This is a draft, adapted from the DIY Oil Testing guide, authored with @gretchengehrke and @eustatic and supported by the Knight Foundation. Please leave feedback and corrections or questions below.

In addition to calling and reporting the oil you pollutant to a local or national agency, if it is possible to do so safely, you could collect a sample of the pollutant.

Find a laboratory

If you are interested in having the sample tested to determine the type (and potential source of the oil) by a laboratory, it can be helpful to decide which laboratory you will send the sample to before collecting that sample. To find an analytical laboratory, you can either call the county government environmental department and ask their recommendations (as they often need to out-source their lab work), or do a series of Internet searches to find an appropriate accredited lab in your area. You can also post a question about this, and ask the thousands of Public Lab community members from around the world may be able to help you find the appropriate resources. (Likewise, if you can help, please offer assistance to others who ask.)

Collection technique

When you find a laboratory to use, it will be important to learn the collection techniques that are required for the method they are planning to use. Since most methods require very specific bottle preparation (possibly including a final step of baking glassware to 450 Celsius for four hours, since by that temperature most organic matter should have combusted), you may want to ask to see if they will send you an appropriate collection container. Note that improper pre-cleaning of sampling containers might be the primary reason that many citizen-collected samples are thrown away by official labs, so cleaning bottles according to specific methods, or obtaining cleaned bottles from laboratories, is important. Different methods may require specific sample collection techniques, but here we include some general sample collection principles to help you prepare.

Analyzing for organic compounds

For samples that you want to analyze for organic compounds, such as oils, you generally want to use amber glass vials -- note that you do NOT want to use plastic bottles (read about storage here, below), as those will contaminate the sample.

If you are collecting possible oil contamination, it is best to use a UV filtering glass (such as most amber glass vials) because several compounds in oils are sensitive to UV.

Mason jars

If you do not have amber glass bottles, plain glass, such as a mason jar, will work if you keep the jars in a dark box out of the sunlight -- but be aware that many official guidelines require amber glass, so if you're planning to submit a sample to a lab, this is important.

(Image: https://www.flickr.com/photos/healthygulf/22639088097/in/album-72157660526072069/)

Quantity

If you are collecting straight oil or oily solids (e.g. sand, soil), the collection container should be large enough for a minimum of 5 grams of sample plus 10 mL water, which will likely be a 40 mL vial, or larger.

Lid

The analytical method the laboratory will use will indicate whether a PTFE-lined solid cap is sufficient or if you need a cap with a septa (used when the sample vial cannot be opened, and is directly pierced by the analytical instrument). Some protocols use aluminum foil over the sample before closing the lid, so that the contents do not touch plastic.

When collecting solid oil or oily solids samples, you want to avoid using any plastic scoops, and rather, use a stainless steel scoop or spatula that you have rinsed with water and wiped with isopropyl alcohol. When collecting water samples with an oil sheen or emulsion, you want to collect the sample upstream from any disturbance you have caused, with the bottle open to the current in a river, and fill the sample container completely such that there is no headspace. (see collecting sheens, below)

Storage

Samples should be stored cold, on ice, attempting to reach 4 Celsius (39 Fahrenheit), or colder if the analytical methods requires it. For samples that must be stored colder than 4 Celsius, you can purchase dry ice. If you purchase dry ice, be careful when handling it, as it can burn bare skin and be a respiratory irritant. Samples should be transported from the field in a cooler and transferred into a refrigerator or freezer of the appropriate temperature as soon as possible.

Suspected oil samples, kept in a cooler; photo by Scott Eustis (@eustatic)

Chain of Custody

When collecting a sample for third-party laboratory analysis, to submit to a local government agency, or to analyze yourself, it is important to establish a Chain of Custody of the sample to ensure there is a responsible party for it. Information to include in the Chain of Custody are:

• Name and contact information of sample collector
• Sample code (if applicable)
• Date and time of collection
• Location of collection
• Type of media (e.g. soil, sediment, water)
• Environmental conditions
• Collection method used
• How it is stored or transported
• Type of preservation (if applicable)
• Analyses requested

Questions

(Jeff) I have a lot of questions about this, so I'm adding a Questions section here:

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