student profile: Mr Daniele La Cecilia


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Thesis work

Thesis title: Comprehensive modelling for agrochemicals biodegradation in soil. A multidisciplinary approach to make informed choices to protect human health and the environment

Supervisors: Chengwang LEI , Federico MAGGI

Thesis abstract:

Numerical models to predict agrochemical dynamics in the environment are relied upon by risk assessors to (re)approve the use of potentially hazardous substances in farming activities. Those models may account for fundamental processes affecting agrochemicals dispersion and disappearance in soil, such as environmental and edaphic conditions, water flow, degradation, and adsorption. However, those models lack to account for complex biogeochemical feedbacks, which create challenges in achieving robust predictions because they disregard agrochemicals effects on soil quality and ecosystem processes. In particular, no attention has been paid on the mechanistic description of microbial dynamics and the implications on agrochemicals biodegradation and soil and groundwater contamination while accounting for soil organic matter (SOM) cycling. This thesis aims to provide this description by developing a comprehensive framework through a multidisciplinary approach for predicting agrochemical dynamics in soil.

Microbiological regulation of agrochemical dynamics was investigated by coupling theoretical and numerical approaches with experiments carried out in our environmental laboratory or sourced from the literature. We propose the use of reaction networks to highlight the possibly multiple biochemical degradation pathways of agrochemicals and the feedbacks with the SOM cycle. Biochemically-similar pathways are mediated by a specific microbial functional group, which represents the overall microbial community carrying out particular functions; these functions are biodegradation of toxic agrochemicals and metabolism of nitrogen and carbon substrates. We describe biochemical reactions by means of Michaelis-Menten-Monod (MMM) kinetics, and we suggest that the MMM framework should be used in environmental risk assessment models rather than first-order kinetics. Indeed, MMM parameters fully encompass the diverse strategies microbes use to live and thrive including rapid growth, high affinity for substrates, or high substrate consumption efficiency. Yet, Michaelis-Menten terms allow to include microbial competition for nutrients and byproducts, growth inhibition, and the herein presented memory-associated catabolite repression, which all can alter agrochemicals biodegradation and SOM cycle.

Because we mechanistically characterized each biogeochemical process, its uncertainty or relevance can be quantified by mean of sensitivity analyses. The latter are therefore crucial to explore likely outcomes under a suite of scenarios, thus allowing risk managers to make informed decisions. We numerically show that relatively small variability in MMM kinetic parameters and soil hydraulic parameters can result in large variability in agrochemicals environmental concentration. These results are in line with monitoring campaigns worldwide reporting agrochemicals accumulation in soil and water resources, despite currently-enforced first-order kinetic models may predict quick and complete biodegradation.

The proposed high level of process coupling processes introduced using a multidisciplinary approach is urged to capture Nature’s strategies to cope with environmental changes, provide robust evidence to make informed choices, and develop sustainable solutions.

Selected publications

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Journals

  • La Cecilia, D., Riley, W., Maggi, F. (2019). Biochemical modeling of microbial memory effects and catabolite repression on soil organic carbon compounds. Soil Biology and Biochemistry, 128, 1-12. [More Information]
  • La Cecilia, D., Maggi, F. (2018). Analysis of glyphosate degradation in a soil microcosm. Environmental Pollution, 233, 201-207. [More Information]
  • La Cecilia, D., Tang, F., Coleman, N., Conoley, C., Vervoort, R., Maggi, F. (2018). Glyphosate dispersion, degradation, and aquifer contamination in vineyards and wheat fields in the Po Valley, Italy. Water Research, 146, 37-54. [More Information]
  • Porta, G., La Cecilia, D., Guadagnini, A., Maggi, F. (2018). Implications of uncertain bioreactive parameters on a complex reaction network of atrazine biodegradation in soil. Advances in Water Resources, 121, 263-276. [More Information]
  • La Cecilia, D., Maggi, F. (2017). In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime. Journal of Contaminant Hydrology, 203, 104-121. [More Information]
  • Maggi, F., La Cecilia, D. (2016). Implicit Analytic Solution of Michaelis-Menten-Monod Kinetics. ACS Omega, 1(5), 894-898. [More Information]
  • La Cecilia, D., Maggi, F. (2016). Kinetics of atrazine, deisopropylatrazine, and deethylatrazine soil biodecomposers. Journal of Environmental Management, 183, 673-686. [More Information]

Conferences

  • Tang, F., La Cecilia, D., Vervoort, R., Coleman, N., Conoley, C., Maggi, F. (2017). Integrating biological degradation potential into ecological risk assessment. 22nd International Congress on Modelling and Simulation (MODSIM 2017), Australia: Modelling and Simulation Society of Australia and New Zealand Inc (MSSANZ).
  • La Cecilia, D., Maggi, F. (2017). Stochastic sensitivity analysis of glyphosate biochemical degradation. 22nd International Congress on Modelling and Simulation (MODSIM 2017), Australia: Modelling and Simulation Society of Australia and New Zealand Inc (MSSANZ).

2019

  • La Cecilia, D., Riley, W., Maggi, F. (2019). Biochemical modeling of microbial memory effects and catabolite repression on soil organic carbon compounds. Soil Biology and Biochemistry, 128, 1-12. [More Information]

2018

  • La Cecilia, D., Maggi, F. (2018). Analysis of glyphosate degradation in a soil microcosm. Environmental Pollution, 233, 201-207. [More Information]
  • La Cecilia, D., Tang, F., Coleman, N., Conoley, C., Vervoort, R., Maggi, F. (2018). Glyphosate dispersion, degradation, and aquifer contamination in vineyards and wheat fields in the Po Valley, Italy. Water Research, 146, 37-54. [More Information]
  • Porta, G., La Cecilia, D., Guadagnini, A., Maggi, F. (2018). Implications of uncertain bioreactive parameters on a complex reaction network of atrazine biodegradation in soil. Advances in Water Resources, 121, 263-276. [More Information]

2017

  • La Cecilia, D., Maggi, F. (2017). In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime. Journal of Contaminant Hydrology, 203, 104-121. [More Information]
  • Tang, F., La Cecilia, D., Vervoort, R., Coleman, N., Conoley, C., Maggi, F. (2017). Integrating biological degradation potential into ecological risk assessment. 22nd International Congress on Modelling and Simulation (MODSIM 2017), Australia: Modelling and Simulation Society of Australia and New Zealand Inc (MSSANZ).
  • La Cecilia, D., Maggi, F. (2017). Stochastic sensitivity analysis of glyphosate biochemical degradation. 22nd International Congress on Modelling and Simulation (MODSIM 2017), Australia: Modelling and Simulation Society of Australia and New Zealand Inc (MSSANZ).

2016

  • Maggi, F., La Cecilia, D. (2016). Implicit Analytic Solution of Michaelis-Menten-Monod Kinetics. ACS Omega, 1(5), 894-898. [More Information]
  • La Cecilia, D., Maggi, F. (2016). Kinetics of atrazine, deisopropylatrazine, and deethylatrazine soil biodecomposers. Journal of Environmental Management, 183, 673-686. [More Information]

Note: This profile is for a student at the University of Sydney. Views presented here are not necessarily those of the University.