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EXTOXNET PIP - BROMACIL http://ace.ace.orsl.edu/in(o/ex~oxne~pips/bromacil.hu • • invertebrates [8]. • Effects on other organisms: Bromacil is not toxic to honeybees [ 1 ]. Environmental Fate: Breakdown in soil and groundwater: Bromacil binds, or adsorbs, only slightly to soil particles, is soluble in water, and is moderately to highly persistent in soil. Its half-life is about 60 days, but may be as much as 8 months under some conditions [11]. Soil persistence is correlated to the organic content of the soil [8,75]. At 18 months after 22.4 kg of bromacil were sprayed on abandoned field sites, residues of the herbicide were detectable, in decreasing amounts, in loamy sand, silt loam, silty clay loam, and light silty clay loam soils. Organic matter content, cation exchange capacity, total nitrogen, and soluble salt concentrations were significantly correlated with residue persistence [8]. Bromacil is expected to leach quite readily through the soil and contaminate groundwater. The amount of leaching is dependent on the soil type and the amount of rainfall or irrigation water. The potential for bromacil to leach and contaminate groundwater is greatest in sandy soils. In normal soils, it can be expected to leach to a depth of 2 to 3 feet [8]. Tests show that at increased temperatures and long exposures to sunlight, [here is very little loss of bromacil from dry soil. It does not readily volatilize, nor does it break down in sunlight [8]. Laboratory studies show that 5 to 30% of bromacil is lost 6 to 9 weeks after application to the soil, as carbon dioxide [8]. Breakdown in water: Bromacil is estimated to have a 2-month half-life in clean river water, which is low in sediment [76]. Breakdown in vegetation: In plants, bromacil is taken up rapidly by the roots and slightly absorbed through the leaves [58]. When it is applied at ]0 ppm, some types of algae show slowed growth, but most strains are unaffected [75]. Improper application of bromacil will destroy shade trees and other desirable vegetation [76]. Physical Properties: • Appearance: Bromacil is an odorless, white crystalline solid [1]. • Chemical Name: 5-bromo-6-methyl-3-(1-methylpropyl)-2,4(IH,3H)pyrimidinidione [1] • CAS Number: 314-40-9 • Molecular Weight: 261.10 • Water Solubility: 815 mg/L @ 25 C [1] • Solubility in Other Solvents: xylene v.s.; acetone v.s.; acetonitrile v.s.; ethyl alcohol v.s.; sodium hydroxide v.s. [1] • Melting Point: 158-159 C [1] • Vapor Pressure: 0.033 mPa @ 25 C [1] • Partition Coefficient: Not Available • Adsorption Coefficient: 32 (acid) [11] Exaosure Guidelines: • ADI: Not Available • MCL: Not Available • RfD: Not Available • PEL: Not Available • HA: 0.09 mg/L [74] • TLV: 10 mg/m3 (8-hour) [17] 3 of4 11/18/98 10:40 AM1':