Changes in surface water quality from small-scale gold mining operations in the Surinamean rainforest

Abstract

Small-scale miners often engage in environmentally damaging activities, are subject to poor safety conditions, and utilize inefficient mineral extraction technologies. Here, we explore environmental impacts to surface waters from regional artisanal small-scale gold placer mining operations conducted in iron and aluminum-rich saprolites found within the lateritic, interior Amazon rainforest of Suriname. Heavy equipment was utilized to release gold from its host material followed by amalgamation and gravity separation. In contrast with background tributary recordings, streams adjacent to these gold mining operations consistently contained turbidity measurements that exceeded United States’ EPA guidelines for aquatic species of 50 nephelometric turbidity units and were typically in the hundreds to thousands of units. Turbidity was further heightened in association with precipitation events. Mercury played a prominent role in whole ore amalgam concentration practices. Freshwater fish from the region were found to harbor mercury that encroached upon public health criteria. Dissolved phase metals present further ecotoxicological challenges to the region, but their association with mining activities was less clear. These findings collectively reveal that small-scale placer gold mining practices in the Surinamese rainforest result in an increase of suspended sediments and release of mercury into waterways that could impact communities that depend upon local fisheries.

Keywords:

• Small-scale mining
• placer mining
• turbidity
• water quality
• gold
• mercury

Acknowledgments

The authors thank Newmont Mining and its employees for laboratory, field, and logistical support. Benjamin Teshner, Dr. Jessica Smith, and Dr. Nicole Smith provided vision, camaraderie, and intellectual support throughout the project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was enabled by a financial gift by Newmont Mining, Inc. to Colorado School of Mines and distributed by Dr. Kevin Moore, Dean of the College of Engineering and Computational Sciences, in support of Humanitarian Engineering projects. Further financial support during the writing phase was provided by Universidad Nacional de San Agustín de Arequipa (UNSA).