This week, Kauai households face a key choice: to investigate the presence of 1,2,3-trichloropropane, commonly called 1,2,3-TCP or TCP, in their water and consider treatment options based on regional data. Understanding the background and treatment principles will aid in making an informed decision.
Agricultural Land-Use History Mapped to 1,2,3-TCP Detections in Lihue-Kapaa
Kauai County’s Lihue-Kapaa water system draws from surface water sources serving over 34,000 residents. Historical agricultural practices, especially those involving soil fumigants used from the mid-20th century, contribute to the presence of 1,2,3-TCP in water bodies. Government monitoring of this public water system recorded 45 measurements of 1,2,3-TCP between 2013 and 2015, with detectable levels above the reporting threshold in 5 samples. These detections, up to 0.086 micrograms per liter (µg/L), align with known transport of legacy fumigant impurities through soil and water pathways. However, these findings reflect system-wide conditions, not the quality of water at any individual household connection.
Resistance of 1,2,3-Trichloropropane to Air Stripping and Implications for Treatment Selection
1,2,3-TCP is a chlorinated solvent characterized by chemical stability that limits its removal by air stripping techniques. Air stripping typically targets volatile organic compounds that readily transfer to the air phase, but TCP’s low volatility hinders this mechanism. Consequently, treatment approaches for TCP require adsorption or specialized filtration technologies designed to target stable chlorinated compounds. For households considering options, filters designed to address 1,2,3-TCP provide a practical solution capable of addressing the chemical’s persistence.
Distinguishing Aesthetic Secondary Standards From Health-Based Limits in the Context of 1,2,3-TCP
Regulatory standards distinguish between health-based maximum contaminant levels (MCLs) and aesthetic secondary standards that address taste, odor, staining, and corrosivity. For 1,2,3-TCP, the EPA has not established a federal MCL, and no health-based violations are recorded for the Lihue-Kapaa system. Detected concentrations are below levels known to trigger federal health-based actions. Some states, such as California, have set non-federal limits solely for precautionary or additional risk management purposes, which do not imply unsafe water but guide treatment decisions. For consumers, it is important to understand these distinctions when assessing water quality reports and potential treatment needs.
Additional Considerations for Commercial or Industrial Operators Compared to Household Users
Commercial and industrial water users often face additional questions about 1,2,3-trichloropropane related to process water requirements, equipment compatibility, and regulatory compliance beyond residential concerns. These users may require more frequent or detailed sampling and consider the impact of TCP on manufacturing or agricultural processes. Households typically focus on drinking water quality and the practicality of filtration solutions. This difference simplifies residential decision-making, centering it on water testing and effective filtration, without the broader operational considerations.
Comparing California’s 5 Nanogram per Liter Limit to the Lack of a Federal MCL
California's state limit for 1,2,3-TCP stands at 5 nanograms per liter (ng/L), equivalent to 0.005 µg/L, significantly lower than the maximum level detected in Lihue-Kapaa’s system sampling. Unlike OSHA or EPA federal standards, California’s limit is a state-driven precautionary guideline without federal enforcement. In contrast, the EPA’s absence of a federal MCL reflects ongoing evaluation of TCP’s health impacts and occurrence patterns. Consumers benefit from knowing that current federal records report no health-based violation for their water system, while state limits may inform decisions toward conservative water treatment choices.
The critical step for Kauai households is to obtain a specific test of their own home's water for 1,2,3-TCP. This analysis will establish their actual exposure level rather than rely solely on system monitoring data. If TCP is detected at elevated levels in a household sample, using an Autotrol 1,2,3-TCP Filter, which ships ready to configure, may be the documented solution capable of addressing the chlorinated solvent effectively. This approach empowers residents to proceed based on concrete results rather than assumptions drawn from regional data.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-07-31. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Lihue-Kapaa (HI0000400), HI: 45 results across 1 listed contaminants, 5 detections above the reporting level; no federal MCL
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