EXPERIMENTAL STUDIES ON THE TOXICITY OF BENZENE HEXACHLORIDE (BHC) IV. EFFECTS OF LINDANE VAPOR TO INSECTS AND MAMMALS

摘要

Summarizing the above-mentioned experiments, in the case of fumigation of 0.1 gr. lindane in one cubic meter of atmosphere, if we let the rats inhale the gas or aerosol for one hour to five hours each day, they could all survive without showing any change for 127 days but the lindane vapor in this concentration killed 50 Sarcophaga in 100% within several hours, and if there is no toxicity for the higher animals, this concentration is exceedingly effective.But by the histopathological examination, because of the considerable long inhalation test of 127 days by one hour each successive day, trachea, liver, kidney, suprarenal, heart, brain and spinal cord showed no changes, but lung showed slight hemorrhage and bronchitis, moreover, the group of animals which inhaled five hours each day for 127 days showed the disorders in the trachea and lung, then we must take care of the lesion effect of the lindane vapor for the respiratory organs.Thus, the more the concentration of the lindane vapor increased, the more the insecticidal effect increased; at the same time the damages for the high mammals became extreme and the toxicity of the inhaled vapor following the fumigation of lindane raised our interest more.The tests of the insecticidal effects of gamma BHC for various insects were considerably made by many research workers in the past and its effects were ascertained.Sweetman et al. said that the continuous fumigation of the gamma BHC in the concentration of 1 gr/24 hours/26, 000 cub, ft, in the barn made the flies in the barn decrease gradually. Sullivan said as follows: an acetone solution of lindane was put in a fiber-glass filter and after evaporating the acetone, lindane gas was gradually vaporized. At that time about 25 mg lindane was vaporized for an hour in 8, 500 cub, ft. room and in this density, 80 to 100% of flies and mosquitoes died within twenty-four hours exposed for an hour in the vapor. Ten minutes exposure caused 74 to 100% death-rate, besides the house flies were said to die within 90 minutes; the effects for human being and domestic animals, however, were not ascertained and so its use in the house of human being and domestic animals was not recommended by him.Moore examined the insecticidal action of 0.36 to 2.84 gr/20, 000 cub, ft, lindane gas every day by an automatic fumigation apparatus and the density of 1 gr/ 20, 000 cub, ft./24 hrs, was enough to prevent the breeding of houseflies.About the toxicity of this gas, some already sent warnings and the permitted quantity decided by the “Interdepartmental Committee on Pest Control” was 1 gr/ 15, 000 to 20, 000 cub, ft./day.Moore examined its toxicity for calf, horse, sheep, pig, rats, chicken, tropical fish, canary and pigeon, and said it was not harmful for calf, horse, sheep and pig, but toxic for canary and tropical fishes, then the concentration of 1 gr/20, 000 cub, ft. was effective for many insects and safe for human being, at the same time this concentration caused canary sensitive.Sullivan et al, said even 0.02 to 0.2 microgram lindane was effective for small flying insects if used for long time and could be used for warm-blooded animals taking care of it toxicologically.Besides, Kodama et a1. tested the effects of gamma BHC aerosol to mice, and reported the toxicity of gamma BHC and the stimulation to the mucous membrane and con junctiva of rabbit. Kano examined the toxicity of the vaporized gas of gamma BHC, and according to the finding of the blood of guinea pig inhaled for thirty minutes, reported the damage of hematopoetic function of the marrow system and anaemic symptoms.Thus, the gas and aerosol of gamma BHC are excellent in the insecticidal action and the few degrees of density used are sufficient, while, according to the study of Furubayashi et al., the same density of lindane vapor did not effect at all for some considerable many insects, and did not decide the lowest concentration and the effective time as a whole.In the case of