When scientists refer to hydrocarbons, they typically mean petroleum or crude oil. Hydrocarbons are organic compounds made of oxygen and petroleum. In nature, liquid forms of hydrocarbons exist in pockets in the earth's crust. Except in naturally occurring springs where petroleum or oil bubbles to the surface, hydrocarbons aren't typically found in the soil. Instead, soil hydrocarbons are typically the result of pollution, either through a small gasoline spill, a leak from a fuel storage tank, or the presence of a nearby oil refinery. If you suspect your soil is contaminated with hydrocarbons, several types of tests are available.
Collect soil from the location you suspect is contaminated. Dig 1 tbsp. of soil from the surface with a shovel. Place this into a clean glass baby food jar. Dig down into the soil 6 inches and remove another tbsp. of soil. Add this soil to the jar.
Observe the soil for an oil-soaked appearance. Add a little water to the jar to determine if the water beads away rather than being soaked up by the soil. Fill the jar with water, place the lid on the jar and shake it. Allow the soil to settle. Open the jar and examine the surface of the water for an oily film. A petroleum film will appear to have a rainbow shine to it.
Place a small amount of soil into the center of a slide. Place the slide under a microscope and turn off all lights. Turn on a black light. Examine the slide through the microscope. Hydrocarbons will fluoresce under the microscope in the presence of a black light.
Purchase a soil-remediation survey test kit. Using the instructions, analyze your soil for hydrocarbon content. These tests are calibrated to determine which petroleum products are present in your soil, as well as the quantity of hydrocarbons.
Collect soil samples from several locations on your property following the procedure in step 1. Take these samples to an environmental testing laboratory for analysis.