NORM from the monazite cycle and from the oil and gas industry: Problems and tentative solutions

Laboratório de Radioecologia e Mudanças Globais (LARAMG), Universidade do Estado do Rio de Janeiro (UERJ), Pavilhão Haroldo Lisboa da Cunha, Subsolo, Rua São Francisco Xavier, 524. Maracanã, Rio de Janeiro, RJ 20550-013, Brazila and Instituto de Radioproteção e Dosimetria (IRD), Comissão Nacional de Energia Nuclear (CNEN), Av. Salvador Allende s/n°, Recreio dos Bandeirantes, Rio de Janeiro, RJ 22780-160, Brazil

Abstract

Naturally occurring radioactive material (NORM) associated with monazite had its origin before the 20^th century. The volume and complexity of monazite NORM wastes increased as the industrial applications of monazite also increased. During and after the WWII the diversified uses of thorium turned monazite into an important commodity. At the end of the 20^th century the production of oil and gas from offshore platforms in continental shelves increased remarkably. Hundreds of millions of m³ of produced water from the oil and gas industry, containing NORM wastes and other byproducts, are discharged into the oceans every year. E&P processes mobilize the natural occurring radio-nuclides extant in the oil and gas reservoirs. A wide range of concentrations of ²³⁸U and ²³²Th and their respective progenies, mainly ²²⁶Ra, ²²²Rn and ²¹⁰Pb (from the ²³⁸U series), and ²²⁸Ra and ²²⁸Th (from the ²³²Th series) appear in tube scales and sludge. The radium isotopes in NORM wastes generated in the monazite cycle become more bio-available than those isotopes found in wastes from the oil and gas industry. This work discusses some of the problems arising from the existence of monazite cycle and oil and gas industry NORM wastes, and proposes a tentative solution.