Periodic Reporting for period 1 - ARISTO (The European Industry - Academia Network for RevIsing and Advancing the Assessment of the Soil Microbial TOxicity of Pesticides)
Periodo di rendicontazione: 2020-12-01 al 2022-11-30
Pesticides are major environmental pollutant. To protect the environment and human health the European Commission (EC) has imposed a stringent regulatory scheme for pesticides (Regulation 1107/2009), where risk assessment for aquatic organisms and terrestrial macro-organisms is well defined. In contrast the assessment of the toxicity of pesticides on soil microorganisms is lagging behind, still relying on an outdated protocol, the OECD 216 N transformation test. This test fails to identify effects on key microbial functions and microbial diversity, now being determined through high-resolution, advanced and standardized methods introduced in soil microbiology in the last decade. In 2010 EFSA identified soil microorganisms as an attribute to monitor in pesticides environmental risk assessment. In 2017 EFSA reinforced the need for novel tests to assess pesticides toxicity on soil microorganisms. The ARISTO comes to address this scientific and regulatory gap through a unique doctoral program, based on the strong interaction of academia and industry, aiming to train the next generation of Microbial Ecotoxicologists. These will produce the benchmarking knowledge required for the development of advanced tools to comprehensively assess the soil microbial toxicity of pesticides in Europe in the forthcoming years. Hence microbial indicator groups like Ammonia Oxidizing Microorganisms (AOM) and Arbuscular Mycorrhizal Fungi (AMF) were selected. The backbone of ARISTO is a tiered risk assessment scheme where fellows will assess the toxicity of pesticides on soil microorganisms at different experimental levels of complexity, from in vitro (Tier I) to soil at laboratory (Tier II) and field scale (Tier III) (Figure 1). In addition ARISTO will go beyond the state of the art and address issues which remain unresolved.
The main research challenge of ARISTO will be addressed through 5 objectives structured in corresponding research WPs:
1. to develop and standardize pioneering in vitro tests, to assess pesticides toxicity on phylogenetically and ecophysiologically distinct soil ammonia oxidizing microorganisms (AOM) (ESR1) and arbuscular mycorrhizal fungi (ESR2)
2. to develop and implement advanced experimental lab and field tests to assess pesticides toxicity on natural soil assemblages of ammonia-oxidizing microorganisms (AOM) (ESR3) and AMF (ESR4), as a more realistic assessment step
3. to go beyond the "single organism (in vitro)" and "single group assays (natural soil assemblages)" and offer an ecosystem-level assessment of the toxicity of pesticides on soil microbial networks (ESR5) and on microorganisms from different trophic-levels within the soil food-web (predator - prey) (ESR6), and the consequences of these on ecosystem functioning
4. to develop novel tools and procedures to determine in a comprehensive way the soil microbial toxicity of pesticide mixtures (ESR7) and bio-pesticides (ESR8) which remains unexplored
5. to develop and validate advanced in silico tools for prioritizing transformation products (TPs) of pesticides with potential toxicity to soil microorganisms (ESR9)
The main research challenge of ARISTO will be addressed through 5 objectives structured in corresponding research WPs:
1. to develop and standardize pioneering in vitro tests, to assess pesticides toxicity on phylogenetically and ecophysiologically distinct soil ammonia oxidizing microorganisms (AOM) (ESR1) and arbuscular mycorrhizal fungi (ESR2)
2. to develop and implement advanced experimental lab and field tests to assess pesticides toxicity on natural soil assemblages of ammonia-oxidizing microorganisms (AOM) (ESR3) and AMF (ESR4), as a more realistic assessment step
3. to go beyond the "single organism (in vitro)" and "single group assays (natural soil assemblages)" and offer an ecosystem-level assessment of the toxicity of pesticides on soil microbial networks (ESR5) and on microorganisms from different trophic-levels within the soil food-web (predator - prey) (ESR6), and the consequences of these on ecosystem functioning
4. to develop novel tools and procedures to determine in a comprehensive way the soil microbial toxicity of pesticide mixtures (ESR7) and bio-pesticides (ESR8) which remains unexplored
5. to develop and validate advanced in silico tools for prioritizing transformation products (TPs) of pesticides with potential toxicity to soil microorganisms (ESR9)
Nine fellows were recruited by ARISTO. In WP4, fellows tested at in vitro level the toxicity of 15-20 pesticides on a range of AOM and AMF strains of varying ecophysiological attributes. They identified AOA, AOB, NOB and AMF strains which were consistently the most sensitive and could be used in Tier I testing. In WP5, fellows assessed the toxicity of pesticides on soil microbial assessmblages at lab scale (Tier II), while two field tests will follow. The impact of pesticides on natural assemblages of AOM in the presence of extra stressors like drought (in accordance with climate change) was determined in three lab experiments. Regarding AMF, two pot experiments with potato and corn have been employed to determine the toxicity of pesticides on AMF function and diversity (in soil and in planta). In WP6, the two fellows looked at the effects of pesticides beyond the single group/single trophic level and determined the toxicity of pesticides on soil microbial networks and across the soil food web. One of the fellows checked the hypothesis that pesticide application will not only directly affect certain microbial taxa, but will also have indirect effects throughout the community mediated through their interactions. The second fellow assessed the effects of pesticides on soil microbiota considering trophic predator-prey interactions. In WP7 fellows addressed the toxicity of pesticide mixtures and biopesticides. The first fellow has employed lab and field experiments looking at the effect of mixtures of pesticides on the soil microbiota, and on soil nematodes which are direct interactors with the soil microbiota. Regarding biopesticides, two microcosm lab experiments and one pot experiment were undertaken to assess the toxicity of selected botanical pesticides on the soil microbiota. First results suggested unexpected effects of some of the botanical pesticides on the abundance of AOM although effects on the activity were not evident. In WP8 an in silico tool for predicting and prioritizing pesticide transformation products according to their potential toxicity to AOM will be developed. So far an algorithm for automatic rule extraction has been implemented and has been demonstrated to improve prediction performance for pesticide transformation products. It has been used to generate a first list of potential transformation products of the pesticides used in ARISTO. In addition, the toxicity of four transformation products on AOM strains has been determined to be used to validate the in silico prediction tool.
During the first 24 months, ARISTO has already produced data that will benchmark the soil microbial toxicity of pesticides in the following ten years:
- Established procedures to assess the toxicity of pesticides on AOM and AMF
- Established experimental protocols to assess the toxicity of pesticides on natural microbial assemblages of AMF and AOM, for the latter in the presence or absence of further stressors like drought
- Established experimental protocols of various complexity to assesess the indirect effects of pesticides at the soil microbial community level and at the soil food web level
- They have first evidence for the toxicity of biopesticides on the soil microbiota
- They will setup the first in silico tool for predicting the toxicity of pesticide TPs on soil microorganisms (AOM as indicators)
It is anticipated that in the second reporting period, the fellows and the ARISTO network will produce ground-breaking results as follows;
- Use amplicon sequencing data in an ecotoxicological context using species sensitivity distribution
- Develop the first in silico tool for predicting the toxicity of pesticide transformation products on soil AOM,
- Develop proof-of-concept tiered risk assessment for specific pesticides combining data from WP4, 5, 6 and 7.
All these pioneering results will be presented to the European Commission, regulatory bodies and stakeholders facilitating the implementation of tools and procedures developed by ARISTO in the regulatory framework of Europe. The implementation of the ARISTO risk assessment scheme and its associated tools is expected to minize the risk for the integrity, diversity and function of the soil microbiota which constitutes the growth engine of terrestrial ecosystems and agricultural production.
- Established procedures to assess the toxicity of pesticides on AOM and AMF
- Established experimental protocols to assess the toxicity of pesticides on natural microbial assemblages of AMF and AOM, for the latter in the presence or absence of further stressors like drought
- Established experimental protocols of various complexity to assesess the indirect effects of pesticides at the soil microbial community level and at the soil food web level
- They have first evidence for the toxicity of biopesticides on the soil microbiota
- They will setup the first in silico tool for predicting the toxicity of pesticide TPs on soil microorganisms (AOM as indicators)
It is anticipated that in the second reporting period, the fellows and the ARISTO network will produce ground-breaking results as follows;
- Use amplicon sequencing data in an ecotoxicological context using species sensitivity distribution
- Develop the first in silico tool for predicting the toxicity of pesticide transformation products on soil AOM,
- Develop proof-of-concept tiered risk assessment for specific pesticides combining data from WP4, 5, 6 and 7.
All these pioneering results will be presented to the European Commission, regulatory bodies and stakeholders facilitating the implementation of tools and procedures developed by ARISTO in the regulatory framework of Europe. The implementation of the ARISTO risk assessment scheme and its associated tools is expected to minize the risk for the integrity, diversity and function of the soil microbiota which constitutes the growth engine of terrestrial ecosystems and agricultural production.