Water Conditioning & Purification Magazine

WQA Expands the Arsenic Issues

By Henry Nowicki, Ph.D., and Barbara Sherman

Our goal in this article is to be a messenger for some of the “new facts and ideas” about the arsenic problem in drinking water supplies presented at the Water Quality Association (WQA) Convention & Exhibition in New Orleans, March 5-9, 2002. The WQA’s presenters and vendors did an excellent job in educating conference attendees and brought in many experts from different disciplines on the arsenic issues. About 16 hours of continuing education was available on the subject. The interconnectivity of experts from several scientific areas brings to mind a quote from famous naturalist John Muir: “When one tugs at a single thing in Nature, he finds it hitched to the rest of the Universe.”

Importance of regulations
What a difference an official new federal regulation makes on speaker presentations, vendor and conference attendee participation. At an April 2001 NSF International conference, much momentum was moving on the drinking water arsenic problem until President George W. Bush delayed the final new maximum contaminant level (MCL) and called for the re-evaluation of studies used to justify the 10 parts per billion (ppb) MCL.1 It wasn’t until Oct. 31 that we actually got the final rule for the new MCL, which was lowered from 50 ppb. Regulation appears to be critical in driving this subject. Now, everyone appears to be pulling together to meet the January 2006 mandatory compliance date.

Firms supplying solutions to the problem now have a few years to develop products to see who gets the market share for solving customer problems. Many new product claims will be tested and evaluated in the future. A number are already on the market. Presently, no one has the universal simple low-cost fix to the problem. It has a wide variety of solutions because of the complexity of the hydrochemistry of arsenic and the importance of the water matrix to be treated. The consensus of opinion is that one vendor product won’t solve all problems and several products or product combinations may be required.

Unfortunately, many think arsenic isn’t a U.S. problem because our drinking water concentrations are relatively low compared to more critical areas such as Bangladesh, India and Taiwan. The human health effects from drinking water contaminated with arsenic, due to natural geology or manmade pollution, depends on the general health of the exposed population. The arsenic problem has long been ignored because it’s been difficult to address. In the 1600s, there’s good evidence arsenic may have caused the deaths of more than 90 percent of the original settlers in Jamestown, Va.2 Not until 1942 did the U.S. government promulgate a regulation of arsenic in drinking water. The 50 ppb limit stood until the Clinton Administration made it 10 ppb. The Bush Administration’s delay of this new MCL helped to raise the public awareness and confirm the need for a lower MCL. The original Clinton compliance date—as set by the 1996 Reauthorization of the Safe Drinking Water Act (SDWA)—hasn’t changed.

Need for lab testing
Vendors are supplying a wide variety of remediation technologies. The identification of the natural forms of arsenic (As III and As V) and the matrix components in the contaminated water will be needed to determine the best technology to solve individual drinking water arsenic problems. Often, between the time of sampling and laboratory analysis, there’s a large conversion of As III to As V—the first being more soluble and more difficult to remove, the second more of a precipitate form and more easily filterable. Thus, sample preparation methods are needed to preserve the actual natural species and concentrations at each sampling site. The best sampling preservative appears to be EDTA and acetic acid. The EDTA ties up the iron in the water and thus decreases conversion to As V. This species is the easiest to treat and less toxic form of arsenic; As III is more difficult to treat and about 60 times more toxic than the As V species.

Municipalities and individuals need to test their water to determine the arsenic species and concentrations as well as the matrix of competing ions and the pH. The individual water quality will determine the best technology to solve the individual’s problems. There are many available products for arsenic remedia-tion but not a single one product that solves all of the different water types. Testing information will also help specify the treatment sizing and filter change-out frequency.

Annual arsenic testing by municipalities with inclusion in Consumer Confidence Reports this July is mandated by the SDWA. Wisconsin regulators pointed out that wells previously tested arsenic negative are now positive and reaching 1,500 ppb. These levels in the drinking water are believed to cause observed skin lesions. The regulators reported skin lesions that are typical for millions in lesser-developed countries. They attributed the changes in aqueous arsenic going positive to lowering of the water table. Falling groundwater levels are a common global phenomena. The Wisconsin case had lowered groundwater coupled with atmospheric oxygen oxidation of rock-exposed, sulfur-bound compounds to sulfuric acid. This phenomena was described as causing the high arsenic levels in wells that previously tested negative. Leaching of rock-bound arsenicals can occur by many different chemical and mechanical processes.3 Geologists, microbiologists and other scientific experts will play important roles in elucidating the pathways and chemistries for arsenicals. It was pointed out that areas near volcanoes, which provide rich agricultural resources, may also provide fine grain arsenic dust that becomes water soluble, i.e., the Bangladesh case.

Subsurface bioremediaton of pollutants sometimes use oxygen or hydrogen releasing compounds to stimulate the activity of selected microorganisms. The environmental impact of this practice on the arsenic hydrochemistry should be studied. Where oxygen has been added to groundwater, arsenic compounds should be determined. We need to know if this causes problems similar to those in the Wisconsin case.

Geochemists estimate that the average crustal rocks around the world contain about two parts per million (ppm) of arsenic by weight.3 Arsenic bound in rock is harmless; it’s merely a dark stain. But several mechanical and chemical processes can release the rock-bound arsenic to the mobile groundwater phase. These complex detachment mechanisms may account for the spotty and dynamic changes in the presence of dissolved toxic arsenic above the new MCL.

Liabilities and risks
Risks of arsenic exposure globally are at the epidemic level. There has never been a water contaminant to cause this much misery. Arsenic laboratory testing continues to increase the size of the global population affected. In the United States, much testing needs to be done to complete the total groundwater survey for this toxic material. Even drinking water supplies not presently exhibiting this problem need to continue monitoring, as pointed out by the Wisconsin regulators. Property sales in the near future may include arsenic water quality assessments. The public is developing a strong awareness and realtors don’t want the liability.

The arsenic issues will be attractive to legal professionals because of its well-documented, broad-spectrum human toxicity. About 5 percent of the 55,000 U.S. municipal community water supplies don’t currently meet the 10 ppb MCL. Many of the present non-compliant municipalities are small and will have the most problems complying. With their professional staff and budgetary resource limitations, the point-of-use/point-of-entry (POU/POE) solutions become economically the best option. The 1996 SDWA provides the municipal supplier with the POU option by recognizing its efficacy. The U.S. Environmental Protection Agency (USEPA) will need to do some background research to facilitate POU, even with the upcoming budgetary cuts at the agency; however, the municipality maintains the liability because it owns, operates and maintains the POU devices. This option requires the cooperation of homeowners, municipal officials and contractors to install and maintain water supply remediation technologies. While some conclusions can be drawn based on already completed studies, we’re still in the discovery phase of determining what technologies work best with different types of water. The use of large-scale POU devices to comply with legally enforceable drinking water standards hasn’t been done in the past. Many individuals won’t be willing to wait until January 2006. They’ll install POU devices to fix their immediate arsenic problems, as they should.

Conclusion
The arsenic issues will challenge the drinking water industry for several years. The full understanding of arsenic will require many scientists of different expertise to connect and work together. Examples of needed connectivity is expected to come from chemists and biochemists, product developers and manufacturers, third-party product validation and certification experts, risk assessors and toxicologists, geologists and geo-chemists, microbiologists, funding of R&D and financial aid for small communities down to the private well-owner, educating the public about point-of-use devices, water chemistries and others. Synergy obtained from this connectivity and discipline cooperation are expected to facilitate solving this problem and opening the door for many other opportunities for the water conditioning and purification industry.

References

  1. Nowicki, H., “NSF Covers the Arsenic Debate,” WC&P, pg. 38-41, July 2001.
  2. Public Broadcasting Services, “Secrets of the Dead, Death at Jamestown,” July 2001, website: www.pbs.org/wnet/secrets2/case3_clues.html
  3. Morrison, P., and P. Morrison, “No One Checked Natural Arsenic in Wells,” American Scientist, Vol. 90, March-April 2002.

About the authors
Dr. Henry G. Nowicki directs PACS Inc., of Pittsburgh, a laboratory testing and consulting service. He has published over 100 articles about environmental issues and activated carbon adsorption and has been an expert witness in over 30 legal cases. He’s also a member of the WC&P Technical Review Committee.

Barbara Sherman directs PACS short course and focused conference programs. PACS provides 57 different courses and four annual conferences. Four short courses are on activated carbon and PACS hosts the International Activated Carbon Conference in Pittsburgh in September.

Both authors can be reached at (724) 457-6576, email: HNpacs@aol.com or website: www.pacslabs.com

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