H2020 RESOURCE project: Assessing groundwater quality in intensive livestock farming areas: Is manure recycling a major source of contamination and the spread of antibiotic resistance genes?
- Type Project
- Status Filled
- Execution 2017 -2020
- Assigned Budget 170.121,6 €
- Scope Europeo
- Main source of financing H2020
- Project website RESOURCE
Several tasks were carried out within RESOURCE to achieve the project objectives. Specific analytical methodologies and protocols were developed to analyze selected antibiotics and ARGs in both manure (mainly pig slurry) and groundwater. A simplified protocol was established for the characterization of dissolved organic matter (DOM) in groundwater and its subsequent statistical analysis. Extensive field monitoring studies, collecting groundwater and manure samples, were conducted in areas with intensive livestock production and where groundwater is also used as a source of drinking water. In addition to analyzing antibiotics and ARGs in manure, their reduction with different treatment technologies was also evaluated as a strategy to reduce potential environmental and human health risks.
The results showed a widespread presence of antibiotics widely used in livestock farming in manure (i.e., pig slurry) at high concentrations (from high µg L-1 to even mg L-1). Some of these antibiotics were also present in groundwater samples, mostly at low concentrations (ng L-1). However, in some cases, they even reached significant levels (µg L-1). Genes conferring resistance to the detected antibiotic classes were also found in both manure and groundwater, with values ranging from 4×10⁻ to 5×10⁻ copy numbers/L of water in groundwater. The reduction in antibiotics during manure treatment was moderate (from 40% to complete elimination for some compounds), suggesting that their pre-treatment before field application is a suitable alternative to reduce environmental risks.
Dissolved organic matter (DOM) analysis revealed that the majority of molecular formulas were CHO compounds, while a considerable percentage also contained nitrogen and sulfur (~15–20%, respectively). The use of van Krevelen diagrams (plots of H/C versus O/C atomic ratios) showed that all our samples were dominated by molecules from the lignin-like region. Finally, we were also able to establish relationships between antibiotics and DOM composition. Analysis of groundwater samples across different seasons showed high variability in the detected compounds and their concentrations. This makes it difficult to assess groundwater quality for public use and to implement efficient monitoring strategies.
The project results were disseminated through different strategies, such as: (i) the publication of articles in open access journals (two articles are in preparation and will be submitted once completed); (ii) oral and poster contributions at national and international conferences; (iii) the organization of a workshop with stakeholders, farmers, and end-users; (iv) the development of an open access technical guide on antibiotic reduction in manure treatment and for drafting guidelines for safe manure reuse; (v) the dissemination of project activities and results in the institute's annual newsletter, the 10th anniversary conference "Water Research in Perspective: Beyond 2020" and the EU Climate Change Initiative, all open to the general public; and (vi) the presentation of a Master's thesis, among others.
Groundwater is a fundamental resource, especially in areas where surface water is limited or of poor quality. Around 75% of the population in the European Union depends on groundwater as a source of drinking water, making it an important resource for both industry and agriculture. In agricultural areas with intensive livestock farming, the chemical and microbiological quality of groundwater could be seriously compromised by the excessive use of animal manure as organic fertilizer.
From a chemical perspective, animal manure is rich in nutrients beneficial for crop growth and soil conditioning, and offers the potential to close the nutrient loop. However, it can also contain high concentrations of antibiotics and antibiotic resistance genes (ARGs), and its reuse as fertilizer can be a significant pathway for groundwater contamination.
The spread of antibiotic resistance has become a major global public health problem, as several infectious organisms have become resistant to the most commonly prescribed antibiotics, reducing or eliminating their therapeutic effect. An alarming fact is that approximately 25,000 European citizens (5.1 per 100,000 inhabitants) die each year from infections caused by bacteria that have developed antimicrobial resistance.
The main objective of RESOURCE was to expand the knowledge on the role of animal manure reuse as a major source of groundwater contamination in agricultural areas with high livestock production by: (i) analyzing multi-class antibiotics and selected ARGs and (ii) using an innovative approach, based on the mass characterization of dissolved organic matter (DOM) by high-resolution mass spectrometry (HRMS), to uncover the chemical fingerprint of selected manure-impacted groundwater bodies used as sources for drinking water production. DOM is a combination of numerous substances, such as humic and fulvic acids, polysaccharides, proteins, lipids, among others. Its characterization is of interest since it can react with disinfectants during drinking water treatment and generate disinfection byproducts that are potentially toxic to human health.
Groundwater protection is one of the last remaining environmental battlegrounds in Europe. Groundwater is used as an important source for drinking water production throughout Europe, and as such, preserving its chemical and microbiological quality is of vital importance. In agricultural areas with intensive livestock farming, groundwater quality could be seriously compromised by the excessive use of manure as organic fertilizer.
Animal manure can contain high levels of organic contaminants (e.g., antibiotics, nitrogen-containing compounds) and bacteria carrying antibiotic resistance genes (ARGs), and its reuse as a soil amendment could be an important route of entry of these contaminants into groundwater bodies.
This project aims to expand the knowledge on the role of animal manure recycling as a major source of groundwater contamination by: (i) analyzing selected multi-class antibiotics and ARGs and (ii) using an innovative approach, based on bulk dissolved organic matter (DOM) characterization using high-resolution mass spectrometry (HRMS), to uncover the chemical pattern of selected manure-impacted groundwater bodies used as sources for drinking water production, and to provide evidence on the role of manure recycling as a major source of aquifer contamination.
RESOURCE is a project of great social significance in Spain. The closure of large manure treatment plants in 2014 and the resulting generation of large quantities of untreated waste could jeopardize the good chemical and microbiological status of drinking water wells. Therefore, the results of this project will be invaluable in assessing the current status of groundwater bodies and will contribute to preventing serious problems for the environment and human health. The fellow's experience, gathered at leading international research institutions and the excellent infrastructure and capabilities available at ICRA, create an ideal combination for the successful completion of the project.
RESOURCE contributed to filling existing knowledge gaps regarding the role of animal manure reuse as a significant source of groundwater contamination by antibiotics and ARGs. It also provided novel insights into the footprint of dissolved organic matter (DOM) and its hydrogeological flow system in groundwater bodies impacted by manure. The combination of chemical (objective methods and DOM footprinting) and microbiological tools to assess groundwater quality was also a novel aspect of the project.
The research conducted at RESOURCE had great social relevance, both nationally and internationally. Spain is one of the leading livestock producers in Europe. Due to this intensive livestock production, there is a large surplus of manure applied to agricultural fields, which can lead to the degradation of groundwater resources. Furthermore, antibiotic resistance and its spread to the environment constitute a major global public health problem and a topic of broad interest for EU policy objectives.
RESOURCE contributed to shedding light on these important environmental and human health issues. The results identified priority antibiotics to focus on in future monitoring studies and that should be included in future legislation as priority contaminants. They also highlighted the need to ensure safe manure management practices and emphasized the need to reduce antibiotic use in animal husbandry to avoid potential risks to the environment and human health.
- FUNDACIO INSTITUT CATALA DE RECERCA DE L'AIGUA (ICRA-CERCA)
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