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Dr. Nynke Hofstra
Water Systems and Global Change Group, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands

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0 Modeling
0 Scenario Analysis
0 Systems Analysis
0 Water Quality
0 Health-related water microbiology

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Commentary
Published: 20 May 2021 in Sustainability
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User-friendly, evidence-based scientific tools to support sanitation decisions are still limited in the water, sanitation and hygiene (WASH) sector. This commentary provides lessons learned from the development of two sanitation decision support tools developed in collaboration with stakeholders in Uganda. We engaged with stakeholders in a variety of ways to effectively obtain their input in the development of the decision support tools. Key lessons learned included: tailoring tools to stakeholder decision-making needs; simplifying the tools as much as possible for ease of application and use; creating an enabling environment that allows active stakeholder participation; having a dedicated and responsive team to plan and execute stakeholder engagement activities; involving stakeholders early in the process; having funding sources that are flexible and long-term; and including resources for the acquisition of local data. This reflection provides benchmarks for future research and the development of tools that utilize scientific data and emphasizes the importance of engaging with stakeholders in the development process.

ACS Style

Innocent Tumwebaze; Joan Rose; Nynke Hofstra; Matthew Verbyla; Daniel Okaali; Panagis Katsivelis; Heather Murphy. Bridging Science and Practice-Importance of Stakeholders in the Development of Decision Support: Lessons Learned. Sustainability 2021, 13, 5744 .

AMA Style

Innocent Tumwebaze, Joan Rose, Nynke Hofstra, Matthew Verbyla, Daniel Okaali, Panagis Katsivelis, Heather Murphy. Bridging Science and Practice-Importance of Stakeholders in the Development of Decision Support: Lessons Learned. Sustainability. 2021; 13 (10):5744.

Chicago/Turabian Style

Innocent Tumwebaze; Joan Rose; Nynke Hofstra; Matthew Verbyla; Daniel Okaali; Panagis Katsivelis; Heather Murphy. 2021. "Bridging Science and Practice-Importance of Stakeholders in the Development of Decision Support: Lessons Learned." Sustainability 13, no. 10: 5744.

Review
Published: 02 November 2020 in Water Research
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Water and wastewater utilities, water and sanitation hygiene (WASH) practitioners, and regulating bodies, particularly in developing nations, rely heavily on indicator microorganisms, as opposed to pathogens, for much of their regulatory decisions. This commentary illustrates the importance of considering pathogens and not relying only on indicator organisms when making decisions regarding water and sanitation, especially with respect to meeting the current targets of the Sustainable Development Goal (SDG) 6. We use quantitative microbial risk assessment (QMRA) to present three common scenarios that WASH and public health practitioners encounter to illustrate our point. These include 1) chlorination of surface water for drinking, 2) land application of latrine waste as a fertilizer, and 3) recreation/domestic use of surface waters impacted by wastewater discharge. We show that the calculated probabilities of risk of infection are statistically significantly higher when using treatment/survival information for pathogens versus using indicator species data. Thus, demonstrating that relying solely on indicators for sanitation decision making is inadequate if we truly want to achieve the SDG6 targets of safely managed water and sanitation services.

ACS Style

Alexis L. Mraz; Innocent K. Tumwebaze; Shane R. McLoughlin; Megan E. McCarthy; Matthew E. Verbyla; Nynke Hofstra; Joan B. Rose; Heather M. Murphy. Why pathogens matter for meeting the united nations’ sustainable development goal 6 on safely managed water and sanitation. Water Research 2020, 189, 116591 .

AMA Style

Alexis L. Mraz, Innocent K. Tumwebaze, Shane R. McLoughlin, Megan E. McCarthy, Matthew E. Verbyla, Nynke Hofstra, Joan B. Rose, Heather M. Murphy. Why pathogens matter for meeting the united nations’ sustainable development goal 6 on safely managed water and sanitation. Water Research. 2020; 189 ():116591.

Chicago/Turabian Style

Alexis L. Mraz; Innocent K. Tumwebaze; Shane R. McLoughlin; Megan E. McCarthy; Matthew E. Verbyla; Nynke Hofstra; Joan B. Rose; Heather M. Murphy. 2020. "Why pathogens matter for meeting the united nations’ sustainable development goal 6 on safely managed water and sanitation." Water Research 189, no. : 116591.

Discussion
Published: 14 October 2020 in Current Opinion in Environmental Sustainability
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ACS Style

Nynke Hofstra; Gertjan Medema; Lucie C Vermeulen. Reflection on health-environment research in the light of emerging infectious diseases: modelling water quality and health. Current Opinion in Environmental Sustainability 2020, 46, 8 -10.

AMA Style

Nynke Hofstra, Gertjan Medema, Lucie C Vermeulen. Reflection on health-environment research in the light of emerging infectious diseases: modelling water quality and health. Current Opinion in Environmental Sustainability. 2020; 46 ():8-10.

Chicago/Turabian Style

Nynke Hofstra; Gertjan Medema; Lucie C Vermeulen. 2020. "Reflection on health-environment research in the light of emerging infectious diseases: modelling water quality and health." Current Opinion in Environmental Sustainability 46, no. : 8-10.

Articles
Published: 07 December 2018 in Human and Ecological Risk Assessment: An International Journal
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Access to safe water is the primary goal of all development plans, yet population increase, urbanization lead to contamination of water resources. This paper focuses on microbial contamination and aims to analyze the fate and transport of Escherichia coli in the Kabul River Basin using SWAT model to evaluate the contribution of different sources. The SWAT is calibrated and validated for the monthly time step using observed E. coli concentrations for April 2013–July 2015. The model skill score; coefficients of determination (R2) equal 0.72 and 0.70, Nash–Sutcliffe efficiencies (NSE) equal 0.69 and 0.66, and percentages bias (PBIAS) equal 3.7 and 1.9 respond well for both calibration and validation, respectively. Regional measured and modeled concentrations are very high with peaks of up to 5.2 10log cfu/100 ml in the wet season. Overall, point sources that are comprised of human feces from the big cities and livestock manure from animal sheds, contribute most (44%) to the E. coli concentrations. During peak discharge the non-point sources become the most important contributors due to wash-off from the land and diluted point sources. Allthough such studies are lacking in developing countries, they can be helpful for sanitation management by developing and accessing regional sanitation scenarios.

ACS Style

Muhammad Shahid Iqbal; Nynke Hofstra. Modeling Escherichia coli fate and transport in the Kabul River Basin using SWAT. Human and Ecological Risk Assessment: An International Journal 2018, 25, 1279 -1297.

AMA Style

Muhammad Shahid Iqbal, Nynke Hofstra. Modeling Escherichia coli fate and transport in the Kabul River Basin using SWAT. Human and Ecological Risk Assessment: An International Journal. 2018; 25 (5):1279-1297.

Chicago/Turabian Style

Muhammad Shahid Iqbal; Nynke Hofstra. 2018. "Modeling Escherichia coli fate and transport in the Kabul River Basin using SWAT." Human and Ecological Risk Assessment: An International Journal 25, no. 5: 1279-1297.

Review article
Published: 01 December 2018 in Current Opinion in Environmental Sustainability
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Assessing global water quality issues requires a multi-pollutant modelling approach. We discuss scientific challenges and future directions for such modeling. Multi-pollutant river models need to integrate information on sources of pollutants such as plastic debris, nutrients, chemicals, pathogens, their effects and possible solutions. In this paper, we first explain what we consider multi-pollutant modelling. Second, we discuss scientific challenges in multi-pollutant modelling relating to consistent model inputs, modelling approaches and model evaluation. Next, we illustrate the potential of global multi-pollutant modelling for hotspot analyses. We show hotspots of river pollution with microplastics, nutrients, triclosan and Cryptosporidium in many sub-basins of Europe, North America and South Asia. Finally, we reflect on future directions for multi-pollutant modelling, and for linking model results to policy-making.

ACS Style

Maryna Strokal; J Emiel Spanier; Carolien Kroeze; Albert A Koelmans; Martina Flörke; Wietse Franssen; Nynke Hofstra; Simon Langan; Ting Tang; Michelle T.H. van Vliet; Yoshihide Wada; Mengru Wang; Jikke van Wijnen; Richard Williams. Global multi-pollutant modelling of water quality: scientific challenges and future directions. Current Opinion in Environmental Sustainability 2018, 36, 116 -125.

AMA Style

Maryna Strokal, J Emiel Spanier, Carolien Kroeze, Albert A Koelmans, Martina Flörke, Wietse Franssen, Nynke Hofstra, Simon Langan, Ting Tang, Michelle T.H. van Vliet, Yoshihide Wada, Mengru Wang, Jikke van Wijnen, Richard Williams. Global multi-pollutant modelling of water quality: scientific challenges and future directions. Current Opinion in Environmental Sustainability. 2018; 36 ():116-125.

Chicago/Turabian Style

Maryna Strokal; J Emiel Spanier; Carolien Kroeze; Albert A Koelmans; Martina Flörke; Wietse Franssen; Nynke Hofstra; Simon Langan; Ting Tang; Michelle T.H. van Vliet; Yoshihide Wada; Mengru Wang; Jikke van Wijnen; Richard Williams. 2018. "Global multi-pollutant modelling of water quality: scientific challenges and future directions." Current Opinion in Environmental Sustainability 36, no. : 116-125.

Review article
Published: 11 November 2018 in Current Opinion in Environmental Sustainability
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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.

ACS Style

Nynke Hofstra; Lucie Vermeulen; Julia Derx; Martina Flörke; Javier Mateo-Sagasta; Joan Rose; Gertjan Medema. Priorities for developing a modelling and scenario analysis framework for waterborne pathogen concentrations in rivers worldwide and consequent burden of disease. Current Opinion in Environmental Sustainability 2018, 36, 28 -38.

AMA Style

Nynke Hofstra, Lucie Vermeulen, Julia Derx, Martina Flörke, Javier Mateo-Sagasta, Joan Rose, Gertjan Medema. Priorities for developing a modelling and scenario analysis framework for waterborne pathogen concentrations in rivers worldwide and consequent burden of disease. Current Opinion in Environmental Sustainability. 2018; 36 ():28-38.

Chicago/Turabian Style

Nynke Hofstra; Lucie Vermeulen; Julia Derx; Martina Flörke; Javier Mateo-Sagasta; Joan Rose; Gertjan Medema. 2018. "Priorities for developing a modelling and scenario analysis framework for waterborne pathogen concentrations in rivers worldwide and consequent burden of disease." Current Opinion in Environmental Sustainability 36, no. : 28-38.

Review article
Published: 08 November 2018 in Current Opinion in Environmental Sustainability
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Several model inter-comparison projects (MIPs) have been carried out recently by the climate, hydrological, agricultural and other modelling communities to quantify modelling uncertainties and improve modelling systems. Here we focus on MIP design for large-scale water quality models. Water quality MIPs can be useful to improve our understanding of pollution problems and facilitate the development of harmonized estimates of current and future water quality. This can provide new opportunities for assessing robustness in estimates of water quality hotspots and trends, improve understanding of processes, pollution sources, water quality model uncertainties, and to identify priorities for water quality data collection and monitoring. Water quality MIP design should harmonize relevant model input datasets, use consistent spatial/temporal domains and resolutions, and similar output variables to improve understanding of water quality modelling uncertainties and provide harmonized water quality data that suit the needs of decision makers and other users.

ACS Style

Michelle Th van Vliet; Martina Flörke; John A Harrison; Nynke Hofstra; Virginie Keller; Fulco Ludwig; J Emiel Spanier; Maryna Strokal; Yoshihide Wada; Yingrong Wen; Richard J Williams. Model inter-comparison design for large-scale water quality models. Current Opinion in Environmental Sustainability 2018, 36, 59 -67.

AMA Style

Michelle Th van Vliet, Martina Flörke, John A Harrison, Nynke Hofstra, Virginie Keller, Fulco Ludwig, J Emiel Spanier, Maryna Strokal, Yoshihide Wada, Yingrong Wen, Richard J Williams. Model inter-comparison design for large-scale water quality models. Current Opinion in Environmental Sustainability. 2018; 36 ():59-67.

Chicago/Turabian Style

Michelle Th van Vliet; Martina Flörke; John A Harrison; Nynke Hofstra; Virginie Keller; Fulco Ludwig; J Emiel Spanier; Maryna Strokal; Yoshihide Wada; Yingrong Wen; Richard J Williams. 2018. "Model inter-comparison design for large-scale water quality models." Current Opinion in Environmental Sustainability 36, no. : 59-67.

Journal article
Published: 30 October 2018 in Water Research
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Cryptosporidium is a leading cause of diarrhoea and infant mortality worldwide. A better understanding of the sources, fate and transport of Cryptosporidium via rivers is important for effective management of waterborne transmission, especially in the developing world. We present GloWPa-Crypto C1, the first global, spatially explicit model that computes Cryptosporidium concentrations in rivers, implemented on a 0.5 x 0.5 degree grid and monthly time step. To this end, we first modelled Cryptosporidium inputs to rivers from human faeces and animal manure. Next, we use modelled hydrology from a grid-based macroscale hydrological model (the Variable Infiltration Capacity model). Oocyst transport through the river network is modelled using a routing model, accounting for temperature- and solar radiation-dependent decay and sedimentation along the way. Monthly average oocyst concentrations are predicted to range from 10-6 to 102 oocysts L-1 in most places. Critical regions (‘hotspots’) with high concentrations include densely populated areas in India, China, Pakistan and Bangladesh, Nigeria, Algeria and South Africa, Mexico, Venezuela and some coastal areas of Brazil, several countries in Western and Eastern Europe (incl. the UK, Belgium and Macedonia), and the Middle East. Point sources (human faeces) appears to be a more dominant source of pollution than diffuse sources (mainly animal manure) in most world regions. Validation shows that GloWPa-Crypto medians are mostly within the range of observed concentrations. The model generally produces concentrations that are 1.5 – 2 log10 higher than the observations. This is likely predominantly due to the absence of recovery efficiency of the observations, which are therefore likely too low. Goodness of fit statistics are reasonable. Sensitivity analysis showed that the model is most sensitive to changes in input oocyst loads. GloWPa-Crypto C1 paves the way for many new opportunities at the global scale, including scenario analysis to investigate the impact of global change and management options on oocysts concentrations in rivers, and risk analysis to investigate human health risk.

ACS Style

Lucie C. Vermeulen; Marijke van Hengel; Carolien Kroeze; Gertjan Medema; J. Emiel Spanier; Michelle T.H. van Vliet; Nynke Hofstra. Cryptosporidium concentrations in rivers worldwide. Water Research 2018, 149, 202 -214.

AMA Style

Lucie C. Vermeulen, Marijke van Hengel, Carolien Kroeze, Gertjan Medema, J. Emiel Spanier, Michelle T.H. van Vliet, Nynke Hofstra. Cryptosporidium concentrations in rivers worldwide. Water Research. 2018; 149 ():202-214.

Chicago/Turabian Style

Lucie C. Vermeulen; Marijke van Hengel; Carolien Kroeze; Gertjan Medema; J. Emiel Spanier; Michelle T.H. van Vliet; Nynke Hofstra. 2018. "Cryptosporidium concentrations in rivers worldwide." Water Research 149, no. : 202-214.

Journal article
Published: 28 September 2018 in Science of The Total Environment
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Microbial pollution is a major problem worldwide. High concentrations of Escherichia coli have been found in Kabul River in Pakistan. E. coli concentrations vary under different socio-economic conditions, such as population and livestock densities, urbanisation, sanitation and treatment of wastewater and manure, and climate-change aspects, such as floods and droughts. In this paper, we assess potential future E. coli loads and concentrations in the Kabul River using the Soil and Water Assessment Tool with scenarios that are based on the most recent Shared Socio-economic Pathways and Representative Concentration Pathways (SSPs and RCPs) developed for the Intergovernmental Panel on Climate Change (IPCC). Scenario_1 considers moderate population and livestock density growth, planned urbanisation and strongly improved wastewater and manure treatment (based on SSP1, “Sustainability”), and moderate climate change (RCP4.5, moderate greenhouse gas (GHG) emissions). Scenario_2 considers strong population and livestock density growth, moderate urbanisation, slightly improved wastewater treatment, no manure treatment (based on SSP3, “Regional rivalry”) and strong climate change (RCP8.5, high GHG emissions). Simulated E. coli responses to Scenario_2 suggest a mid-century increase in loads by 111% and a late century increase of 201% compared to baseline loads. Similarly, simulated E. coli loads are reduced by 60% for the mid-century and 78% for the late century compared to the baseline loads. When additional treatment is simulated in Scenario_1, the loads are reduced even further by 94%, 92% and 99.3% compared to the baseline concentrations when additional tertiary treatment, manure treatment or both have been applied respectively. This study is one of the first to apply combined socio-economic development and climate change scenario analysis with an E. coli concentration model to better understand how these concentrations may change in the future. The scenario analysis shows that reducing E. coli concentrations in Pakistan's rivers is possible, but requires strongly improved waste water treatment and manure management measures.

ACS Style

Muhammad Shahid Iqbal; M.M. Majedul Islam; Nynke Hofstra. The impact of socio-economic development and climate change on E. coli loads and concentrations in Kabul River, Pakistan. Science of The Total Environment 2018, 650, 1935 -1943.

AMA Style

Muhammad Shahid Iqbal, M.M. Majedul Islam, Nynke Hofstra. The impact of socio-economic development and climate change on E. coli loads and concentrations in Kabul River, Pakistan. Science of The Total Environment. 2018; 650 ():1935-1943.

Chicago/Turabian Style

Muhammad Shahid Iqbal; M.M. Majedul Islam; Nynke Hofstra. 2018. "The impact of socio-economic development and climate change on E. coli loads and concentrations in Kabul River, Pakistan." Science of The Total Environment 650, no. : 1935-1943.

Journal article
Published: 01 September 2018 in Journal of Environmental Quality
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Rotavirus (RV) and diarrheagenic Escherichia coli are waterborne pathogens commonly causing diarrhea in children below five years old worldwide. Our study is a first step toward a loads–concentrations–risk modeling and scenario analysis framework. We analyzed current and future human RV and indicator E. coli (EC) emissions from sanitation facilities to surface waters in Uganda using two process-based models. Emissions were estimated for the baseline year 2015 and for three scenarios in 2030 using population, excretion rates, sanitation types, and wastewater treatment. The first model is a downscaled GloWPa-Rota H1 version, producing emissions at a 1-km2 resolution. The second model is newly developed for Kampala and adds emissions from pit latrines and septic tanks excluded in the first model. The scenarios Business as Usual, Industrious, and Low Emissions reflect government prospects in sanitation coverage and wastewater treatment. For the first model, 6.14 × 1014 RV particles d−1 and 1.31 × 1012 EC colony-forming units (CFU) d−1 are emitted to surface waters in 2015. The RV emissions are expected to increase in 2030 by 75% for Business as Usual and 212% for Industrious and decrease by 58% in Low Emissions. Emissions from the second model are higher for Kampala than in the first model, at 3.74 × 1014 vs. 5.95 × 1013 RV particles d−1 and 8.18 × 1011 vs. 1.75 × 1011 EC CFU d−1 in 2015, most of which come from the onsite-not-contained category. Simulated emissions for Kampala show the importance of including onsite sanitation in our modeling. Our study is replicable in other locations and helps identify key emission sources, their hotspots, and the importance of wastewater treatment. The scenarios can guide future sanitation safety planning. Copyright © 2018. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Daniel A. Okaali; Nynke Hofstra. Present and Future Human Emissions of Rotavirus and Escherichia coli to Uganda's Surface Waters. Journal of Environmental Quality 2018, 47, 1130 -1138.

AMA Style

Daniel A. Okaali, Nynke Hofstra. Present and Future Human Emissions of Rotavirus and Escherichia coli to Uganda's Surface Waters. Journal of Environmental Quality. 2018; 47 (5):1130-1138.

Chicago/Turabian Style

Daniel A. Okaali; Nynke Hofstra. 2018. "Present and Future Human Emissions of Rotavirus and Escherichia coli to Uganda's Surface Waters." Journal of Environmental Quality 47, no. 5: 1130-1138.

Journal article
Published: 01 September 2018 in Journal of Environmental Quality
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Microbial water quality lies in the nexus of human, animal, and environmental health. Multidisciplinary efforts are under way to understand how microbial water quality can be monitored, predicted, and managed. This special collection of papers in the Journal of Environmental Quality was inspired by the idea of creating a special section containing the panoramic view of advances and challenges in the arena of microbial water quality research. It addresses various facets of health-related microorganism release, transport, and survival in the environment. The papers analyze the spatiotemporal variability of microbial water quality, selection of predictors of the spatiotemporal variations, the role of bottom sediments and biofilms, correlations between concentrations of indicator and pathogenic organisms and the role for risk assessment techniques, use of molecular markers, subsurface microbial transport as related to microbial water quality, antibiotic resistance, real-time monitoring and nowcasting, watershed scale modeling, and monitoring design. Both authors and editors represent international experience in the field. The findings underscore the challenges of observing and understanding microbial water quality; they also suggest promising research directions for improving the knowledge base needed to protect and improve our water sources. Copyright © 2018. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Y. A. Pachepsky; A. Allende; L. Boithias; K. Cho; R. Jamieson; N. Hofstra; M. Molina. Microbial Water Quality: Monitoring and Modeling. Journal of Environmental Quality 2018, 47, 931 -938.

AMA Style

Y. A. Pachepsky, A. Allende, L. Boithias, K. Cho, R. Jamieson, N. Hofstra, M. Molina. Microbial Water Quality: Monitoring and Modeling. Journal of Environmental Quality. 2018; 47 (5):931-938.

Chicago/Turabian Style

Y. A. Pachepsky; A. Allende; L. Boithias; K. Cho; R. Jamieson; N. Hofstra; M. Molina. 2018. "Microbial Water Quality: Monitoring and Modeling." Journal of Environmental Quality 47, no. 5: 931-938.

Journal article
Published: 01 August 2018 in Journal of Hydrology
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To improve microbial water quality and to prevent waterborne disease outbreaks, knowledge on the fate and transport of contaminants and on the contributions from different faecal sources to the total contamination is essential. The fate and transport of faecal indicators E. coli and enterococci within the Betna River in Bangladesh were simulated using a coupled hydrodynamic and water quality model. The hydrodynamic model for the river was set up, calibrated and validated with water level and discharge in our earlier study. In this study, the hydrodynamic model was further validated using measured water temperature and salinity and coupled with the water quality module. Bacterial load data from various faecal sources were collected and used as input in the water quality model. The model output corresponded very well with the measured E. coli and enterococci concentrations in the river; the Root Mean Square Error and the Nash-Sutcliffe efficiency for Log10-transformed concentrations were found to be 0.23 (Log10 CFU/100 ml) and 0.84 for E. coli, and 0.19 (Log10 CFU/100 ml) and 0.86 for enterococci, respectively. Then, the sensitivity of the model was tested by removing one process or forcing at a time. These simulations revealed that the microbial decay, the upstream concentrations and the discharge of untreated wastewater were the primary factors controlling the concentrations in the river, while wind and the contribution from the diffuse sources (i.e. urban and agricultural runoff) were unlikely to have a major influence. Finally, the model was applied to investigate the influence of wastewater treatment on the bacteria concentrations. This revealed that wastewater treatment would result in a considerable improvement of the microbial water quality of the Betna River. This paper demonstrates the application of a comprehensive state-of-art model in a river in a data-poor tropical area. The model can potentially be applied to other watersheds and can help in formulating solutions to improve the microbial water quality.

ACS Style

M.M. Majedul Islam; Ekaterina Sokolova; Nynke Hofstra. Modelling of river faecal indicator bacteria dynamics as a basis for faecal contamination reduction. Journal of Hydrology 2018, 563, 1000 -1008.

AMA Style

M.M. Majedul Islam, Ekaterina Sokolova, Nynke Hofstra. Modelling of river faecal indicator bacteria dynamics as a basis for faecal contamination reduction. Journal of Hydrology. 2018; 563 ():1000-1008.

Chicago/Turabian Style

M.M. Majedul Islam; Ekaterina Sokolova; Nynke Hofstra. 2018. "Modelling of river faecal indicator bacteria dynamics as a basis for faecal contamination reduction." Journal of Hydrology 563, no. : 1000-1008.

Journal article
Published: 24 July 2018 in Geosciences
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Climate change, comprising of changes in precipitation patterns, higher temperatures and sea level rises, increases the likelihood of future flooding in the Betna River basin, Bangladesh. Hydrodynamic modelling was performed to simulate the present and future water level and discharge for different scenarios using bias-corrected, downscaled data from two general circulation models. The modelling results indicated that, compared to the baseline year (2014–2015), the water level is expected to increase by 11–16% by the 2040s and 14–23% by the 2090s, and the monsoon daily maximum discharge is expected to increase by up to 13% by the 2040s and 21% by the 2090s. Sea level rise is mostly responsible for the increase in water level. The duration of water level exceedance of the established danger threshold and extreme discharge events can increase by up to half a month by the 2040s and above one month by the 2090s. The combined influence of the increased water level and discharge has the potential to cause major floods in the Betna River basin. The results of our study increase the knowledge base on climate change influence on water level and discharge at a local scale. This is valuable for water managers in flood-risk mitigation and water management.

ACS Style

M. M. Majedul Islam; Nynke Hofstra; Ekaterina Sokolova. Modelling the Present and Future Water Level and Discharge of the Tidal Betna River. Geosciences 2018, 8, 271 .

AMA Style

M. M. Majedul Islam, Nynke Hofstra, Ekaterina Sokolova. Modelling the Present and Future Water Level and Discharge of the Tidal Betna River. Geosciences. 2018; 8 (8):271.

Chicago/Turabian Style

M. M. Majedul Islam; Nynke Hofstra; Ekaterina Sokolova. 2018. "Modelling the Present and Future Water Level and Discharge of the Tidal Betna River." Geosciences 8, no. 8: 271.

Journal article
Published: 30 March 2018 in Geosciences
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Devastating floods adversely affect human life and infrastructure. Various regions of the Hindukush-Karakoram-Himalayas receive intense monsoon rainfall, which, together with snow and glacier melt, produce intense floods. The Kabul river basin originates from the Hindukush Mountains and is frequently hit by such floods. We analyses flood frequency and intensity in Kabul basin for a contemporary period (1981–2015) and two future periods (i.e., 2031–2050 and 2081–2100) using the RCP4.5 and RCP8.5 scenarios based on four bias-corrected downscaled climate models (INM-CM4, IPSL-CM5A, EC-EARTH, and MIROC5). Future floods are modelled with the SWAT hydrological model. The model results suggest an increasing trend due to an increasing precipitation and higher temperatures (based on all climate models except INM-CM4), which accelerates snow and glacier-melt. All of the scenario results show that the current flow with a 1 in 50 year return period is likely to occur more frequently (i.e., 1 in every 9–10 years and 2–3 years, respectively) during the near and far future periods. Such increases in intensity and frequency are likely to adversely affect downstream population and infrastructures. This, therefore, urges for appropriate early precautionary mitigation measures. This study can assist water managers and policy makers in their preparation to adequately plan for and manage flood protection. Its findings are also relevant for other basins in the Hindukush-Karakoram-Himalayas region.

ACS Style

Muhammad Shahid Iqbal; Zakir Hussain Dahri; Erik P Querner; Asif Khan; Nynke Hofstra. Impact of Climate Change on Flood Frequency and Intensity in the Kabul River Basin. Geosciences 2018, 8, 114 .

AMA Style

Muhammad Shahid Iqbal, Zakir Hussain Dahri, Erik P Querner, Asif Khan, Nynke Hofstra. Impact of Climate Change on Flood Frequency and Intensity in the Kabul River Basin. Geosciences. 2018; 8 (4):114.

Chicago/Turabian Style

Muhammad Shahid Iqbal; Zakir Hussain Dahri; Erik P Querner; Asif Khan; Nynke Hofstra. 2018. "Impact of Climate Change on Flood Frequency and Intensity in the Kabul River Basin." Geosciences 8, no. 4: 114.

Journal article
Published: 01 March 2018 in International Journal of Hygiene and Environmental Health
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Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014-2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks.

ACS Style

M.M. Majedul Islam; Muhammad Iqbal; Rik Leemans; Nynke Hofstra. Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality. International Journal of Hygiene and Environmental Health 2018, 221, 283 -292.

AMA Style

M.M. Majedul Islam, Muhammad Iqbal, Rik Leemans, Nynke Hofstra. Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality. International Journal of Hygiene and Environmental Health. 2018; 221 (2):283-292.

Chicago/Turabian Style

M.M. Majedul Islam; Muhammad Iqbal; Rik Leemans; Nynke Hofstra. 2018. "Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality." International Journal of Hygiene and Environmental Health 221, no. 2: 283-292.

Research article
Published: 11 July 2017 in Environmental Science & Technology
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Understanding the environmental pathways of Cryptosporidium is essential for effective management of human and animal cryptosporidiosis. In this paper we aim to quantify livestock Cryptosporidium spp. loads to land on a global scale using spatially explicit process-based modeling, and to explore the effect of manure storage and treatment on oocyst loads using scenario analysis. Our model GloWPa-Crypto L1 calculates a total global Cryptosporidium spp. load from livestock manure of 3.2 × 1023 oocysts per year. Cattle, especially calves, are the largest contributors, followed by chickens and pigs. Spatial differences are linked to animal spatial distributions. North America, Europe, and Oceania together account for nearly a quarter of the total oocyst load, meaning that the developing world accounts for the largest share. GloWPa-Crypto L1 is most sensitive to oocyst excretion rates, due to large variation reported in literature. We compared the current situation to four alternative management scenarios. We find that although manure storage halves oocyst loads, manure treatment, especially of cattle manure and particularly at elevated temperatures, has a larger load reduction potential than manure storage (up to 4.6 log units). Regions with high reduction potential include India, Bangladesh, western Europe, China, several countries in Africa, and New Zealand.

ACS Style

Lucie C. Vermeulen; Jorien Benders; Gertjan Medema; Nynke Hofstra. Global Cryptosporidium Loads from Livestock Manure. Environmental Science & Technology 2017, 51, 8663 -8671.

AMA Style

Lucie C. Vermeulen, Jorien Benders, Gertjan Medema, Nynke Hofstra. Global Cryptosporidium Loads from Livestock Manure. Environmental Science & Technology. 2017; 51 (15):8663-8671.

Chicago/Turabian Style

Lucie C. Vermeulen; Jorien Benders; Gertjan Medema; Nynke Hofstra. 2017. "Global Cryptosporidium Loads from Livestock Manure." Environmental Science & Technology 51, no. 15: 8663-8671.

Original article
Published: 20 May 2017 in Environmental Processes
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Environmental variables influence Faecal Indicator Bacteria (FIB) in surface water. Understanding that influence is important, because presence of FIB, which are an indication of faecal contamination, means that harmful pathogens could be present that could also be influenced by environmental variables. Although some recent studies have focused on this topic, most of this work has been conducted in developed countries. Similar studies in developing countries and in a (sub)tropical climate are lacking. In this study we assess the influence of environmental variables on fluctuations in FIB concentrations of the Betna River in southwest Bangladesh that floods almost every year. Monthly water samples from five locations along Betna River were tested for FIB (E. coli and enterococci) in 2014–2015. A linear regression model was developed to assess the effect of the environmental variables on FIB concentrations. The study revealed increased FIB concentrations during wet weather conditions. Precipitation and water temperature were positively correlated with FIB concentrations. Water temperature was positively correlated, because the warm May to September period coincides with frequent precipitation. Precipitation increases manure release from land to surface water. The regression model explains nearly half of the variability in FIB concentrations (R2 of 0.46 for E. coli and 0.48 for enterococci). This study indicates that increased precipitation combined with higher water temperature, as is expected in this region with climate change, likely increases FIB concentrations. Waterborne pathogens are expected to respond similarly to these environmental changes, indicating that disease outbreaks could well become more frequent and severe.

ACS Style

M. M. Majedul Islam; Nynke Hofstra; Atikul Islam. The Impact of Environmental Variables on Faecal Indicator Bacteria in the Betna River Basin, Bangladesh. Environmental Processes 2017, 4, 319 -332.

AMA Style

M. M. Majedul Islam, Nynke Hofstra, Atikul Islam. The Impact of Environmental Variables on Faecal Indicator Bacteria in the Betna River Basin, Bangladesh. Environmental Processes. 2017; 4 (2):319-332.

Chicago/Turabian Style

M. M. Majedul Islam; Nynke Hofstra; Atikul Islam. 2017. "The Impact of Environmental Variables on Faecal Indicator Bacteria in the Betna River Basin, Bangladesh." Environmental Processes 4, no. 2: 319-332.

Journal article
Published: 01 January 2017 in AIMS Environmental Science
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ACS Style

Muhammad Shahid Iqbal; Muhammad Nauman Ahmad; Nynke Hofstra. The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan. AIMS Environmental Science 2017, 4, 690 -708.

AMA Style

Muhammad Shahid Iqbal, Muhammad Nauman Ahmad, Nynke Hofstra. The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan. AIMS Environmental Science. 2017; 4 (5):690-708.

Chicago/Turabian Style

Muhammad Shahid Iqbal; Muhammad Nauman Ahmad; Nynke Hofstra. 2017. "The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan." AIMS Environmental Science 4, no. 5: 690-708.

Journal article
Published: 01 January 2017 in AIMS Environmental Science
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ACS Style

Muhammad Shahid Iqbal; Muhammad Nauman Ahmad; Nynke Hofstra. The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan. AIMS Environmental Science 2017, 4, 690 -708.

AMA Style

Muhammad Shahid Iqbal, Muhammad Nauman Ahmad, Nynke Hofstra. The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan. AIMS Environmental Science. 2017; 4 (5):690-708.

Chicago/Turabian Style

Muhammad Shahid Iqbal; Muhammad Nauman Ahmad; Nynke Hofstra. 2017. "The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan." AIMS Environmental Science 4, no. 5: 690-708.

Journal article
Published: 01 December 2016 in Current Opinion in Environmental Sustainability
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ACS Style

Carolien Kroeze; Silke Gabbert; Nynke Hofstra; Albert A Koelmans; Ang Li; Ansje Löhr; Fulco Ludwig; Maryna Strokal; Charlotte Verburg; Lucie Vermeulen; Michelle T.H. van Vliet; Wim de Vries; Mengru Wang; Jikke van Wijnen. Global modelling of surface water quality: a multi-pollutant approach. Current Opinion in Environmental Sustainability 2016, 23, 35 -45.

AMA Style

Carolien Kroeze, Silke Gabbert, Nynke Hofstra, Albert A Koelmans, Ang Li, Ansje Löhr, Fulco Ludwig, Maryna Strokal, Charlotte Verburg, Lucie Vermeulen, Michelle T.H. van Vliet, Wim de Vries, Mengru Wang, Jikke van Wijnen. Global modelling of surface water quality: a multi-pollutant approach. Current Opinion in Environmental Sustainability. 2016; 23 ():35-45.

Chicago/Turabian Style

Carolien Kroeze; Silke Gabbert; Nynke Hofstra; Albert A Koelmans; Ang Li; Ansje Löhr; Fulco Ludwig; Maryna Strokal; Charlotte Verburg; Lucie Vermeulen; Michelle T.H. van Vliet; Wim de Vries; Mengru Wang; Jikke van Wijnen. 2016. "Global modelling of surface water quality: a multi-pollutant approach." Current Opinion in Environmental Sustainability 23, no. : 35-45.