By-Products in Earth Construction: Environmental Assessments

In Finland, some industrial residuals (by-products) have been used in earth construction since the 1970s. The lack of a general code of practice on environmental assessments of by-product utilization has led to nonuniform approval practices. In most countries, environmental standards are mainly based on health risks related to contaminant leachability. Leaching tests and solubility standards vary. Standards on waste composition and mix proportions have also been adopted in many countries. Based on a survey of practices in various countries, a hierarchical procedure is presented for the environmental assessments relevant to the utilization of by-products. In this model, the verification of environmental suitability can be based on a composition analysis, studies on leaching of contaminants, or a risk assessment procedure. In the next stage, composition and solubility standards (MPE values) need to be issued. Despite some identified drawbacks and data gaps, the Dutch methodology proved to be the most appropriate with respect to the derivation of substance-specific MPEs.