How can EPA conclude that the Joint Base Pearl Harbor-Hickam (JBPHH) and Aliamanu Military Reservation (AMR) JBPPH/) public water systems are free of fuel while also acknowledging that there were low level total petroleum hydrocarbon (TPH) detections when conducting drinking water testing?
For bulk measurements of organic compounds, such as TPH, analytical methods may not be designed to distinguish between toxic fuel organic matter and non-toxic organic matter. In addition, TPH detections observed were often below the reporting limits, making it challenging to distinguish between instrument noise at extremely low levels, nearing the detection limit. Instrument noise is random fluctuation occurring in a signal that is inherent in the combination of instrument and method. EPA further discusses the limitations of the TPH analysis in the Drinking Water Assessment Report ( Final Report: Assessment of the Joint Base Pearl Harbor-Hickam and Aliamanu Military Reservation Public Water Systems (pdf) ). EPA's determination is based on a comprehensive "Lines of Evidence" protocol rather than any single data point. Therefore, while TPH detections were observed during the Navy’s Long-Term Monitoring (LTM) and Extended Drinking Water Monitoring (EDWM) programs, detailed forensic analysis of the chromatograms consistently showed that these results did not match the specific chemical signatures of fuel. Instead, these detections are attributed to "analytical artifacts" (e.g., noise) or non-petroleum organic matter.
To further validate these results, during EDWM, the Navy tested select samples with TPH detections above the method detection limit for Polycyclic Aromatic Hydrocarbons (PAHs), which are the most stable components of fuel that remain detectable even after significant weathering occurs. Because these specific fuel indicators are not present and the results do not align with the known behavior of petroleum, EPA concludes that the water continues to meet all federal and state safety standards for human consumption.