Collecting Oil and Grease Samples
The general permit requires that oil and grease samples be collected by all permit holders. Because oil and grease tends to stick to the inside surfaces of containers or tubing, oil and grease samples cannot be transferred between containers or through tubing. The sample for oil and grease analysis cannot be formed from combining separate grab samples.  If more than one oil and grease sample is desired from a sampling site during a storm event, additional oil and grease grab samples must be collected and analyzed separately. Samples for oil and grease analysis can not be collected through the tubing of an automatic sampler.
Based on the EPA Method 1664 for Oil and Grease and Total Petroleum Hydrocarbons, approximately one liter (1000 ml) of representative field sample will be collected in a glass bottle with PTFE-lined screw cap following conventional sampling practices, except that the bottle must not be pre-rinsed with sample before collection . |
