Current pollution source identification methods focus on tracking bacteria associated with the human gut, but many of these bacterial indicators also thrive in the environment and reside in multiple other mammalian hosts. It is now widely accepted that coliform bacteria are unreliable for source tracking due to their ability to survive for extended periods of time in the environment, making it difficult to distinguish the source or timing of a contamination event. This project proposes a new approach for precise source identification through human mitochondrial hypervariable region II DNA which is a new and potentially transformative approach to combating fecal contamination in drinking water.
The proposed work extends the PI's recent human mitochondrial hypervariable region II source tracking study to a particularly unique and important ecosystem the coastal waters of Lord Howe Island (Australia). Lord Howe Island is recorded as a UNESCO world heritage site of global natural significance with a relatively small population (less than 1000) and is slated to undergo renovations to an aging septic wastewater infrastructure. The benefits of this sampling location are 3 fold: 1) a limited population should produce a tractable number of human mitochondrial hypervariable region II sequences, enabling a more discrete linkage between human waste source and coastal water contamination, 2) identifying impacting septic tanks will enable cost effective remediation for resource limited residents of Lord Howe Island, and, 3) Lord Howe Island is an ecosystem of global significance. The hypothesis of this proposal is that sequencing human mitochondrial DNA from impacted environmental water can definitively source and quantify pollution contributors. Unlike ambiguous bacterial assays, conclusive sourcing will enable mitigation of waste related sources and health risks. That is, human mitochondrial DNA enabled source identification can be achieved through sequence information found in the human mitochondrial hypervariable region II region, an approach more commonly used in criminal forensic analysis and anthropologic phylogenetics.
