In stored-product fumigations mainly methyl bromide and phosphine are used. These toxic gases can contaminate the environment.
A harmful effect on vegetable and animal organisms cannot fundamentally be excluded.
The threshold concentrations of methyl bromide and phosphine in air were determined for water cress and lettuce. These species were chosen because of their high sensitivity representing other species of plants. Whereas lettuce was harmed already at about 400 mg CH3Br/m3, on water cress plants at 1400 mg CH3Br/m3 external harmful changes couldn't be found. The threshold concentration for lettuce treated with phosphine is between 3 and 8 mg PH3/m3.
There is no difference between the development of water cress seeds in soil, which had been treated for 3 days with 4 mg–36g CH3Br/m3 or 20–1400 mg PH3/m3 and not treated soil. At high PH3-concentrations a higher growth of water cress plants occurred.