SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 75990
CASRN 75-99-0
SynonymsDalapon
2,2-Dichloropropanoic acid
Analytical Methods EPA Method 515.3
EPA Method 552.1
EPA Method 615
EPA Method 8151
Molecular FormulaC3H4Cl2O2

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use IN NON-CROP AREAS SUCH AS ROADSIDES, RAILWAYS, DITCHES. ALSO IN CERTAIN ESTABLISHED CROPS SUCH AS ALFALFA, ASPARAGUS, FLAX, POTATOES, RAPE SEED, SUGAR BEETS. For quackgrass, bermudagrass, johnsongrass, other perennial and annual grasses, cattails, rushes. Often preplant for established perennial grasses in cropland, noncropland areas, irrigation ditch banks. Translocates to the roots of most species as a growth regulator. Selective herbicide; growth regulator HERBICIDE SODIUM SALT
Consumption Patterns Non-food use, 92.9% (89.9% use on rights of way); main food crop treated was sugarbeet (6.7% of total) (1984) California use, calculated from table
Apparent Color LIQUID; COLORLESS
Odor Acrid
Boiling Point 190 deg C
Melting Point 20 DEG C
Molecular Weight 142.97
Density 1.4014 @ 20 DEG C
Odor Threshold Concentration 2,500 mg/cu m
Sensitivity Data SKIN - MODERATE IRRITATION UPON REPEATED PROLONGED CONTACT. EYES - MODERATE IRRITATION . INHALATION - DUSTS MAY BE IRRITATING TO UPPER RESP TRACT.
Environmental Impact Dalapon is released directly to the environment in its use as a herbicide for the control of annual and perennial grasses. If released to soil, microbial degradation and leaching appear to be the important environmental fate processes. Dalapon leaches readily in soil; however, under conditions favorable for microbial growth, microbial degradation will probably proceed at a faster rate than leaching. In the absence of microbial action, dalapon degradation in soil is slow. The resultant average persistence of dalapon at recommended rates of application has been reported to be two to four weeks in most agricultural soils during the growing season, although a persistence of six months has been observed in soils of various forests and tree nurseries. If released to water, microbial degradation, hydrolysis, and photolysis are potentially important in the removal of dalapon. The hydrolysis half-life of dalapon and its salts in water is on the order of several months at temperatures less than 25 deg C, with the hydrolysis forming pyruvic acid. Under conditions favorable for microbial growth, dalapon decomposition via microorganisms will probably be complete within one month which will diminish the importance of chemical hydrolysis. Direct photolysis in water may be possible, although photolytic rates have not been investigated under environmental conditions. Aquatic volatilization, adsorption to sediments, or bioconcentration are not expected to be significant. If released to the atmosphere, dalapon will react in the vapor-phase with photochemically produced hydroxyl radicals at an estimated half-life rate of 72.3 days. Atmospheric removal via washout may be possible since dalapon is extremely water soluble. Occupational exposure to dalapon may occur through dermal and inhalation routes associated with the formulation and application of dalapon herbicide.
Environmental Fate TERRESTRIAL FATE: Microbial degradation and leaching appear to be the important fate processes in soil with respect to dalapon. Dalapon leaches readily in soils. Under conditions favorable for microbial growth, microbial degradation will probably proceed at a faster rate than leaching . In the absence of microbial action, dalapon degradation in soil is slow . The resultant average persistence of dalapon at recommended rates of application has been reported to be two to four weeks in most agricultural soils during the growing season . Dalapon has been observed to breakdown completely in Hawaiian soils within a few weeks . Using a plant bioassay under greenhouse conditions (28 deg C), dalapon persisted only 4-8 days in muck soil, 8-16 days in loam and silty clay loam soils, 16-32 days in sandy loam soil, and 32-64 days in silt clay soil . The speed of degradation is greatly dependent on soil conditions favorable to microorganisms, with favorable conditions being temperatures of 20 to 30 deg C, adequate soil moisture, and a pH range of 5.3 to 7.5 . The persistence of dalapon in the soil of various forests and tree nurseries has been observed to be as long as 6 months(4,SRC). AQUATIC FATE: The environmental fate processes which are potentially important for removing dalapon from natural waters include hydrolysis, microbial degradation, and photolysis. The hydrolysis half-life of dalapon and its salts is on the order of several months at temperatures less than 25 deg C, with the hydrolysis forming pyruvic acid. Under conditions favorable for microbial growth, dalapon decomposition via microorganisms will probably be complete within one month which will diminish the significance of chemical hydrolysis . Direct photolysis of dalapon in water is possible since it absorbs UV light above 290 nm; however, rates of photolysis has not been investigated under environmental conditions. Aquatic volatilization, adsorption to sediments, or bioconcentration are not expected to be significant. ATMOSPHERIC FATE: The vapor-phase reaction of dalapon with photochemically produced hydroxyl radicals has been estimated to be 72.3 days in typical atmosphere . Since dalapon is extremely water soluble (> 80 g/100 g water at 25 deg C) , atmospheric removal via washout may be possible.
Drinking Water Impact NEGLIGIBLE CONCN OF DALAPON WOULD REMAIN IN WATER AFTER WATER TRAVELED DISTANCE OF 32.2-40.2 KM . DRINKING WATER: Dalapon has been detected in drinking water concentrates collected from Cincinnati OH (in Oct 1978 and Jan 1980) and Seattle WA (in Nov 1976) . Dalapon was detected in 1 out of 237 wells sampled during 1969-78 in Ontario, Canada at a concentration range of 0.1-1 ppb . EFFL: Dalapon has been detected in effluent concentrates collected from advanced waste treatment facilities in Lake Tahoe CA (in Nov 1974) and Washington DC (in Sept 1974) .

DISCLAIMER - Please Read

Florida-Spectrum List of Services
Florida-Spectrum Homepage