Metal contamination of home garden soils and cultivated vegetables in the province of Brescia, Italy: Implications for human exposure

Abstract

Background For the past century, ferroalloy industries in Brescia province, Italy produced particulate emissions enriched in manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), iron (Fe), aluminum (Al). This study assessed metal concentrations in soil and vegetables of regions with varying ferroalloy industrial activity levels. Methods Home gardens (n=63) were selected in three regions of varying ferroalloy plant activity duration in Brescia province. Total soil metal concentration and extractability were measured by X-ray fluorescence (XRF), aqua regia extraction, and modified Community Bureau of Reference (BCR) sequential extraction. Unwashed and washed spinach and turnips cultivated in the same gardens were analyzed for metal concentrations by flame atomic absorption spectrometry. Results Median soil Al, Cd, Fe, Mn, Pb, and Zn concentrations were significantly higher in home gardens near ferroalloy plants compared to reference home gardens. The BCR method yielded the most mobile soil fraction (the sum of extractable metals in Fractions 1 and 2) and all metal concentrations were higher in ferroalloy plant areas. Unwashed spinach showed higher metal concentrations compared to washed spinach. However, some metals in washed spinach were higher in the reference area likely due to history of agricultural product use. Over 60% of spinach samples exceeded the 2- to 4-fold Commission of European Communities and Codex Alimentarius Commission maximum Pb concentrations, and 10% of the same spinach samples exceeded 2- to 3-fold maximum Cd concentrations set by both organizations. Turnip metal concentrations were below maximum standard reference values. Conclusions Prolonged industrial emissions increase median metal concentrations and most soluble fractions (BCR F1+F2) in home garden soils near ferroalloy plants. Areas near ferroalloy plant sites had spinach Cd and Pb metal concentrations several-fold above maximum standard references. We recommend thoroughly washing vegetables to minimize metal exposure.

Cadmium and lead in vegetable and fruit produce selected from specific regional areas of the UK

“…The lack of observed correlations between soil and plant heavy metal concentration has also been observed in a number of other studies (Menzies et al, 2007;Ferri et al, 2015). The absence of correlations between soil cadmium and plant cadmium concentration and soil lead and plant lead concentration may be due to a number of factors already discussed, i.e.…”

“…In a study by Ferri et al (2015) it was observed that unwashed spinach leaves had a higher concentration of heavy metals compared to washed spinach leaves. This has also been observed in a number of other studies where thorough washing decreases the concentration of heavy metals in leaves (Caselles, 1997;Oliva and Valdés, 2006).…”

How can ecological urbanism promote human health?

“…Finally, we draw attention to the role of contaminated soil in urban areas, which often contains dangerous levels of heavy metals (Cheng et al, 2011;Ferri et al, 2015). Heavy metals are present in the soil of many urban vegetable gardens in the United States and Europe (Clark et al, 2008;Cheng et al, 2011;Burt et al, 2014;Ferri, et al, 2015), prompting questions about the potential health consequences of UPA in contaminated areas.…”

“…Heavy metals are present in the soil of many urban vegetable gardens in the United States and Europe (Clark et al, 2008;Cheng et al, 2011;Burt et al, 2014;Ferri, et al, 2015), prompting questions about the potential health consequences of UPA in contaminated areas.…”

“…Researchers agree that the exposure routes for humans occur through accidental ingestion of the soil and inhaling of contaminated dust (Kessler, 2013), posing risks to farmers, particularly children. There is less consensus about the health effects of the consumption of crops grown in contaminated soil (Warming et al, 2015;Ferri et al, 2015;Augustsson et al, 2015), probably due to the general lack of studies, particularly in LA. The broad range of variables involved -soil constitution, type of pollutant, type of crop -has impaired comparisons between studies.…”