Trace elements in farmland soils and crops, and probabilistic health risk assessment in areas influenced by mining activity in Ecuador

Abstract

Consumption of food grown in contaminated soils may be a significant human exposure pathway to pollutants, including toxic elements. This study aimed to investigate the pollution level of trace elements in farmland soil and crops collected in orchards from Ponce Enriquez, one of the Ecuador’s most important gold mining areas. The concentration of arsenic (As), cadmium (Cd), chrome (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) was analyzed in soil and crop samples (celery, chives, corn, herbs, lettuce, turnips, green beans, cassava, and carrots). In addition, a probabilistic human health risk assessment, in terms of hazard quotients (HQ) and cancer risk (CR), was conducted to assess the potential risk related to local crop ingestion. The contents of As, Cr, Cu, and Ni in soils exceeded the Ecuadorian quality guidelines for agricultural soils. The trace elements concentration in local crops was higher than the maximum permissible levels set by the Food and Agriculture Organization of the United Nations (FAO). The HQ and CR of local crop ingestion were several orders higher than the safe exposure threshold, mainly for lettuce, chives, and turnips. Our results revealed that inhabitants of the study area are exposed to developing carcinogenic and non-carcinogenic effects due to long-term food consumption with high trace elements. This study sheds light on the need to assess further the quality of agricultural soils and crops grown in mining areas with signs of contamination to guarantee consumer food safety.

Risks to Human Health from Mercury in Gold Mining in the Coastal Region of Ecuador

“…In this context, based on a conservative criterion, the use of rivers located in contaminated mining environments is not recommended, since long-term exposure to contaminants such as Hg could affect the health of its users. Furthermore, it is important to consider that in areas of illegal gold mining, there are, in addition to Hg, other potentially toxic elements that could generate adverse effects on the ecosystem and the population: a detailed study of other pollutants such as arsenic, cadmium, chromium, lead, etc., is recommended, since these elements have been detected in other gold mining areas of Ecuador [30][31][32]73]. Deterministic and probabilistic analysis approaches are considered appropriate to adequately account for data uncertainty.…”

“…For decades, artisanal and small-scale gold mining (ASGM) has been a well-established core economic activity in Ecuador [23]. In Ecuador, severe environmental impacts caused by mining activities have been reported between 1998 and 2023, such as the contamination of air, surface waters, soils, and sediments [24][25][26][27][28][29][30][31][32]. In this regard, our research aims to complement the cited studies and provide updated information on the degree of mercury contamination in mining environments.…”

Effect of fertilization on the accumulation and health risk for heavy metals in native Andean potatoes in the highlands of Perú

“…(2) : where and represent the metal concentrations in tuber and soil samples, and and represent the reference concentrations of metals in tubers and soil, respectively [10] . Peru does not have a standard regulating the content of heavy metals in food, so limit values (standard concentrations of metals) for tubers were used as established by FAO/WHO (2015) [60] and those suggested by Romero-Crespo et al [61] and Khan et al [25] ( Table S4 ). Likewise, the standard concentration values for Cd, Cr, Cu, Fe, Pb and Zn in the soil samples, as suggested by Taylor and McLennan [62] ( Table S4 ) were used.…”

Heavy metal(loid)s pollution indices and strategies for contaminants mitigation in crops near La Independencia community in Ponce Enriquez, southern Ecuador

“…En este estudio, se consideraron muestras de vegetales (n = 9) y suelo (n = 8) recolectadas en junio de 2021, en los huertos de la Asociación "Unión y Progreso" del cantón Camilo Ponce Enríquez, cuyos datos se encuentran reportados por Romero-Crespo et al (2023) [30]. Además, se incluyeron muestras de vegetales (n = 5) tomadas en noviembre de 2022 para su comparación.…”