Abstract
Saudi Arabia has some of the biggest oil and gas reserves in the world, and has expanded its drilling operations gradually to meet the global demand. Improper handling of contaminated drilling wastes may cause serious negative environmental impacts. The current study investigates the toxicological effects of heavy metals in drilling waste by quantification and developing different contamination indices. Solid and liquid samples from different drilling waste pits were collected and analyzed for heavy metals. The average concentration varies significantly and decreases in the order of Fe > Al > Sr > Mn > Cu > Cr > Zn > Ni > Pb > Cd > Ag > Co. The spatial variation showed the highest concentration at SDGM Site 1, West. Comparison of current data showed continental crust average values within the specifications for most of the sites. For metals like Cd, Cr and Cu, the concentration is higher than the continental crust value. Indices such as pollution load index, modified degree of contamination etc. were calculated from the available data. The contamination level for different site calculations showed nil to a very low degree of contamination. Spatial variation of the contamination level indicated comparatively higher values for sites UTMN-4 and SDGM-1 North, which indicates the necessity of precautionary methods. The metal concentration in the pit water samples exceeded generally accepted standards, if this water was to be discharged/leaked from the pit. The current study concluded presence of different heavy metals in samples from the drilling waste pits, whereas the degree of contamination is minute.
Highlights
Concentration of total heavy metals at each sampling locations was tabulated in Table 1 and Table 2 and Figure 2
The above variation is in the same order reported by Elilyas et al (2019) for drill cuttings, which indicates that drill cuttings are contributing heavy metals to the waste pits
Our current results indicated within maximum allowable limit for lead according to USEPA, which is safer and won’t pose any health concerns
Summary
It has shaped our world in many important ways including economic and social development. Petroleum is one of the Earths most in-demand natural resources Even though it has number of uses, the environmental impact of the petroleum industry is correspondingly extensive and expansive. All activities related to oil & gas exploration, production, storage and transportation involve waste generation associated to potential risk to the environment. Waste types are related to activities such as drilling operations, production operations, completion operations, Work-over operations, and gas plant operations. During drilling operations, drilling fluid or mud is pumped down the drill string to lift drill cuttings to the surface. The exact chemical composition of the all varieties of drilling fluids is not known, but studies on their general composition have revealed that they contain complex mixtures of highly volatile materials and toxic substances, such as aromatic compounds and heavy metals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
