What a Gold Mining Mishap Taught Us About Rivers

Miners in Alaska rerouted a river to search for gold. One hundred years later, the new channel is teaching scientists how rivers shape Earth.

Risk assessment of heavy metal contamination in agricultural sites and river sediments at the Vatukoula gold mine, Fiji Islands

A comprehensive study was conducted to explore the concentration and distribution of heavy metals in farm soils and river sediments around a gold mining area in Fiji with particular emphasis on ecological and human health risks. Representative samples were acquired from farm sites in Matanagata Village and the Nasivi river, both situated around the Vatukoula gold mine limited (VGML), the largest operational gold mine in Fiji. Following aqua regia digestion and analysis by AAS, the average soil concentrations for Cu (110.4 mg kg–1), Cr (136.2 mg kg–1) and Cd (1.7 mg kg–1), and sediment concentrations for Pb (69.31 mg kg–1), Cd (1.82 mg kg–1), Cu (88.95 mg kg–1) and Cr (143.12 mg kg–1) were found to exceed the recommended guideline values. Based on the geo–accumulation index (Igeo) and enrichments factor (EF), the farm soils were moderately contaminated with Cd while the and sediments showed moderate to significant contamination with Pb, Ni and Cr. Ecological risk assessment confirmed moderate to considerable ecological risk in the metal–contaminated samples, with Cd and Pb generally presenting greater risk compared to other metals. Multivariate analyses including principal component analysis pointed to gold mining activities as a potential source for heavy metals in the area. Furthermore, human health risk assessment (HRA) indicated that while adults faced no significant carcinogenic or non–carcinogenic risks from metal exposure (HI < 1), children were at more risk from Co, Mn, Cr and Fe exposure, as well as potential carcinogenic risk from Cd (ILCR = 1.46E–04).

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.

The ecological characteristics of small rivers in the Shilka river basin by zoobenthos organisms

Zoobenthos organisms are directly related to the biogeochemical processes occurring at the bottom and in the water column of the channel. The paper presents the results of studies of the quantitative characteristics of the zoobenthos and the water quality of small rivers in the river basin of Shilka in the area of gold mining enterprises.

Current state, prospects and problems of the gold mining industry of the Trans-Baikal Territory

The article considers the current state, problems and prospects of gold mining in the Trans-Baikal Territory. There has been an increase in the volume of gold production from ore and placer deposits over the past 5 years. Placer deposits make up a significant part of the total production volume. The reduction of reserves in placers and the decrease in the quality of minerals in them open up new prospects for the extraction of precious metals, namely in ore gold mining. The extraction of placer gold, even with the best existing technologies, remains a sector of high environmental risk, in many settlements there is a gradual decline in the population and the “extinction” of settlements, as well as illegal gold mining is gaining momentum. Neither regional nor federal environmental supervision bodies have the opportunity to resist the destruction and degradation of nature from the extraction of placer gold. In general, this leads to an increase in the negative impact of placer gold mining on natural complexes and socio-economic sustainable development of regions and municipalities on the territory of which this type of activity is carried out, an increase in accumulated environmental damage.