Title : Development of analytical methods for the detection of food-relevant contaminants in polluted agricultural areas
Abstract:
The contamination of agricultural soils with persistent toxic substances represents one of the major threats to food safety, requiring highly sensitive analytical methodologies to accurately assess the transfer of pollutants from soil to plants intended for human or livestock consumption, especially in historically compromised areas such as Sites of National Interest (SINs). This research, conducted by the Istituto Zooprofilattico Sperimentale, aims to develop and validate analytical techniques for detecting environmental contaminants in spontaneous herbs growing near the Sacco River Basin SIN (Italy). The study is part of an agreement between the Italian Ministry of the Environment and Energetic Security (MASE) and Lazio Region for the implementation of safety and remediation measures in the area. Eighteen years after the designation of the Sacco River Basin as a SIN, this study aims to reassess contamination levels in riparian agricultural zones. The objective is to characterize these environments and evaluate the potential for the safe resumption of food crop cultivation while maintaining restrictions on agricultural use in areas where contamination persists.
To this end, analytical methods were developed and validated with a primary focus on the detection of organochlorine pesticides (OCPs) and inorganic elements. The method for OCPs combined a QuEChERS-based extraction with subsequent solid-phase extraction (SPE) clean-up, followed by isotope dilution and gas chromatography–tandem mass spectrometry (GC-MS/MS). Metal analysis was performed using inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion. Validations were conducted in accordance with the guidelines provided in document SANTE/11312/2021 and the criteria established by Commission Regulation (EC) No 333/2007 (consolidated text). Additionally, an extraction protocol was developed for the determination of polycyclic aromatic hydrocarbons (PAHs), aimed at providing a more comprehensive characterization of sample contamination. The method involved a Soxhlet extraction step, followed by clean-up using SPE-MIP cartridges to remove potential interferences. The purified extracts were then analyzed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD).
The analytical methods developed demonstrated excellent performance, achieving extremely low limits of quantification (LOQs): 0.5 μg/kg for organochlorine pesticides, 10 μg/kg for inorganic elements, and 0.2 μg/kg for PAHs. These sensitivities, significantly below regulatory thresholds, ensure reliable risk assessment even in the presence of trace-level contamination. The validated protocols provide reliable tools for environmental biomonitoring, for the evaluation of direct/indirect human exposure to pollutants and can contribute to ecological risk assessment in historically polluted areas. Ultimately, their implementation may support the safe production of food in vulnerable ecosystems, helping to mitigate long-term impacts on both human health and the environment.
