COMMUNITY INITIATED ASSESSMENT OF HEAVY METAL TRANSPORT PATHWAYS WITH CHANGING LAND USE AND CLIMATE IN THE TAR CREEK WATERSHED, OK

At the Tar Creek Superfund Site in the Northeast corner of Oklahoma, large mine waste (chat) piles and acid mine seepage continue to contaminate surrounding communities with zinc, lead, cadmium, and manganese. We estimate that 5,000-16,000 tons of highly bioavailable and geomobile (grain sizes <100 μm) Pb remains in the chat piles, and that 160 kg/yr of Pb are transported into creek sediments. Increased knowledge of the complex biogeochemical interactions that are affected by changing land use patterns, transport pathways, and changing climate will aid in setting activism agendas and prioritizing engineered interventions to reduce environmental and public health risk.

This research builds on decades-long collaboration between Wellesley College and the LEAD Agency, an environmental advocacy group with a long history of co-designing research agendas to address community concerns and study trace legacy metals in Ottawa County, Oklahoma. We characterized changes in the Tar Creek watershed with new land use patterns. This project investigates wind transportable Pb in the lower sections of chat piles, which will be exposed due to reworking, mining, and transporting of chat piles. Nutrient loading and eutrophication was monitored to assess changes in metal transport and mobility in Tar Creek, which is influenced by practices like amending contaminated floodplain soils with spent mushroom compost. We characterized changes in metal deposition in the watershed following historic floods in 2007 and 2019 by examining floodplain soils, Creek sediments, and vegetation in the watershed. Deposition analysis is especially important because flooding will increase with raised reservoir elevation with the pending relicensing of the Pensacola Dam, and ongoing climate change.

Our action based research aims to support LEAD’s goals of: (1) assessing risk of reworking chat piles, (2) establishing the Rights of Tar Creek through LEAD’s Clean Water Protection Ordinance, which would establish the right to clean water and legally recognize the rights of Tar Creek to exist, regenerate, and flourish, and (3) calling on EPA, FERC, the Army Corps of Engineers, and the Grand River Dam Authority to enter a Memorandum of Understanding to address Tar Creek metals contamination in the relicensing of the Pensacola Dam.