Comparison of two model environmental burdens with massive light non-aqueous phases liquids (LNALP) pollution – the extent of pollution identified by geological survey vs. reality uncovered by remediation

Abstract

The paper deals with the results of exploration and remediation in two railway operations. Locomotive depots in Štúrovo and Leopoldov belonged to heavily polluted sites with the occurrence of light non-aqueous phases liquids (LNAPL) on the groundwater table. Remediation began on the sites in 2018. The results of the pre-remediation surveys did not indicate the presence of large volumes of pollution in the form of free phase, however, during the remediation LNAPL flowed into new wells. At the same time, the spreading of LNAPL accumulations and the progressing of pollution in dissolved form by groundwater has not been confirmed. Comparison of surveys and remediation points to various facts that must be considered when evaluating the degree of pollution of the site. It is necessary to perceive the whole space of the railyard as possible source of pollution. Remediation project should not be based solely on the presence of LNAPL. Its presence and the risk it poses must be verified. Outcomes of activities, based on limited data, may in that case differ from the remediation goals.