Why the Reporting Level for This Solvent Is Thousands of Times Lower Than for Common Metals
The reporting level for 1,2,3-trichloropropane (TCP), a chlorinated solvent, is set at 0.03 micrograms per liter (µg/L), or parts per billion, which is far lower than common metals often measured in water. This is because TCP is a synthetic chemical found in trace amounts and its detection at very low concentrations helps track its presence before any health-based legal limits might be established. Metals like lead or arsenic have reporting levels measured in much higher amounts due to their different chemical properties and risk profiles. This low threshold does not indicate hazard at these levels; it is a precautionary measure to monitor a contaminant that was historically used as a soil fumigant.
How a Soil Fumigant Impurity from the 1950s-1980s Reached Deep Groundwater Decades Later
TCP entered water systems primarily as an impurity in fumigants used in agriculture from the mid-20th century until the 1980s. Because of its chemical persistence, it migrated slowly through soil, reaching groundwater and surface water over time. Even though Sheridan's water comes from surface sources, TCP’s history as a persistent pollutant means it can be detected years after its use ended. Government sampling in Sheridan's public water system found no detections above the reporting level during the last federal survey period.
What Changes for a Large Household, a Second Home, or a Seasonal Property
Households with varying occupancy patterns may experience different water use profiles that affect treatment needs. Larger households or homes with more water use might require more frequent regeneration or maintenance of treatment media to keep performance steady. Seasonal or second properties that are unused for parts of the year require care to prevent stagnation and ensure treatment media remain effective when the home is occupied again. Understanding your household’s water demand helps in selecting the right capacity and type of treatment equipment to handle chlorinated solvents like TCP efficiently.
Which Fixtures, Appliances or Processes Are Affected First and Why
The presence of 1,2,3-TCP in water does not typically cause immediate aesthetic issues like taste or odor changes, but it can impact certain sensitive uses. Appliances such as water heaters and ice makers, as well as fixtures like faucets and showers, may be the first points of regular contact with treated water. Treatment focus may center on whole-house water quality because TCP is a contaminant best addressed before the water reaches these endpoints, maintaining water safety for ingestion and skin contact. Point-of-use filters catch only part of the water supply and may not fully address TCP exposure.
Why Aesthetic Secondary Standards Differ from Health-Based Limits, Applied to This Constituent
Aesthetic secondary standards govern factors like taste, odor, and staining, which do not imply health risk but affect consumer satisfaction. For 1,2,3-trichloropropane, no aesthetic thresholds are set because it is a colorless, odorless compound at trace levels. Health-based limits, which have not yet been federally established for TCP, focus on potential long-term risks at higher concentrations. Sheridan's public water system has no recorded health-based violations related to TCP, reflecting concentrations below levels necessitating regulatory action.
What 'Detected', 'Median' and 'Range' Mean in the Sampling Record on This Page
In the context of Sheridan’s public water monitoring, 'detected' means that a measurement instrument has found TCP at or above the reporting level of 0.03 micrograms per liter, the threshold for noting the presence of this contaminant. The 'median' is the middle value of all measurements collected, representing a typical level observed. 'Range' details the span from lowest to highest detections recorded. Sheridan’s system documented no detections above the reporting level for TCP, indicating that if present, the chemical is at or below trace amounts undetectable by the monitoring method used. This data pertains to the water system as a whole, not to individual household taps.
What You Should NOT Conclude from Area Data
Area-wide data showing no detections above the reporting level for 1,2,3-TCP does not guarantee the absence of TCP in any specific home’s water. Your household water quality can only be confirmed by a specialized test of your tap or well. Additionally, the lack of a federal maximum contaminant level (MCL) means there is no enforceable limit to compare your own testing results against, so treatment decisions should be based on your personal risk tolerance and test outcomes rather than solely on public system data.
For households in Sheridan considering how to address TCP, a treatment option such as the Autotrol 1,2,3-TCP Filter, which ships ready to configure, offers technology documented to reduce trace levels of this chlorinated solvent. Choosing the right category of treatment depends on confirmed water test results and household water use characteristics.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-04-15. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for City of Sheridan (WY5600052), WY: 8 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level