Distribution of total and organic mercury in soils around an artisanal and small-scale gold mining area in West Java, Indonesia

Abstract

This study was conducted to understand the environmental behavior of mercury released by artisanal and small-scale gold mining (ASGM) activities. For this purpose, we attempted to assess the effect of diffused mercury on mercury concentrations in soil, demonstrate the presence of methylmercury in soil affected by the deposited mercury and determine the reactions associated with methylmercury production. The vertical profiles of mercury were obtained from two sites in the forest of the ASGM village in Pongkor (West Java, Indonesia) and from two sites in Mount Halimun-Salak National Park, which is approximately 12 km from the ASGM village. The highest total mercury concentration, 8.9 mg kg −1 , was observed for soil samples collected at the ASGM village. The mercury was concentrated at the surface or in the subsurface layers, and the concentrations were several times to more than ten times higher than the lowest values observed in the deeper layers at each site. Even in the national park, the highest concentration of 1.9 mg kg −1 was observed in the upper soil layer. These results suggest that the primary source of mercury in the forest soil is atmospheric deposition; fallen plant leaves also deliver accumulated mercury to the soil surface. The organic mercury percentages of the total mercury were 0.2 ± 0.1% for the national park and 0.3 ± 0.2% for ASGM sites. The vertical variation in organic mercury concentration did not always match that in total mercury concentration, which suggested that the formation of methylmercury in soil was closely related to the decomposition of organic matter near the surface. The soil surface is an important reaction field for methylmercury production in forested areas.

Distribution and differences of soil mercury and methylmercury affected by coal mining activities

“…From the vertical distribution results, the THg is mainly concentrated in the soil surface, showing a continuous decrease trend of THg content with the increase of soil depth. This is similar to studies in other studys (Tomiyasu et al, 2017(Tomiyasu et al, , 2020Lazareva et al, 2019;Morosini et al, 2021). Although there are slight differences in the surface content of soil MeHg, it has a similar trend with the increase of depth, and both reach a peak at a depth of 40cm.…”

“…This result indicates that the THg in the area with high Som will also be high, but it will slightly reduce or inhibit the methylation reaction of mercury, resulting in a lower %MeHg. Previous studies have widely mentioned that there is a positive correlation between MeHg concentration in soil and Som content (Meng et al, 2016;Tang et al, 2019;Tomiyasu et al, 2017;Tomiyasu et al, 2020). While, there are also studies Tomiyasu et al, 2017) that Som only indirectly affects the activity of mercury methylation in soil.…”

Struktur Komunitas Fitoplakton di Kolam Bekas Tambang Emas sebagai Budidaya Ikan

“…Beberapa tahun yang lalu masyarakat melakukan penambangan emas secara ilegal menggunakan metode tradisional. Proses penambangan emas umumnya menggunakan sianida dan merkuri (Hg) Merkuri digunakan untuk memisahkan emas dari material lain dan pemurnian emas (Tomiyasu et al, 2020). Aktivitas penambangan emas tersebut menyisakan lubang atau cekungan-cekungan bekas galian yang ditinggalkan begitu saja dan digenangi air, sehingga disebut sebagai kolam dan di dalamnya hidup berbagai organisme, misalnya fitoplankton.…”

Toksisitas Merkuri (Hg) pada struktur jaringan ikan

“…Pertambangan emas umumnya menggunakan sianida dan merkuri (Hg) untuk memisahkan emas dari material lain dan pemurnian emas (Mallongi et al, 2020;Tomiyasu et al, 2020). Merkuri (Hg) banyak digunakan oleh pertambangan emas tanpa izin (PETI) atau disebut dengan pertambangan rakyat (Spiegel et al, 2018).…”