Autotrol 1,2,3-TCP Filter

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1. How a soil fumigant impurity from the 1950s-1980s reached deep groundwater decades later

1,2,3-trichloropropane (TCP) is a chlorinated solvent once used as an impurity in soil fumigants primarily between the 1950s and 1980s. These fumigants were applied to agricultural land, and although their use has ceased, residues of TCP have persisted in the environment. Over time, this compound has leached into surface and groundwater sources in regions like Lihue-Kapaa in Kauai County, Hawaii. The movement of TCP into water supplies is delayed due to slow degradation rates and the depth at which groundwater flows, making it detectable decades after original application.

2. Granular activated carbon contact time: why bed depth matters more for TCP than for taste

When treating water containing trace amounts of 1,2,3-TCP, the method of filtration plays a critical role. Granular activated carbon (GAC) is a common media for adsorbing chlorinated solvents including TCP. Unlike compounds affecting taste or odor, TCP requires longer contact time with the carbon bed because of its chemical structure and low concentrations typical in treated water. This means that the depth of the carbon bed matters significantly; deeper beds allow water to remain in contact with the carbon longer, improving adsorption efficiency and reducing TCP content effectively.

3. How to compare this area's record with a neighbouring county's without overreading it

The public water system record for Lihue-Kapaa, Kauai County, shows that out of 45 sampling results collected from July 2014 to July 2015, 5 detections of 1,2,3-TCP were above the reporting level of 0.03 micrograms per liter (µg/L), with the highest recorded measurement at 0.086 µg/L (equivalent to parts per billion, ppb). Importantly, this system has no EPA health-based violations on record. When contrasting these findings with neighboring counties, it is crucial not to interpret detected levels as an indication that any individual household water supply contains the same or any higher concentration. Differences in sampling methodology, source water type, and land use histories can cause variation in occurrence data.

4. Why aesthetic secondary standards differ from health-based limits, applied to this constituent

The EPA does not currently have a federal Maximum Contaminant Level (MCL) for 1,2,3-trichloropropane, so there are no enforceable health-based limits for this compound in public water systems. Secondary standards exist for parameters such as chloride or total dissolved solids that relate to taste, staining, and corrosiveness but do not apply to TCP. Therefore, a detection of 1,2,3-TCP at or above reporting levels is a measurement of presence, not a measure of safety or risk. Household owners should understand that these detections are not violations or indications of unsafe water according to the public water system’s health compliance record.

5. What happens when this problem is left untreated for years, stated without exaggeration

Without treatment, chlorinated solvents like TCP remain persistent in water because of their chemical stability. Over years, this can result in chronic low-level exposure if an individual’s water supply contains measurable 1,2,3-TCP, though the specific health risk varies depending on concentration and consumption. Since no health-based violation has been recorded in Lihue-Kapaa’s water system, any potential impact on household water would likely come from sources beyond typical municipal supply or plumbing factors. Considering prolonged presence without intervention, consumers may choose filtration methods targeting chlorinated solvents to reduce this compound from their water.

6. How sample depth, well depth or source type changes what a reader should expect

TCP presence varies with water source characteristics. Lihue-Kapaa’s public water system uses surface water, which can be influenced by runoff and land-use patterns, including past agricultural activities. Groundwater wells, particularly those of different depths, may show different levels of TCP depending on the extent of contamination at various soil layers. Household wells drawing from greater depths or different aquifers might have concentrations differing from system-wide public water results. To determine the exact level of TCP in an individual household’s water, a well-specific or tap-specific laboratory test is required.

In response to detected levels in the surrounding system, some households consider direct-purchase options such as the Autotrol 1,2,3-TCP Filter, a water filtration technology designed to target chlorinated solvents in residential water supplies. This system ships ready to configure and can provide an additional measure for reducing TCP content within the home.

All data referenced comes from the EPA’s Safe Drinking Water Information System (SDWIS) for the Lihue-Kapaa public water system and reflect results from a federal unregulated contaminant monitoring survey, not compliance testing. For further information or to review this system’s water quality details, consult the EPA’s public records.

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