TPH-gasoline

Confirmatory soil sampling was subsequently performed. Three soil borings were drilled and samples retrieved from the impacted area. Soil from a depth of 30 ft and below were reported as nondetectable however, samples from a depth of 21 ft still contained significant gasoline components with TPH-gasoline ranging up to 3600 ppm. This zone of elevated hydrocarbons was anticipated due to the presence of clays and silt at this depth. Ventilation of these low-permeability soils was not deemed cost-effective, and significant reduction of the residual hydrocarbon concentrations unlikely. 

California Department of Health Services, 1989, Total Petroleum Hydrocarbons (TPH) Analysis — Gasoline and Diesel In California Water Resources Control Board Leaking Underground Fuel Tank (LUFT) Manual, Appendix C. 

The dominantly unsaturated nature of the upper smear zone was also distinct in that it had a substantially lower percentage (10%) of total volatile (gasoline-range) vs. total recoverable (diesel-range) hydrocarbons. In contrast, the lower smear zone contained 25% total volatile hydrocarbons. The difference was thought to be due to the dominantly saturated nature of the lower smear zone, which limited the amount of volatilization that could occur. However, the dramatic difference in TPH concentration was thought to be largely attributable to intrinsic bioremediation. 

The PetroClean bioremediation system treats biodegradable contaminants (i.e., gasoline, diesel fuel, aviation fuel, solvents, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), total petroleum hydrocarbons (TPH), and other organic compounds in soils and groundwater. 

To identify the type of a petroleum product, laboratories rely on characteristic fingerprints obtained as chromatographic patterns and use petroleum product standards for the pattern recognition and fuel quantitation. That is why TPH results are usually reported in relation to a fuel standard TPH as gasoline, TPH as diesel, TPH as motor oil. 

Gasoline and its components are usually analyzed with the PID/FID combination (EPA Methods 8021 and 8015). In these methods, the PID and the FID may be connected in series to one column or in parallel to two columns. The PID is used for the analysis of individual compounds (BTEX and oxygenated additives, such as MTBE), and the FID is used for TPH analysis. 

TPH analyses are particularly prone to false positive results. False positive GRO results are often reported for samples with a single peak, typically a solvent, present in the chromatogram in the absence of a gasoline pattern. Memory effects (carryover in the chromatographic column) often produce false positive results in TPH analysis. 

One TPH compound (benzene) has been shown to cause cancer (leukemia) in people. The International Agency for Research on Cancer (IARC) has determined that benzene is carcinogenic to humans (Group 1 classification). Some other TPH compounds or petroleum products, such as benzo(a)pyrene and gasoline, are considered to be probably and possibly carcinogenic to humans (IARC Groups 2A and 2B, respectively) based on cancer studies in people and animals. Most of the other TPH compounds and products are considered not classifiable (Group 3) by IARC. See Chapter 6 for more information on how TPH can affect your body. 

There is no medical test that shows if you have been exposed to TPH. However, there are methods to determine if you have been exposed to some TPH compounds, fractions, or petroleum products. For example, a breakdown product of n-hexane can be measured in the urine. Benzene can be measured in exhaled air and a metabolite of benzene, phenol, can be measured in urine to show exposure to gasoline or to the TPH fraction containing benzene. Exposure to kerosene or gasoline can be determined by its smell on the breath or clothing. Methods also exist to determine if you have been exposed to other TPH compounds. For example, ethylbenzene can be measured in the blood, urine, breath, and some body tissues of exposed people. However, many of these tests may not be available in your doctor s office. 

Nearly all states have cleanup standards for TPH or components of TPH (common cleanup standards are for gasoline, diesel fuel, and waste oil). Analytical methods are specified, many of which are considered to be TPH methods. 

The analysis is often called the gasolines range organics (GRO) method. The semivolatile range is determined by analysis of an extract by GC/FID and is referred to as diesel range organics (DRO). Individual states have adopted methods for measuring GRO and DRO contamination in soil and water. The specific method details and requirements vary from state to state. Some of the GC TPH methods are summarized in Table 3-4. 

DRO = diesel range organics GRO = gasoline range organics TPH = total petroleum hydrocarbons... 

Petroleum products are an integral part of our modern lives. It is nearly impossible to avoid exposure to hydrocarbons from petroleum products, whether it is from gasoline fumes at the pump, spilled crankcase oil on asphalt, solvents used at home or work, or pesticide applications that use petroleum products as carriers. There are concerns with both short-term (accidents) and long-term exposures to petroleum hydrocarbons (e.g., contaminated drinking water). Gross measures of Total Petroleum Hydrocarbons (TPH) in soil or water are not particularly valuable for assessing either the potential for exposure to TPH or the impacts of such exposure on public health. This chapter addresses questions related to the first point what are the levels of contamination in the environment, what happens to petroleum hydrocarbons in the environment, and what is the likelihood that individuals or populations will be exposed to petroleum hydrocarbons at levels thought to be of concern ... 

Since most TPH contamination involves a complex mixture of hydrocarbons, it is unlikely that aqueous readings beyond the NAPL zone will be near the limits of solubility (based on assumptions of a pure hydrocarbon type in equilibrium with water). If concentrations are near or above solubility limits, NAPL was probably present in the sample. TPH materials are relatively insoluble in water, with only the BTEX chemicals or some short-chain aliphatic hydrocarbons showing any appreciable potential for water solubility. When they are part of complex mixtures, the individual components never reach the concentrations predicted from their solubility constants as individual chemicals. For example, chemicals like benzene or toluene, which may constitute a small percentage within an initial bulk product like gasoline, jet fuel, or diesel fuel, have a much greater tendency to stay dissolved in the NAPL system than to become integrated into the water-based system beyond the NAPL boundary. Therefore, the effective solubility of these chemicals as part of a complex mixture is less than it would be in a release of the pure chemical. 

Exposure Levels in Environmental Media. TPH is commonly measured where hydrocarbon releases have occurred (e.g., leaking gasoline, diesel, or fuel oil tanks and petroleum product spills). 

This profile covers total petroleum hydrocarbons (TPH), which is defined as the measurable amount of petroleum-based hydrocarbon in an environmental medium (Chapter 2). TPH is measured as the total quantity of hydrocarbons without identification of individual constituents. Sources of TPH contamination in the environment range from crude oil, to fuels such as gasoline and kerosene, to solvents, to mineral-based crankcase oil and mineral-based hydraulic fluids. These products contain not only a large number and variety of petroleum hydrocarbons, but also other chemicals that, strictly speaking, are not the subject of this profile, such as non-hydrocarbon additives and contaminants. The TPH issue is further complicated by the number of petroleum-derived hydrocarbons that have been identified—more than 250—and the variability in composition of crude oils and petroleum products (see Section 3.2 and Appendices D and E for details). 

Because TPH is a complex and highly variable mixture, assessment of health impacts depends on several factors, assumptions, and circumstances. Of prime importance is the specific exposure scenario. For example, immediately following a large release of a lighter petroleum product (e.g., automotive gasoline), central nervous system depression could occur in people in the immediate vicinity of the spill if... 

The international, national, and state regulations and guidelines regarding total petroleum hydrocarbons (TPH) in air, water, and other media are summarized in Table 7-1. No health or environmental benchmarks have been developed for TPH as a general category, though many exist for individual petroleum chemicals or products, such as gasoline. 

Xiang Y, Morgan SL, Watt BE. 1995. TPH and BTEX quantitation in gasoline and diesel contaminated soils by capillary gas chromatography-mass spectrometry. J Chromatographic Science 33 98-108. 

TPH is a value that represents the amount of petroleum hydrocarbons in a given sample, as previously presented in Section 2.1. There are far more than 250 individual chemicals that are known as petroleum hydrocarbons. Some of these are listed in Appendix D. More often, many of the petroleum hydrocarbons are known by the names associated with the more common whole petroleum products, such as gasoline, fuel oil, mineral oil, and jet fuels, for example. These whole products are actually mixtures of numerous individual compounds, such as those listed in Appendix D, as well as, sometimes, non-petroleum hydrocarbon additives. Because of the complexity involved in chemically and physically describing and categorizing these whole products this Appendix contains more detailed information about the more prominent products that are likely to be associated with TPH. A list of the information is given below. 

---