Particle and carbon export from a restored goldmine in an Amazonian catchment: hydro-sedimentary source tracing
Abstract
Artisanal and small-scale gold mining (ASGM) is prevalent in South America and the Amazon. It involves soil reworking, leading to an increase in downstream river turbidity and ecosystem degradation. In French Guiana, restoration, including landscaping and tree-replanting, is mandatory for legal gold mines, but the fate of post-exploitation sites is poorly characterised. To investigate the extent of particle export originating from a restored gold-mining site, high frequency suspended solid concentrations (SSC) and discharge measurements were performed upstream and downstream of a site in French Guiana. Two flood events were followed with geochemical tracers involving multielemental concentrations and Fourier-transformed infrared spectroscopy (FTIR) data in the particulate and filtered fractions, to unravel the origin of water (overland flow and groundwater), and particles (forest topsoil, mine topsoil, or riverbed sediments) within the watershed. Results show that within the year following restoration, the mining site remains a significant source of particles and carbon to the river, with an excess 100–300 kg km−2 (1.5–2.4 times increase) of particles exported due to the mining site, and specific carbon exports amounting to 9.8 ± 0.6 t C yr−1 km−2, comparable to exports observed in larger watersheds in the Amazon region. Hydrogeochemical and mineralogical data in the particulate fraction hint towards riverbank erosion and riverbed sediment remobilisation as an important source of suspended particles rather than mining site surface erosion. This underlines the importance of restoring and stabilising the riverbed in the goldmine rehabilitation process.
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BibTeX
@article{nitschke2026particle,
title = {{Particle and carbon export from a restored goldmine in an Amazonian catchment: hydro-sedimentary source tracing}},
author = {Naomi Nitschke and Stéphane Guédron and Cedric Legout and Antonio Martinez-Cortizas and Stanislav Jelavic and Jennifer Harris and Emmanuel Tessier and Sylvain Campillo and Stéphane Taravella and David Amouroux},
journal = {Journal of Hydrology},
year = {2026},
month = sep,
doi = {10.1016/j.jhydrol.2026.135926},
url = {https://brgm.hal.science/hal-05676160v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Particle and carbon export from a restored goldmine in an Amazonian catchment: hydro-sedimentary source tracing
AU - Naomi Nitschke
AU - Stéphane Guédron
AU - Cedric Legout
AU - Antonio Martinez-Cortizas
AU - Stanislav Jelavic
AU - Jennifer Harris
AU - Emmanuel Tessier
AU - Sylvain Campillo
AU - Stéphane Taravella
AU - David Amouroux
PY - 2026
DA - 2026/09/01
JO - Journal of Hydrology
DO - 10.1016/j.jhydrol.2026.135926
UR - https://brgm.hal.science/hal-05676160v1
AB - Artisanal and small-scale gold mining (ASGM) is prevalent in South America and the Amazon. It involves soil reworking, leading to an increase in downstream river turbidity and ecosystem degradation. In French Guiana, restoration, including landscaping and tree-replanting, is mandatory for legal gold mines, but the fate of post-exploitation sites is poorly characterised. To investigate the extent of particle export originating from a restored gold-mining site, high frequency suspended solid concentrations (SSC) and discharge measurements were performed upstream and downstream of a site in French Guiana. Two flood events were followed with geochemical tracers involving multielemental concentrations and Fourier-transformed infrared spectroscopy (FTIR) data in the particulate and filtered fractions, to unravel the origin of water (overland flow and groundwater), and particles (forest topsoil, mine topsoil, or riverbed sediments) within the watershed. Results show that within the year following restoration, the mining site remains a significant source of particles and carbon to the river, with an excess 100–300 kg km−2 (1.5–2.4 times increase) of particles exported due to the mining site, and specific carbon exports amounting to 9.8 ± 0.6 t C yr−1 km−2, comparable to exports observed in larger watersheds in the Amazon region. Hydrogeochemical and mineralogical data in the particulate fraction hint towards riverbank erosion and riverbed sediment remobilisation as an important source of suspended particles rather than mining site surface erosion. This underlines the importance of restoring and stabilising the riverbed in the goldmine rehabilitation process.
SN - 0022-1694
SN - 1879-2707
ER -