Risk assessment of naturally occurring radioactive materials (NORM) in the hydrocarbon sludge extracted from the south pars gas field in Iran

Abstract

Natural radionuclides are always present in soil, water, and in particular in materials extracted from the depths of the earth. The accumulation of natural radionuclides and the increase in their radioactivity to excessive levels will lead to health hazards and environmental damages. Therefore, carrying out studies, evaluations and risk assessments in industries with the possibility of excessive accumulation of these materials in their various processes is inevitable to protect occupational health of employees and stakeholders and prevent the pollution of environmental resources including soil, water and air. Oil and gas fields are among the most prepared areas in this regard. Iran is one of the largest owners and producers of huge oil and gas resources in the world. The great concentration of hydrocarbon reservoir extraction and production facilities in some parts of the country, and the presence of a large number of oil & gas organizations employees in these areas, necessitate such studies. For this reason, one of the South Pars gas field refineries located in Pars special economic energy zone, Assaluyeh, Iran, was selected to investigate the concentration of radioactivity of hydrocarbon sludge and soil and the related hazards indices (potential hazards). The obtained results showed that the concentrated sludge in the condensate pre-flash drum of the condensate stabilization unit and some of heat exchangers had higher than normal radioactivity levels. Furthermore, health and environmental risks were assessed and the results indicate that there are high risks in some activities and environmental aspects that it is necessary to consider controls to reduce them to acceptable levels.