Analytical Methods Used to Characterize Petroleum Releases

Overview

Spills and releases of petroleum products are a leading source of environmental contamination.  Petroleum products are a complex and highly variable mixture of hundreds of individual hydrocarbon compounds.

The Remediation Standard Regulations, sections 22a-133k-1 through 22a-133k-3 of the Regulations of Connecticut State Agencies (RSRs), as originally promulgated, contained criteria for Total Petroleum Hydrocarbons (TPH), which is based on EPA Method 418.1 that utilized Freon-113. In an effort to help bring about the end of Freon use in Connecticut, the Connecticut Department of Energy and Environmental Protection (DEEP) will not accept analytical data derived by EPA Method 418.1 for samples collected on or after June 30, 2009.

The Extractable Total Petroleum Hydrocarbons (ETPH), Extractable Petroleum Hydrocarbons (EPH), and Volatile Petroleum Hydrocarbons (VPH) are analytical methods that are commonly used in Connecticut to characterize petroleum releases. These methods do not utilize Freon. The ETPH, EPH and VPH Methods do not measure TPH as reported by EPA Method 418.1.  Reasonable Confidence Protocols are provided for the Quality Assurance and Quality Control for ETPH, EPH and VPH Methods.

Pursuant to the RSRs, requests to use these methods and associated analytical results may be submitted for the Commissioner’s review and approval, on a site-specific basis, as Additional Polluting Substances.

Extractable Total Petroleum Hydrocarbons

On June 22, 1999, the Commissioner of the State of Connecticut Department of Public Health (CTDPH) approved an analytical method for determination of ETPH. The method is titled "Analysis of Extractable Total Petroleum Hydrocarbons (ETPH Method) Using Methylene Chloride Gas Chromatograph/Flame Ionization Detection," prepared by the Environmental Research Institute, University of Connecticut, dated March 1999.

The ETPH Method is a helpful tool because it allows for quick and inexpensive analysis.  The results of the ETPH Method are compared to a non-risk or qualitative based clean up criteria. The ETPH Method measures the C9 to C36 range of hydrocarbons which includes the major components of a number of widely used petroleum products such as kerosene, jet and diesel fuels, No. 2 to No. 6 fuel oils, and motor oil. Because this method does not measure the lighter major components of gasoline, it is not suitable for the characterization of gasoline releases.

ETPH Reporting Limit

DEEP has evaluated the reporting limit for the ETPH Method and anticipates proposing a Groundwater Protection Criterion for the ETPH Method in consultation with the Connecticut Department of Public Health.  At this time, DEEP anticipates proposing a Groundwater Protection Criterion of 250 micrograms per liter (ug/L) as determined by the ETPH Method.

Currently most laboratories use a reporting limit of 100 ug/L for aqueous samples.  At this level, the method suffers from “noise” resulting in false positives, and some laboratories have experienced difficulty quantifying ETPH at 100 ug/L and have requested that the reporting limit for the ETPH Method be raised.  DEEP recommends that environmental laboratories performing this method should consider raising their reporting limit for aqueous samples to a concentration above 100 ug/L, but equal to or less than 250 ug/L.  However, laboratories should still be able to demonstrate the capability of quantifying at the lowest concentration possible above the instrument signal to noise level through the performance of annual method detection limit (MDL) studies.

Laboratories can implement this change when they are ready to do so. Reporting limits are not to be artificially raised by the laboratory.  It is never appropriate for an environmental professional to request that the laboratory raise a reporting limit.

To utilize an ETPH Method reporting limit for aqueous samples at a concentration above 100 ug/L but less than 250 ug/L, environmental professionals must request the use of a Groundwater Protection Criteria of 250 ug/l for the ETPH Method as a site-specific additional polluting substance (APS), as described on the DEEP webpage, Requesting the Commissioner's Approval for the Use of the ETPH, EPH, VPH and APH Analytical Methods and Associated Criteria as Additional Polluting Substances.

ETPH reported present in a sample collected from a drinking water supply well at any concentration may be a potential concern and may necessitate further evaluation, such as more definitive analytical testing or identification of sources, consistency with Action Levels established by CTDPH, and, as determined necessary, mitigation and water treatment.

If ETPH is reported at any concentration in a sample collected from a drinking water supply well, it can be considered a polluting substance and the requirements of the Significant Hazard Program section 22a-6u of the Connecticut General Statutes must be evaluated to determine if a Significant Hazard Condition Notification is required.  Information regarding the Significant Hazard Program can be found on the DEEP webpage, Significant Environmental Hazard Program. Please contact the Remediation District Supervisor or the Connecticut Department of Public Health for further guidance on this issue. 

Extractable Petroleum Hydrocarbons

The EPH Method evaluates petroleum hydrocarbons by reporting the results for specific carbon ranges and target compounds found in petroleum hydrocarbons.  The EPH method produces results which allow for cleanups to be based on the risk of the substances present.  This method will promote more appropriate risk management, where a spill from a peanut oil release (less toxic, less risk) is not treated the same as waste oil spill (more toxic, more risk).

Petroleum products suitable for evaluation by this method include kerosene, No.2 fuel oil, No. 4 fuel oil, No. 6 fuel oil, diesel fuel, jet fuels, and certain petroleum-based lubricating oils. The EPH Method, in and of itself, is not suitable for the evaluation of gasoline, mineral spirits, petroleum naphthas, or other petroleum products that contain lower or higher boiling components or distillates of aliphatic and/or aromatic hydrocarbons that are outside analytical range (C9 through C36 aliphatic and aromatic ranges) of the EPH Method. The EPH Method identifies and measures:

• Extractable aliphatic hydrocarbons within two specific ranges: C9 through C18, and C19 through C36;
• Extractable aromatic hydrocarbons within the C11 through C22 range; and
• Target polyaromatic hydrocarbon (PAH) analytes, including diesel PAH analytes.

Volatile Petroleum Hydrocarbons

Similar to the EPH Method, the VPH Method evaluates petroleum hydrocarbons by reporting the results for specific carbon ranges and target compounds found in petroleum hydrocarbons.  The VPH method produces results which allow for cleanups to be based on the risk of the substances present.  This method will promote more appropriate risk management, where a spill from a peanut oil release (less toxic, less risk) is not treated the same as waste oil spill (more toxic, more risk).

Petroleum products suitable for evaluation by the VPH Method include gasoline, mineral spirits, and certain petroleum naphthas.  In and of itself, the VPH Method is not suitable for the evaluation of kerosene, jet fuel, heating oils, lubricating oils, and/or other petroleum products that contain higher boiling components, or distillates of aliphatic and/or aromatic hydrocarbons that are beyond the analytical range of the VPH Method. The VPH Method identifies and measures:

• Volatile aliphatic hydrocarbons within two specific ranges: C5 through C8, and C9 through C12;
• Volatile aromatic hydrocarbons are collectively within the C9 to C10 range; and
• Target analytes: Benzene, Toluene, Ethylbenzene, Xylenes (BTEX), Naphthalene, and Methyl-tert-butyl ether (MTBE).

Analytical Methods

The table below presents suggested analytical methods for the characterization of petroleum releases.  When designing an analytical plan, the environmental professional should consider the substances which may be present based on the site history and select the appropriate analytical methods to detect and characterize a release.

The criteria in Appendices A through F of the RSRs are used to determine if a potential risk to human health or the environment may exist. The results of analyses performed on environmental media are used to determine if remediation is needed based on comparison to these criteria.  Because of the nature of environmental media, limitations of analytical methods, characteristics of analytes, and human error, the results of environmental analysis may contain an element of uncertainty and in some cases may be significantly biased, and therefore may not be representative of the actual concentrations of the analytes in the environmental media.  Thus, an evaluation of the quality of the analytical data in relation to the intended use is important in order for the environmental professional to make decisions which are supported by data of known and adequate quality. 

There are many ways to obtain data of known and documented quality.  Use of the Reasonable Confidence Protocols will provide consistency in evaluation and presentation of data quality information that will facilitate review. If alternative analytical procedures are used, such procedures should be documented in order to demonstrate that the analytical data produced is of known and documented quality. Such a demonstration and review may involve a commitment of significant resources.

Suggested Analytical Methods for Evaluation of Petroleum Releases