Determination of arsenic and mercury in various environmental matrices by chemical neutron activation analysis

Chemical neutron activation analysis was developed for determining trace am ounts of arsenic and mercury in a variety of environmental matrices, includ ing water, sediment, rock, plants, animal organs, etc: The adsorption proce dure via magnesium oxide as the agent was applied to preconcentrate arsenic from the digested environmental matrices where arsenic in the form of As(V ) ion could be highly efficiently adsorbed by hydrous magnesium oxide. On t he other hand, the extraction procedure via lead diethyldithiocarbamate as the agent was applied to preconcentrate mercury from the digested environme ntal matrices where mercury in the form of Hg(I) ion could be highly effici ently extracted into the solution of lead diethyldithiocarbamte in dichloro methane. Both of the preconcentrated materials prepared ultimately in the s olid states, i.e., arsenic in magnesium oxide and mercury in lead diethyldi thiocarbamte were taken to be neutron irradiated. The gamma spectra of the preconcentrated samples irradiated generally showed clear peaks of the prod uct radionuclides from arsenic or from mercury by the different separation procedures. The possible interfering elements such as Na, Br, etc., were pr ominently minimized in respect of most of the preconcentrated samples. The reliability and accuracy of the proposed analytical methods for detecting a rsenic and mercury can be confirmed by the assay of commercial standard ref erence materials including sediment, rock, plants, and animal organs.