How a Soil Fumigant Impurity From the 1950s-1980s Reached Deep Groundwater Decades Later
Legacy Use of 1,2,3-Trichloropropane
1,2,3-trichloropropane (TCP) is a chlorinated solvent that was historically used as an impurity in soil fumigants during farming operations between the 1950s and 1980s. Over time, this compound migrated downward through soils and eventually reached groundwater supplies. This delayed movement means TCP may still be found lingering in groundwater today, even decades after its original application ceased.
Presence in Groundwater Source for Westerly Water
Westerly Water Department’s public water system draws from groundwater sources, meaning any legacy soil contaminants like TCP have potential pathways to the water supply. Federal occurrence data from 2013-2015 show no detections of TCP above the reporting level in this system, indicating that if present, levels are below instrumentation capabilities at 0.03 micrograms per liter (µg/L), or parts per billion (ppb).
Why the Reporting Level for This Solvent is Thousands of Times Lower Than for Common Metals
Stringent Reporting Due to Chemical Properties
The reporting level for TCP is set at a very low threshold—0.03 µg/L—reflecting its classification as an unregulated contaminant with potential health concerns in very low concentrations. This threshold is thousands of times lower than reporting levels for many common metals, which typically appear in water at much higher concentrations and often have established maximum contaminant levels (MCLs).
Implications of the Low Reporting Level
Being detectable at such low concentrations does not mean the water is unsafe or in violation of any federal standard. Instead, this sensitivity allows monitoring programs to track the presence of TCP and inform future regulatory decisions or treatment needs if rising levels are observed.
Which Fixtures, Appliances or Processes Are Affected First and Why
Impact on Household Water Use
TCP, as a volatile chlorinated solvent, can affect household water where it accumulates. Appliances or fixtures that use untreated water, such as ice makers, humidifiers, or reverse osmosis systems without proper filtration, may experience TCP passing through. Additionally, water used in cooking or drinking is of primary concern for residential consumers seeking to limit exposure.
Limitations of Existing Equipment
Homes in Westerly relying on older or less specialized water treatment units may find their equipment unable to keep up with any emerging traces of TCP, as typical filtering methods often do not address this compound effectively. Treatment designed specifically for chlorinated solvents is necessary to address TCP presence if testing confirms levels of concern inside the home.
What Happens When This Problem Is Left Untreated for Years, Stated Without Exaggeration
Potential Long-Term Effects
If chlorinated solvents like 1,2,3-TCP persist in household water without the appropriate filtering technology, they can accumulate over time in appliances and potentially affect water taste or odor. Chronic exposure implications are a subject of ongoing study, and prudent water management involves monitoring and mitigating such compounds where feasible.
Practical Household Considerations
Ignoring the presence of TCP does not cause immediate damage to household plumbing or fixtures, but it may limit water quality satisfaction and could present concerns for users wanting to avoid exposure to synthetic solvents. Testing home water specifically confirms whether TCP is present above negligible levels for targeted treatment.
What the Measured Range Means Against the Relevant Federal Standard, and What It Does Not Mean
Understanding Monitoring Results
Government sampling for the Westerly Water Department found zero detections of 1,2,3-TCP above the reporting limit of 0.03 µg/L during the 2013-2015 EPA occurrence survey. There is no established federal maximum contaminant level (MCL) for TCP, so these findings do not indicate a violation or unsafe condition.
Limitations of Public System Data for Individual Homes
These monitoring results reflect water quality at the public system level, not at any individual tap or well. Home testing is necessary to determine specific concentrations inside residences, as household plumbing and local conditions may vary.
Summary
Public water monitoring in Westerly, Washington County, RI, under EPA’s Unregulated Contaminant Monitoring Rule found no detectable 1,2,3-trichloropropane above the reporting threshold, a sensitive level far below typical metal reporting limits. TCP originated from historic soil fumigant impurities decades ago and can persist in groundwater drawn by the local water system. Existing household equipment may not fully address TCP if present at noticeable levels, so testing home water is essential for personalized treatment decisions. This information pertains solely to the Westerly Water Department’s public water system as documented by EPA records at https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule.
For households concerned about 1,2,3-TCP, the Autotrol 1,2,3-TCP Filter ships ready to configure, providing targeted filtration technology designed to address chlorinated solvents in residential water supplies.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-09-16. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Westerly Water Department (RI1559512), RI: 14 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level