The persistence of crude benzene hexachloride in the soil

Abstract It is shown that the residual benzene hexachloride (BHC), determined analytically in a loam soil, is a function of the amount of benzene hexachloride (13% y‐isomer) (referred to in this paper as BHC‐13) applied per acre and the time elapsing after application. A significant correlation was found between the level of residual BHC and degree of tainting of potatoes grown in the same soil. The taint measurements involved in the present work are in agreement with the much more numerous and independent measurements that formed the basis of an earlier paper. BHC‐13 thoroughly worked into the top six inches of a loam soil, at rates up to 8 lb. per acre, was lost at an exponential rate of approximately 50% per annum over the period of the trial. Provided that the application of BHC‐13 to the soil does not exceed 1/4 1b. /acre annually, the risk of growing tainted potatoes on loam soil in this country seems slight; surface application at rather higher rates may also be safe.