There are 4 common tests to determine organic pollution in wastewater: BOD (or CBOD), COD, TOC, and Oil & Grease.
Total Organic Carbon (TOC) is the amount carbon atoms tied up in organic compounds in a water sample, and it is a non-specific indicator of water quality (because pure water contains NO carbon). It does not identify specific carbon-containing compounds, only the presence of unwanted organic compounds in pure water.
Unlike BOD and COD, TOC is a quite sensitive measure of organic carbon present in a sample. The sensitivity of the test makes it valuable for evaluating water that might be used in manufacturing drugs or food for human consumption, or for testing the purity of water that will be used in sensitive manufacturing processes like making semi-conductors.
TOC can be used in the wastewater treatment industry as a quick way to estimate the Biochemical Oxygen Demand (BOD) of effluent water, once a stable ratio of TOC to BOD has been established at a particular site (BOD testing takes 5 days to TOC's few minutes).
Total Organic Carbon (TOC) is derived by measuring the amount of Total Carbon (TC) and subtracting the Inorganic Carbon (IC). Inorganic carbon consists primarily of dissolved CO2 gas and carbonic salts.

-from Suissdent, Wikipedia
Resources
Wikipedia: "Total Organic Carbon"
"Understanding Laboratory Wastewater Tests: Organics" , University of Georgia Extension (.pdf)
MEL Test Method for TOC
Drinking Water, Wastewater - SM 5310B, 22nd ed. (SDWA, CWA, NPDES compliant)
aka EPA 9060A (SW-846) (RCRA compliant)
Sample Requirements
Aqueous
Container: plastic, glass (amber glass preferred)
Volume: 40 mL - fill to top
Hold Time: 28 days
Preservation: H2SO4 or HCl to pH <2; ≤6°C
Solid
Container: plastic, glass
Volume: --
Hold Time: 28 days
Preservation: n/a
See Also...
Total Carbon (TC)
Total Inorganic Carbon (TIC)
Dissolved Organic Carbon (DOC)