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.

Nurfitri Abdul Gafur,Koichiro Sera,Satoru Komatsu,Masayuki Sakakibara,Sakae Sano

doi:10.3390/ijerph19010530

Abstract

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.

Highlights

Artisanal and small-scale gold mining (ASGM) is one of the largest emitters of mercury (Hg) into the environment in the world
Mine tailings and wastewater from the two ASGM sites located upstream of the Bone River and smelted slag from the sites along the valley have been dumped along the river, and they are mixed into the river water
The densest overgrowth of P. vittata is observed along the sunny slopes and valleys around the Motomboto ASGM site (Figure 4)

Summary

Introduction

Artisanal and small-scale gold mining (ASGM) is one of the largest emitters of mercury (Hg) into the environment in the world. In ASGM, miners use elemental Hg to extract gold (Au) from finely crushed rocks or Holocene sediments, forming an Hg–Au amalgam. This amalgam is burned, releasing Hg as vapor and leaving impure Au residue. The adverse effects on the health of miners are severe, with exposure to Hg causing neurological damage and other health issues. The people residing near the ASGM sites are affected by the Hg contamination of water, air, and soil and by the effects of Hg on ecosystems, such as fishes and plants. 15 million people in ASGM sites in over 70 countries use Hg to refine Au, causing Hg pollution [1]

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Conclusion