| CODE | NAME | DESCRIPTION |
| A | Ambient Air | Samples withdrawn from the atmosphere |
| B | Biota | May include biological organisms or tissue samples from organisms collected from any of the other media |
| D | Atmospheric Dry Deposition | Samples obtained by collecting dry particulate material that falls from the atmosphere |
| L | Soil | Solid materials collected from terrestrial sources excluding waste dumps |
| P | Precipitation | Precipitation sample collected during one or more precip events |
| R | Waste | Refuse from a variety of human activities that may exist in the form of a liquid, solid or gaseous emission. |
| S | Sediment | Bottom material or deposits sampled from beneath surface water |
| W | Water | Includes both surface water and groundwater |
