. "TKN_Unfilt" . "Concentration of nitrogen contained in organic substances plus the nitrogen in inorganic ammonia and ammonium (NH3/NH4+) per unit volume of the water column held both in solution and particles of any size."@en . . . "accepted"@en . "Concentration of total nitrogen {total_N} per unit volume of the water body [dissolved plus reactive particulate phase] by Kjeldahl method"@en . "SDN:P01::NTOTKJM1" . . . . . . . . . . . . . . . . . . . . . . . . . . . . .