Julia Derx - Academia.edu (original) (raw)
Papers by Julia Derx
Österreichische Wasser- und Abfallwirtschaft, Jul 29, 2023
PFAS are a class of synthetic chemicals used for many industrial and domestic purposes. However, ... more 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, its effectiveness in removing PFAS is still unknown. The aim of this study is to investigate the occurrence, as well as the spatial distribution of PFAS at riverbank filtration sites and compare these to two pharmaceuticals and various chemical parameters. A one-year sampling campaign was carried out at four transects with different characteristics along the Danube river. Samples were analysed using Liquid Chromatography Mass Spectrometry.
Water contaminated with human and animal enteric pathogens puts public health at serious risk. Al... more Water contaminated with human and animal enteric pathogens puts public health at serious risk. All countries and regions of the world require highly robust and effective water management and treatment systems to guarantee safe water and protect public health. To this end, we need accurate predictions of the origin of pathogens , how they move through the environment and where they end up.This study is part of a four-year project and aims to develop new bacterial overland transport - BOT models to provide answers to the above questions. The project takes a holistic, quantitative approach to transfer BOT model parameters onto large scales. Small-scale precipitation experiments are conducted in the laboratory and larger-scale experiments are conducted using a rainfall simulation under real environmental conditions. The state-of-the-art combination of quantitative, microbiological, and molecular methods and parameters will provide the scientific basis for more accurate predictions of BOT, which eventually may be extended to viruses and protozoa in the future.
<p>Streams can carry and spread numerous pathogen species, either free floating or ... more <p>Streams can carry and spread numerous pathogen species, either free floating or attached to the surface of fine particles. These pathogens can pose serious threats to human health in places where untreated water is directly consumed or by contact with the water when using for recreation, washing or irrigation purposes. The most important sources of pathogens to streams in urbanized catchments are wastewater treatment plants that continuously release wastewater effluent, which is still infectious. Moreover, untreated wastewater is also discharged to streams through combined sewer overflows during heavy rain events, resulting in the release of high loads of pathogens.</p> <p>Once pathogens are introduced to a stream from these sources, their fate is controlled not only by transport in surface water but also by exchange with streambed sediments. Within streambeds, pathogens are subject to a complex array of processes that include seepage transport, sorption to sediment surface, and decay, with some pathogens being eventually released back to surface water.</p> <p>Recently, a model for stream transport of pathogens has been developed that is based on the Continuous Time Random Walk (CTRW) framework. This model describes the stream corridor as the interaction of a mobile and immobile zones, and a few applications to pathogen transport have been discussed in the literature. This contribution will present an application of this model approach to predict the fate of pathogens in an urban stream in Vienna. The model application will be tailored to work with the uncertainty that typically affects the information that is available in these situations. Thus, stochastic boundary conditions will be applied to consider the variability of pathogen loads to the stream, and model parameters will be calibrated on available concentrations of <em>C. perfringens</em> spores (used as conservative microbial tracer for municipal sewage) and the human genetic fecal marker HF183/BacR287, and eventually validated based on concentrations of the reference pathogens <em>Cryptosporidium</em> and <em>Giardia</em>, observed at the catchment outlet.</p>
Fems Microbiology Reviews, Jun 7, 2023
The proposed discipline of genetic faecal pollution diagnostics helps addressing complex water, s... more The proposed discipline of genetic faecal pollution diagnostics helps addressing complex water, sanitation and human health-related issues: this systematic review elucidates application areas, key research questions and study designs from over 1,100 scientific articles and provides critical insights and conclusions.
Per- and Polyfluoroalkyl Substances (PFAS) are chemicals used for many domestic and industrial pu... more Per- and Polyfluoroalkyl Substances (PFAS) are chemicals used for many domestic and industrial purposes related to their physicochemical properties. However, those same properties make them mobile and persistent in the environment, and on top of that, they are toxic and can affect human health in the short and long term, as they are bio-accumulative. Many processes govern the transport of PFAS in the surface waters and groundwater, e.g., sorption, biodegradation, co-transport, and transformation. Monitoring PFAS at different locations can help understand these processes and provide datasets to calibrate and validate reactive transport models simulating PFAS fate and transport. This study compares PFAS presence and distribution in river water and groundwater at two Danube river sites. One site is characterized by a steady water level in the river and natural flow from the river to the groundwater, with a clogging layer at the aquifer-river interface. In contrast, the other site has a...
Recent years have seen increasing interest in Per- and Polyfluoroalkyl Substances (PFAS) in the u... more Recent years have seen increasing interest in Per- and Polyfluoroalkyl Substances (PFAS) in the urban water cycle. PFAS are human-manufactured chemicals that have been employed globally in industrial and household products with outstanding chemical stability and mobility. This study set out a one-year monitoring scheme as a basis to better understand the sources, transport and fate of PFAS at a large catchment scale. The monitoring results will further assist the development of a contamination distribution model. Nine Danube tributary sites including regions with low and high pollution risk were selected, based on the existing monitoring results from other research and inventories of hotspots like industries and landfills, to investigate the appearance of pollutants along the surface water of the catchment. Two locations on the Danube mainstream were targeted for more frequent monitoring of surface water and connected groundwater, furthermore, bank-filtration models will be built fo...
Karst springs provide drinking water for approximately 700 million people worldwide. Complex subs... more Karst springs provide drinking water for approximately 700 million people worldwide. Complex subsurface flow processes lead to challenges for modelling spring discharges. Machine learning (ML) models possess the ability to learn non-linear patterns and show promising results in forecasting dynamic spring discharge. We compare the performance of three ML models of varying complexity in forecasting karst spring discharges: the multivariate adaptive regression spline model (MARS), a feed-forward neural network (ANN) and a long short-term memory model (LSTM). The well-studied alpine karst spring LKAS2 in Austria is used as test case. We provide model explanations including feature attribution through Shapley additive explanations (SHAP), a method based on Shapley values. Our results show that the higher the model complexity, the higher the accuracy, based on the evaluated symmetric mean absolute percentage error of the three investigated models. With SHAP every prediction can be explained through each feature in each input time step. We found seasonal model differences. For example, snow influenced the model mostly in winter and spring. Analyzing the combinations of input time steps and features provided further insights into the model performance. For instance, the SHAP results showed that a high electrical conductivity in recent time steps, which indicates that the karst water is less diluted with precipitation, leads to a reduced discharge forecast. These feature attribution results coincide with physical processes within karst systems. Therefore, the introduced SHAP method can increase the confidence in ML model forecasts and emphasizes the raison d’être of complex and accurate deep learning models in hydrology. This allows the operator to better understand and evaluate the model’s output, which is essential for drinking water management.
<p>Streams can carry and spread numerous pathogen species, either free floating or ... more <p>Streams can carry and spread numerous pathogen species, either free floating or attached to the surface of fine particles. These pathogens can pose serious threats to human health in places where untreated water is directly consumed or by contact with the water when using for recreation, washing or irrigation purposes. The most important sources of pathogens to streams in urbanized catchments are wastewater treatment plants that continuously release wastewater effluent, which is still infectious. Moreover, untreated wastewater is also discharged to streams through combined sewer overflows during heavy rain events, resulting in the release of high loads of pathogens.</p> <p>Once pathogens are introduced to a stream from these sources, their fate is controlled not only by transport in surface water but also by exchange with streambed sediments. Within streambeds, pathogens are subject to a complex array of processes that include seepage transport, sorption to sediment surface, and decay, with some pathogens being eventually released back to surface water.</p> <p>Recently, a model for stream transport of pathogens has been developed that is based on the Continuous Time Random Walk (CTRW) framework. This model describes the stream corridor as the interaction of a mobile and immobile zones, and a few applications to pathogen transport have been discussed in the literature. This contribution will present an application of this model approach to predict the fate of pathogens in an urban stream in Vienna. The model application will be tailored to work with the uncertainty that typically affects the information that is available in these situations. Thus, stochastic boundary conditions will be applied to consider the variability of pathogen loads to the stream, and model parameters will be calibrated on available concentrations of <em>C. perfringens</em> spores (used as conservative microbial tracer for municipal sewage) and the human genetic fecal marker HF183/BacR287, and eventually validated based on concentrations of the reference pathogens <em>Cryptosporidium</em> and <em>Giardia</em>, observed at the catchment outlet.</p>
Introduction: Inland navigation has seen explosive growth over the past few decades, leading to i... more Introduction: Inland navigation has seen explosive growth over the past few decades, leading to increasing concerns about its environmental and health impacts. Coastal waters are usually monitored for wastewater contamination by maritime traffic, but little is known about faecal pollution caused by the inland waterways transport in large rivers. The Danube River in Europe is a very popular destination for cruise ship trips. The extent to which the faecal pollution in the Danube is caused by shipping traffic in general and the growing number of cruise ships specifically is still largely unknown. The Danube River Information Service (DoRIS) has been established to track ship traffic and provide data for monitoring in Austria. This database allows the estimation of the faecal pollution potential of ships with a high level of spatial and temporal resolution for the first time.Methodology: An approach was developed to investigate the potential contribution of various ship categories to f...
Current Opinion in Environmental Sustainability, 2019
Diarrhoea caused by waterborne pathogens still has a large burden of disease. We introduce a mode... more 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 development of the framework at the large scale is analysed, together with research gaps and opportunities for future research. Priorities have been identified and these include implementation of Quantitative Microbial Risk Assessment and application of the models in scenario analyses. The credibility of the model outputs should be central in the analysis, for example by developing stochastic models. Implementation of the framework contributes towards achieving the Sustainable Development Goals.
Science of The Total Environment
Reference Module in Earth Systems and Environmental Sciences, 2022
Global Water Pathogen Project, 2017
The designations employed and the presentation of material throughout this publication do not imp... more The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The ideas and opinions expressed in this publication are those of the authors; they are not necessarily those of UNESCO and do not commit the Organization.
Global Water Pathogen Project, 2019
The designations employed and the presentation of material throughout this publication do not imp... more The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The ideas and opinions expressed in this publication are those of the authors; they are not necessarily those of UNESCO and do not commit the Organization.
EGU General Assembly 2010, held 2-7 …, 2010
The river-aquifer mixing zone has been identified in the past by both observations in the field a... more 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 eg for macrozoobenthos or fish eggs, which react sensitively to changes in flow velocities. The groundwater quality ...
Frontiers in Microbiology
Reference Module in Earth Systems and Environmental Sciences, 2022
Österreichische Wasser- und Abfallwirtschaft, Jul 29, 2023
PFAS are a class of synthetic chemicals used for many industrial and domestic purposes. However, ... more 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, its effectiveness in removing PFAS is still unknown. The aim of this study is to investigate the occurrence, as well as the spatial distribution of PFAS at riverbank filtration sites and compare these to two pharmaceuticals and various chemical parameters. A one-year sampling campaign was carried out at four transects with different characteristics along the Danube river. Samples were analysed using Liquid Chromatography Mass Spectrometry.
Water contaminated with human and animal enteric pathogens puts public health at serious risk. Al... more Water contaminated with human and animal enteric pathogens puts public health at serious risk. All countries and regions of the world require highly robust and effective water management and treatment systems to guarantee safe water and protect public health. To this end, we need accurate predictions of the origin of pathogens , how they move through the environment and where they end up.This study is part of a four-year project and aims to develop new bacterial overland transport - BOT models to provide answers to the above questions. The project takes a holistic, quantitative approach to transfer BOT model parameters onto large scales. Small-scale precipitation experiments are conducted in the laboratory and larger-scale experiments are conducted using a rainfall simulation under real environmental conditions. The state-of-the-art combination of quantitative, microbiological, and molecular methods and parameters will provide the scientific basis for more accurate predictions of BOT, which eventually may be extended to viruses and protozoa in the future.
<p>Streams can carry and spread numerous pathogen species, either free floating or ... more <p>Streams can carry and spread numerous pathogen species, either free floating or attached to the surface of fine particles. These pathogens can pose serious threats to human health in places where untreated water is directly consumed or by contact with the water when using for recreation, washing or irrigation purposes. The most important sources of pathogens to streams in urbanized catchments are wastewater treatment plants that continuously release wastewater effluent, which is still infectious. Moreover, untreated wastewater is also discharged to streams through combined sewer overflows during heavy rain events, resulting in the release of high loads of pathogens.</p> <p>Once pathogens are introduced to a stream from these sources, their fate is controlled not only by transport in surface water but also by exchange with streambed sediments. Within streambeds, pathogens are subject to a complex array of processes that include seepage transport, sorption to sediment surface, and decay, with some pathogens being eventually released back to surface water.</p> <p>Recently, a model for stream transport of pathogens has been developed that is based on the Continuous Time Random Walk (CTRW) framework. This model describes the stream corridor as the interaction of a mobile and immobile zones, and a few applications to pathogen transport have been discussed in the literature. This contribution will present an application of this model approach to predict the fate of pathogens in an urban stream in Vienna. The model application will be tailored to work with the uncertainty that typically affects the information that is available in these situations. Thus, stochastic boundary conditions will be applied to consider the variability of pathogen loads to the stream, and model parameters will be calibrated on available concentrations of <em>C. perfringens</em> spores (used as conservative microbial tracer for municipal sewage) and the human genetic fecal marker HF183/BacR287, and eventually validated based on concentrations of the reference pathogens <em>Cryptosporidium</em> and <em>Giardia</em>, observed at the catchment outlet.</p>
Fems Microbiology Reviews, Jun 7, 2023
The proposed discipline of genetic faecal pollution diagnostics helps addressing complex water, s... more The proposed discipline of genetic faecal pollution diagnostics helps addressing complex water, sanitation and human health-related issues: this systematic review elucidates application areas, key research questions and study designs from over 1,100 scientific articles and provides critical insights and conclusions.
Per- and Polyfluoroalkyl Substances (PFAS) are chemicals used for many domestic and industrial pu... more Per- and Polyfluoroalkyl Substances (PFAS) are chemicals used for many domestic and industrial purposes related to their physicochemical properties. However, those same properties make them mobile and persistent in the environment, and on top of that, they are toxic and can affect human health in the short and long term, as they are bio-accumulative. Many processes govern the transport of PFAS in the surface waters and groundwater, e.g., sorption, biodegradation, co-transport, and transformation. Monitoring PFAS at different locations can help understand these processes and provide datasets to calibrate and validate reactive transport models simulating PFAS fate and transport. This study compares PFAS presence and distribution in river water and groundwater at two Danube river sites. One site is characterized by a steady water level in the river and natural flow from the river to the groundwater, with a clogging layer at the aquifer-river interface. In contrast, the other site has a...
Recent years have seen increasing interest in Per- and Polyfluoroalkyl Substances (PFAS) in the u... more Recent years have seen increasing interest in Per- and Polyfluoroalkyl Substances (PFAS) in the urban water cycle. PFAS are human-manufactured chemicals that have been employed globally in industrial and household products with outstanding chemical stability and mobility. This study set out a one-year monitoring scheme as a basis to better understand the sources, transport and fate of PFAS at a large catchment scale. The monitoring results will further assist the development of a contamination distribution model. Nine Danube tributary sites including regions with low and high pollution risk were selected, based on the existing monitoring results from other research and inventories of hotspots like industries and landfills, to investigate the appearance of pollutants along the surface water of the catchment. Two locations on the Danube mainstream were targeted for more frequent monitoring of surface water and connected groundwater, furthermore, bank-filtration models will be built fo...
Karst springs provide drinking water for approximately 700 million people worldwide. Complex subs... more Karst springs provide drinking water for approximately 700 million people worldwide. Complex subsurface flow processes lead to challenges for modelling spring discharges. Machine learning (ML) models possess the ability to learn non-linear patterns and show promising results in forecasting dynamic spring discharge. We compare the performance of three ML models of varying complexity in forecasting karst spring discharges: the multivariate adaptive regression spline model (MARS), a feed-forward neural network (ANN) and a long short-term memory model (LSTM). The well-studied alpine karst spring LKAS2 in Austria is used as test case. We provide model explanations including feature attribution through Shapley additive explanations (SHAP), a method based on Shapley values. Our results show that the higher the model complexity, the higher the accuracy, based on the evaluated symmetric mean absolute percentage error of the three investigated models. With SHAP every prediction can be explained through each feature in each input time step. We found seasonal model differences. For example, snow influenced the model mostly in winter and spring. Analyzing the combinations of input time steps and features provided further insights into the model performance. For instance, the SHAP results showed that a high electrical conductivity in recent time steps, which indicates that the karst water is less diluted with precipitation, leads to a reduced discharge forecast. These feature attribution results coincide with physical processes within karst systems. Therefore, the introduced SHAP method can increase the confidence in ML model forecasts and emphasizes the raison d’être of complex and accurate deep learning models in hydrology. This allows the operator to better understand and evaluate the model’s output, which is essential for drinking water management.
<p>Streams can carry and spread numerous pathogen species, either free floating or ... more <p>Streams can carry and spread numerous pathogen species, either free floating or attached to the surface of fine particles. These pathogens can pose serious threats to human health in places where untreated water is directly consumed or by contact with the water when using for recreation, washing or irrigation purposes. The most important sources of pathogens to streams in urbanized catchments are wastewater treatment plants that continuously release wastewater effluent, which is still infectious. Moreover, untreated wastewater is also discharged to streams through combined sewer overflows during heavy rain events, resulting in the release of high loads of pathogens.</p> <p>Once pathogens are introduced to a stream from these sources, their fate is controlled not only by transport in surface water but also by exchange with streambed sediments. Within streambeds, pathogens are subject to a complex array of processes that include seepage transport, sorption to sediment surface, and decay, with some pathogens being eventually released back to surface water.</p> <p>Recently, a model for stream transport of pathogens has been developed that is based on the Continuous Time Random Walk (CTRW) framework. This model describes the stream corridor as the interaction of a mobile and immobile zones, and a few applications to pathogen transport have been discussed in the literature. This contribution will present an application of this model approach to predict the fate of pathogens in an urban stream in Vienna. The model application will be tailored to work with the uncertainty that typically affects the information that is available in these situations. Thus, stochastic boundary conditions will be applied to consider the variability of pathogen loads to the stream, and model parameters will be calibrated on available concentrations of <em>C. perfringens</em> spores (used as conservative microbial tracer for municipal sewage) and the human genetic fecal marker HF183/BacR287, and eventually validated based on concentrations of the reference pathogens <em>Cryptosporidium</em> and <em>Giardia</em>, observed at the catchment outlet.</p>
Introduction: Inland navigation has seen explosive growth over the past few decades, leading to i... more Introduction: Inland navigation has seen explosive growth over the past few decades, leading to increasing concerns about its environmental and health impacts. Coastal waters are usually monitored for wastewater contamination by maritime traffic, but little is known about faecal pollution caused by the inland waterways transport in large rivers. The Danube River in Europe is a very popular destination for cruise ship trips. The extent to which the faecal pollution in the Danube is caused by shipping traffic in general and the growing number of cruise ships specifically is still largely unknown. The Danube River Information Service (DoRIS) has been established to track ship traffic and provide data for monitoring in Austria. This database allows the estimation of the faecal pollution potential of ships with a high level of spatial and temporal resolution for the first time.Methodology: An approach was developed to investigate the potential contribution of various ship categories to f...
Current Opinion in Environmental Sustainability, 2019
Diarrhoea caused by waterborne pathogens still has a large burden of disease. We introduce a mode... more 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 development of the framework at the large scale is analysed, together with research gaps and opportunities for future research. Priorities have been identified and these include implementation of Quantitative Microbial Risk Assessment and application of the models in scenario analyses. The credibility of the model outputs should be central in the analysis, for example by developing stochastic models. Implementation of the framework contributes towards achieving the Sustainable Development Goals.
Science of The Total Environment
Reference Module in Earth Systems and Environmental Sciences, 2022
Global Water Pathogen Project, 2017
The designations employed and the presentation of material throughout this publication do not imp... more The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The ideas and opinions expressed in this publication are those of the authors; they are not necessarily those of UNESCO and do not commit the Organization.
Global Water Pathogen Project, 2019
The designations employed and the presentation of material throughout this publication do not imp... more The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The ideas and opinions expressed in this publication are those of the authors; they are not necessarily those of UNESCO and do not commit the Organization.
EGU General Assembly 2010, held 2-7 …, 2010
The river-aquifer mixing zone has been identified in the past by both observations in the field a... more 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 eg for macrozoobenthos or fish eggs, which react sensitively to changes in flow velocities. The groundwater quality ...
Frontiers in Microbiology
Reference Module in Earth Systems and Environmental Sciences, 2022