Given a known source of PFAS release or a suspected source based on the facility type, SAWGraph can leverage hydrological features to trace downstream of the contamination. This use case is particularly relevant for surface water contamination, as PFAS can be transported downstream from industrial facilities via rivers and streams. Visualizing the downstream test results can indicate the extent of the water contamination and also the varying impact on different aquatic species. By tracing downstream of suspected sources, SAWGraph can help identify areas that may be at risk of contamination and prioritize testing and remediation efforts.
This example traces downstream of Converted Paper Manufacturing Facilities, to examine the pattern in downstream samples of fish and water.
This query begins by locating all Converted Paper Manufacturing Facilities from the FIO graph based on the NAICS code (naics:NAICS-IndustryGroup-3222).
Next it gets hyf:HY_FlowPath (stream reaches) that are in the same S2 Cell as the Facilities using the Hydrology graph. From the stream reaches, it finds connected downstream reaches by following the hyf:downstreamWaterbody links in the Hydrology graph
The last step is to find samples that are in the same S2 Cells as the downstream reaches, and get all the sample properties including the test results for each chemical for the sample types of interest.
In Maine only one of the river systems that is downstream from Converted Paper Manufacturing Facilities has had repeated testing of surface water and fish tissue samples. The Kennebec River does demonstrate high PFAS levels that diminish as you move downstream, however it is worth noting that Converted Paper Manufacturing is only one of the sources of PFAS that have contributed to this river system. Nevertheless this type of query demonstrates how researchers could test new hypotheses based on suspected sources of PFAS contamination, and existing test results.
A further demonstration and code for this query is available here