Environmental Sampling and Analysis of Coal Fly Ash Intended for Use in Roads

Abstract

Government and private organizations around the world are currently encouraged to recycle wastes that were formerly placed in toxic waste landfills based on concerns for human and environmental health impacts. As a result, potentially toxic wastes are being diverted from monitored landfills to consumer and construction products. Unfortunately, the shift of these materials from the status of “landfilled wastes” to “commercial products” has not been accompanied by routine product testing to determine product chemical and physical consistency over time. One such waste, coal fly ash, has been strongly recommended by government agencies and the private sector for use in Minnesota road projects, both mixed with soil beneath roads and in pavement. To determine the potential human and environmental health hazards posed by the use of coal fly ash in transportation systems, as part of its liability limitation activities, the authors have conducted extensive library and laboratory research, telephone interviews and e-mail dialogues with coal fly ash experts concerning coal fly ash chemical contaminant levels, environmental mobility, chemistry, toxicology, waste/product variability, and regulatory considerations. Preliminary findings indicate great variation in coal fly ash contaminant levels which may be due, in part, to the types of coal burned, combustion conditions, pollution control equipment, ash size fraction, and analytical chemistry techniques used to quantitate ash sample concentrations. Rigorous testing of several analytical methods, including neutron activation analysis, is underway to determine which methods provide the most reliable analytical data.