Foreword
Pollution C()ntrolBoatds (PCBs) are responsible for a wide variety of environmental observations, many of which are based on measurements of low levels,of toxic/hazardous materials. These ~easurements must be of the highest quality for the PCBs to meet their statutory responsibilities that require data for assessment, predictions, deciding control plans, and prosecutions of the defaulters. Use of reference standards.is the critical part of measurement of high quality. It is, therefore, very important .that PCBs should be aware of the availability of referem:e standards. A review of the existing Indian situation, in this context, reveals that awareness in this regard is less than satisfactory. Sophisticated analytical instruments, such as atomic absorption spectrophotometer, gas liquid chromatograph etc. are often not optimally used for want of these standards. This prompted the Central Pollution Control Board to look for the market availability of the standards. Accordingly, the Board conducted a systematic study to collect, collate and compile information on the global sources of the availability of reference standards of metals and organics. The present report is the outcome of such a study,

I am thankful to theEnvironmcnul1 Protection Agency, USA (US, EPA); National Institute of Standards and Technology (NIST), (USA); Laboratory of the Government Chemist (LaC), UK; Community Bure-au of Reference (BCR), Belgium; Federal Institute for Material Research ~ Testing (BAM), Berlin; and several Indian Laboratories including, National Institute of Oceanography (NIO), Goa and Bombay; National Environmental Engineering Research Institute (NEERI), Nag pur; National Chemical Laboratory (NCL), Pune; Indian Institute of Chemical Technology, Hyderabad etc. for providing useful information for the preparation of this report. Dr. K.R. Ranganathan, Member Secretary, Central Board, reviewed the draft report anQ ~ave usefut suggestions which enabled organised presentation of the c()llected information.

It is hoWd that the document would be useful for the Pollution Control Boards as well as other laboratories involved in the analysis of environmental samples.