Can a petroleum spill near my plastic water service line get into my household water supply?

Yes. This is a weakness of plastic plumbing components. Petroleum products and other solvents can leach through plastic to contaminate the water inside. There have been a number of instances where fuel tanks have leaked into the ground and entered plastic service lines to contaminate someone’s water supply.

It is important to note that not every time you get a petroleum smell when running water in your house that the culprit is petroleum. Sometimes the petroleum smell is due to a reaction involving chlorine dioxide which is a disinfectant used in the water treatment process. When the water treated with chlorine dioxide passes through the aerator (or strainer) of a home faucet some chlorine dioxide escapes into the air as a gas. Once the chemical is a free floating gas it reacts with the solvents in new carpets and causes a smell that is similar to that of petroleum. In most cases the smell does not go away for several months until the carpet ages and the carpet solvent dissipates.

If the odor does not dissipate, then there is one likely culprit that could be infiltrating your water service lines (as long as the infiltration is not coming from a leaky petroleum source within your house). The culprit is called TPH.

What are total petroleum hydrocarbons (TPH)? Total Petroleum Hydrocarbons (TPH) is a term used to describe a broad family of several hundred chemical compounds that originally come from crude oil. In this sense, TPH is really a mixture of chemicals. They are called hydrocarbons because almost all of them are made entirely from hydrogen and carbon. Crude oils can vary in how much of each chemical they contain, and so can the petroleum products that are made from crude oils. Most products that contain TPH will burn. Some are clear or light-colored liquids that evaporate easily, and others are thick, dark liquids or semi-solids that do not evaporate.

Many of these products have characteristics of gasoline, kerosene, or oily odors. Because modern society uses so many petroleum-based products (for example, gasoline, kerosene, fuel oil, mineral oil, and asphalt), contamination of the environment by them is potentially widespread. Contamination caused by petroleum products will contain a variety of these hydrocarbons. Because there are so many, it is not usually practical to measure each one individually. However, it is useful to measure the total amount of all hydrocarbons found together in a particular sample of soil, water, or air.

The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal cleanup activities. TPH, itself, has been reported at 34 of the 1,519 current or former NPL sites. Many NPL sites are contaminated with components of TPH, though no estimate has been made of the number of these sites. This information is important because exposure to these components may harm you and because these sites may be sources of exposure.

When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance or by skin contact. If you are exposed to TPH, many factors determine whether you'll be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider the other chemicals you're exposed to and your age, sex, diet, family traits, lifestyle, and state of health.

Everyone is exposed to TPH from many sources, including gasoline fumes at the pump, spilled crankcase oil on pavement, chemicals used at home or work, or certain pesticides that contain TPH components as solvents. A small amount of lighter TPH components are found in the general air you breathe. Many occupations involve extracting and refining crude oil, manufacturing petroleum and other hydrocarbon products, or using these products. If you work with petroleum products, you may be exposed to higher levels of TPH through skin contact or by breathing contaminated air. If TPH has leaked from underground storage tanks and entered the groundwater, you may drink water from a well contaminated with TPH. You may breathe in some of the TPH compounds evaporating from a spill or leak if you are in the area where an accidental release has occurred. Children may be exposed by playing in soil contaminated with TPH.

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.

Regulations and recommendations can be expressed in not-to-exceed levels in air, water, soil, or food that are usually based on levels that affect animals. Then they are adjusted to help protect people. Sometimes these not-to-exceed levels differ among federal organizations because of different exposure times (an 8-hour workday or a 24-hour day), the use of different animal studies, or other factors. Recommendations and regulations are also periodically updated as more information becomes available. For the most current information, check with the federal agency or organization that provides it and keep all petroleum-base chemicals away from plastic plumbing.