Development of Sediment Environmental Reference Materials of the Songhuajiang River in Haerbin

The development of an Environmental Reference Material for the analysis of inorganic elements in stream sediment is described. The stream sediments were collected from the Songhuajiang River in Haerbin and processed as follows: shady-dried, ground, sieved, blended, packed and radiation-sterilized. The homogeneity was verified by analyzing Cu, Pb, Zn, As, Hg, Fe and Al from 18 bottles selected randomly from different strata with sampling at 0.25 g sample size. The results indicate that the sample is homogeneous. Under the preservation conditions of room temperature and avoidance of light, the stability was studied by analyzing Cu, Pb, Zn, As and Hg. Data were treated using a linear model and no instability was observed for the past 15 months. The certified concentration values and uncertainties for 20 inorganic elements and reference values for 1 inorganic element were obtained by statistical analysis of the results from 11 qualified in-network laboratories. The relative uncertainties (k=3) were smaller than 15%. This method has been successfully applied to the determination of inorganics in soils and stream sediments.