UC Berkeley

Informal, small-scale gold mining is a complex, entangled social-natural system that is also the principal livelihood for greater than 40 million individuals residing across more than 70 countries in the global South. While informal gold mining provides extensive socio-economic benefits to people in rural, underdeveloped areas of the globe, there are significant environmental and public health impacts from the use of toxic elements like mercury and cyanide in gold production. Like most mining, informal gold mining all too often degrades and contaminates land and in the absence of remediation this land is rendered unsuitable for production of consumptive goods.

In the Amazonian region of Madre de Dios, Peru, miners use elemental mercury to concentrate fine particles of gold in informal, small-scale mining. This dissertation uses an interdisciplinary, political ecology approach to examine the multiply scaled and multi-layered issues surrounding the use of mercury in informal, small-scale gold mining in Madre de Dios. The overarching claim of this dissertation is that mercury pollution is a phenomenon emerging out of and coproduced by the interrelation between both social and biophysical factors at particular spatial scales and in particular historical moments. Through the three chapters that form the body of this dissertation, I show how an understanding of a particular place as ‘polluted’ must be historicized in relation to past iterations of resource extraction and land use management. In Madre de Dios, the Peruvian central state once sold mercury to gold miners as part of a larger program to spur rural economic development via gold extraction. These past legacies of state-sanctioned mercury use have not been publicly addressed and yet they contribute to present narratives and policies regarding widespread mercury contamination in the region. In addition, the toxic legacy of nearly 300 years of extraction of mercury from cinnabar mines in the Andean highlands is almost never mentioned in relation to what is commonly understood as a recently emerging issue of mercury pollution in Madre de Dios. It is only when history, politics, culture, and ecology are taken together and considered in relation with one another that the causes and consequences of mercury pollution can be fully understood and adequately addressed.

This dissertation is divided into three stand-alone chapters, meant to be read in order, and a brief conclusion. In Chapter One, I historically contextualize the problem of mercury pollution in small-scale gold mining, examining the long history of state promotion of gold mining in Madre de Dios. In the Amazonian region of Madre de Dios, Peru, ever-larger and prolonged military-led interventions claim to ameliorate the environmental and social impacts caused by the expansion of illegal, small-scale gold mining by forcibly displacing miners from certain lands designated as zones of mining exclusion. Central to state and extra state actors’ justification for these coercive interventions is the need to protect sensitive Amazonian ecosystems from environmental degradation caused by illegal gold mining. Chapter One engages with these contested politics, ultimately arguing for a need to re-imagine both the history of mercury pollution associated with illegal gold mining in Madre de Dios and to reconsider the negative effects of militarized containment strategies. I argue that coercive containment solutions negate the biogeochemical complexity of mercury cycling, ultimately failing to contain or control mercury or the miners that rely on it. Further, I demonstrate how the framing of the problem of mercury pollution - as solely associated with illegal gold mining - both belies the histories of Peruvian state support of small-scale gold mining and justifies the criminalization of small-scale miners operating in certain places. Ultimately, in ignoring the ways in which mercury is used in small-scale gold mining throughout Madre de Dios – whether ‘legal’ or ‘illegal’ – and also moves freely through the environment on currents of air, water, and in the bodies of wildlife, the act of policing miners to reduce mercury pollution ends up exacerbating the risk of mercury exposure for both humans and wildlife by diffusing mercury to ever more remote corners of the forest.

In Chapter Two, I trace the use of mercury in gold mining to mercury pollution in abandoned gold mines, by examining how differences in gold production practices mediate mercury’s accumulation and magnification in aquatic food webs. I push back against the notion of a permanently polluted world by demonstrating how pollution is uneven and mediated by both ecological food web structure and anthropogenic mercury loading in abandoned mines. I demonstrate that the level of pollution as measured in the bodily burden of mercury in individual organisms is connected in part to the social histories of these abandoned mines and also to site-specific gold production and processing practices as well as differences in ecological food web structure.

In Chapter Three, I delve further into the heterogeneity in gold production practices in Madre de Dios, focusing on characterizing the differences in extraction technologies used in Madre de Dios, by examining how different modalities of gold production have evolved over time and contribute to the socio-economic differentiation of the small-scale gold mining economy.