If the Reporting Level is Much Lower Than Common Metals, What Does That Mean for 1,2,3-TCP?
The federal occurrence survey for the Mayaguez public water system in Puerto Rico shows no detections of 1,2,3-trichloropropane, also known as TCP, above the reporting threshold of 0.03 micrograms per liter (0.03 parts per billion). This threshold is thousands of times lower than typical reporting levels for metals like lead or copper, reflecting the advanced sensitivity required to measure chlorinated solvents. A measurement below this level indicates that any TCP present is very low and may be difficult to detect with routine testing. Understanding this is key in evaluating whether specialized treatment is needed for household water.
If This Chlorinated Solvent Was an Ingredient in Soil Fumigants from the 1950s to 1980s, How Did It Reach Groundwater Today?
1,2,3-TCP historically appeared as an impurity in soil fumigants used decades ago. Although its use was discontinued, this chemical can persist in the environment due to slow degradation. Over time, it migrated through soil layers into deep groundwater wells that supply public water systems. The lag between contamination and detection means legacy sources continue to be relevant for current water quality decisions, especially in areas with past agricultural fumigation.
If California Sets a 5 Nanogram per Liter Limit but No Federal MCL Exists, How Should Puerto Rico Residents Interpret This?
California enforces a stringent health-based limit of 5 ng/L (5 parts per trillion) for 1,2,3-TCP, a level much lower than the federal reporting threshold. The absence of a federal maximum contaminant level means the EPA has not set an enforceable limit for TCP in drinking water nationally. The Mayaguez water system records no health-based violations, indicating EPA monitoring has not found concerning levels. Residents in Puerto Rico should recognize that federal standards rely on different criteria than California’s precautionary limit, which affects how treatment needs are assessed.
If You Are Choosing Treatment Equipment, How Can You Judge the Capacity Against Household or Facility Demand?
Choosing between classes of water-treatment equipment for 1,2,3-TCP involves considering the volume of water used daily. A household typically requires equipment sized for flow rates and contaminant loads that correspond to its daily water consumption. The treatment technology must have documented effectiveness for chlorinated solvents like TCP at the expected usage levels. Equipment that ships ready to configure with documented capacity matching household demand can provide targeted control without oversizing. Evaluating capacity against demand helps optimize effectiveness and operational efficiency.
If 1,2,3-Trichloropropane Enters Groundwater or Distribution in Mayaguez, What Are the Likely Sources?
In the Mayaguez service area, 1,2,3-trichloropropane would most likely originate from historical soil fumigants used in agriculture or industrial solvents leaking decades ago. Even though no detections above the reporting level occurred in recent monitoring from 2013 to 2016, the risk of trace levels entering groundwater or the distribution network remains a concern given the chemical’s persistence. Public water systems routinely monitor these occurrences to inform water quality management and public health protection.
Summary
The EPA’s unregulated contaminant monitoring data for the Mayaguez public water system in Puerto Rico show no detections of 1,2,3-TCP above 0.03 micrograms per liter, with zero health-based violations recorded. This federal monitoring reflects conditions across the system, not individual homes. Selecting water-treatment equipment for residential use requires evaluating capacity relative to household demand and understanding that TCP persists mainly as a legacy contaminant from mid-20th-century agricultural fumigation. For households seeking to address potential chlorinated solvent presence, the Fleck 1,2,3-TCP Filter offers a documented approach to managing this constituent.
The source for this information is the EPA SDWIS public water system records at https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2016-12-13. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Mayaguez (PR0003283), PR: 52 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level