Native Hyperaccumulator Plants with Differential Phytoremediation Potential in an Artisanal Gold Mine of the Ecuadorian Amazon

Abstract

In tropical forests of southern Ecuador, artisanal gold mining releases heavy metals that become xenobiotic with indefinite circulation and eventual bioaccumulation. Restoration and rehabilitation of degraded mining sites represent a major ecological, technological and economic issue. In this study, we estimate the capacity of two native woody plants to accumulate cadmium (Cd), lead (Pb), zinc (Zn) and mercury (Hg), with the goal of developing effective strategies for phytoremediation of mining sites. Individuals of Erato polymnioides and Miconia sp., as well as their rhizospheric soils, were sampled from a natural zone (NZ) of montane cloud forest, used as a control, and a polluted zone (PZ) subjected to active gold mining. Concentrations of the four heavy metals were analyzed using atomic absorption spectrophotometry. Cd, Zn and Hg concentrations were higher in soils of PZ than NZ. Bioaccumulation (BCF) and translocation factors (TF) showed that Miconia sp. has potential for Cd and Zn phytostabilization, E. polymnioides has potential for Cd and Zn phytoextraction, and both species have potential for Hg phytoextraction. Despite the low productivity of these species, their adaptability to the edaphoclimatic conditions of the region and the possibility of using amendments to increase their biomass could compensate for the effectiveness of these species in reclaiming soils contaminated by mining.

Screening potential hyperaccumulator plant for phytoremediation approach due to ASGM Activity: Study case of Katingan Regency and Tanggamus Regency

“…Hg uptake by the plants were reported, like Erato polymnioides and Miconia sp. [20]. In this study all the species have high accumulation of Hg.…”

An updated review of the salient geomedical aspects of mercury for enhancement of data quality in simulation modelling and other prognostic applications: Africa case descriptions

“…There are certain plants referred to as "hyperaccumulators" belonging to unrelated families, and able to grow in metalliferous soils, accumulating very high levels of toxic metals in their aerial parts, far above the levels found in the majority of species without showing any phytotoxic effects (Pasricha et al, 2021;Chamba-Eras et al, 2022). These plants, according to Rascio and Navari-Izzo (2011) are characterised by three basic traits: "a strongly enhanced rate of heavy metal uptake, a faster root-to-shoot translocation and a greater ability to detoxify and sequester heavy metals in leaves."…”

Cadmium toxicity and sensitivity responses in Enterolobium contortisiliquum

“…Developing and applying technologies involving physical and chemical processes to remediate Cdcontaminated soils tend to be costly and result in harmful changes to soil functions and properties. Therefore, a viable alternative for soil decontamination would be phytoremediation, a practical, economical, and environmentally ecological tool (CHAMBA-ERAS et al, 2022).…”