Determination of selected fate and aquatic toxicity characteristics of acrylic acid and a series of acrylic esters

Acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate are commercially important and widely used materials. This paper reports the results of a series of fate and aquatic toxicity studies. The mobility in soil of acrylic acid and its esters ranged from 'medium' to 'very high'. Calculated bioconcentration factors ranged from 1 to 37, suggesting a low bioconcentration potential. Acrylic acid and methyl acrylate showed limited biodegradability in the five day biochemical oxygen demand (BOD5) test, while ethyl acrylate and butyl acrylate were degraded easily (77% and 56%, respectively). Using the OECD method 301D 28-d closed bottle test, degradability for acrylic acid was 81% at 28 days, while the acrylic esters ranged from 57% to 60%. Acrylic acid degraded rapidly to carbon dioxide in soil (t1/2 < 1 day). Toxicity tests were conducted using freshwater and marine fish, invertebrates, and algae. Acrylic acid effect concentrations for fish and invertebrates ranged from 27 to 236 mg/l. Effect concentrations (LC50 or EC50) for fish and invertebrates using methyl acrylate, ethyl acrylate, and butyl acrylate ranged from 1.1 to 8.2 mg/l. The chronic MATC for acrylic acid with Daphnia magna was 27 mg/l based on length and young produced per adult reproduction day and for ethyl acrylate was 0.29 mg/l based on both the reproductive and growth endpoints. Overall these studies show that acrylic acid and the acrylic esters studied can rapidly biodegrade, have a low potential for persistence or bioaccumulation in the environment, and have low to moderate toxicity.     

A conceptual model for response to Arctic oil spills

The potential for oil spills in Arctic regions has increased significantly because of the development of petroleum resources. Response to an oil spill in the Arctic is likely to be much slower than that in the temperate region because of the remoteness of the area and its severe climate. In the face of these unique problems, accurate prediction of the extent and subsequent movement of an oil spill is vital to any cleanup effort. Presented is the framework of a program to study the movement of oil spills in the Arctic. Existing models of oil spreading and polar ice dynamics are reviewed and areas where new model development is required are defined. A system design is developed that may be used for developing a plan to act in the event of a major spill.     

Evaluation of alternatives for extending the life of landfills

Given the difficulty, as well as the high cost, of siting and constructing municipal solid waste (MSW) landfills it is incumbent on landfill managers to evaluate all practical measures to extend the useful life of existing landfills. This necessitates not only identifying potential methods to extend their life, but also the means to assess at what time horizons in the landfill's life such measures are cost effective. Some typical examples of methods to extend their life include: size reduction of incoming waste, improved in-place compaction density, use of alternative daily cover, waste diversion, and accelerating the degradation to enhance attendant settlement on the MSW. Most, if not all, of these methods incur capital/operating costs that must be evaluated. The methodology for this analysis is presented using the existing landfill at Andersen Air Force Base (AAFB), Guam, as a model for the procedure. The Landfill Extension Model (LEM) computer program was written to model the AAFB landfill and to analyze various extension alternatives to include compaction, shredding, alternative daily cover and operation outsourcing (contracting). The LEM computer program may be used to evaluate any landfill operation and is consequently useful for evaluating any existing landfill. It was found that by utilizing all of the proposed alternatives the life of AAFB landfill could be extended from 10 years to 48 years.