Significance and Use
5.1 The presence and concentration of total petroleum hydrocarbons, as well as total oil and grease, in domestic and industrial wastewater is of concern to the public because of its deleterious aesthetic effect and its impact on aquatic life.
5.2 Regulations and standards have been established that require monitoring of total petroleum hydrocarbons as well as total oil and grease in water and wastewater.
1.1 This test method covers the determination of total oil and grease (TOG) that can be extracted from water or wastewater samples by cyclohexane and measured by non-dispersive IR spectroscopy from 1370–1380 cm-1. Treating the extract with Florisil to remove polar substances prior to the IR measurement enables determination of the total petroleum (TPH).
1.2 This method also considers the volatile fraction of petroleum hydrocarbons which is lost by gravimetric methods that require solvent evaporation prior to weighing, as well as by solventless IR methods that require drying of the employed solid phase material prior to measurement. Similarly, a more complete fraction of extracted petroleum hydrocarbon is accessible by this method as compared to GC methods that use a time window for quantification, as petroleum hydrocarbons eluting outside these windows are also quantified.
1.3 This method defines total oil and grease in water as material that can be extracted with cyclohexane and measured by IR absorption in the region of 1370–1380 cm-1 (7.25–7.3 µm). Similarly, total petroleum hydrocarbon in water is defined as material that can be extracted with cyclohexane, remains in the extract after filtration over Florisil and is measured by IR absorption in the region of 1370–1380 cm-1 (7.25–7.3 µm). The concentration of total grease is defined as the difference between the total oil and grease and total petroleum hydrocarbon concentrations.
1.4 This method covers the range of 0.5 to 1000 mg/L for total oil and grease as well as for total petroleum hydrocarbons and has a method detection limit (MDL) of 0.5 mg/L. The range and method detection limit may be extended to higher or lower concentrations by adjusting the water or solvent volume used in the liquid-liquid extraction.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.