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

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Polar Compounds in Alaska North Slope Oil and Other Oils

A Literature Review and Synthesis

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
• verall 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

Napthalene a two- ring PAH

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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

Napthalene a two- ring PAH

Solubility in oil vs water – that’s very important for polar compounds

• More water soluble compounds are
• ften 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

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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

Dibenzothiophene a three-ring Polar Compound

Recommendations

• The best (and economical) project would be to do a 8-way study
• f toxicity with weathering, biodegradation and photooxidation
• 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

Unweathered oil weathered oil Photooxidized

• il

Biodegraded oil water from under water from under water from under water from under