Environmental Survey of the Distribution and Metal Contents of Pteris vittata in Arsenic–Lead–Mercury-Contaminated Gold Mining Areas along the Bone River in Gorontalo Province, Indonesia

In this paper, we report ecological and environmental investigations on Pteris vittata in the As–Pb–Hg-polluted Bone River area, Gorontalo Province, Indonesia. The density distribution of P. vittata decreases from around the artisanal and small-scale gold mining (ASGM) site to the lower reaches of the Bone River, and it is rarely found near Gorontalo City. The maximum concentrations of As, Hg, and Pb recorded in the soil samples were 401, 36, and 159 mg kg−1, respectively, with their maximum concentrations in P. vittata recorded as 17,700, 5.2, and 39 mg kg−1, respectively. Around the ASGM sites, the concentrations of As, Pb, and Hg in P. vittata were highest in the study area. These data suggest that P. vittata, a hyperaccumulator of As, may be useful as a bioindicator for assessing environmental pollution by Pb and Hg.

Phytoextraction Potential of Arsenic And Cadmium And Response of Rhizosphere Microbial Community By Intercropping With Two Types of Hyperaccumulators

Intercropping with hyperaccumulators/accumulators is a promising alternative to enhance phytoextraction of heavy metal(loid)s in contaminated soil. In this research, a pot experiment was conducted to evaluate the influences of intercropping As hyperaccumulator Pteris vittata L. with Cd hyperaccumulator Sedum alfredii Hance or accumulator Hylotelephium spectabile (Boreau) H. Ohba on the plant growth, As and Cd phytoextraction, and rhizosphere bacterial microbiota. The results indicated that intercropping can promote the growth of plants. The total biomass of P. vittata, S. alfredii and H. spectabile in intercropping systems was significantly improved by 19.9% - 34.1%, 16.8% and 11.5%, respectively in comparison with corresponding plant monoculture. The As content in rhizoid and frond of P. vittata when intercropped with S. alfredii was increased by 28.3% and 19.0% (P < 0.05), respectively as compared with P. vittata monoculture, and this treatment acquired the maximum As and Cd accumulation with 2032 and 397 µg∙pot-1, respectively. Intercropping enhanced the soil bacterial community diversity. The genera of Lysobacter in S. alfredii rhizosphere soil and Massilia in P. vittata rhizosphere soil had higher abundance in the intercropping system of P. vittata and S. alfredii. And the significantly positive correlation relationships were found between Massilia, Lysobacter and plant As content, and Arthrobacter with plant Cd content, indicating that they may play important roles in As and Cd phytoextraction. The results suggested that intercropping P. vittata with S. alfredii could be a potential strategy for phytoextraction of As and Cd from co-contaminated soil.