Effects of DDT Mosquito Larviciding on Wildlife: Part I. The Effects on Surface Organisms of the Routine Hand Application of DDT Larvicides for Mosquito Control

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Abstract
In-vestigations were made on the effects of DDT dusts, emulsions and solns. in 22 ponds in the vicinity of Savannah. Stable emulsions in an organic solvent, water and an emulsi-fier were detrimental to aquatic organisms. Solns. of DDT in fuel oil and dusts were selected as being most satisfactory. Applications were made weekly or bi-weekly over periods as long as four months. "Square foot surface samples" were taken before, and 48 hours after, treatment. DDT dust caused little damage although the seasonal trend was somewhat shifted. DDT fuel oil solutions killed the larger surface insects even at concentrations as low as 0.025 lb. DDT per acre. Seasonal effects were marked: Chironomidae, Hemiptera, Coleoptera and Ephemeroptera decreased while Oligochaetes, Nematodes, and Copepods increased. Tables give details of the counts. The results were difficult to evaluate but did indicate reduction in fish food although it was doubtful if this reduction had any significant effect on the fish population.