TOXICITY OF AIRCRAFT DEICER AND ANTI-ICER SOLUTIONS TO AQUATIC ORGANISMS

Laboratory studies were undertaken to assess the toxicity of industria l mixtures of aviation de-icers and anti-icers. Various additives and contaminants are present in these solutions at proportions of 10 to 20 % of the total volume. Static-renewal toxicity tests were performed at concentrations that bracketed published LC50 values for the primary i ngredients (9-51 ml glycol/L) using fathead minnow (Pimephales promela s), Daphnia magna, Daphnia pulex, Ceriodaphnia dubia, and Photobacteri um phosphoreum (Microtox(R)) bioassays. Water from a stream that recei ves runoff from a large commercial airport was also tested during a la te winter storm (March), and spring baseflow (April). The anti-icer so lution was more toxic than the de-icer solution by two orders of magni tude (96-h LC50 range 0.03-0.44 ml/L, 3.02-13.48 ml/L, respectively). Both types of solutions exhibited greater toxicity than previously rep orted values for the primary ingredients. Toxic effects were observed in the March stream sample, but not the April sample. Significant inhi bition of reproduction in C. dubia in the anti-icer and de-icer soluti ons occurred at 0.05 and 0.38 ml/L, respectively. Effects were observe d in the Microtox assay at concentrations of 0.125 and 0.25 ml/L for t he anti-icer and de-icer, respectively. Results suggest that the addit ives, rather than the glycols, are the major source of toxicity. Histo logical damage observed in fathead minnows primarily involved gill, ki dney, and skin tissue, with the most prominent responses seen in fish exposed to the anti-icer solution. The de-icer solution elicited respi ratory epithelial ''disruption'' and renal damage, and the anti-icer c aused proliferative branchitis (hyperplastic response) and delaminatio n of the epidermis from the dermis of the skin.