By Rick Andrew
Water Conditioning & Purification March 2013 Water Matters By Rick Andrew I n recent years, a number of scientific studies have identified traces of a variety of contaminants in source water and drinking water that had not been previously detected. These studies, possible in large part due to improved capabilities in analytical detection, have caught the attention of the media and consequently, the attention of health-conscious consumers as well. The compounds, some of which are potentially endocrine-disrupting compounds, are related to pharmaceuticals, personal-care products and other sources that have made their way into source water and drinking water, typically through wastewater. A question that logically follows the detection of these compounds in drinking water and the consumer focus on the issue is whether POU/POE technology will be effective for treatment. This question was brought to the NSF Joint Committee on Drinking Water Treatment Units in 2008.
Task group formed
In response to this issue, the joint committee formed the DWTU Task Group on Endocrine Disrupting Chemicals (EDCs) and Pharmaceutical and Personal Care Products (PPCPs) in mid- 2008. This task group reviewed and assessed the scientific work done in the area as they educated themselves to address it in a technically sound, fact-based manner. Their ultimate goal was to develop a standard to evaluate the capability of POU/POE equipment to treat these compounds at the concentrations being detected in drinking water. The effort became complex for several reasons as the group considered the following issues:
The type of claims to be made—broad category versus specific compound
The simplest, most understandable consumer-friendly claims would be based on broad categories of compounds, such as reduction of pharmaceuticals. This approach avoids potential confusion, such as the name of the compounds compared to how consumers might identify them. Pharmaceuticals, however, covers a huge number of different compounds. One possibility might be to identify specific compounds that could be tested to be representative of broad categories, much like chloroform is used to cover the broad category of volatile organic compounds under NSF/ANSI 53 and NSF/ANSI 58. The complexity with this approach is that many of these compounds are chemically very different from each other, with different properties in water, and would likely react differently to treatment technologies. Additionally, only certain compounds have actually been detected in drinking water. These compounds are also very different in terms of physical activity, or the amount of the compound necessary to cause a physiological reaction.
The type of claims to be made—health effects, aesthetic effects or other
The NSF/ANSI DWTU Standards have traditionally placed contaminants into one of two categories: health effects, for contaminants with known health effects if present in drinking water; or aesthetic effects, for contaminants not affecting health if present in drinking water, but affecting the taste, appearance or odor of the water. Are pharmaceuticals and personal-care products in drinking water at trace concentrations a health risk, an aesthetic issue or something else?
The ability to conduct testing in the laboratory
Laboratory testing for contaminant reduction becomes very difficult when the contaminants are present at trace concentrations. There are two reasons for this. First, it becomes difficult to maintain a stable contaminant reduction challenge. If the compounds break down, adhere to the test apparatus or volatilize, the challenge water can be unstable with too much variation in the concentration of the compounds. Second, it is more difficult and expensive to produce accurate analytical results when the concentrations of the compounds in the water are very low.
Obviously, addressing these complex issues requires technical expertise to achieve a common understanding. The task group utilized expertise from the manufacturing, regulatory, academic and analytical chemistry communities to reach the point where their shared knowledge allowed them to reach a common understanding. The result for the task group was the following guidelines supporting their approach to the standard:
- The claims must be specific compounds as opposed to categories. The idea of identifying specific compounds to test to create a valid claim of reduction of an entire category of compounds is an appealing one, but technically very complex, and requires a massive and well-funded research effort that may require a period of months or even years to complete. This could be a future development for the standard, but was something the task group determined was not immediately achievable.
- The compounds included as potential claims must have been detected in drinking water. There are some risks of consumer confusion with this standard. One of those risks is that consumers will assume that any contaminants that could be treated could actually be present in their drinking water. It would be disingenuous to include claims of contaminant reduction for POU/POE systems for compounds that have never been detected in drinking water.
- The claims are neither health effects nor aesthetic effects. This is, to me at least, one of the most interesting aspects of this standard. The current state of the research on potential health effects of these compounds being present in drinking water An Emerging Standard for Emerging Compounds and Incidental Contaminants Water Conditioning & Purification March 2013 at trace concentrations shows no evidence of health effects. Also, these compounds cannot be seen, tasted or smelled in the drinking water, so there is not an aesthetic issue with their presence at trace levels. What it really comes down to is consumer preference; consumers would simply prefer to not have these compounds present, even though there is no evidence of health effects, nor are there any aesthetic issues. This standard is really creating a new category of contaminant-reduction claim for POU/POE products. And, the task group felt it very important in avoiding consumer confusion to clarify that given the current understanding, the presence of these compounds in drinking water at trace concentrations is not a health risk.
- The testing for contaminant reduction will be conducted at concentrations as close to those detected as technically possible. There was discussion in the task group about potentially conducting the testing at higher concentrations to allow for greater reproducibility and for lower analytical costs. Ultimately, though, the task group determined that testing at higher concentrations may not necessarily represent performance at the concentrations being detected in drinking water. The task group opted to take the more difficult and more expensive path, the one most assured to offer an accurate real-world assessment of true product performance.
These guidelines allowed the task group to move forward and develop a draft of Standard NSF 401. The contaminant reduction claims, influent challenge concentrations and maximum allowable effluent concentrations currently included in the draft are included in Figure 1. Please also note that the material safety and structural integrity requirements of NSF 401 are adopted directly from NSF/ANSI 42 and NSF/ANSI 53.
On January 28, the draft was submitted to the NSF Joint Committee for balloting and that period remained open until February 19. Once the ballot period ended, any comments received from joint committee members were considered and adjudicated. Changes to the criteria and requirements of NSF 401 may have occurred in this process. Additionally, laboratory validation testing will have to be completed to assure the testing as specified can be accurately repeated and reproduced. Although significant lab work has already gone into the development process, it is important to conduct the entire tests to assure validity of the standard.
Finally, the standard must be approved by NSF’s Council of Public Health Consultants, an independent group tasked with ensuring that NSF’s standards and policies are consistent with NSF’s mission to protect and improve human health. Ultimately, because it was developed through an accredited consensus process, the standard will also become an American National Standard through ANSI.
About the author
Rick Andrew is NSF’s Director of Global Business Development-Water Systems. Previously, he served as General Manager of NSF’s Drinking Water Treatment Units (POU/ POE), ERS (Protocols) and Biosafety Cabinetry Programs. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at (800) NSF-MARK or email: Andrew@nsf.org