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SDWA A Publication of HDR




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Sequestration Impacting Stream Gages EPA Finalizes Approval of New Analytical Methods

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EPA Releases 2012 Water Reuse Guidelines California Proposes Maximum Contaminant Level for Cr(VI) of 10.0 ppb


FALL 2013

Contribution of Drinking Water to Total Nitrosamine Exposure


Sequestration Impacting Stream Gages By Sarah Clark, P.E.

The United States Geological Survey (USGS) operates approximately 7,000 stream gages throughout the country which are accessed by a variety of organizations. Each gage annually costs between $14,000 and $18,000 to operate and are used for everything from watershed management, to bridge design, to water supply predictions. In mid-FY13, sequestration of USGS funds required the USGS to discontinue a number of stream gages. The stars on the map below identify the streams that were affected. The yellow stars indicate temporary continuation of the stream gages through the end of September made possible by funding through state and local agencies. Red stars are for gages where

funding is not secure; these gages will likely soon be shutdown. Gages represented by black stars have been or will soon be discontinued. Originally, cuts in USGS funds would have shut down 375 gages nationally. However, some of the funding cuts were absorbed by other programs to ensure the gages would be maintained. The goal of USGS was to preserve gages that are legally required (those that support administration of interstate compacts, international treaties and Supreme Court decrees); protect life and property (used in river forecasts and warnings); and provide long-term monitoring for assessing the effects of land use and climate change. v



For a complete list of gages that are being discontinued, please go to the web at

41 threatened stations due to sequestration, state/local agency provided temporary funding through Sept. 30, 2013 12 endangered stations due to sequestration, replacement funding has not been secured, gage in process of being discontinued

73 threatened stations, funding unlikely; station maybe discontinued or a gage converted to stage only 59 endangered stations, replacement funding has not been secured; gage in process of being discontinued or converted to stage only

31 recently-discontinued stations due to sequestration

97 recently-discontinued stations due to funding shortfall

84 total stations with funding issues due to sequestration

229 total stream flow stations with funding issues due to funding shortfall

SDWA Newsletter | HDR


EPA Finalizes Approval of New Analytical Methods By Sarah Clark, P.E.

On May 31, 2013, the U.S. Environmental Protection Agency (EPA) published two lists of approved analytical methods for analyzing contaminants under the Safe Drinking Water Act (SDWA). The EPA used a streamlined authority to approve new methods and publish them in the Federal Register.

methods to earlier versions to determine they are equally effective as previously approved methods.

When the EPA determines an alternative analytical method is “equally effective” as an existing method, the SDWA allows EPA officials to approve the method by publication in the Federal Register. Several lists of methods are included as part of this regulatory action.

The third list consists of methods developed by vendors includes a wide range of contaminants. They include total coliforms, E.coli, fecal coliforms, enterococci, coliphages, and extensive groups of inorganic contaminants, VOCs, SOCs and radionuclides.

These lists include 79 updated Standard Methods from the 22nd Edition of the Standard Methods for the Examination of Water and Wastewater (APHA 2012) which are approved by the EPA.

New methods for free and total chlorine, chlorine dioxide, ozone, TOC, SUVA, and disinfection byproducts are listed, along with methods for taste, odor, color and total dissolved solids. v

Most of the changes to the 79 methods are procedural clarifications and corrections to errors in previous editions. EPA officials compare the updated standard

The complete lists of approved methods is located at: expedited-approval-of-alternative-test-procedures-for-the-analysis-ofcontaminants-under-the-safe

The second list includes only three methods developed by ASTM International. Revisions to ASTM methods for sulfate, alkalinity and pH are all approved by the EPA.

Aquifer Depletion is Accelerating By Sarah Clark, P.E.

A recent United States Geological Survey (USGS) study shows that the nation’s aquifers are being drawn down at an accelerating rate. The report, titled Groundwater Depletion in the United States 19002008, evaluates long-term depletion in 40 different aquifers across the country.

variations or short-term climatic fluctuations. For the study, the USGS directly calculated depletion for each aquifer using calibrated groundwater models, analytical approaches, or volumetric budget analyses. Estimated storage changes are most accurate to within ± 20 percent.

Groundwater depletion is an increasing global concern that threatens sustainability of water supplies. Large cumulative long-term groundwater depletion directly contributes to rising sea levels. Additionally, it may contribute indirectly to regional relative sealevel rise as a result of land subsidence issues.

During 1900-2008, estimated groundwater depletion in the United States was approximately 1,000 cubic kilometers (km3). However, the rate of groundwater depletion increased significantly starting about 1950, with maximum rates occurring most recently, from 2000–2008. During that time, the depletion rate average jumped to almost 25 km3 per year compared to 9.2 km3 yearly average over the 108-year timeframe. v

The study’s goal was to assess the cumulative longterm change in water volume stored in the subsurface, rather than to capture changes related to seasonal



EPA Releases 2012 Water Reuse Guidelines By Matthew McFadden

In September the United States Environmental Protection Agency (EPA) released the 2012 Guidelines for Water Reuse. From its inception in 1980 to the most recent edition in 2004, the document has evolved from an exploratory research document to a summary of reuse guidelines and supporting technical information serving reference point for regulators or utilities for developing water reuse programs. © ISTOCKPHOTO.COM/HDR

Since the 2004 edition, there was considerable expansion in water reuse programs in 30 states and other organizations around the world. The recent 2012 edition now incorporates these water reuse key developments and serves as a comprehensive overview of reuse considerations, addressing everything from developing regulatory frameworks and standards at the state level to planning, design and operation of systems at the utility level. The expanded guidelines are supported technically by the inclusion of 100 U.S. and international case study summaries. The areas of emphasis in the 2012 Guidelines are noteworthy because they tend to be indicative of important trends in water reuse development over the past decade. The document is approached from the context of increasing world population and urbanization, increased water demand associated with agriculture, and changing climate conditions which could adversely impact world drinking water supplies. Particular importance is placed on the water-energy nexus, and the opportunity that increased water reuse offers for reducing the energy demand associated with water production while reducing water consumption associated with energy production. These factors and others are explored and discussed as critical motivations for continuing expansion of reuse development and widespread adoption of integrated water management strategies that consider wastewater a resource and a key to augmenting supplies while reducing waste streams.


The need for reuse is addressed throughout the Guidelines by using a “fit for purpose” approach that emphasizes efficiency and integrated management strategies to be developed around specific applications, including: • Agricultural reuse • Wetlands polishing or stream augmentation • Industrial reuse • Aquifer recharge • Indirect or direct potable reuse Technical discussions and development of guidelines focus on differences between the specific requirements for developing each of these applications. For example, guidelines for regulatory programs (including summaries of existing programs) address specific differences in water quality, level of treatment, monitoring and offset requirements appropriate for each application. Applicable treatment technologies, planning and funding considerations, infrastructure and operational requirements are discussed in depth within this context of identifying efficient approaches for specific applications. Technical discussion centered on the various reuse applications is augmented by discussion of regional and global variations in reuse approaches. (continued on back cover)

SDWA Newsletter | HDR


California Proposes Maximum Contaminant Level for Cr(VI) of 10.0 ppb By Phil Brandhuber

On Aug. 23, 2013, the California Department of Public Health (CDPH) released for public comment the proposed maximum contaminant level (MCL) for hexavalent chromium (Cr(VI)) in drinking water. CDPH is proposing a Cr(VI) MCL of 10.0 parts per billion (ppb) measured at the distribution system entry point. Currently total chromium, which is calculated as the total of the trivalent (Cr(III )) and Cr(VI) species, is regulated by both the United States Environmental Protection Agency and the CDPH. This is the first MCL specifically for Cr(VI) proposed at the state or national level. The proposed Cr(VI) MCL is five times less than the current California MCL for total chromium of 50 ppb and 10 times less than the current EPA MCL of 100 ppb. The proposed rule applies to both community and non-transient, non-community water systems.

In 2011, the California Office of Environmental Health Hazard Assessment (OEHHA) established a public health goal (PHG) of 0.010 ppb for Cr(VI). By California legal code, CDPH must set the MCL as close as technically and economically feasible to the PHG. CDPH performed a cost-benefit analysis for alternative MCLs ranging from 1 to 30 ppb, and determined that the optimum cost-benefit ratio was reached at the proposed MCL of 10 ppb. At this MCL, CDPH estimated an amortized annual capital, operations and maintenance cost of $156 million for Cr(VI) treatment would result in the avoidance of 12 cancer cases per year. This estimate was based on treatment at 310 groundwater entry points. v The proposal may be viewed at DPOPP/regs/Pages/DPH-11-005HexavalentChromiumMCL.aspx. The rule is expected to be promulgated in 2014.

Canadian Draft Guideline on Selenium in Drinking Water By Sarah Clark

The Canadian Federal-Provincial-Territorial Committee on Drinking Water (CDW) recently assessed information available on selenium and issued a new draft guideline and technical document on selenium in drinking water. The existing 1992 guideline set a maximum acceptable concentration (MAC) of 0.01 mg/l. The new document proposes a MAC of 0.050 mg/l based on current studies and understanding of the mode of action. Selenium is a naturally occurring element widely distributed in the earth’s crust and is found in trace amounts in plant and animal tissue. Found in drinking water, it occurs predominantly in the Se(iV) and Se(Vi) oxidation states. Selenium is also released as a byproduct of coal-fired refineries and smelters of metals and used in manufacturing processes.

Selenium is an essential trace element in the human diet, serving as a component of several proteins and enzymes that play important roles, including regulation of thyroid hormones and antioxidant defenses. A selenium deficiency can lead to several chronic diseases, but it is not classified as a carcinogen. A non-cancer approach was used in the selenium assessment. The draft guidelines include a brief discussion of treatment options. Removal of selenium is dependent on oxidation state, pH, and redox potential of the water. Limited data exists on laboratory and pilot plant tests of treatment options, with no full scale studies available. Tailoring of treatment to each oxidation state separately may be necessary for reasonable removal efficiencies. v A copy of the complete draft guideline can be obtained by following instructions at consult/_2013/selenium/index-eng.php.



Contribution of Drinking Water to Total Nitrosamine Exposure By Sarah Clark, P.E.

As part of regulatory determinations associated with the Third Contaminant Candidate List (CCL 3), the United States Environmental Protection Agency (EPA) Nitrosamines in drinking will determine if nitrosamines should be regulated water between 0.0002% & in the fourth quarter of 2013. Of the six nitrosamines 0.01% of lifetime average included in monitoring of the second Unregulated daily NDMA dose Contaminant Monitoring Rule (UC MR2), NDMA Nitrosamines in Nitrosamines (N-nitrosodimethylamine) tobacco products in workplace is the most prevalent in environment Endogenous formation drinking water. • Precursors in food • Precursors synthesized Therefore, the Nitrosamines endogenously occurrence of NDMA in cosmetics in drinking water along with the contribution Nitrosamines NDMA makes to total Total in foods (including individual exposure has Nitrosamines Nitrosamine breast milk and sparked interest in the water in beer Dose formula) industry. Research study results determining the proportions of volatile N-nitrosamines contributed by drinking water were published recently by Hrudy, et al. (see reference at the end The precursors to NDMA formation are readily of this article). available in the body, independent of food intake. Nitrosamines are a class of cancer-causing chemicals formed by the reaction of a secondary amine and a nitrosating agent. People can be exposed to nitrosamines through several routes, including: • Inhalation from occupational sources or from smoking (up to 17,000 ng/d) • Oral intake from food sources (cured or smoked meat, and fish and fermented foods) or drinking water • Dermal exposure from cosmetics • Endogenous synthesis – humans form nitrosamines internally Researchers reported estimates of nitrosamines in current diets of children to be 50 ng/day of NDMA, and of adults to be 60 ng/day. Estimates of the endogenous exposure to NDMA are >44,000 ng/day for children and >110,000 ng/day for adults.


SDWA Newsletter | HDR

Endogenous NDMA formation is assumed to vary based on age and changes in individual physiological state (inflammation or infection). Using the data collected during the UC MR2, researchers estimated exposure levels from drinking water from different water source types and for different age groups. Combining this information with the estimates of exposure from routes other than drinking water, they developed average daily NDMA dose proportions contributed by sources. For two types of water sources, the relative doses are shown in the Table 1. The range of the mean proportion for the lifetime average daily NDMA dose for adults is 0.0002 percent to 0.001 percent for surface water systems using free chlorine, or between 0.001 percent and 0.01 percent for surface water systems using chloramines. These are all very low percentages.


As a result of this research, the potential regulation of nitrosamines is somewhat controversial. Compared to nitrosamine formation inside the body and the amount found in some foods, the percentage of total risk reduction available by regulating nitrosamines in drinking water is very small. This makes it debatable as to whether the regulation of nitrosamines would meet the Safe Drinking Water Act criteria for “a meaningful opportunity for health risk reduction.” In addition, the risk management strategies for water systems to reduce nitrosamine concentrations are not clear at this time. Many potential treatment options create simultaneous compliance issues. For example, a system that discontinues the use of PolyDADMAC polymers to reduce nitrosamine formation could

potentially create compliance issues with the turbidity standards. As the EPA makes regulatory determinations from the CCL 3, nitrosamines remain high on the watch list. The complete study regarding nitrosamine exposure can be found at doi/10.1111/risa.12070/pdf. The citation for the study is Drinking Water as a Proportion of Total Human Exposure to Volatile N-Nitrosamines. Authored by Steve E. Hrudey, Richard J. Bull, Joseph A. Cotruvo, Greg Paoli, and Margaret Wilson. v First published online: 20 JUN 2013. DOI: 10.1111/risa.12070. ©2013 Society for Risk Analysis

Table 1. Proportion of Average Daily Dose of NDMA Contributed by Sources for Two Source Types Chlorinated Ground Water

Chloraminated Surface Water

Formula-fed Infant

Breast-fed Infant


Formula-fed Infant

Breast-fed Infant
















Drinking water (mean NDMA intake)







Total of Average Daily Dose







Drinking water (95th percentile NDMA intake)








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SDWA Editor Sarah Clark, P.E., is the editor of SDWA. Please contact her with any comments or questions regarding this publication at (303) 764-1560. To join, change an address or be removed from the SDWA mailing list, please send requests to .

Drinking Water Operations Wall Chart Available The Drinking Water Operations wall chart is available from HDR’s website, This poster-sized chart is designed to assist utility personnel with the operation and maintenance of their water systems. It includes a combination of reference tools and guidance information designed to improve system performance and achieve optimal water quality for both water treatment and distribution systems.

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13th Edition SDWA Wall Chart Now Available The SDWA Update wall chart, published in February 2011, is available from HDR’s website, The poster-sized chart provides an easy-to-use reference to all drinking water regulations, including a detailed listing of contaminants and maximum contaminant levels, health effects and monitoring requirements.

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EPA Releases 2012 Water Reuse Guidelines (continued from page 4)

The discussions include numerous considerations from regional climate differences to differences in water rights and use rights. The goal of these discussions is to characterizing the current state of reuse within the United States, though a chapter of the new Guidelines is devoted to describing global experiences. One final component that substantially distinguishes the 2012 Guidelines from previous editions is the redoubled emphasis on public outreach, communication and stakeholder engagement.

A full chapter of the document is devoted to guidelines associated with these subjects. This underlies growing recognition within the industry that actively working toward a shift in public perception is critical for the success of local industrial or agricultural applications today. Perhaps it will pave the way for acceptance of more controversial perceived applications such as direct potable reuse in the future. v

SDWA Newsletter, Fall 2013