Asparagus officinalis L.: a food plant model for monitoring heavy metal contamination in fields bordering roadways in the Ferrara province (Italy)?

Marcello Bigoni ¹, Angela Martina ¹, Lorenzo Ferroni ¹, Elena Marrocchino ¹

University of Ferrara, Department of Environmental and Prevention Sciences, Ferrara, 44121, Italia ¹

The expansion of road networks has intensified environmental contamination, particularly through the deposition of metallic xenobiotics into agricultural soils, posing critical challenges to food safety ecosystem sustainability, and public health. Elements such as Pb, Cd, Cr, Ni are of particular concern owing to their persistence, bioaccumulative nature and capacity to transfer through trophic levels, impacting both ecosystem integrity and public health. Soil contamination arises from both geogenic and anthropogenic sources, with industrial and agricultural activities serving as predominant contributors. Metals from vehicular emissions, fertilizers, and wastewater irrigation exacerbate soil contamination near roadways. In the Ferrara province, where extensive roadway systems intersect agricultural landscapes, assessing the impact of such contamination is essential to safeguard the quality of agroecosystems and agricultural products. Among crops, the geophyte Asparagus officinalis L. (Asparagaceae) can be an interesting model to monitor metal contamination. Its rhizomes and roots are exposed for several years to the potential presence of metal contaminants in the soil, which can be transferred to the edible turions. In the study, six sampling locations were chosen in agricultural zones in the inland, close or not to Ferrara, or in the coastal strip, which is traversed by the state road SS309 Romea. In the entire territory, asparagus cultivation complies with the “Asparago Verde di Altedo” PGI specification, which allows for a defined set of varieties. Such variability can be informative on the role of genotype in influencing metal absorption rates and distribution within plant tissues. Cr, Ni, Pb, Cd, V and Cu were analysed in soils and turions. Soils underwent preliminary screening using X-ray fluorescence (XRF) for semi-quantitative assessment. Elemental contents in soils and turions were then analysed by inductively coupled plasma mass spectrometry (ICP-MS). The elemental concentrations were evaluated against regulatory benchmarks including Italian legislation DM 46/2019 and European Regulation (EU) 2023/915, which establish safety thresholds. Pb and Cd concentrations in all soils and turions were well below regulatory limits. The concentration ratio turion/soil indicated a selective accumulation of Cu and Ni, but also Cd, but not Cr and V. However, the latter two elements in turions were close or above reference values because of relatively high concentrations in soils. Particularly, Cr, Ni, and V confirmed their natural relative abundance in Ferrara province soils, as is well documented in the literature. Data did not allow evidence of consistent patterns as related to the field proximity to roads, most probably because of metal accumulation specificities of the cultivars. However, the site located near the town emerged for higher levels of metals in soils and turions. An effective use of asparagus as a plant system to monitor heavy metal enrichments in soils should therefore take into consideration particularly (i) the evident selectivity of element uptake and accumulation, also related to different cultivars, and (ii) the geochemical background of a certain soil, which can make it difficult to discern potential anthropogenic enrichments.

Main author career stage: PhD student

Contribution type: Poster

First choice session: 4. Structure, physiology, and development

Second choice session: 6. Plants, Fungi and Society