How did a soil fumigant impurity from the 1950s-1980s reach deep groundwater decades later?
1,2,3-trichloropropane (TCP) is a chlorinated solvent originally found as an impurity in soil fumigants used primarily from the 1950s through the 1980s. These chemicals were applied to agricultural fields but, over time, TCP leached through soil layers, reaching groundwater reservoirs. Its persistence and chemical stability allow it to remain in subsurface water long after its use ceased. In Kauai County's Lihue-Kapaa area, the source water for the public water system is surface water, which can contain runoff from nearby lands. Historical usage patterns and regional hydrogeology contribute to TCP presence in this system’s supply.
Why does 1,2,3-trichloropropane resist air stripping, and what does that mean for treatment choice?
TCP is resistant to air stripping due to its low volatility and its chemical properties that prevent it from easily evaporating into the air phase. This means that conventional aeration-based treatment methods often used for removing volatile organic compounds will not effectively reduce TCP levels. Consequently, water treatment approaches relying on adsorption or advanced filtration methods are typically necessary. Equipment designed specifically for TCP addresses this resistance by targeting the molecular characteristics of the contaminant rather than relying on volatilization.
How to judge treatment capacity against the household's or facility's daily demand?
Choosing equipment for treating 1,2,3-TCP requires matching the device's capacity to the household’s or facility’s daily water usage. Treatment units have throughput limits indicating the volume of water they can effectively process before maintenance or media replacement is required. Estimating your daily water consumption helps determine which equipment size or model is appropriate for continuous efficient performance. Undersized equipment may lead to reduced effectiveness or more frequent media changes, while oversized units could be unnecessarily costly and space-consuming. Assess your household’s peak and average daily water use to select a suitable option.
What distinguishes this problem from the two problems most often confused with it?
TCP contamination can be visually and analytically mistaken for other water quality issues such as general chlorination byproducts or agricultural pesticides. Unlike some pesticides, TCP is a chlorinated solvent impurity without a federal maximum contaminant level (MCL). This differs from taste or odor problems caused by other chemicals. Also, some water problems stem from plumbing materials or corrosion that TCP presence does not indicate. Therefore, understanding that TCP is a discrete chlorinated compound helps avoid misdiagnosis of the water issue and the inappropriate selection of treatment methods.
How many samples and wells stand behind the figures, and what does a small sample mean?
The EPA’s Unregulated Contaminant Monitoring Rule (UCMR3) data for the Lihue-Kapaa public water system, collected from July 2014 to July 2015, includes 45 samples analyzed for 1,2,3-TCP. Of these, 5 showed detections above the reporting level (0.03 micrograms per liter). The highest detected concentration was 0.086 micrograms per liter, with a median of detections at 0.055 micrograms per liter. This data represents the public water system’s source and not individual household wells. Because the sample size is moderate and focused on system-level monitoring, individual homes with private wells may have different conditions. A small number of detections relative to total samples indicate the presence of TCP is limited but measurable in the system’s water supply.
What is the single test the reader should order, and what result would settle the question?
The best way to confirm your home’s actual 1,2,3-trichloropropane level is to request a certified laboratory test specifically for TCP. This test analyzes your household water source and plumbing to determine if TCP is present and at what concentration in micrograms per liter (µg/L or ppb). A result below the reporting or detection limit would effectively rule out TCP as a concern in your water. If TCP is detected, the result will guide you in choosing suitable water treatment equipment. For households in Kauai seeking treatment designed explicitly for 1,2,3-TCP, the Autotrol 1,2,3-TCP Filter ships ready to configure and is engineered to address this chlorinated solvent's characteristics, offering a tailored option for this particular challenge.
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