Decision SUpport ToolS for Risk-based Prioritization and Control of Contaminants of Emerging Concern

In October 2018 the SUSPECt project has officially started. The project aims to develop a set of flexible decision-support tools that can be used by stakeholders for location specific analysis, risk based prioritization and cost-effective control of contaminants of emerging concern and other chemicals. Being structured around an urban and a rural case the project appointed for both the urban and the rural case a PhD student. For both cases one or more case study locations will be selected for testing the developed methods and integration.

Urban case - CEC emissions from healthcare institutions, households and industry in Nijmegen

Due to constantly improving measuring techniques, new pollutants are detected at lower and lower concentrations. These newly discovered pollutants are often referred to as ‘contaminants of emerging concern’ (CECs) because their effect on the environment is not yet fully understood. Pharmaceutical residues are examples of CECs. Of every pill that a person consumes, some part is excreted as original compound whereas also one or more metabolites may be formed. Therefore, our urban wastewaters are very diverse cocktails of basically everything that is consumed within a city: antibiotics, antidepressants, pain killers, x-ray contrast media, but also detergents, micro plastics, disinfectants or illicit drugs.

Everything that goes down the drain, ends up in the sewer system and ultimately at the local wastewater treatment plant. Depending on their chemical structure, most contaminants are removed only to a certain degree because treatment plants are originally designed to remove nutrients from wastewater. Consequently, after discharge, low concentrations of all kinds of chemicals end up in aquatic systems where fish and other water organisms are being exposed to our city life. Besides, this surface water may be a source for drinking water, confronting drinking water companies with an increasing effort to remove these compounds.

But what is needed to remove really all contaminants that might harm the environment? Which compounds are exactly in wastewater and at what concentrations? Should we invest in a separate wastewater treatment at hospitals which are often seen as point sources for pharmaceutical residues? Or does it make more sense to invest in the municipal treatment plant because much more pharmaceuticals are consumed at home? Maybe prevention and educative measures are even more effective? To questions like these, our research project SUSPECt is going to search for answers.

The urban case study focusses on the city of Nijmegen and follows CEC, like for examples, pills from prescription to intake and excretion, through the sewer system into the wastewater treatment plant. We investigate which processes take place throughout this journey and how these affect the different compounds. If we know what a city consumes and how much of it, we should be able to predict the composition of the wastewater and thus the effluent quality of the treatment plant. From this, we can predict local water quality of receiving water bodies and estimate the effects on fish and water organisms. To validate our model, we will analyze water samples at strategic points throughout the city, the treatment plant and at the river.

Rural case - Emissions of veterinary pharmaceuticals from livestock breeding

The rural case focuses on modelling the emission and fate of veterinary pharmaceuticals (VPs) from manure application to agricultural fields. Considering sales and usage data, as well as previous investigations (monitoring and measurements) and at the same time taking into account range of different applications and physico-chemical characteristics, we decided to further follow substances such as: antibiotics, hormones, antiparasitics and disinfectants.

VP loads in manure will be estimated based on local, regional and/or national data. As the fate of VPs applied at the soil surface shows similarities with that of pesticides , pesticide risk assessment approaches used in e.g. EU admission procedures provide a suitable starting point for fate modelling of VPs. However, certain modifications related with transformation during storage and processing before emission to the soil surface will explicitly be considered. Regarding transport pathways, we can say that major routes that will be examined are:

  1. Overland flow into surface water (includes direct emission into surface water)
  2. Infiltration and leaching towards drains
  3. Infiltration and groundwater base flow to surface water.

For the rural case finding a suitable location is considered as an important step. Several aspects can be identified in the process of suitable area selection. Some of them are related to practical features (e.g. current monitoring campaigns), while others are related to factors influencing the emission routes of VP, like the application of  manure (identification of the livestock type, amount of applied manure, treat and storage conditions), land use, soil type and runoff. Most of these criteria will affect modelling parameters and so recognizing a fitting location is of prior importance. In a later stage of the project, there will be a possibility for expansion to the regional/landscape scale.

In order to develop the most suitable decision support system stakeholder involvement is essential and present in both the rural case as well as in the urban one.

The expected outcome from both cases is a modular model that helps stakeholders throughout the entire water cycle to assess and predict water quality based on a number of relevant parameters (usage, fate, risks) without need to perform expensive and time-consuming monitoring campaigns. Future scenario analysis can help to evaluate strategic decisions so that action can be taken before serious issues arise.

Download this file (SUSPECt Rural Case.pdf)SUSPECt Rural Case.pdf[ ]648 kB
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