitoring analysis of
the mouths of Grand, Saugeen and Thames River (Ontario, Canada), dichloroprop was detected
at concns of the 1 ug/l magnitude in 1 of 96 Grand River samples, 1 of 143 Saugeen River
samples, and 16 of 222 Thames River samples .
GROUNDWATER: In a 1969 to 1978 monitoring analysis of well water from 237 wells from
agricultural areas of Ontario, Canada, dichloroprop was detected in only two wells at levels of
1.1-10 and 101-1,000 ug/l . Dichloroprop was detected at a concn range of 0.05-0.1 ug/l in
water samples from 206 waterworks wells in various parts of the Federal Republic of
Germany .
EFFL: Dichloroprop wasdetected in landfill leachate from a site in New Jersey at respective
average concns of 5 and 1 ug/l in 1989 and 1990. It was detected in landfill leachage from a site in
Oregon at an average concn of 2 ug/l (in 1990). Dichloroprop was also found at at concn of 2 ug/l
in 1989 and 3 ug/l in 1990 in landfill leachate from a site in Wisconsin .
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