Understanding the Science Surrounding Environmental Consequences and Rehabilitation Actions Stemming from Brazil's Fundão Tailing Dam Rupture.

Collapse of the Fundão tailings dam in November 2015 in Minas Gerais, Brazil, resulted in the release of approximately 36 million cubic meters of primarily clay and fine sand-sized particles to the environment. The spill event extended over 600 km of the Rio Doce catchment and affected terrestrial and aquatic ecosystems and compromised socioeconomic activities throughout the watershed. Numerous monitoring programs and research investigations in the catchment since that time contribute to better understanding of the environmental consequences and plans for rehabilitation of the landscape.

Ecotoxicological Assessment of the Doce River Surface Water After the Fundão Dam Collapse.

On 5 November 2015, the Samarco Fe ore mining operations released approximately 50 million cubic meters of mining waste into the environment, due to a dam collapse. Aiming at understanding the potential effects on the Doce River, different regions of the course of tailings were monitored using acute and chronic ecotoxicological tests with 4 species: Ceriodaphnia dubia, Daphnia similis, Danio rerio, and Vibrio fischeri. The results showed no acute toxicity for water column organisms.

Rio Doce Acoustic Surveys of Fish Biomass and Aquatic Habitat.

Following the failure of the Fundão mine tailings dam in Brazil, approximately 32 million cubic meters of Fe ore tailings were released into the downstream riverine system. The postevent monitoring surveys implemented the use of noninvasive acoustic methods to improve the understanding of the fish biomass distribution patterns and aquatic habitat condition of the impacted reaches of the Rio Gualaxo do Norte, Rio do Carmo, and Rio Doce. The primary focus of the program was to collect hydroacoustic measurements of fish biomass, which was accompanied by sonar imaging of aquatic habitats using high-resolution side scan and downward imaging sonar at each site visited.