Pentek Chromium-6 Filter

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Local Water Supply and Chromium-6 Presence

The City of Martinsburg in Berkeley County, West Virginia, draws drinking water from surface water sources. This water undergoes treatment and distribution to serve approximately 16,250 people through 7,175 service connections. Federal monitoring data from 2013 to 2015 under the Unregulated Contaminant Monitoring Rule (UCMR3) found chromium-6, also known as hexavalent chromium or chromium(VI), present in all samples, with levels ranging up to 2.4 micrograms per liter (µg/L) or parts per billion (ppb). These measurements relate to the water system as a whole and do not measure individual household tap water directly.

How Ion Exchange and Reverse Osmosis Differ in Treating Chromium(VI)

Chromium-6 in water exists as a dissolved ionic form that requires specialized treatment technology to address. Ion exchange treatment targets chromium(VI) by exchanging ions in water with those fixed in a resin medium, effectively capturing the chromium(VI) ions. Reverse osmosis treatment uses a semipermeable membrane to filter out chromium(VI) along with other dissolved contaminants. Both methods differ in mechanism and target scope but share the ability to reduce hexavalent chromium concentrations in water. Each approach has specific operational considerations, but either can prepare a household water point for lower chromium(VI) presence.

Purpose and Limits of UCMR3 Sampling for This System

The 2013-2015 UCMR3 federal monitoring survey aimed to gather occurrence data on unregulated contaminants like chromium-6 across many public water systems nationwide, including Martinsburg's system. The goal was to understand how often and at what concentrations chromium(VI) may appear in municipal water supplies. Importantly, the survey results do not represent compliance testing or individual household water quality assessments. Since the data reflects system-wide sampling, local variations at any single tap could differ. This means the data helps characterize regional and system-level occurrence but cannot confirm the exact concentration in your own home without separate testing.

Distinguishing Chromium-6 from Other Similar Water Constituents

Chromium-6 is one of several chromium forms found in water. The sample data includes measurements of both chromium-6 and total chromium. Total chromium encompasses all chromium oxidation states, including trivalent chromium (chromium-3), which behaves differently in water chemistry and health concerns. Total chromium levels measured were consistently lower than the established maximum contaminant level (MCL) of 100 µg/L, indicating a distinct profile from chromium-6 specific detection. It's important not to confuse chromium-6 with total chromium, as each has different treatment and monitoring implications.

Interpreting Detection, Median, and Range in Sampling Records

The terms used in the EPA sampling records each have specific meanings. A 'detection' means the laboratory instrument found measurable chromium-6 above a minimum reporting level (0.03 µg/L), not that it constitutes a violation or unsafe condition. The 'median' is the middle value of the detected concentrations, showing that half the samples were above and half below this point. The 'range' tells the spread between the lowest and highest detected values. In Martinsburg’s system, chromium-6 was detected in all samples with a median at 1.0 µg/L and the highest measurement at 2.4 µg/L. These details illustrate the typical and maximum observed levels for the system during the survey period.

Changes in Chromium Oxidation State from Source to Tap

Chromium in water can exist in different oxidation states, with chromium-6 being the hexavalent, more oxidized form. Conditions in the source water, such as pH and presence of oxidants or reducers, influence transformation between chromium forms. As water moves from the surface source through treatment plants and distribution mains to household taps, various physical and chemical conditions may alter chromium's oxidation state. For example, some processes or pipe materials may reduce chromium-6 to chromium-3, which has different behavior and health considerations. Understanding these changes helps explain why sampling at different points may show different chromium species and concentrations.

Sources of Chromium-6 in Berkeley County Water

Chromium-6 can enter surface waters from both natural and human activities. Naturally occurring chromium may leach from certain rock formations into groundwater or surface water. Industrial processes, including metal plating, manufacturing, or improper waste disposal, can contribute chromium-6 to the environment. In the Martinsburg area, the presence of chromium-6 in the surface water source indicates it has been detected at measurable levels before treatment. This knowledge underscores the importance of system-wide monitoring and potential point-of-use measures to address chromium(VI) presence.

Key Test to Clarify Your Household Water's Chromium-6 Level

Because the EPA monitoring data reports system averages and ranges, the only way to know the chromium-6 concentration in your specific household water is an independent test of your tap water for hexavalent chromium. This targeted analysis will provide a direct measure of chromium-6 in parts per billion or micrograms per liter, enabling an accurate assessment of your water quality. If the test reports chromium-6 at levels of concern to you, you may consider treatment options designed to reduce chromium(VI), such as the Pentek Chromium-6 Filter. This device ships ready to configure and employs technology suitable to lower chromium-6 concentrations at the point of use.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2014-11-12. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for City of Martinsburg (WV3300212), WV: 32 results across 2 listed contaminants, 32 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L