Environmental Monitoring of the Effects of Conventional and Artisanal Gold Mining on Water Quality in Ngwabalozi River, Southern Zimbabwe

Abstract

Abstract:Mineral extraction contributes positive to the socioeconomic fabric of many African countries but has also contributed to the deterioration of environmental quality. It has been branded the most destructive industry in the world. This study sought to assess the effects of conventional gold mining which use cyanide for gold extraction and artisanal gold mining which uses mercury amalgamation on water quality in Ngwabalozi River. Along the river, there are gold panning activities upstream and a conventional mine downstream. Water samples were collected at four sampling points: 1) upstream of the gold panning activities; 2) just downstream of gold panning area; 3) upstream of the conventional mine; 4) downstream of the conventional mine. Benthic macro-invertebrates were also collected at the name four points, identified to family level and counted. Water samples were analyzed for mercury, iron, arsenic, sulphates and turbidity. There were significant differences (p = 0.000) in the measurements of mercury, arsenic, sulphates, taxa richness, total count of individuals, Shannon-Weiner index, evenness index and average tolerance scores among the four sampling sites. Gold panning activities were found to pollute Ngwabalozi River with mercury while the conventional mine polluted the river with sulphates. Gold panning activities also feed a lot of sand into the river resulting in high turbidity. Gold mining reduced the taxa richness, total count of individual and the diversity of benthic macro-invertebrate community in the river. There was pollution induced succession in the river as pollution sensitive species were replaced by pollution tolerant ones.

The diversity of aquatic insects surrounding the gold mining areas of Central Sulawesi and their relation with mercury levels and water quality

“…This is probably related to the low content of the mercury at our study sites with levels that do not differ significantly among sites. However, some previous studies showed that mercury contamination in water due to smallscale community gold mining activities affects the abundance, species richness, and diversity of aquatic insects, especially Ephemeroptera, Plecoptera, and Trichoptera (Chula et al 2013;Mudyazhezha & Kanhukamwe 2014).…”

Study Amendment of Post-Field Classification of Illegal Gold in Kolaka Regency, Southeast Sulawesi Province

“…The mercury metal is identified as one of the elements with high toxicity properties and the ease of undergoing transformation into a more toxic form [7]. Mercury endangers human life through the process of food chains.…”

Stabilisasi/Solidifikasi Tanah Tercemar Merkuri Tambang Emas Rakyat Kulon Progo Yogyakarta Menggunakan Campuran Semen Portland dan Tanah Tras

“…Limbah tailing hasil aktivitas pertambangan dialirkan ke tanah serta sungai menyebabkan kontaminasi tanah dan lumpur sungai oleh merkuri. Hasil analisis gravimetri menunjukkan dalam kegiatan ini sekitar 70-80% merkuri hilang ke dalam sedimen sungai, tailing, dan tanah [7]. Hasil penelitian sebelumnya menunjukkan tanah sekitar tambang emas rakyat Kulon Progo mengandung merkuri dengan kadar lebih dari 50 ppm [4].…”