A number of chemical analyses of environmental samples have been carried out in laboratories.  Unfortunately, the data possess lower reliability because there is a lack of appropriate standard reference materials.

National Institute for Environmental Studies (NIES) has developed Certified Reference Materials (CRMs) for such environmental analyses.  NIES has been preparing and distributing environmental and biological Certified Reference Materials for the past 20 years.  At present, 14 CRMs are available (including 1 CRM which cannot be sent overseas).