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The environmental impacts of Ice Sheartrade mark, an alternative highway deicer, have been evaluated using standard laboratory tests; biochemical oxygen demand (BOD) tests, chemical oxygen demand (COD) tests, acute rainbow trout bioassays, and phytotoxicity tests were used. Ice Shear consists of equimolar sodium acetate and sodium formate. The organic matter of the deicer can be readily degraded microbiologically in the natural environment with a slow rate of degradation at lower temperatures but an increased rate at higher temperatures. At elevated temperatures, highway runoffs of the deicer may reduce the level of dissolved oxygen in the receiving waters to cause an adverse impact. However, the apparent activation energy calculated for the BOD rate of Ice Shear is low (8.78 kcal mole-1), indicating that the temperature variation may not significantly influence the biodegradation of the deicer compound. Ice Shear appears relatively harmless to aquatic animals, showing a high 96-h LC50 value (16.1 g/L) derived for rainbow trout (Oncorhynchus mykiss). Ice Shear causes minimal toxicity to representative roadside vegetation; herbaceous (e.g., sunflowers, beans, and lettuce) and woody (e.g., pine seedlings) plants. Rather, the deicer at low concentrations (less than 2 g/kg soil) seems to work as a fertilizer, promoting the yield of biomass. The test results indicate that Ice Shear poses minimal environmental disturbance in both aquatic and terrestrial ecosystems.

A recombinant Escherichia coli expressing the Neurospora crassa metallothionein gene (NCP) has previously been shown to remove low levels of Cd and other metals from solution. For further development as a biosorbent, the encapsulation of the NCP is investigated by various matrices. The NCP was encapsulated in alginate, chitosan-alginate or kappa-carrageenan, and its physical properties characterized. Results indicated that encapsulation in alginate resulted in fragile beads, whereas encapsulation in kappa-carrageenan or chitosan-alginate provided more physical and chemical integrity to the beads. Maximal heavy metal removal by cells encapsulated in carrageenan occurred within 3 h, while a gradual increase in removal was observed up to 24 h for cells encapsulated in chitosan-alginate. Metal removal by cells encapsulated in alginate beads was lower than those encapsulated in carrageenan or chitosan-alginate.

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