Inhibition of Corn Growth by Aldrin and the Insecticide's Fate in the Soil, Air, Crop, and Wildlife of a Terrestrial Model Ecosystem

Abstract

The subsurface application of aldrin to the vermiculite substrate of a terrestrial model ecosystem resulted in a 9.5% reduction in the plant height of corn ( Zea mays , ‘Rieds Yellow Dent Synthetic’) at 2 wk postplanting when the application rate simulated one lb AI/acre (or 1.12 kg/ha), and a reduction of 14.3% occurred at a rate simulating 2 lb AI/acre (or 2.24 kg/ha). Similar results occurred in greenhouse studies using Drummer loam soil and commercially formulated aldrin. A simulated one lb AI/acre application of [ ¹⁴ C]aldrin produced an initial concentration in vermiculite of 2.24 ppm, which decreased to 0.622 ppm of total residue after 20 days. Simultaneously, aldrin products were released into the atmosphere; most of the volatilization occurred during the initial 5 days, and the vapor density progressively decreased with time. The com acquired a pesticide residue of 2.85 ppm after 2 wk of growth; 78% of the residue was in the roots and 22% was in the shoots. The major ¹⁴ C-compounds detected in the roots were aldrin and dieldrin, but neither of these compounds was the major ¹⁴ C-metabolite in the aerial portion of the crop. The pesticide residue detected in the entire vole, Microtus ochrogaster , which fed at will in the ecosystem during the terminal 5 days of the experiment, was 3.81 ppm; the concentration within its mammary glands was 20.2 ppm, 99.0% of which was dieldrin. The system appears useful for screening the potential environmental impacts of pesticides.