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Deicer Products under Development to deicers at lower temperatures and fathead minnows (P. promelas) slightly more sensitive to deicers During the past two decades there have been a at lower temperatures. One complication when con- number of efforts to develop more environmentally ducting toxicity tests with samples containing deicer friendly deicers. Some of these new products are en- is low dissolved oxygen resulting from high BOD. A tering the market, while others are not yet available successful method for improving dissolved oxygen commercially. Octagon Process, Inc., introduced a Type I ADF based on propylene glycol and glycerol levels during fathead minnow tests is to reduce the that is described as having lower 5-day BOD (BOD5) number of fish per replicate and reduce the sample and aquatic toxicity compared to many previous volume. Type I formulations. Battelle recently released an ADFAAF and a PDM, both based on glycerol as Representativeness of Laboratory Analyses. Results the primary FPD. Battelle is also working on alter- of BOD and toxicity tests performed in a laboratory native PDM formulations that are less damaging to under controlled light and temperature conditions aircraft components and less expensive than current provide valuable ecological information, but such products. Foster-Miller has previously developed two conditions do not mimic environmental conditions, Type I fluids and one Type II fluid, with the objective especially during deicer application events. of producing environmentally advantaged formu- lations that consider BOD and toxicity. METSS TOXICITY CHARACTERIZATION Corporation has developed two Type I fluids using agriculturally based products intended to further Baseline toxicity tests were conducted on seven reduce toxicity and BOD. While some of these for- Type I formulations, four Type IV formulations, and mulations have been certified according to SAE three PDMs. One group of five Type I products re- standards, problems involving residue formation, sulted in LC50 averaging about 10,000 mg/l, whereas foaming, and unfavorable thickening after applica- two products showed LC50 near 30,000 mg/l. Type IV tion have been encountered during field testing. The deicer products consistently demonstrated much prospects for near-term commercial availability of greater toxicity than the Type I products, with LC50 these products are unclear. near 2,500 mg/l and lower. Toxicity results were sim- ilar for marine and freshwater species. Toxicity in fractionated Type I and Type IV Methodological Issues deicers was associated with the presence of poly- The literature review identified a number of ethoxylated nonionic surfactants, including both APE methodological issues. surfactants and aliphatic alcohol ethoxylate surfac- tants. Relatively high concentrations of triazole-based Biochemical Oxygen Demand. BOD5 testing and corrosion inhibitors in one Type IV deicer triggered extended-length BOD testing pose unique challenges toxicity in toxicity identification and evaluation (TIE) in samples containing deicers. Issues include deter- assays. Toxicity in pavement deicers is associated pri- mining proper dilutions to characterize BOD accu- marily with the FPD. rately, properly acclimating microorganisms, and the possibility of seeds with insufficient microorganism BIOCHEMICAL OXYGEN DEMAND densities. AND CHEMICAL OXYGEN DEMAND Analysis of Additives. There are no standard tech- BOD and COD were characterized in seven niques for determining concentration of deicer addi- deicer formulations, including ethylene glycol and tives such as benzotriazoles and APE. Techniques propylene glycol formulations of Type I ADF, ethyl- are currently in flux, necessitating regular review of ene glycol and propylene glycol formulations of Type literature to evaluate the most current methods. IV AAF, a liquid PDM based on potassium acetate, and solid PDMs based on sodium acetate and sodium Aquatic Toxicity. The results of acute deicer toxicity formate. Expanded testing was conducted on one for- testing at low temperature were not dramatically dif- mulation of propylene glycol Type I ADF, one propy- ferent from those at standard temperatures, with the lene glycol Type IV AAF, and one potassium acetate freshwater crustacean C. dubia slightly less sensitive PDM to determine decay rates over a 40-day period 4