"Concentration of sodium {Na CAS 7440-23-5} per unit mass of the sediment pore water [dissolved plus reactive particulate <0.2um phase] by extraction by squeezing, filtration, acidification and inductively-coupled plasma atomic emission spectroscopy"@en . . "SDN:P01::SEDPWNA1" . "The concentration of the specified analyte in sediment pore water passed through a 0.2um filter."@en . .