Challenges in assessing the health risks of consuming vegetables in metal-contaminated environments

Abstract

A great deal of research has been devoted to the characterization of metal exposure due to the consumption of vegetables from urban or industrialized areas. It may seem comforting that concentrations in crops, as well as estimated exposure levels, are often found to be below permissible limits. However, we show that even a moderate increase in metal accumulation in crops may result in a significant increase in exposure. We also highlight the importance of assessing exposure levels in relation to a regional baseline. We have analyzed metal (Pb, Cd, As) concentrations in nearly 700 samples from 23 different vegetables, fruits, berries and mushrooms, collected near 21 highly contaminated industrial sites and from reference sites. Metal concentrations generally complied with permissible levels in commercial food and only Pb showed overall higher concentrations around the contaminated sites. Nevertheless, probabilistic exposure assessments revealed that the exposure to all three metals was significantly higher in the population residing around the contaminated sites, for both low-, median- and high consumers. The exposure was about twice as high for Pb and Cd, and four to six times as high for As. Since vegetable consumption alone did not result in exposure above tolerable intakes, it would have been easy to conclude that there is no risk associated with consuming vegetables grown near the contaminated sites. However, when the increase in exposure is quantified, its potential significance is harder to dismiss - especially when considering that exposure via other routes may be elevated in a similar way.

Probabilistic Human Health Risk Assessment of Heavy Metal Intake via Vegetable Consumption around Pb/Zn Smelters in Southwest China

“…The 95th percentiles of the HIs via vegetable consumption for children, adolescents, and adults were 15.71, 11.15, and 9.34, respectively, indicating potential risks for all age groups. Children were more vulnerable to dietary heavy metal intake, which may be ascribed to their higher metabolisms and absorption capacities compared with adolescents and adults [59].…”

Exposure and body burden of environmental pollution and risk of cancer in a historically contaminated areas

“…These metals may be deposited on vegetables, fruit and berries as well as the residents, resulting in chronic exposure to low-level metal concentrations over a lifetime. Metal uptake in vegetables in areas with industrial emissions have been documented in several studies (Hellström et al 2007;Helmfrid et al 2007;Sundstrom & Jorhem 2008;Nyberg et al 2012;Uddh-Söderberg et al 2015;Dziubanek et al 2015;Yousaf et al 2016;Ur Rehman et al 2017;Augustsson et al 2018). Göransson (1983).…”

“…In the glassworks area, elevated Cd and Pb concentrations in vegetables have been reported (Augustsson et al 2015;Uddh-Söderberg et al 2015;Augustsson et al 2018). It can thus be hypothesized that long-term consumption of local food from the contaminated areas may contribute to elevated body burdens of contaminants.…”

Cadmium and Lead Levels in Blood and Arsenic Levels in Urine among Schoolchildren Living in Contaminated Glassworks Areas, Sweden

“…A potential exposure route for those residing in the study area is the consumption of contaminated food. A recent study from The Kingdom of Cristal [ 34 ] analyzed the levels of Cd, Pb and As in a range of vegetables grown and collected near 22 contaminated glasswork sites. Their results indicated that only levels of Pb were higher in vegetables from glasswork sites compared to those grown and harvested in reference areas.…”