Widespread Legacy Brine Contamination from Oil Shales Reduces Survival of Chorus Frog Larvae-Data

Advances in drilling technique have facilitated a rapid increase in hydrocarbon extraction from energy shales, including the Williston Basin in central North America. This area overlaps with the Prairie Pothole Region and greater than 35% of wetlands are less than or equal to 1 km from a petroleum-related well. Legacy practices often released saline co-produced waters (brines) that were chloride rich wastes, affecting wetland water quality directly or persisting in sediments. Despite the potential threat of brine contamination to aquatic habitats, there has been little research into their ecological effects. We capitalized on a gradient of legacy brine-contaminated wetlands in northeast Montana to conduct laboratory experiments to assess variation in survival of larval Boreal Chorus Frogs (Pseudacris maculata) reared on sediments from 3 local wetlands and a control source. To help provide environmental context for the experiment, we also measured chloride concentrations in 6 brine-contaminated wetlands in our study area, including the 2 contaminated sites used for sediment exposures.