The IAEA, in cooperation with the Food and Agriculture Organization of the United Nations (FAO), is calling on research institutes to join a new Coordinated Research Project (CRP) on assessing the environmental impact of plastics in soil and crop ecosystems, with a time frame of five years from 2023 to 2027.
Plastic use has increased from 1.7 million metric tonnes in 1950 to 359 million tonnes in 2018 due to factors such as population and income growth, and the increase in plastic packaging. Modern agricultural practices employ a wide range of plastic products to help improve productivity. The properties that make plastics so useful also create problems when they reach the end of their intended lives. As plastics begin to disintegrate and degrade, most end up on land and in the soil (long term sink), degrading into microplastics, particles measuring less than 5 mm in diameter.
According to FAO and UNEP, the earth's soil is more saturated with plastics and microplastics than the ocean, and 80% of them found in the marine environment are first disposed of on land. Plastics and microplastics that accumulate in soils can impact soil properties, which in turn can affect agricultural productivity. Reducing the impact of microplastics pollution on agricultural soil and crop ecosystem and water quality will contribute to meeting the United Nations Sustainable Development Goals (SDGs) related to zero hunger (SDG2), good health and well-being (SDG 3) and life on land (SDG 15).
To date, most scientific research on plastics pollution has been directed at aquatic ecosystems, especially oceanic environments. This CRP will respond to the urgent need to develop and harmonize rapid, reliable and affordable sampling and analytical protocols for tracing the fate and dynamics of microplastics in soils and crops and to identify good practices. It will also develop state-of-the-art tools/methods for informed decision making to help mitigate possible negative environmental impact of microplastics in soils.
A wide range of specialized nuclear and isotopic techniques are powerful tools that can help to determine the fate of plastics and microplastics in the soil and crop ecosystem. A combination of Raman microspectroscopy (RM) with the stable isotope approach, the stable isotope Raman microspectroscopy (SIRM), and the application of compound-specific stable isotopes (CSSI) can advance our understanding of plastic and microplastics turnover in soil and shed light on phylogenetic identity of those microorganisms responsible for the degradation. SIRM provides characteristic fingerprint spectra of samples with the spatial resolution of a confocal optical microscope, containing information on stable isotope-labelled substances and the amount of a label (based on red-shift of bands of the labelled substances).
Thus, stable isotopic and nuclear techniques play a crucial role in assessing the turnover rate of degradable microplastics, the final products of decomposition, and the effects on soil and crop health. Complementing these techniques are pyrolysis-gas chromatography-mass spectrometry, thermal desorbed gas chromatography, Fourier transform infrared (FTIR) spectroscopy, and thermal analysis techniques to monitor plastics in soils and the environment.
CRP Overall Objectives
The CRP is aimed at developing guidance for improving the understanding of the fate and impacts of plastics and microplastics in agricultural soils based on nuclear and related techniques. Another goal is to establish a network and to coordinate inter-laboratory studies of analytical techniques and data interpretation to support CRP network member states in developing common strategies to effectively mitigate the plastic pollution of agricultural soils and crops.
Specific research objectives of the CRP are
1. To develop, evaluate and standardize integrative isotopic and standard approaches for identifying and elucidating the fate of plastics and microplastics in agricultural soils.
2. To apply the isotopic approaches, in combination with existing methodologies, for assessing the fate and impact of plastics and microplastics in agricultural soils under different environmental conditions.
3. To provide knowledge and guidance for informed decisions that help minimize the possible negative impacts of plastics and microplastics on soil health and ecosystem services.
The expected outputs of the project are
- Harmonized techniques and procedures for sampling, analysis and interpretation of data to help CRP network to understand the fate and impacts of plastics and microplastics in agricultural soils and crops.
- Improved human resources (through training) and methodological capabilities of counterparts in the analysis of plastics and microplastics and its degradation products in agricultural soils and crops.
- Field and laboratory validated case studies to monitor the fate of naturally labelled plastics, including its transport through the soil and (bio)degradation products in the soil, and assessing its impacts on soil health and ecosystem services.
How to join this CRP
Technical and research contracts will be awarded; and no-cost agreement holders from advanced laboratories are expected to participate. Research institutes with recognized expertise in the targeted technologies will be invited to share their experience with the contract holders and contribute to the development and validation of planned integrative isotopic and standardized protocols.
Coordination and technical management will be handled by the scientific secretary in the IAEA's Soil and Water Management & Crop Nutrition Section and its Laboratory at the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture
