Opening: What EPA Sampling Indicates About Chromium-6 in Franklin County Water
EPA monitoring from 2013 to 2015 found chromium-6 detected in all 20 samples taken from the Columbus public water system serving Franklin County. Concentrations ranged from just above the reporting limit of 0.03 micrograms per liter (µg/L), or parts per billion (ppb), up to 0.35 µg/L, with a median of 0.195 µg/L among detections. These figures describe the system, not any individual household's tap water, and none exceed federal maximum contaminant levels.
1. Understanding Changes in Chromium Oxidation State from Source to Tap
Chromium exists mainly in two oxidation states in water: trivalent chromium (Cr III) and hexavalent chromium (Cr VI). Hexavalent chromium, or chromium-6, is more mobile and soluble, often found in surface water sources such as those supplying Franklin County. It can undergo chemical changes between source water and tap due to natural processes and treatment steps, affecting the proportion of chromium-6 versus total chromium reaching the household.
2. Sources of Chromium-6: Natural Aquifers Versus Industrial Influences
Hexavalent chromium may originate geogenically from certain aquifers, especially those that are arid and alkaline, releasing chromium-6 naturally into groundwater. However, Franklin County's public water system relies on surface water that can also carry chromium-6 from industrial activities such as metal plating. Understanding this mix helps in evaluating the presence but does not indicate the levels in any specific well or home water supply.
3. Assessing Treatment Capacity for Household Daily Water Demand
When considering equipment to address chromium-6, it is important to match the treatment capacity with the household’s daily water use. Residential demand varies by number of occupants and water consumption patterns. Systems designed to handle typical residential flow rates for chromium-6 ensure effective contact time and consistent performance without unnecessary oversizing or undersizing.
4. Potential Outcomes of Leaving Chromium-6 Untreated Over Time
While the EPA has not established a federal maximum contaminant level specifically for chromium-6, concerns about prolonged consumption have led some homeowners to seek treatment options. Untreated chromium(VI) in household water at EPA-detected levels does not necessarily pose a documented immediate health risk according to federal records. Still, understanding the potential for trace contaminant accumulation informs decisions for long-term water quality management.
5. Sample Size and Its Implications: What 20 Tests Reveal
The available EPA data comes from 20 sample results taken from the public water supply system within Franklin County. This relatively small sample size provides an overview of chromium-6 occurrence in the system but does not capture variability across all taps or times. Therefore, homeowners should recognize the limits of this dataset in predicting their personal water quality.
Closing: The Essential Next Step — Confirm Chromium-6 Levels in Your Tap Water
The definitive way to determine chromium-6 concentration in your household water is through a water test conducted on a sample from your own tap. This test will clarify your water’s chromium(VI) profile and guide your choice among treatment options. The Pentair Chromium-6 Filter ships ready to configure for residential use, designed to effectively address chromium(VI) levels when present. Selecting the appropriate option depends on confirming your household’s specific water quality through testing.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-12-16. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Columbus (OH2504412), OH: 40 results across 2 listed contaminants, 37 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L