An evaluation of vocational vulnerability to hydrogen sulfide (preliminary study ��? Libya pilot study)

Abstract

Ubaydah Thamir

Hydrogen sulfide gas is a major gaseous pollutant associated with the oil and gas industry, with a direct toxic effect in the workplace in oilfields, and causing damage to the surrounding ecosystem. The Arabian Gulf Oil Company, which was established in 1965, is responsible to the Libyan government, and produces oil and gas in cooperation with international companies. The company has four fields spread over the Libyan desert, one of which was the location for this study. This field is located within 51 kilometers approximately of Oasis Gallo, and employs 650 workers, including engineers and technicians. However, hydrogen sulfide gases produced by oil and gas companies cause the most serious environmental damage to habitats and to aquatic populations. Release to the environment is primarily in emissions to the ambient air, where the chemical is likely to remain for less than 1 day, but may persist for as long as 42 days in winter. Hydrogen sulfide may evaporate easily from water, depending on temperature and PH; it is unlikely to bioconcentrate and biomagnify in the food chain. The concentration of hydrogen sulfide in air in unpolluted areas is very low, between 0.03 and 0.1 µg/m³. The samples were distributed in and around the field, and measurements were carried out at frequent intervals. The study focused on measuring the concentration levels of hydrogen sulfide. Sampling procedures were carried out according to regulations of the company, and were distributed around the different areas of the turbine plant site. Therefore, exposure doses among the workers depended on the exposure time according to internationally accepted standards. Consequently, the assessment of H2S in the field, are as follows: 100 ppm recorded near gas stations, 88 ppm in sections, 97ppm near the wells, and 33 ppm recorded after 1 kilometer away, east of the main terminal. Though, the length of time for which workers were exposed to the gas in those locations determined the severity of the risk of minimum values of H2S concentration being exceeded. but, the chronic daily intake assumed to be 1060 mg , and the risk will be 1,1* 10-5 .