Determination Of The Spreading-velocity Of Nitroaromatic Compounds In Aquifers Represented On The Basis Of Column Tests Under In Situ Conditions
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Groundwater in the discharge area of former ammunition production facilities often reveals severe contamination by production residues and waste products. Thus, these can cause a health hazard to human beings in the case untreated water is consumed. Based on a case study dealing with a more than 1.5 km elongated contamination plume consisting of various nitroaromatic compounds (NACs) such as TNT, DNT, DNB, TNB, ADNT and DNN the transportation mechanisms were investigated for implementing a reliable risk-assessment. Column tests were carried out by using both local soil in undisturbed cores and the contaminated local groundwater. The investigations showed that the sorption and respectively the velocity of transportation of every NAC strongly correlates with the percentage composition of clay and organic matter in the soil as well as with their own concentration in solution, resulting in complex interactions between single NACs. Nevertheless the parameters obtained from the column tests for retardation, adsorption-capacity and the resultant mobility of the NACs are confirmed by the observed spreading of the contamination plume in situ. Although a time-dependent distribution of the NACs in the wells downstream can be observed, no notable degradation of their total concentration could be ascertained up to now. Therefore calculations were made in view of the amount of the former waste products, their amount of NACs, the soil parameters quoted above and the dissolution-capacity of NACs for determining the former infiltration and respectively the expected duration of dissolution and desorption. Keywords: nitroaromatic compounds, sorption, spreading-velocity, multicompound system.
nitroaromatic compounds, sorption, spreading-velocity, multicompound system.