Mercury Pollution in Amapá, Brazil: Mercury Amalgamation in Artisanal and Small-Scale Gold Mining or Land-Cover and Land-Use Changes?

Abstract

Mercury (Hg) poses a public health burden in the Amazon and worldwide. Although usually attributed to Hg used in artisanal and small-scale gold mining (ASGM), the primary source of elevated Hg in Amazonian aquatic ecosystems is contested since there have not been tools to differentiate between Hg from ASGM and Hg from other sources such as increased soil erosion associated with landcover and land-use change. To directly assess Hg contamination from ASGM, stable Hg isotope analyses were applied to sediment cores, surface sediments, and soils from two aquatic ecosystems in Amapa, Brazil, one downstream of ASGM activities and one isolated from ASGM. Downstream of the ASGM sites, the Hg isotope data is consistent with elevated Hg coming dominantly from increased erosion of soils and not from Hg used during gold extraction. Although these two sources represent different pathways of contamination to downstream ecosystems, ASGM may contribute to both land-cover and land-use change and local contamination of soils. Accordingly, these findings demonstrate that in some regions of the Amazon effective Hg mitigation strategies need to address land-use practices in addition to ASGM.

Synthesis of Calixarene-Capped Silver Nanoparticles for Colorimetric and Amperometric Detection of Mercury (HgII, Hg0)

“…1−4 The sources of mercury include gold mining operation, coal mining power plants, natural degassing of the earth surface, etc., and it affects millions of people working in these industries. 5,6 Mercury in its all three oxidation states (0, +1, and +2) is highly toxic to the living species, among which Hg 2+ has high solubility in water and hence found in surface water in maximum quantity. 7−9 It can damage kidney, central nervous system, and cardiovascular respiratory system.…”

Quantifying the impacts of artisanal gold mining on a tropical river system using mercury isotopes

“…After the amalgamation process in ASGM activities, 12e40% of Hg is evaporated while 1e35% is discharged with tailings as liquid Hg to soils or river (Vel asquez-L opez, 2010). Gold extraction also indirectly leads to Hg release into aquatic ecosystems through the erosion of naturally Hg-rich tropical soils during soil washing and deforestation (Roulet et al, 1999;Maurice-Bourgoin et al, 2002;Adler Miserendino et al, 2017).…”

“…Hg isotopes have recently been used to quantify anthropogenic inputs and understand Hg cycling in natural water systems (Perrot et al, 2010;Liu et al, 2011;Gray et al, 2013;Sherman and Blum, 2013;Yin et al, 2013;Wiederhold, 2015;Donovan et al, 2016;Schudel et al, 2018;Adler Miserendino et al, 2017). Mercury has seven natural stable isotopes and displays large variations in both mass dependent fractionation (MDF, d 202 Hg) and mass independent fractionation (MIF, D 199 Hg, D 201 Hg) in the environment (Blum and Bergquist, 2007;Blum et al, 2014;Yin et al, 2014).…”

Human Mercury Exposure in Yanomami Indigenous Villages from the Brazilian Amazon

“…In the Brazilian Amazon, mercury contamination due to ASGM has been reported since the early 1980s. High levels of mercury have been shown by several authors, mainly in riparian populations in that region [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Despite being recognized as particularly susceptible populations, there are few studies of Hg exposure in indigenous Amazonian communities.…”