Study on the selection of indicator parameters in marine water quality evaluation and the evaluation methodology

In order to obtain the indicator types which must be introduced in marine water quality evaluation as well as the suitable evaluation methodology, GB3097-1997 National Marine Water Quality Standards is, in the first place, analyzed to establish a hypothetical sample which is consisting of 2000 stances, each stance containing the information of 21 indicators. And then a stepwise discriminant method is utilized to filter the 21 indicators in accordance with their water quality classification discriminant abilities. And finally, 6 indicators with significant discriminant ability, biochemical oxygen demand(BOD5), oil type(Oil), total phosphorus(P), cadmium(Cd), cyanide(HH) and chemical oxygen demand(COD), are selected and the water quality evaluation chart of the corresponding six indicators is also established. Theoretically, the water quality indicator types and the suitable evaluation methodology, which must be introduced when the water quality evaluation is done in all the waters under the jurisdiction of China, are discussed in this paper, providing theoretical basis for the subsequent marine water quality evaluation based on field observation.