What work does ‘contamination’ do? An agential realist account of oil wastewater and radium in groundwater

Oil wastewater often contains high levels of radium, a carcinogenic and radioactive element. This article closely engages with two investigations of radium in groundwater downstream from oil wastewater storage pits. While one investigation found that radium did not travel beyond the storage pits, the other found evidence of elevated radium some two kilometers downstream. With an agential realist analysis, we resolve these differences, showing that these two experimental apparatuses defined and mobilized two different phenomena of radium, and of radium-as-contaminant. What geologists call 'rock-water interactions' are materially meaningful <i>intra</i>-actions. Far from being a mere philosophical gloss on otherwise conventional science, the 'intra-' signifies that, in these processes, the sediment and the groundwater are bringing each other into being. Groundwater sampling entails a specific set of intra-actions with the subsurface that enact different agential cuts. In addition, a geochemical focus on objects, rather than relations, also constrains understandings of chemical harm and accountability. These concepts do not only affect experimental apparatuses; rather, they come into being through and with each other. Therefore, rigorous approaches to groundwater and remediation do not lie in the pull to reify individual groundwater constituents, or to arbitrate between 'contaminant' and 'contaminated'. Rather, rigorous approaches lie in the role of chemical relations in constituting specific groundwater phenomena. We elaborate three aspects of these relations: the constitution of radium-as-isolated-element through the ontological work of sampling schema, the formation of scale and attendant spacetimematterings within experimental apparatuses, and the work of contamination logics within conceptualizations of chemical harm. This analysis has major implications for understanding the potential harm of oil wastewater to groundwater.