Toxicity of aircraft de-icer and anti-icer solutions to aquatic organisms

Laboratory studies were undertaken to assess the toxicity of industrial 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. Staticrenewal toxicity tests were performed at concentrations that bracketed published LC50 values for the primary ingredients (9-51 ml glycol/L) using fathead minnow (Pimephales promelas), Daphnia magna, Daphnia pulex, Ceriodaphnia dubia, and Photobacterium phosphoreum (Microtoxr̀) bioassays. Water from a stream that receives runoff from a large commercial airport was also tested during a late winter storm (March), and spring baseflow (April). The anti-icer solution was more toxic than the de-icer solution by two orders of magnitude (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 reported values for the primary ingredients. Toxic effects were observed in the March stream sample, but not the April sample. Significant inhibition of reproduction in C. dubia in the anti-icer and de-icer solutions occurred at 0.05 and 0.38 ml/L, respectively. Effects were observed in the Microtox assay at concentrations of 0.125 and 0.25 ml/L for the anti-icer and de-icer, respectively. Results suggest that the additives, rather than the glycols, are the major source of toxicity. Histological damage observed in fathead minnows primarily involved gill, kidney, and skin tissue, with the most prominent responses seen in fish exposed to the anti-icer solution. The de-icer solution elicited respiratory epithelial “disruption” and renal damage, and the anti-icer caused proliferative branchitis (hyperplastic response) and delamination of the epidermis from the dermis of the skin.