Phosphine

CAS RN: 7803-51-2
UN/NA: 2199

Environmental Fate

TERRESTRIAL FATE: Phosphine is a gas(1) and, therefore, is expected to dissipate rapidly from both moist and dry soil(SRC). Studies have shown that sub-surface phosphine may bind to soil(2-3).
TERRESTRIAL FATE: The sorption and desorption of phosphine from wheat treated with a concentration of 0.5-5 mg/kg wheat were determined at 25, 45, and 85 deg C. The desorbed phosphine was extracted from the air by passing through a cold trap. Most of the phosphine was desorbed in the first 2-3 days but small amounts continued to desorb for many weeks following treatment. After 220 days of aeration, phosphine was still present and desorbing. Even when the temp was increased to 85 deg C for several days, unreacted phosphine still desorbed slowly from wheat. Corn aerated 26 days desorbed 0.004 ng/g in 2 days.
AQUATIC FATE: Phosphine is a gas and, therefore, is expected to dissipate rapidly from water surfaces(1). Biodegradation, hydrolysis and bioconcentration are not expected to be important fate processes when compared to dissipation(SRC).
ATMOSPHERIC FATE: Phosphine is a gas at ambient temperature(1). Gas-phase phosphine is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and has a reported atmospheric half-life of 5 hours(2).
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