Assessment of Naturally Occurring Radionuclides in a pre-operational stage of a shrimp farm in southern Bahia, Brazil

Environmental radioactivity has both natural and anthropogenic origins, with radionuclides such as Ra-226, Ra-228, and K-40 found in the Earth's crust and distributed in environments through environmental cycles and the food chain. Human activities, such as oil exploration and nuclear power plants, also introduce radioactive materials into the environment. However, soil movements can also alter environmental radioactivity through the movement of naturally occurring radionuclides. In aquatic environments, radioactive elements can cause processes such as bioaccumulation in animals, posing a global issue requiring monitoring. Due to their sinkhole characteristics and being transitional zones, estuaries are heavily impacted by contaminations. This is because the chemical composition of their sediments is controlled by a complex relationship between physical factors, biogeochemical processes, interactions between river and ocean, as well as the environmental and anthropogenic characteristics of upstream regions. The discharge of sediments from anthropogenic activities affects coastal and marine ecosystems, such as mangroves and coral reefs, including benthic fauna and flora. The concentration of radionuclides and heavy metals in sediments varies over time and can have significant effects and bring serious consequences to the coastal environment. One of the activities gaining momentum on the northeast coast of Brazil is shrimp farming, although there are few studies presenting data linking this activity to environmental contamination, it is not possible to dissociate it from environmental problems [2]. The south region of Bahia is known for its biodiversity and preservation due to various environmental protection areas, as well as communities engaged in ecological extraction in the region. In this context, with the construction of a shrimp farm in the region, data collection on radiation levels was conducted in the growth pond and treatment pond to determine the background radiation levels in the area. (author)