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Despite considerable research effort put into characterizing environmental aspects of disposal and construction with high- volume 'non-hazardous' waste materials, there is still lack of satisfactory knowledge of their life cycle leaching behavior in the actual field conditions. This often results in false- negative errors in the long-term environment impact assessment (EIA) and severe damage to the renewable ground water resources in the area of the disposal sites either in the operational or post-closure period. This statement has been exemplified in two case studies: (1) Powerplant ash pond under operation sited in the Erai River basin (Maharastra, India), with open water circuit; (2) Reclaimed fly ash (FA) pond in a post-closure period at the dewatering stage sited in a sand quarry (Silesia, Poland). In the first case, EIA on the basis of the monitoring of entirely excess water discharged into the river, caused serious failure in preventing deterioration of usable ground water resources in several communities within and down-gradient of the FA pond. The second case study based on screening pore solution along the vertical profiles of the FA pond displayed deep transformation of FA properties in the post-closure period. At this stage, FA acidification and massive heavy metal release from its matrix due to the change of the saturation zone conditions into the vadose zone occurred. These examples clearly show a need of properly designed and operated life cycle screening/monitoring of the large-volume waste sites to provide an early alert to prevent degradation of recoverable ground water resources. Some concepts of cost-effective monitoring/screening for an early alert have been proposed.
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