Polar Compounds in Alaska North Slope Oil A Literature Review and - PDF document

5/4/16 Polar Compounds in Alaska North Slope Oil A Literature Review and and Other Oils Synthesis Napthalene a two- ring PAH The study • Purpose – study the presence and toxicity of polar compounds in Alaskan oils and synthesize the information • but Alaskan info very limited, study extended to all oils • Polar compounds have elements or groups or such as, N, S or O which gives the overall molecule an electric charge or polarity • General findings ~ over 100 papers, many on periphery of the topic • Toxicity – somewhat understood for simple polar compounds. Lags the chemistry • Analysis and separation – advancing very rapidly for groups – but not for single compound identification 1

5/4/16 Napthalene a two- ring PAH Summary • Little work done for Alaskan oils • Evaporative weathering studies and PAH analysis has shown that most toxic components of oils are 2 to 5 ring PAHs • These studies indicate that the polar compounds are toxic, but not highly toxic • Studies of other oils such as oil sands oils, appears to indicate that they also are of same toxicity as conventional oils, despite containing more polar compounds Solubility in oil vs water – that’s very important for polar compounds • More water soluble compounds are often more toxic • But… these are typically dissolved into production water before oil is transported to refineries • Larger compounds are typically not water soluble and are often highly oil soluble and may not be Bioavailable on their own 2

5/4/16 Dibenzothiophene a three-ring Polar Compound More information • Report listed more than 200 polar compounds found in oils – many with acute aquatic toxicity listed • The only known polar compounds in Alaskan oils measured are that of Dibenzothiophenes which are similar to PAHs • Alberta oil sands have many polar compounds: smaller and soluble ones go into ponds with process water – • toxicity concerns: larger ones go with oil - no real toxicity concerns • Studies are progressing – for now, it seems that there are no identified highly-toxic polar compounds in known oils such as Alaskan North Slope Crude Recommendations • The best (and economical) project would be to do a 8-way study of toxicity with weathering, biodegradation and photooxidation Photooxidized Unweathered oil weathered oil oil Biodegraded oil water from water from under water from under under water from under • This study could yield valuable information on the relative toxicity resulting from weathering, biodegradation and photooxidation • Other studies may yield little information with large expenditure 3