Municipal and Industrial Waste Application in Agriculture: Why Standard Data Analysis Underestimates Adverse Impacts.

Promotion of “beneficial use” diverts municipal and industrial waste materials to agricultural applications for which they were not designed.  Wastes approved for use in agriculture can provide short-term benefit from macronutrients (e.g., nitrogen, phosphorus, potassium), micronutrients, organic matter additions or liming reaction. Such waste materials, however, tend to be highly variable over time, heterogeneous and unpredictable with respect to properties or contaminants that could lead to long-term harmful effects in soils. The current emphasis on beneficial use and recycling focuses on short-term economic benefits while largely neglecting less certain longer-term effects that may be harmful but are difficult to quantify.  

         This presentation explores sources of uncertainty and risk inherent to “beneficial use” of wastes in agriculture. It is proposed that risks of adverse effects have been systematically underestimated by standard approaches to data analysis that assume Gaussian distributions of measured variables and set the threshold for proof of harm too high for protection of our vital resources of soil and water. There is also the problem of “missing evidence” because not all contaminants in waste materials and their possible impacts have been identified and studied.  In summary, it is argued that research efforts directed to waste application on farmland have been inadequate to allow a confident assessment of long-term impacts of individual wastes on particular soils, agricultural systems and ecosystems.