Radiological dose assessment of naturally occurring radioactive materials generated by the petroleum industry in wildlife: A case study of chinkaras of Lavan Island, Iran

Human activities such as oil and gas production can enhance the natural level of naturally occurring radioactive materials (NORM) in by-product and waste streams. Iran has been among the top five oil producing countries since 2005. This high production rate emphasizes the importance of NORM management to ensure the safety of humans and wildlife. Petroleum storage and transport facilities are located at Lavan Island, Iran. Presence of animals including dolphins, sea turtles, and chinkaras make this island one of the most unique wildlife refuges in Iran. This paper combines waste disposal methods relevant to the petroleum offshore industries, NORM waste characteristics, and geographical, geological, and climate conditions of Lavan Island in order to develop enveloping exposure scenarios. Sludge burning is determined as the most concerning scenario by assuming chinkaras as the endpoint. Ecological and radiological assessment procedure is modeled with MATLAB-Simulink as a dynamic system. Clearance level for radiation protection of chinkaras is calculated as 41 Bq/kg. This value may be insufficient for radiation protection of workers, because exposure pathways are not derived based on human behavior. According to environmental pathways and condition of chinkaras, this value sufficiently covers all aspects of radiation protection.