Improving Understanding of Nitrate Sources in Connected River and Groundwater Systems Through Linking Nitrate Isotopes

The IAEA is launching a new Coordinated Research Project (CRP) to address a problem of continuously growing impacts of nitrate pollution on freshwater ecosystems around the globe. The CRP, entitled “Improving understanding of nitrate sources in connected river and groundwater systems through linking nitrate isotopes and contaminants of emerging concern”, will be conducted over 4 years.

Nitrate contamination reduces the access to drinking water – a key factor of well-being. While the nitrate source identification remains challenging using hydrochemical measurements, the analysis of stable isotopes in nitrate helps to track nitrate sources and processes. However, nitrate isotopes are not suitable in differentiating closely related sources of nitrate contamination with overlapping isotopic signature, such as sewage and manure, but also treated and raw sewage inputs.

In this CRP, isotopic techniques will be used in conjunction with compounds of emerging concern (CECs) that are ideal chemical markers of faecal contamination (sewage or manure) as they are ubiquitous in the source, persistent and present at detectable concentrations in contaminated environmental samples but not in clean water. The CRP will put forward this innovative approach of combining stable isotopes of nitrate with CECs in surface and groundwater. Case studies as part of this CRP will provide guidelines to water managers on the use of isotope tools to assess nitrate contamination and sources in Member States.

This CRP is open to research institutes in all Member States that already have or plan to launch in 2022 a project within this stated scope funded by their own sources. Priority will be given to those institutes that have on-going projects related to this CRP, but also laboratory facilities (or access to these facilities) to analyse stable isotopes of nitrate and/or compounds of emerging concern. Within this context, the aim of the CRP is to bring researchers together and to enhance exchange of new and shared knowledge.

CRP Overall Objective

The overall objective is to demonstrate the benefits of environmental isotopes combined with CECs to better understand nitrate pollution sources and processes in surface water and groundwater.

Specific Research Objectives:

  1. Introduce the combined use of isotopes and CECs to delineate nitrate sources and evaluate nitrate pathways and related processes in surface water and groundwater.
  2. Assess and improve the understanding and interpretation of environmental isotopes to trace anthropogenic nitrogen inputs and evaluate nitrate related processes in surface water and groundwater resources.
  3. Appraise the utility of the nitrogen isotope – CECs approach to distinguish sewage and manure sources and improve the interpretation of nitrate processes, sources, and pathways in surface water and groundwater.

How to join this CRP:

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