Uncertainty Resolved... Accurately Detecting 'Group 1 Carcinogen' in Playground Sand Where Children Play [Reading Science]

KRISS and Pohang Accelerator Laboratory Develop First Certified Reference Material for Hexavalent Chromium Measurement

It is now possible to more accurately detect hexavalent chromium, a Group 1 carcinogen hidden in groundwater and playground sand. A scientific solution has been presented to address measurement errors, which have long affected the reliability of environmental test results.

Not related to the article content. Getty Images

The Korea Research Institute of Standards and Science (KRISS) announced on January 28 that it has developed a certified reference material (CRM) of diatomaceous earth for precise measurement of hexavalent chromium content in environmental samples, in collaboration with the Pohang Accelerator Laboratory (PAL). This reference material serves as a standard that allows environmental analysis agencies to objectively verify and calibrate the accuracy of their measurement results.

Manufacturing process of diatomaceous earth powder certified reference material (CRM) for hexavalent chromium analysis. Commercially available diatomaceous earth powder was first sieved, then trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) were added. The sample was homogenized through freeze-drying and repeated sieving. Subsequently, to maintain stability, the sample was aliquoted and packaged under an argon (Ar) atmosphere. Provided by the research team

No Standard Criteria in the Field Despite Varying Measurements

Hexavalent chromium is a highly toxic and oxidative substance designated as a Group 1 carcinogen by the International Agency for Research on Cancer. It can be detected not only in industrial facilities but also in groundwater, soil, and living spaces, and is therefore strictly regulated under domestic environmental management laws.

However, there have been ongoing concerns that, even when measurement results for hexavalent chromium differed between environmental testing agencies, there was no standardized criterion for objective comparison or verification. This has limited the ability to ensure analytical accuracy and consistency.

Conventional analysis of hexavalent chromium has relied on wet chemical methods, which dissolve solid samples into solution. During this process, chemical species transformation can occur, causing hexavalent chromium to change to other oxidation states, leading to repeated underestimation of the actual content.

The joint research team from KRISS and the Pohang Accelerator Laboratory applied synchrotron X-ray absorption spectroscopy (XAS) to the development of the hexavalent chromium CRM to address these issues. By using synchrotron X-rays that are hundreds of millions of times brighter than sunlight, they directly detected the unique energy absorption signals of hexavalent chromium without destroying the sample, fundamentally eliminating analytical errors that occurred during sample pretreatment.

Research team for the development of Certified Reference Material (CRM) of diatomaceous earth powder for hexavalent chromium analysis. From the front row left, clockwise: Hana Cho, Principal Researcher at KRISS; Giwon Gong, Engineer at Pohang Accelerator Laboratory (PAL); Sungwoo Heo, Head of Inorganic Measurement Group at KRISS; Youngran Lim, Principal Research Engineer; Sangyeop Hong, Senior Engineer; Seonhee Choi, Principal Researcher at PAL. Provided by KRISS

Achievement Realized as a 'Measurement Standard' for Practical Use

This achievement is significant in that it has been realized as a national measurement standard (CRM) that can be immediately used in the field. Rather than remaining at the laboratory stage, the research results have been completed as a reference material that environmental analysis agencies can use in actual measurement processes.

Through this, environmental analysis agencies can independently verify the accuracy of their equipment and analytical methods, and the reliability of groundwater and soil contamination monitoring is also expected to improve significantly.

This CRM is expected to serve as a foundation for enhancing the credibility of national environmental policies, while also helping domestic export companies secure analytical reliability in response to global environmental regulations such as the European Union's Restriction of Hazardous Substances (RoHS) directive.

Sungwoo Heo, Head of the Inorganic Measurement Group at KRISS, stated, "By applying the accelerator to measurement standards research, we have achieved a breakthrough in overcoming the limitations of conventional analysis methods. This CRM, which guarantees accuracy and reliability, will become an essential standard in future environmental analysis practices."

This research was supported by the basic program of KRISS, and the developed diatomaceous earth certified reference material can be purchased through the KRISS Standard Performance Fair.