Distribution of Chemical Species in the Water-Soil-Plant (Carya illinoiensis) System near a Mineralization Area in Chihuahua, Mexico-Health Risk Implications

Essential role of multi-element data in interpreting elevated element concentrations in areas impacted by both natural and anthropogenic influences

Background

This article presents a detailed analysis of a dataset consisting of 27 elements found in soils, soil eluates, and vegetables from private gardens in a region with a long history of coal mining and burning. With coal being one of the world's most significant energy sources, and previous studies highlighting elevated element levels in vegetables from this region, the objective of this study was to identify the factors that impact soil geochemistry and metal(loid) uptake in plants.

Methods

Total major and trace element concentrations were analyzed in soils, soil eluates and vegetables by high resolution inductively coupled plasma mass spectrometry. The vegetable samples included six species: fennel, garlic, lettuce, parsley, onion, and radicchio. Each plant was divided into roots, stems, leaves, and/or bulbs and analyzed separately. In addition, the soil pollution status, bioavailable fractions and transfer factors from soil and soil eluates to different plant parts were determined.

Results

The comprehensive dataset revealed that, apart from the substrate enriched with various elements (Al, As, Co, Cr, Mo, Ni, Pb, Sb, Sn, Ti, U, V, and Zn), other anthropogenic factors such as the legacy of coal mining and combustion activities, associated industries in the area, transport, and agricultural practices, also influence the elevated element concentrations (Cd, Cu, Fe, Mn, and Se) in locally grown vegetables. The transfer factors based on element concentrations in aqueous soil eluates and element bioavailable fractions confirmed to be an effective tool for evaluating metal uptake in plants, emphazising to some extent the effects of plant species and revealing unique patterns for each pollution source within its environmental context (e.g., Cd, Mo, S, and Se in this case). The study highlights the crucial importance of utilizing comprehensive datasets that encompass a multitude of factors when interpreting the impacts of element uptake in edible plants.

Dynamics of Major and Trace Elements in Water-Soil-Tree Interaction: Translocation in Pyrus malus in Chihuahua, Mexico Using ICP-OES and Its Health Risk Implications

The transference of metals from water irrigation and soil to plants is a possible pathway of contamination for the trophic chain. This research is focused on the distribution of 16 analytes in the water-soil-tree (Pyrus malus) interaction in an agricultural region in the state of Chihuahua in Mexico from August 2019 (first sampling) to August 2020 (second sampling). The apple variety under investigation was Golden Delicious; it was found that the trace elements of As (0.18-0.34 mg·kg^-1) and Cd (0.11-0.14 mg·kg^-1) in the apple were above the corresponding permissible limit, according to FAO/WHO, and Cr (0.08-0.86 mg·kg^-1) was below the limit. Furthermore, the health risk implications were estimated by the Hazard Quotients (HQ) and carcinogenic risk (CR). For carcinogenic risk, As, Cd, and Cr exceeded the risk limit (CR > 10^-4). This investigation as well provides a link for similar research around the globe. Major and trace elements detection was performed with the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) technique, along with a prior homogenization of samples and microwave acid digestion. To obtain the statistical behavior, an analysis of variance and correlation was performed.