Crude oil and its products and wastes are among the significant sources of naturally occurring radioactive materials (NORMs). These materials may be enhanced to high levels due to technological and human activities, which are called technologically enhanced naturally occurring radioactive materials (TENORMs). Thus, the average radioactivity of these radionuclides sometimes exceeds the exemption level of 10 000 Bq kg⁻¹, which is recommended by the IAEA's safety standards. TENORMs in the oil and gas industry may generate greater radioactivity levels, which eventually represents potential environmental and health risks. This will require continuous attention by monitoring and surveillance during routine processes in the petroleum industry. In this paper, a comprehensive review of the published literature is conducted to evaluate the TENORM concentrations in the oil and gas industry. Moreover, their environmental and health hazards in different regions of the world are discussed.

Produced water that detached from petroleum production process is often reimbursed into the surrounding environment. This might have negative impact for environment; it is usually infiltrate agricultural soil and contaminate groundwater with toxic elements. These waters are often contaminated by technologically enhanced naturally occurring radioactive materials (TENORMs). It may create specific environmental issues and health radiological threats to the inhabitants, especially inside the petroleum facilities or the local population that live in areas and use the groundwater for the usual living purposes. The aim of this work is to provide an intensive review for the previous studies on the (TENORMs) that associating with the produced water from petroleum industry, and its environmental and health impacts in many areas around the globe. It is true that there is long term hazard associated with widespread behaviour of releasing produced water into the environments for both workers and local inhabitants as well as the environment itself. However, there is many studies suggesting that currently the situation could be considered in low hazard level in most of petroleum fields, but with increases in the extraction and use of petroleum, the discharge of produced water into the environment increases accordingly, this might be end up with negative impacts on the environment and health such as radiological contamination of aquatic and agricultural life.

Preparation of uncontaminated phosphogypsum (PG) produced by wet-process phosphoric acid plant for its safe use in industry was investigated. PG is mainly composed of calcium sulfate and contains enhanced natural radioactivity. The activity of ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²³²Th, and ⁴⁰K in PG samples was measured by γ-ray spectrometry. The values of radiation hazard indices, calculated to evaluate the environmental impacts of PG samples, were higher than the permissible safe levels. Therefore, the PG should be treated before use in agriculture and/or building materials. This involves the leaching of PG with organic extractant such as TOPO in kerosene. Reduction in the radionuclide concentration was accompanied by a decrease in the concentration of total rare earth elements (ΣREE). Extraction treatment of PG waste under optimum conditions allows preparation of a decontaminated product that can be safely used in many branches of industry.