A review of the occurrence, analyses, toxicity, and biodegradation of naphthenic acids

This is a complex group of carboxylic acids with the general formula CnH2n+ZO2, where n indicates the carbon number and Z specifies the hydrogen deficiency resulting from ring formation. Measuring the concentrations of naphthenic acids in environmental samples and determining the chemical composition of a naphthenic acids mixture are huge analytical challenges. However, new analytical methods are being applied to these problems and progress is being made to better understand this mixture of chemically similar compounds. This paper reviews a variety of analytical methods and their application to assessing biodegradation of naphthenic acids.