Dacthal

Chemical Properties

Colorless to gray crystalline solid. Practically odorless.

Chemical Properties

Colorless crystalline

Uses

Selective, nonsystemic, preemergent herbicide to control most annual grasses and many broad-leaved weeds.

Uses

Dacthal is used as a preemergent herbicide.

Uses

Pre-emergent herbicide.

Definition

ChEBI: Dacthal is a diester and a methyl ester.

Potential Exposure

DCPA is an alkyl phthalate; benzene- dicarboxylic acid herbicide, pesticide pre-emergent herbi- cide is used on annual broadleaf weeds and grasses in a wide spectrum of vegetable crops.

Environmental Fate

Soil. Bartha and Pramer (1967) reported that DCPA was degraded by soil microorganisms via cleavage of the herbicide molecule into propionic acid and 3,4-dichloroaniline. The acid was mineralized to carbon dioxide and water and two molecules of 3,4-dichloroaniline were condensed to form 3,3′4,4′-tetrachloro-azobenzene. Metabolites identified in soil and turfgrass thatch are monomethyl tetrachloroterephthalate and 2,3,5,6-tetrachloroterephthalic acid (Hartley and Kidd, 1987; Krause and Niemczyk, 1990). Residual activity in soil and the half-life in soil were reported to be approximately 3 months (Hartley and Kidd, 1987; Worthing and Hance, 1991)

Shipping

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Incompatibilities

May react violently with strong oxidi- zers, bromine, 90% hydrogen peroxide, phosphorus trichloride, silver powders or dust. Incompatible with silver compounds. Mixture with some silver compounds forms explosive salts of silver oxalate.

Waste Disposal

Incineration in a unit with efficient gas scrubbing. Containers must be disposed of properly by following package label directions or by con- tacting your local or federal environmental control agency, or by contacting your regional EPA office.