Julia Derx

• PhD
• Assistant Professor at TU Wien

River restoration typically aims at improving and preserving the ecological integrity of rivers and their floodplains. Restoration projects may, however, decrease the ability of the riparian zone to remove contaminants as the river water moves into the aquifer, especially during high river discharges. The purpose of this paper is to analyze several...

Riverbank fi ltration is considered an effi cient method for removing contaminants from infi ltrated surface water in the subsurface. Despite indications that changing water temperatures affect the biochemical and biological mediated removal processes of contaminants, the impact of temperature induced fl uid viscosity and density effects on contami...

The three-dimensional groundwater flow patterns in a gravel bar at the Danube east of Vienna were investigated and are discussed in this paper. The observed groundwater level gradients are highly dynamic and respond very quickly to changes in the river water levels. A variably saturated groundwater model was calibrated to the data to describe the c...

Correction for ‘Exploring the variability of PFAS in urban sewage: a comparison of emissions in commercial versus municipal urban areas’ by N. Krlovic et al. , Environ. Sci.: Processes Impacts , 2024, 26 , 1868–1878, https://doi.org/10.1039/D4EM00415A.

Per- and Polyfluoroalkyl substances (PFAS) are a class of persistent chemicals, whose impact has been observed in various environmental compartments. Wastewater treatment plants (WWTPs) are considered a major emission pathway of PFAS, specifically in the context of the aquatic environment. The goal of this study was to develop a compartmentalized,...

PFAS in an urban environment can come from various sources. The main activity in the area, i.e. commercial versus municipal, can influence the overall loads and speciation of PFAS in the examined wastewater.

The Laboratory Biological Activity Reaction Test (LAB-BART) is an easy-to-use assay that utilizes metabolic capabilities to process an array of substrates to semi-quantitatively assess the presence of potentially adverse bacteria in a groundwater sample. Here, we evaluated LAB-BART for the assessment of groundwater samples obtained under real-life...

PFAS are a class of synthetic chemicals used for many industrial and domestic purposes. However, once released in the environment, they are persistent, mobile and toxic. One of the most important transport routes to drinking water is through riverbank filtration. Although this is usually an effective strategy for removing many organic compounds, it...

The objective of this article is to provide an overview of concentrations of PFAS in different environmental media in the upper Danube catchment area and to draw initial semi-quantitative conclusions about potentially relevant emission pathways of these substances. Within the framework of the EU project PROMISCES, 32 PFAS individual substances were...

The impacts on faecal pollution analysis using nucleic acid-based methods, such as PCR and sequencing, in health-related water quality research were assessed by rigorous literature analysis. A wide range of application areas and study designs has been identified since the first application more than 30 years ago (>1,100 publications). Given the con...

We developed an innovative approach to estimate the extent of fecal pollution sources for urban river catchments. The methodology consists of 1) catchment surveys complemented by literature data where needed for probabilistic estimates of daily produced fecal indicator (FIBs, E. coli, enterococci) and zoonotic reference pathogen numbers (Campylobac...

To guarantee proper protection from fecally transmitted pathogen infections, drinking water wells should have a sufficiently large setback distance from potential sources of contamination, e.g. a nearby river. The aim of this study was to provide insight in regards to microbial contamination of groundwater under different flow velocities, which can...

[This corrects the article DOI: 10.3389/fmicb.2021.668778.].

Groundwater and riverbank filtrate are valuable resources for drinking water production. The presence of pathogens in the environment poses a threat to drinking water quality and human health. This chapter summarizes the current approaches for evaluating pathogen fate and transport in the environment, their removal during subsurface transport in po...

Karst landscapes cover large parts of our globe. The aquifers laying below their surface are of high importance for global drinking water supply—although many of them being vulnerable to chemical and fecal pollution. This chapter intends to give an overview on the available knowledge on the microbiology of karst aquifers, typical sources of microbi...

Recent developments in water resource monitoring have increased the demand for the reliable identification of faecal pollution sources, also defined as microbial (faecal) source tracking (MST). Standardized faecal indicator bacteria (SFIB) enumeration does not directly support MST, as SFIB occur in animal and human sources. The aim of this study wa...

The alluvial backwater areas of the Danube are valuable ecological habitats containing important drinking water resources. Due to the river regulation and the construction of power plants, the river water levels and natural dynamics of the backwater areas continuously decline, threatening their typical characteristics. The aim of this study was to...

Riverbank filtration systems are important drinking water resources. Aquifers of riverbank filtration systems are subjected to considerable dynamics concerning the quantity and quality of the infiltrating water. The microbiological quality is mainly jeopardized by faecal contamination of the main river. Besides, water quality can be impacted by gro...

Groundwater contamination and transport of viruses and bacteria in aquifers are a major concern worldwide. To ascertain the ability of these aquifers to remove pathogens, tracer tests with microbial surrogates are carried out. These tests are laborious and may require special permits, and therefore, column tests are often done instead. Unfortunatel...

Riverine wetlands are important natural habitats and contain valuable drinking water resources. The transport of human- and animal-associated fecal pathogens into the surface water bodies poses potential risks to water safety. The aim of this study was to develop a new integrative modeling approach supported by microbial source tracking (MST) marke...

Rivers are important for drinking water supply worldwide. However, they are often impacted by pathogen discharges via wastewater treatment plants (WWTP) and combined sewer overflows (CSO). To date, accurate predictions of the effects of future changes and pollution control measures on the microbiological water quality of rivers considering safe dri...

A novel concept for fecal pollution analysis was applied at alluvial water resources to substantially extend the information provided by fecal indicator bacteria (FIB). FIB data were linked to river connectivity and genetic microbial source tracking (MST). The concept was demonstrated at the Danube River and its associated backwater area downstream...

Diarrhoea caused by waterborne pathogens still has a large burden of disease. We introduce a modelling and scenario analysis framework that enables better understanding of sources of and possible future changes in the disease burden due to environmental change and management implementation. The state-of-the-art research that can contribute to the d...

The current fecal indicator concept is based on the assumption that the standard fecal indicator bacteria (SFIB) Escherichia coli , intestinal enterococci, and Clostridium perfringens multiply significantly only in the guts of humans and other homeothermic animals and can therefore indicate fecal pollution and the potential presence of pathogens fr...

Riverbank filtration (RBF) systems along rivers are widely used as public water supplies. In these systems, many organic micropollutants (OMPs) are attenuated, but some compounds have shown to be rather persistent. Their fate and transport has been studied in RBF sites along lakes and small rivers, but not extensively along large and dynamic rivers...

Quantitative information regarding the presence of Escherichia coli, intestinal enterococci, and Clostridium perfringens in poikilotherms is notably scarce. Therefore, this study was designed to allow a systematic comparison of the occurrence of these standard fecal indicator bacteria (SFIB) in the excreta of wild homeothermic (ruminants, boars, ca...

Numerous bacterial genetic markers are available for the molecular detection of human sources of fecal pollution in environmental waters. However, widespread application is hindered by a lack of knowledge regarding geographical stability, limiting implementation to a small number of well-characterized regions. This study investigates the geographic...

Information on concentrations of micropollutants (such as pharmaceuticals, pesticides, and industrial chemicals) in most highly dynamic riverbank filtration (RBF) systems is lacking, in contrast to data on standard chemical parameters. Sampling protocols have thus far been based on the stabilization of standard chemical parameters in relatively pri...

Contamination of groundwater by pathogenic viruses from small biological wastewater treatment system discharges in remote areas is a major concern. To protect drinking water wells against virus contamination, safe setback distances are required between wastewater disposal fields and water supply wells. In this study, setback distances are calculate...

For the City of Vienna, the River Danube and its associated water bodies (Alte Donau, Neue Donau, Mühlwasser, Lobau backwater) play an important role for recreation and drinking water supply. Microbiological water quality is of highest relevance for all user-related aspects. Microbiological water quality monitoring for this area has been mainly bas...

Contamination of groundwater by pathogenic viruses from small biological wastewater treatment system discharges in remote areas is a major concern. To protect drinking water wells against virus contamination, safe setback distances are required between wastewater disposal fields and water supply wells. In this study, setback distances are calculate...

QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain rive...

Protection of drinking water resources requires addressing all relevant fecal pollution sources in the considered catchment. A freely available simulation tool, QMRAcatch, was recently developed to simulate concentrations of fecal indicators, a genetic microbial source tracking (MST) marker, and intestinal pathogens in water resources and to conduc...

This study investigates the impact of the sum of the structural measures on groundwater conditions in the context of the pilot test stretch in Bad Deutsch-Altenburg (BDA). The methodological approach was a comparison of the conditions for the exchange processes between groundwater and river water pre and post the selected structural work. The analy...

Ziel der Beweissicherung und des Monitorings des Arbeitspaketes Grundwasser ist es, die kausalen Zusammenhänge zwischen den Eingriffen im Bereich der Pilotversuchsstrecke und den wasserwirtschaftlichen Grundwasserverhältnissen zu beschreiben und aufzuzeigen. Dabei stehen die Veränderungen durch die im Abschnitt von Strom-km 1887,5 bis Strom-km 1884...

Given the complex hydrologic dynamics of water catchments and conflicts between nature protection and public water supply, models may help to understand catchment dynamics and evaluate contamination scenarios and may support best environmental practices and water safety management. A catchment model can be an educative tool for investigating water...

Groundwater locations at alluvial backwaters and its riverbank filtration (RBF) systems are widely used as a means of obtaining public water supplies. Riverbank filtration is an effective way to remove pathogens and micropollutants from the receiving surface water. Due to the low abundance of pathogenic and indicator microorganisms in groundwater,...

[1] Previous work has shown that non linear catchment response related to a storage threshold may translate into a step change in the flood frequency curve. The aim of this paper is to understand the controls of this step change for catchments where runoff is generated by the saturation excess mechanism and a clear separation between a permanently...

During a 3-year study, Clostridium perfringens was investigated in defined fecal sources from a temperate alluvial backwater area of a large river system. The results reveal that using C. perfringens as a conservative water quality indicator for total fecal pollution monitoring is no longer justified but suggest that it can be used as a tracer for...

Estimating the effect of river restoration on groundwater quality is important in the view of nationwide implementations demanded by e.g. the EU Water Framework Directive. DOC transport during river infiltration conditions was examined based on 3D flow and contaminant transport simulations with transient groundwater-surface water interaction. In a...

In the view of global warming and the increase in world population, the demand for efficient treatment methods for drinking water has increased. The potential capacity of riverbank filtration to effectively remove contaminants has been proven. However, during floods river water was found to infiltrate more quickly and at a higher rate into the rive...

The transfer of microbial pathogens from surface or waste water can have adverse effects on groundwater quality at riverbank filtration sites. Previous studies on groundwater protection in sandy unconfined aquifers with the focus on virus transport and health based water quality targets, such as done in the Netherlands, revealed larger protection z...

The river-aquifer mixing zone has been identified in the past by both observations in the field and by applying coupled groundwater models. Its implications are important e.g. for macrozoobenthos or fish eggs, which react sensitively to changes in flow velocities. The groundwater quality is also strongly affected due to the transport of substances...

The transient effects on three-dimensional flow patterns at the stream-aquifer interface of the river Danube east of Vienna are investigated by applying a variable saturated numerical model. Within the study site a monitored gravel bar behaves like a riffle-pool sequence and therewith as a structure capable of high exchange flow rates and high biog...