1. Stable Isotopes for monitoring agricultural-derived pollutants and land management practices to ensure water quality
Joseph Adu-Gyamfi and Lee Heng
Soil and Water Management & Crop Nutrition Section
Joint FAO/IAEA Division of Nuclear techniques in Food and Agriculture
“Integrated Nutrients Pollution Control” Project – “The Blue Waters and Green Agriculture Conference – Romanian Challenges and Perspectives in Nutrients Pollution Control”
10-13 May, 2017
Bucharest, Romania

2. Outline
Joint FAO/IAEA Programme in Food and Agriculture and work of Soil and Water Management and Crop Nutrition (SWMCN) Subprogramme at a glance
Nuclear and stable isotope techniques for water quality, nutrient and sediment/erosion studies
Case Study in Chad, Slovenia and Myanmar

3. Joint FAO/IAEA Division of Nuclear Techniques

4. Soil and Water Management and Crop Nutrition (SWMCN) Section
ANNEX 10
Vienna Headquarters
Develop, implement and coordinate Coordinated Research Projects (CRPs).
Provide technical support to IAEA
Technical Cooperation (TC) Projects.
Seibersdorf Laboratory
Develop, adapt and transfer new
technologies to Member States.
Conduct training courses & fellowship
training.
Provide analytical support & external
quality assurance.

5. in Developed Countries Collaboration Centres
Programme Delivery
CRP
NARS in
Developing
Countries
Institutions
in Developed Countries
CGIAR Centres
Other international
organisations
IAEA
Collaboration Centres
Developing Countries
TCP
organizations
Coordinate and Support
Technical Support
 From the lab to the field

6. What are isotopes?
They are atoms of an element which have different mass number but the same atomic number. atomic number: number of protons (Z) mass number: sum of protons and neutrons proton: positive charge; same mass as neutron neutron: no charge; same mass as proton electron: negative charge; no mass (very little mass) mass number 6 12 𝐶 atomic number

7. Isotopes Two types of isotopes: Stable isotopes
Unstable isotopes (radioactive isotopes, radionuclides)
Isotope
Protons
Neutrons
Atomic Number
Mass Number
13N 7 6 13
radioactive
14N 14
stable
15N 8 15
16O 16
17O 9 17
18O 10 18

8. Isotopes of Nitrogen Mass Number Natural abundance (%) Half-life
(time) 12 -
sec 13
10.05 min 14
(light) 15
0.366 (heavy) 16
7.36 sec 17
4.14 sec

9. Equipment to measure Isotopes
Mass Spectrometer
Cavity Ring Down Spectrometer

10. Services Provided by SWMCNL
Develop and validate nuclear/isotopic techniques for CRPs and TCPs.
Train technical staff and scientists in the analysis of isotopes and the use of nuclear and related techniques
Provide isotope analyses to projects where analytical facilities are not available (8000 analyses in total).
Provide quality assurance services

11. Training at SWMCN Laboratory Seibersdorf
ANNEX 10
Training at SWMCN Laboratory Seibersdorf

12. Stable Isotope Techniques
Nitrogen-15 (15N)
Biological Nitrogen Fixation
Fertilizer Use Efficiency
Soil Organic Carbon Stability
Greenhouse gas emission
Carbon-13
Crop tolerance for drought and salinity stress (Carbon Isotope Discrimination)
Soil Organic Carbon Sequestration
Identification of sources of land degradation (using CSSI of fatty acids)
15N
14N
C3 plants: d 13C = -26‰

13. Nuclear Techniques for Assessing ET, Water Movement and Water Quality
Oxygen-18 (δ18O)/Deuterium (δ2H)
Agricultural water management:
Separating evaporation and crop transpiration to improve water use efficiency
Water movement and water quality studies
Field determination of movement of water
Sources of water quality (e.g. nitrate) with N-15 isotope
Leaf water
+15‰
Transpiration water
-2‰
Soil evaporation water
-30‰
Xylem water
Precipitation
-5‰
Soil water
Surface soil: +3‰
Deeper: -5‰

14. Nuclear Techniques for Assessing Soil Moisture
Neutron Probe
Field-scale soil water measurement for irrigation management
Ideal under cracking soil or saline conditions
Cosmic Ray Soil Moisture Neutron Probe
Measures soil water up to 20 ha in area.
Ideal for landscape/catchment scale water management study

15. Nuclear Techniques for Assessing Soil Erosion
Fallout Radionuclides (FRNs) (Caesium-137; Lead-210; Beryllium-7)
Assessing soil erosion
Determining sediment in reservoir (sedimentation rates vs time)
Developing soil conservation strategies at landscape level
Linking soil redistribution and soil quality (e.g. soil organic matter) in the landscape
The FRNs Guidelines (i.e. IAEA TECDOC 1741)

16. A proposed new Coordinated Research Project
( )
Stable Isotopes for agricultural-derived pollutants and effective land management

17. Isotopic Techniques to study nutrient and pesticide movement and water quality management
Purpose:
To use isotope tracer techniques (isotopes of nitrogen and oxygen and carbon) to investigate the movement of agricultural-derived (nitrates, phosphorus and pesticides) on water quality issues
To determine sources and fate of the agricultural-derived pollutants in catchments and receiving water bodies.
To use best-fit land management practices and design strategies for effective remediation

18. Agricultural-derived pollutants: Nature and Scope
The pressure to produce enough food to feed the growing population has a worldwide impact on water quality.
Pollutants derived from agricultural activities such as intensive cultivation, excessive and inefficient use of chemical and organic fertilizers, pesticides, soil sediments associated agro food-processing industries affect water quality.
Our water systems are currently being threatened by the crops we grow
It is estimated that an amount of US$ 4.8 billion is spend annually in US treat drinking water contaminated with N, P, pesticides and on microbiological contaminants
According to FAO, 5 million people die annually from water-borne diseases

19. A set of Isotopic Techniques
Combined use of stable isotopes of 15N, δ18O in phosphate, δ13C, and nitrate-δ18O
  Compound-specific isotope analysis (CSIA) has been established as a tool to study the environmental fate of a wide range of contaminants

20. Determining Sources of Nitrate using Isotopes of δ18O & δ15N
The recent basin-wide nutrient emissions entering the surface water bodies are 605,000 tons per year total N and 38,500 tons per year total P.
Diffuse pathways clearly dominate the total emissions by 84% (N) and 67% (P).
For N, groundwater (base flow and interflow) is the most important diffuse pathway with a proportion of 54%.
In case of P, soil erosion (32%) and urban runoff (18%) generate the highest emissions.
Regarding the sources, agriculture (N: 42%, P: 28%) and urban water management (N: 25%, P: 51%) are responsible for the majority of the nutrient emissions.
A MULTI-ISOTOPE APPROACH
Kendall, 2004

21. Signatures of Nitrate δ15N & δ18O from Various Sources, Sinks and Processes

22. Determining Sources of Phosphate using Isotopes of Oxygen in Phosphate (PO4) (18Op)
Global sources & isotope of oxygen in phosphate
WWTP: wastewater treatment plant effluent
Source: Paytan and McLaughlin, 2011

23. Compound specific isotope (δ13C) analysis of organophosphorus pesticides

24. Nitrate pollution and water quality
IAEA technical Cooperation projects

25. Lake Chad in Africa
IAEA Project CHD5006 is using isotope to determine the sources of nitrate and best-fit soil and water management practices to improve crop productivity

26. SLOVENIA
Protecting Groundwater and soil against pollutants using Nuclear Techniques (SLO5002)
Zupanc, V., Sturm, M., Lojen, S., Marsic-Kacjana, N., Adu-Gyamfi, J., Bracic-Zeleznik, B., Urbanc, J. and Pintar, M Nitrate leaching under vegetable field above a shallow aquifer in Slovenia. Agriculture, Ecosystems and Environment, 144:167–174.

27. Myanmar Inle Lake Water Quality Issues

28. Myanmar Inle Lake Water Quality Issues

29. Soil and Water Management & Crop Nutrition Subprogramme Website and Newsletter

30. Thank you