Experiments on Toxicity of DDT to Wildlife

Abstract

Studies were made of 4 spp. of birds ana 3 of mammals for detn. of the levels of acute and chronic poisoning with DDT. Results obtained indicate considerable variation in the toxic action due to variation in rate of absorption, elimination and/or differences in physiological reaction in the animals studied. Five-weeks-old bobwhite quail (Colinus virginianus) fed at levels of 0.05 and 0.04% in the diet died and there was a 50% mortality of birds fed at the 0.025% level. Some losses resulted with as little as 0.005%. Adult wild mallard (Anas platyrhynchos) and pintail ducks (Dafila acuta) evidenced toxicity for all levels above 0.025% in the diet. Lesions were observed only in starlings (Sturnus vulgaris) dosed at 600 mg./kg. level. Five of 9 birds dosed at this level were released on the 28th day as normal. Three of 4 cottontail rabbits (Sylvilagus floridanus) fed at 0.4% level in the diet died by the 21st day. The minimal lethal dose for this species was determined to be near 2500 mg./kg. level. Chronic toxicity in meadow mice (Microtus pennsylvanicus) occurred at 0.2% in the diet. All animals fed at the 0.4% died by the 28th day and all animals fed at levels below 0.2% survived the 31-day test. The chronic toxicity tests with white-footed mice (Peromyscus leucopus) showed production of clinical symptoms in those fed diets containing DDT in excess of 1%.