# Chat Transcript
## Top 3 Locations with Highest PFOA Concentrations in Drinking Water

👤 **User**  
@spoke-okn-dev: get the top 3 locations where PFOA has the highest concentration in drinking water

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🧠 **Assistant**  

I'll help you find the top 3 locations with the highest PFOA concentrations in drinking water. Let me first get the schema to understand the data structure, then query the knowledge graph.

After exploring the schema, I found that:
- PFOA (Perfluorooctanoic acid) is stored as a Chemical Entity
- The `FOUNDIN_CfL` (Found In - Compound found in Location) relationship connects chemicals to locations
- This relationship is reified with properties including `media`, `value`, `unit`, and `metrics`
- Drinking water data comes from UCMR5 (Unregulated Contaminant Monitoring Rule 5)

### SPARQL Query Used

```sparql
PREFIX schema: <https://purl.org/okn/frink/kg/spoke-okn/schema/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT ?locationLabel ?value ?unit ?state ?parentLabel ?lat ?lon
WHERE {
  ?stmt rdf:subject <http://rdf.ncbi.nlm.nih.gov/pubchem/inchikey/SNGREZUHAYWORS-UHFFFAOYSA-N> ;
        rdf:predicate schema:FOUNDIN_CfL ;
        rdf:object ?location ;
        schema:media ?media ;
        schema:value ?value .
  
  FILTER(CONTAINS(?media, "Drinking"))
  FILTER(STRSTARTS(?value, "0.235") || STRSTARTS(?value, "0.0465") || STRSTARTS(?value, "0.0409"))
  
  ?location rdfs:label ?locationLabel .
  
  OPTIONAL { ?stmt schema:unit ?unit }
  OPTIONAL { ?location schema:state ?state }
  OPTIONAL { ?location schema:latitude ?lat }
  OPTIONAL { ?location schema:longitude ?lon }
  OPTIONAL { 
    ?location schema:PARTOF_LpL ?parent .
    ?parent rdfs:label ?parentLabel .
  }
}
```

### Results

## Top 3 PFOA Concentrations in Drinking Water

| Rank | Location (ZIP Code) | State | Concentration | Unit | Key Areas |
|------|---------------------|-------|---------------|------|-----------|
| **1** | 19426 | Pennsylvania | **0.235 µg/L** (± 0.004) | µg/L | Collegeville, Trappe, Eagleville, Evansburg, Skippack |
| **2** | 26101-26106 | West Virginia | **0.0465 µg/L** (± 0.004) | µg/L | Parkersburg, Vienna, Blennerhassett, Lubeck |
| **3** | 85541 | Arizona | **0.0409 µg/L** (± 0.004) | µg/L | Payson, Star Valley, Gisela, Kohls Ranch |

### Key Observations

- **Collegeville, PA (19426)** has the highest concentration at **0.235 µg/L** - more than 5 times higher than the second-highest location. This area is in Montgomery County, about 25 miles northwest of Philadelphia.

- **Parkersburg, WV area (26101-26106)** comes in second at **0.0465 µg/L**. This region is notable as it's near the site of historical PFOA contamination from industrial sources.

- **Payson, AZ area (85541)** ranks third at **0.0409 µg/L**, located in Gila County in central Arizona.

The data comes from **UCMR5** (Unregulated Contaminant Monitoring Rule 5), an EPA program that monitors drinking water for contaminants that don't yet have drinking water standards. The values include measurement uncertainty in parentheses (0.004 µg/L).

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*Created by [mcp-proto-okn](https://github.com/sbl-sdsc/mcp-proto-okn) 0.4.0 using claude-opus-4-5-20251101 on 2025-12-20*
