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Field observations on the ‘Exhaustion’ of suspension and emulsion sheep dip formulations
Author(s) -
Graham N. P. H.
Publication year - 1961
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740121113
Subject(s) - zoology , suspension (topology) , dieldrin , drop (telecommunication) , volume (thermodynamics) , chemistry , emulsion , toxicology , biology , pesticide , agronomy , mathematics , biochemistry , telecommunications , physics , quantum mechanics , homotopy , computer science , pure mathematics
The ‘ exhaustion ’, or decrease in insecticide concentration, of sheep dip washes comprising emulsions, suspensions or colloidal suspensions of BHC, dieldrin or DDT was investigated under field conditions. All showed some degree of exhaustion during dipping, but the emulsions exhausted more rapidly than the suspensions. the ‘ exhaustion rate ’ was constant for each formulation, and the percentage drop in concentration was closely related to the percentage of the wash volume removed on the sheep. If dip washes are replenished with a certain concentration, sheep carry out the same mean deposit of insecticide irrespective of the rate of exhaustion of the formulation, the frequency of replenishments or the volume of wash through which they pass. These three factors, however, affect the extent of the variation about the mean value. If the wash is replenished continuously at approximately the same rate as it is being removed by the sheep, the deposit of insecticide per sheep will be constant for all sheep, and, with exhausting formulations, this system will give the highest minimum deposit for any concentration of replenishments.