Denitrification in Intrinsic and Specific Groundwater Vulnerability Assessment: A Review

Abstract

Several groundwater vulnerability methodologies have been implemented throughout the years to face the increasing worldwide groundwater pollution, ranging from simple rating methodologies to complex numerical, statistical, and hybrid methods. Most of these methods have been used to evaluate groundwater vulnerability to nitrate, which is considered the major groundwater contaminant worldwide. Together with dilution, the degradation of nitrate via denitrification has been acknowledged as a process that can reduce reactive nitrogen mass loading rates in both deep and shallow aquifers. Thus, denitrification should be included in groundwater vulnerability studies and integrated into the various methodologies. This work reviewed the way in which denitrification has been considered within the vulnerability assessment methods and how it could increase the reliability of the overall results. Rating and statistical methods often disregard or indirectly incorporate denitrification, while numerical models make use of kinetic reactions that are able to quantify the spatial and temporal variations of denitrification rates. Nevertheless, the rating methods are still the most utilized, due to their linear structures, especially in watershed studies. More efforts should be paid in future studies to implement, calibrate, and validate user-friendly vulnerability assessment methods that are able to deal with denitrification capacity and rates at large spatial and temporal scales.

Three-Dimensional Hole Size (3DHS) Approach for Water Flow Turbulence Analysis over Emerging Sand Bars: Flume-Scale Experiments

“…As reported in Figure 12, the depth-averaged occurrence probability corresponding to even octagonal bursting events is noticeably larger (at least two times) than that associated with odd ones at the measuring points "2" and "4", placed near the upstream end of the emerging sand bar, while it decreases with 3DHS values systematically. On the contrary, nearby the downstream end of the experimental bar, at the measuring points "6" and "10", the depth-averaged occurrence probabilities corresponding to the odd octagonal turbulence bursting events were higher than those observed in the case of even bursting events [88][89][90][91][92][93][94].…”

Hybridization of DRASTIC Method to Assess Future GroundWater Vulnerability Scenarios: Case of the Tebessa-Morsott Alluvial Aquifer (Northeastern Algeria)

“…On the other hand, the concept's suitability for regional-scale assessment is currently the main conceptual drawback, since the numerical simulation requires detailed aquifer information that is not available everywhere, especially on the national scale. Moreover, it is of paramount importance to include in the assessment the pollutants' transport dynamic, nitrogen formation and removal processes in both vadose and saturated zones [53], along with the role of fracture and sinkholes in nitrogen leaching [54], to ensure proper management of land and water resources.…”

A Conceptual Framework for Modeling Spatiotemporal Dynamics of Diesel Attenuation Capacity: A Case Study across Namyangju, South Korea

“…One of the most widely used models, DRASTIC [5] employs seven hydrogeological properties as the input parameters to assess the intrinsic groundwater vulnerability. Unfortunately, however, it failed to include the natural attenuation of contaminants in a vadose zone [6][7][8]. A previous study by Woo et al (2022) addressed the effect of soil physicochemical properties on the overall attenuation capacity (AC) of a vadose zone soil against diesel, a type of refined petroleum product [9].…”