 | Term | Definition |
 | Air | Sample taken from the atmosphere |
| Benthic zone | Ecological region at the lowest level of a body of water, including the sediment surface and some sub-surface layers. |
| Flowback water | A mixture of formation water and hydraulic fracturing injectates deriving from oil and gas wells prior to placing wells into production |
| Groundwater | Sample taken from water located below the surface of the ground, such as from a well or spring |
| Injection water | Water injected into a well or borehole prior to collection of flowback or production water. |
| Municipal waste water | Sample taken from raw municipal waste water stream. |
| Not Relevant | Sample medium not relevant in the context of the measurement |
| Other | Sample medium other than those contained in the CV |
| Precipitation | Sample taken from solid or liquid precipitation |
| Production water | Fluids produced from wells during oil or gas production which may include formation water, injected fluids, oil and gas. |
| Seawater | Observation or sample from a sea or ocean |
| Sediment | Sample taken from the sediment beneath the water column |
| Snow | Observation in, of or sample taken from snow |
| Soil | Sample taken from the soil |
| Soil air | Air contained in the soil pores |
| Soil water | the water contained in the soil pores |
| Storm water | Sample collected from stormwater, runoff generated by precipitation, or stormwater systems |
| Surface water | Observation or sample of surface water such as a stream, river, lake, pond, reservoir, ocean, etc. |
| Suspended particulate matter | Particulate matter entrained in the water column |
| Tissue | Sample taken from the tissue of a biological organism |
| Tree | Sample taken from a tree. |
| Unknown | The sample medium is unknown |
| Wastewater effluent | sample is from wastewater treatment plant effluent that is going directly into a stream |
| Wellhead Gas | Gas taken from a wellhead under positive pressure |
