Keeping Water Safe To Drink

First Lead, Now Arsenic

Early this year, dangerously high levels of lead in the water supply of Flint, Michigan, made global headlines. Now, it seems, it is California's turn.

A recent report by Washington, D.C.-based Environmental Integrity Project (EIP) says that 95 community water systems that serve nearly 56,000 people throughout California are exceeding the 10 ppb (parts per billion) limit for arsenic in drinking water set by the EPA. ¹ If you are wondering how much 10 ppb is, think of one drop of water in an Olympic-sized pool.

Even that small amount, however, is considered too dangerous for extended exposure, especially for children. Arsenic is a common heavy metal found in the environment.  It is also a known carcinogen and potential cause of many health issues, including neurotoxicity in children as well as bladder, lung, and skin cancers. ²

A Growing Problem

Over the past three years, California has spent millions of dollars to satisfy the arsenic limit in drinking water set by the Clean Water Act. It will now likely spend millions more to assist those 95 communities that simply do not have the funds to underwrite a cleanup. ^{3, 4}

No matter how this environmental issue finally plays out in California, there are lessons for everyone, everywhere. Arsenic is only one of the heavy metals naturally present in our environment. Lead also makes the list, as does mercury, cadmium, thallium, and chromium. All of these elements are important in sustaining life, but they can also be highly toxic through overexposure, as in the cases of Michigan and California.

In another new study based on EPA data, the Environmental Working Group (EWG) reports that Chromium-6—perhaps best known for the dubious starring role it played in the Erin Brockovich story— can be found in higher-than-recommended levels in the drinking water of all 50 states, affecting more than 200 million Americans. The element is classified as a carcinogen with an EPA safety exposure limit of 100 ppb. The State of California, meanwhile, has set a limit of 10 ppb for chromium-6 and a public health goal of 20 ppb. ^{5, 6}

The Complexity Of Heavy Metals

Lead, arsenic, and chromium all exist in primarily two forms. In the case of lead, its inorganic form is more dangerous than its organic state since it is more absorbable by humans. While both organic and inorganic arsenic are potentially carcinogenic, its inorganic form is far more toxic and abundant in water. Trivalent chromium (Cr3+), or chromium in its cationic form, on the other hand, is considered an essential nutrient. Hexavalent chromium (Cr6+), however, exists as an anion, or negatively charged ion, and it is highly toxic to humans. ⁷

Since these elements can exist in various concentrations within a single water sample, one of the biggest challenges scientists have traditionally faced has been to simultaneously detect, separate, and measure these several compounds in a timely and cost-effective way and at a level that meets or exceeds current limits of part per billion.

Matching Tools To The Task

Ion exchange is among the most efficient and definitive methods to determine the speciation levels of chromium, such as the very toxic Cr6+ from the nutrient Cr3, in water. Many labs use the PerkinElmer Altus® UPLC® platform in concert with the company's highly regarded NexION® 350D ICP-MS,  because they allow scientists to detect and differentiate inorganic elements in water at levels as low as 10 ppt (parts per trillion), which far exceeds current standards that call for limits measured in parts per billion. ⁸

PerkinElmer also recently introduced the Avio™ 200 ICP-OES. It is the industry's most compact system designed specifically for this type of application. The Avio™ 200 instrument helps laboratory professionals who are running inorganic analyses and facing an expanding range of sample types to test difficult, high-matrix samples without the need for dilution. In fact, laboratory professionals who need to measure more than one element at a time can leverage the Avio 200 system for multi-element analyses with the same ease of use as atomic absorption (AA), but without the flammable gases.

Meeting the demands of multi-elemental analysis using fast, accurate, and easy-to-use instruments is a never ending process of improvement. To meet these demands, PerkinElmer continues its more than 75-year commitment of manufacturing analytical instruments that labs around the globe rely every day on for their quality, stability, and ability to help make scientists make our world a safer place for all of us.

The PerkinElmer instruments included in this article are for research purposes only.  Not for use in diagnostic procedures.

References

1. Tom Pelton, Courtney Bernhardt, and Eric Schaeffer, "Arsenic In California Drinking Water," Environmental Integrity Group, September, 2016, accessed October 24, 2016.
2. Agency for Toxic Substances and Disease Registry, "Toxic Substances Portal: Arsenic," ATSDR, U.S. Department of Health and Human Service, accessed October 24, 2016.
3. WKCBS, "Study: Illegal Arsenic Levels In Drinking Water Of Thousands Of Californians," CBS News Report, September 12, 2016, accessed October 24, 2016.
4. Ada Carr, "Nearly 56,000 Californians Exposed to Arsenic in Drinking Water, Study Says," Weather.com, September 15, 2016, accessed October 24, 2016.
5. Courtney Norris, "What Is Chromium-6 And How Did It Infiltrate America's Drinking Water?," PBS NEWSHOUR, September 21, 2016, accessed October 24, 2016.
6. Helmut Ernstberger, Ken Neubauer, "Chromium Speciation In Drinking Water By LC-ICP-MS," PerkinElmer Application Note, 2015, accessed October 25, 2016.
7. Kenneth Neubauer, Wilhad Reuter, Pamela Perrone, "Chromium Speciation In Water By HPLC/ICP-MS," PerkinElmer Application Note, 2003, accessed October 24, 2016.
8. Ibid.