CHARACTERIZATION OF AIRCRAFT DEICER AND ANTI-ICER COMPONENTS AND TOXICITY IN AIRPORT SNOWBANKS AND SNOWMELT RUNOFF

Authors: CORSI, STEVEN - USGS; GEIS, STEVEN - HYGIENE LAB, WISCONSIN; LOYO-ROSALES, JORGE - UNIV OF MD; Rice, Clifford; SHEESLEY, REBECCA - UNIV OF WISCONSIN; FAILEY, GREG - GEN MITCHELL AIRPORT; CANCILLA, DEVON - WEST WASH UNIV

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2006
Publication Date: 5/15/2006
Citation: Corsi, S.R., Geis, S.W., Loyo-Rosales, J.E., Rice, C., Sheesley, R.J., Failey, G., Cancilla, D.A. 2006. Characterization of aircraft deicer and anti-icer components and toxicity in airport snowbanks and snowmelt runoff. Environmental Science and Technology. 40:3195-3202.

Interpretive Summary: Aircraft deicing operations are known sources of pollution, however,little is known about the chemistry, environmental fate and toxicity of the compounds present in them. Snowbank samples were collected from the primary snowbank within a medium sized airport for four years to characterize aircraft deicer and anti-icer (ADAF) components and their toxicity. Concentrations of ADAF components varied between years with the median glycol concentrations, the single most abundant compound in most formulations, ranging from 65 to 5,940 mg/L. Alkylphenol ethoxylates (APEO) and selected degradation products and 4 and 5-methyl-1H-benzotriazole were detected in snowbank samples as well as airport snowmelt runoff. Concentrations of APEO except for APEO degradation products were higher in snowbank samples than in runoff samples from the primary outfall where melt waters from the snowbank drain. APEO degradation occurred in snowbanks and/or during transport to the airport outfalls even in cold winter temperatures. Toxicity in Microtox assays indicates that an adverse effect remained in snowbanks after most glycol had been removed during rain and melt periods. Comparison of airport snowbanks with other urban snowbanks through organic marker analysis, Microtox assays, and C. dubia toxicity, indicate that a portion of toxicity from the airport snowbank is probably due to similar sources seen in commercial/industrial snowbanks, but increased toxicity in airport snowbanks cannot be explained by additional combustion or fuel contribution in the airport snow.

Technical Abstract: Snowbank samples were collected from the primary snowbank within a medium sized airport for four years to characterize aircraft deicer and anti-icer (ADAF) components and their toxicity. Concentrations of ADAF components varied between years with the median glycol concentrations periods ranging from 65 to 5,940 mg/L. Total glycol content in snowbanks ranged from 0.17 to 11.4 % of that applied to aircraft during the snowbank accumulation periods. The lowest concentrations and least glycol content in snowbanks occurred in snowbanks that were sampled after rainfall and melting periods. Concentrations of ADAF components in airport runoff was similar during periods of snowmelt as compared to active ADAF application periods, however, due to the long duration of snowmelt events with relatively large runoff volumes, greater masses of glycol per runoff event were transported during snowmelt events than ADAF application events. Alkylphenol ethoxylates (APEO) and selected degradation products and 4 and 5-methyl-1H-benzotriazole were detected in snowbank samples as well as airport snowmelt runoff. Concentrations of APEO except for APEO degradation products were higher in snowbank samples than in runoff samples from the primary outfall where melt waters from the snowbank drain. Data suggests that APEO degradation occurred in snowbanks and/or during transport to the airport outfalls even in cold winter temperatures. Toxicity in Microtox assays indicates that an adverse effect remained in snowbanks after most glycol had been removed during rain and melt periods. This data along with organic molecular marker analysis suggest the possibility of different transport mechanisms for different ADAF components with ADAF additives such as APEO selectively retained in snowbanks after most glycol was no longer present. Comparison of airport snowbanks with other urban snowbanks through organic marker analysis, Microtox assays, and C. dubia toxicity, indicate that a portion of toxicity from the airport snowbank is probably due to similar sources seen in commercial/industrial snowbanks, but increased toxicity in airport snowbanks as compared to commercial/industrial snowbanks can not be explained by additional combustion or fuel contribution in the airport snow. Organic markers suggest that ADAF additives increase toxicity in snow even after glycol has been removed.