Used as a reference standard in environmental testing to calibrate analytical instruments for detecting polychlorinated biphenyls (PCBs) in soil, water, and air samples. Commonly employed in gas chromatography and mass spectrometry to identify and quantify trace levels of PCB contamination. Essential for monitoring industrial emissions, assessing hazardous waste sites, and ensuring compliance with environmental regulations. Also used in research studies on pollutant persistence and bioaccumulation in ecosystems.