Assessing the Organic and Inorganic Pollutants of Oil Field Brine Water in Marmul Area, Sultanate of Oman

The present work aim is to quantifying and assessing the organic and inorganic pollutants in the study area. In this study, the data from 19 Monitoring Wells (MWs) and from Marmul Main Production Station (MMPS) were used to assess the Total Petroleum Hydrocarbon (TPH) concentrations ranged from 0.170ppm and 1.582ppm with average of 0.435ppm. The concentrations and distribution of total Poly Aromatic Hydrcarbons (PAHs) in the Marmul study area were measured in MWs ranged between 0ppm and 0.806ppm. There are 7 individual PAHs observed in the monitoring wells of the studying area. Naphthalene has the highest concentration among other individual PAHs with 0.616ppm and the lowest concentration is Fluorine with concentration of 0.004ppm. The distribution of TPH and PAHs in the area trend is to increase toward the area of disposal of brines in the shallow aquifer. Also, water sample collected form well no. MW-10 which is located north of the SWD has shown highly concentrations in both TPH and PAHs over the study area. The Gas Chromatography (GC) device fingerprints of the sampling indicated that the type of petroleum hydrocarbons is same and it is similar to the one from MMPS. In this case the source of organic pollution in the area is attributed to the activity of oilfield brines. All fingerprints contain around 19 of hydrocarbon compounds from C21 to C39 and did not include pristane and phytene isprenoids. The Carbon Preference Index (CPI) in samples of the study area was ranging from 0.6 to 1.7 with average 1.18, reflecting in almost similar anthropogenic sources of pollution rather than biogenic. There are 11 trace metals had results of concentration. The lowest concentration average is for Co of 0.0002ppm and it is detected in only one monitoring well. The average concentrations of the rest of 9 trace metals are range between zeros to 1.2ppm (Sr 11.56ppm, B 1.18ppm, Mn 0.08ppm, Ba 0.03ppm, Mo, Zn and P 0.02ppm, V 0.004ppm and Cr 0.002ppm). No concentration of Cd, Pb, Al, Fe, Cu, and Ni not found in the study area. In addition, trace metals results may regard to anthropogenic and/or natural sources and its level not indicated as trace metal pollution case. Patterns in groundwater pollution are consistent with produced water contamination that affirms the pollution originating is from one source (point source) of a produced water reinjection disposal wells in the study area