In accord with the overall mission of the National Bureau of Standards to provide standards of measurement and means for making measurements consistent with those standards, NBS scientists are participating in the EPA administered program on environmental aspects of energy production and use by developing measurement methods and Standard Reference Materials (SRM's) for water pollution monitoring. Projects currently underway include the development of an SRM consisting of eighteen trace elements in water, the development of methods for the measurement of trace elements in sea water, the development of SRM's for the measurement of organic compounds in water and sediment and the development of methods for measuring polar organic compounds in water and for coupling liquid chromatography with mass spectroscopy for the identification of organic compounds in water. Methods for determining the chemical form (speciation) of trace elements in water are being investigated as are methods for determining the depth profile of trace elements in individual sediment particles using ion microprobe analysis.