Drinking Water & Health Quarterly -Summer 2001

Drinking Water & Health Quarterly
Summer 2001, Volume 7, Issue 1


Washington Update
Federal Advisory Committee Agreement

The Stage 2 Microbial and Disinfection Byproducts (M-DBP) Federal Advisory Committee Agreement in Principle was signed in September and issued to the public (via The Federal Register) in late December. The agreement addresses interrelated drinking water regulations focusing on risks from microbial pathogens and disinfection byproducts (DBPs). The committee consisted of representatives of the EPA, public interest groups, public health and regulatory agencies, local officials, Indian tribes, drinking water suppliers and chemical and equipment manufacturers.

The Stage 2 Disinfection Byproducts Rule (DBPR) was developed simultaneously with the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR ) in order to address the risk trade-offs between pathogen control and exposure to DBPs. The updated DBPR is based on new data collected from 300 large public water systems and 120 surveys of small systems.

The agreement calls for a two-phase approach to control disinfection byproduct peaks in distribution systems. During phase one, the maximum contaminant levels (the maximum permissible level of a contaminant in water which is delivered to any user of a public water system) for total trihalomethanes and five haloacetic acids will be 0.080 and 0.060 mg/L respectively (based on individual utilities system-wide running annual averages). Additionally, site-specific locational running annual averages of 0.120 and 0.100 mg/L will be introduced.

During phase 2, the maximum levels for the more stringent locational running annual averages will be reduced to 0.080 mg/L for trihalomethanes and 0.060 mg/L for the five haloacetic acids. Compliance sites will be changed based on the sites determined by a system wide study of disinfection byproduct levels.

With regard to microbial pathogens, the Committee recommended the classification of water systems based on results of Cryptosporidium monitoring. The systems with greater Cryptosporidium risks will be required to take more aggressive treatment steps to protect their water, including greater source water protection, filtering and disinfection where needed.

The USEPA has agreed to develop a proposed rulemaking for the Stage 2 DBPR and LT2ESWTR in 2001 to reflect recommendations in the Agreement in Principle.

For the complete notice of agreement in principle, visit the Federal Register of Environmental Documents at http://www.epa.gov/ogwdw000/mdbp/st2fr29.html

Revised arsenic standard

On March 20th, U.S. Environmental Protection Agency Administrator Christie Whitman announced that the EPA will propose the withdrawal of the pending arsenic standard for drinking water that was issued during the final days of the Clinton Administration. The rule proposed by the previous Administration would have reduced the acceptable level of arsenic in water from 50 parts per billion to 10 ppb.

Changing the arsenic standard was advocated by a National Academy of Sciences panel that determined the current 50-parts-per-billion standard places people at risk of bladder and lung cancer as well as other heart, skin and lung ailments. Such illnesses were linked to arsenic in water in studies conducted in Argentina, Taiwan and Chile.

The American Water Works Association had issued comments supporting the strengthening of the standard, while others expressed concern that households in poor rural communities may face $30 to $200 per month rate increases to meet the new requirements.

The EPA announced it will seek independent reviews of both the science behind the standard and of the estimates of the costs to communities of implementing the rule.

For more information on the arsenic ruling, go to

http://www.epa.gov/safewater/arsenic.html

EPA’s nutrient criteria

The EPA is setting new water quality standards for nutrients, including nitrogen and phosphorous. The criteria are expected to significantly reduce nutrients in the nation’s supplies. States are expected to adopt or revise their nutrient standards by 2004.

The new standards were developed as an outcome of the federal government’s 1998 Clean Water Action Plan, which called for the creation of nutrient criteria reflecting different types of water bodies and ecoregions of the country.

Concern grew out of figures in the 1996 National Water Quality Inventory warning that 40 percent of rivers, 51 percent of lakes and 57 percent of estuaries surveyed do not adequately support aquatic life because of excess nutrients. Excessive nutrients can choke waterways and lead to algae blooms, including Pfiesteria and red tide, resulting in fish kills and potentially harmful human health effects.

For more information, visit EPA’s website at http://www.epa.gov/ost/standards/nutrient.htm

Ultraviolet Radiation Yields Promising Results
Further Research Necessary to Address Unanswered Questions

In order to provide an additional level of protection against Cryptosporidium, many water utilities across the nation are taking a look at ultraviolet radiation (UV). Many experts consider a multi-barrier approach involving UV radiation as a leading choice for combating treatment-resistant Cryptosporidium. UV penetrates the pathogen’s outer cellular membrane, passes through the cell body and reaches the DNA to alter genetic material. It does not kill pathogens; rather, it sterilizes the invading organisms with “germicidal wavelengths” of similar strength to those found in fluorescent light.

UV in Water Disinfection

Although the technology has been used for 75 years in Europe, UV drinking water treatment is relatively new in the United States. UV can successfully sterilize smaller quantities of water and, as such, is being used in 50 systems in this country (the largest serving 30,000 residents in Fort Benton, Montana). During the next three years, UV disinfection will be tested in larger systems such as Atlanta, Salt Lake City, Austin, Phoenix and St. Louis.

Efficiency Vs. Effectiveness

Perhaps the most important benefit of UV treatment is its ability to deactivate Cryptosporidium by penetrating its cellular membrane and sterilizing the pathogen. In addition, the EPA’s “Guidance Manual on Alternative Disinfectants and Oxidants” states that UV radiation quickly dissipates into water to be absorbed or reflected off material within the water. As a result, no residual is produced, giving the water a chemical-free taste and odor. This lack of a residual has its pluses and minuses. It is attractive because disinfection byproducts do not form; however, a secondary chemical disinfectant remains necessary to maintain residual protection against recontamination and regrowth of bacteria throughout the distribution system.

Once water leaves the facility, it can become contaminated by corroded and broken pipes. The country’s largest water distributors average 500 breaks a year, which can lead to recontamination of the water. Thus, a residual disinfectant is required to protect water from the treatment plant to the tap. For these reasons, UV should be used with chlorine or chloramines as a disinfectant in the distribution system.

There are many variables of UV strength, which can alter its effectiveness. Water composition is the most important because murky, dirty water blocks the UV rays and diminishes their strength. Other variables include water color and regular maintenance.

According to the EPA, sufficient dosages of UV can disinfect water to the degree required. Yet, the EPA recognizes that the doses needed to inactivate the many microorganisms found in water may not yet be adequately defined. Systems may need to be designed to inactivate the most resistant known organisms (e.g., Adenoviruses are currently the most resistant to UV inactivation). While UV can effectively disable harmful elements in water, its efficiency, especially regarding larger systems, is not known.

The Future of UV

UV disinfection has many assets but many questions remain that can only be answered through additional research. James P. Malley, president of the International UV Association and an environmental engineering professor at the University of New Hampshire, notes, “It would be a mistake for the water industry to widely apply UV for the treatment of surface waters for Giardia and Cryptosporidium inactivation until several key research issues are resolved.” These issues include: verification of UV’s ability to inactive Cryptosporidium, the efficacy of removal/inactivation of Giardia lamblia cysts, the long-term performance of sensors, the best placement of UV technologies in a system, the type of UV dosage needed and the cleaning techniques and frequencies required.

For more information on ultraviolet radiation, visit the EPA’s website at http://www.epa.gov/ogwdw000/mdbp/pdf/alter/chapt_8.pdf. Adobe Acrobat Reader is required to read this file. Click here to download Reader for free.

FDA Study Finds Foodborne Illness Risk Factors Not Properly Being Addressed

The U.S. Food and Drug Administration (FDA) recently announced a sweeping 10-year program to decrease foodborne illness in the US by improving food preparation practices and individual employee behaviors at institutional, restaurant and retail food outlets. The effort was prompted by the results of 17,000 food safety inspection observations showing that widespread foodborne illness risk factors were not being properly addressed.

According to the US Centers for Disease Control and Prevention (CDC), as many as 33 million people suffer from foodborne illness every year in the United States, nine thousand of whom die. The FDA’s Healthy People 2010, a national health promotion and disease prevention initiative with the objective of improving the health of all Americans, is aiming to reduce such cases by 25 percent by October 1, 2010.

One of the most startling statistics revealed by the study is that 70 percent of full-service restaurants surveyed do not properly sanitize food preparation surfaces and equipment. Additionally, one-third of all retail seafood departments and two-thirds of produce departments surveyed fail to do the same. As such, the FDA has made surface disinfection a priority health concern requiring immediate attention.

The FDA also identified poor personal hygiene and improper holding times and temperatures as risk factors in need of great attention. The study found that half of restaurants and retail food outlets do not store their foods at the proper temperatures or discard them before they might spoil. Forty percent of hospitals are out of compliance for this risk factor as well. With respect to personal hygiene, employees at 45 percent of restaurants do not practice proper personal hygiene, such as washing their hands, while on the job.

In order to reduce incidences of foodborne illness, the FDA is enlisting the help of state, local and tribal regulatory agencies to address the risk factors identified in the study. They are encouraging such agencies to review current scientific data and national requirements so that they can properly assess the greatest local risk factors and take the most appropriate corrective action when restaurants, institutions and retail food outlets are out of compliance.

The Water Quality and Health Council and the National Restaurant Association developed a poster to encourage proper sanitization in restaurants. It is available at:

http://www.c3.org/chlorine_knowledge_center/poster.html

For more information on the FDA’s Healthy People 2010 program, visit http://vm.cfsan.fda.gov/~dms/retrsk.html.

Commercial Disinfectants Demonstrate Significantly Greater Efficacy than Natural Alternatives

William A. Rutala, Ph.D. and David J. Weber, M.D.
University of North Carolina at Chapel Hill

It has been estimated that foodborne illness results in more than 30 million infections and 9,000 deaths each year in the United States. Mechanisms of acquisition of foodborne pathogens include ingestion of contaminated raw fruits and vegetables, inadequate cooking of contaminated produce or meats and direct contact with contaminated surfaces. Because pathogens can be transferred from surfaces to humans, thereby causing illness, the importance of proper surface disinfection to decrease the number of contaminants should not be underestimated.

Numerous studies have shown that proper disinfection of surfaces decreases or eliminates potential pathogens. Many commonly used hospital and household disinfectants effectively eliminate potential pathogens and therefore may decrease the likelihood of transmission.

Search for natural alternatives

In recent years, concern about chemicals, particularly the use of chemicals in the home, has led people to look for alternatives to commercial disinfectants. However, laboratory tests conducted by researchers at the University of North Carolina at Chapel Hill have shown that the natural products most often used as substitutes for commercial disinfectants are less effective at eliminating pathogens from environmental surfaces.

Scope of the study

The study evaluated both natural products and commercial disinfectants for their efficacy against potential human pathogens. Three hospital disinfectants (Vesphene IIse, TBQ and ethanol), four household disinfectants (Clorox Bleach, Lysol Disinfectant Spray, Lysol Antibacterial Kitchen Cleaner and Mr. Clean Ultra) and two natural products (baking soda and vinegar) were tested.

All products were evaluated against the test organisms Staphylococcus aureus, Salmonella choleraesuis, E. coli O157:H7 and Pseudomonas aeruginosa. These test organisms were exposed to products or controls for 30 seconds or five minutes.

The number of surviving organisms was compared with controls to quantify microbial activity. The effectiveness of the disinfectant was calculated by comparing the number of surviving organisms in the samples exposed to each cleaning product with the average number of organisms in samples not exposed to any of the products.

Commercial disinfectants are more effective

The data demonstrated that currently available commercial disinfectants have excellent activity against potentially pathogenic bacteria likely to contaminate home environmental surfaces. In fact, all of the hospital and household disinfectants exhibited “effective” to “excellent” antimicrobial activity and are therefore sufficiently active to be recommended for use. The two natural products, vinegar and baking soda, were much less effective than commercial disinfectants.

Antibiotic resistance and poliovirus

Prompted by recent questions about the effectiveness of antimicrobials against bacteria that have developed resistance to popular antibiotics, the cleaning agents were tested against both resistant and susceptible bacteria, specifically the vancomycin-susceptible and –resistant Enterococcus species and the methicillin-susceptible and –resistant S aureus. All commercial disinfectants completely inactivated both resistant and susceptible bacteria at both 30-second and five-minute exposures.

To gauge the upper limits of effectiveness, the disinfectants were tested on poliovirus, a representation of small, nonenveloped viruses that are the most resistant to chemical agents. Of the household products tested, only Clorox Bleach and Lysol Disinfectant demonstrated excellent activity against poliovirus.

Decreasing infection rates

This study demonstrates the efficacy of commercial disinfectants for use in the home. While some studies have shown that contaminated environmental surfaces are capable of transmitting viral pathogens, a controlled trial should be undertaken to determine if routine disinfection of home environmental surfaces will lead to decreased infection rates among household members.

In the meantime, persons who wish to use the most effective disinfectant should use commercial disinfectants instead of natural alternatives to decrease potential pathogens.

For more information on antimicrobial activity of home disinfectants and natural products, visit the Inspection Control and Hospital Epidemiology website at http://www.slackinc.com/general/iche/stor0100/1rut.htm. For information on Dr. Rutala, go to http://www.unc.edu/depts/spice/bio2.htm

The Use of Chlorine-based Sanitizers in Food Processing Facilities
By Dave McLaren

Food Processing Center, University of Nebraska

The Food Processing Center at the University of Nebraska – Lincoln recently released a report on the use of chlorine-based sanitizers and disinfectants in the food manufacturing industry. The study examined the various applications of chlorine-based sanitizers as well as emerging technologies to promote waste minimization.

The researchers found that chlorine and chlorine-based products are widely used in the food processing industry because of their low cost and effectiveness in microbial reduction. However,

Though chlorine in food processing is of infinite value, the study also stressed the importance of the responsible stewardship of these products, concluding that manufacturers should apply technologies to minimize chlorine waste in food production while still producing foods that are safe from microbial contamination.

Following is a brief overview of the approaches taken by different industry sectors to increase food safety through chlorine-based sanitization.

Dairy processing

The dairy industry was the first food sector to use chlorine for germicidal purposes. According to Leslie D. Vavak of the University of Nebraska at Lincoln, such usage was later codified in the U.S. Milk Ordinance and Code of 1939 that recommended chlorine for use treatment of milk equipment. Chlorine is primarily used for the purification of potable water used in dairy processes and for disinfection of equipment, pipelines, utensils, surfaces and hands.

Meat and poultry processing

Chlorine is generally used as a bactericidal agent in meat and poultry processing facilities. However, it is also used to clean and bleach stains on equipment and surfaces.

The US Department of Agriculture (USDA) requires poultry to be immersed in water containing 20 parts per million (ppm) available chlorine. It also stipulates that equipment in meat and poultry slaughter facilities must be sanitized in a fresh solution of 5,000 ppm available chlorine.

Egg processing facilities

A survey of egg processing facility managers found that chlorine is the most commonly used sanitizer because it is inexpensive compared to other compounds and is highly effective in removing protein and carbohydrate residues from surfaces. Chlorine can be used at almost every stage of egg processing, from the washing of eggs and equipment, to the sanitization of egg trays used for shipping and hand wash stations.

Fish and seafood processing

Fish and shellfish products have the highest outbreak rates of reported foodborne illness of any food group in the U.S. Chlorine is most often used in fish and seafood processing because it is inexpensive, has fast germicidal action at relatively low concentrations, is easy to use, does not produce a film and is available in multiple forms. However, it is less effective on surfaces with high organic loads and may cause skin irritation.

Fresh fruits and vegetables

Chlorine gas, calcium hypochlorite and sodium hypochlorite are widely used in fresh fruit and vegetable production applications. Seeds are often soaked in chlorinated water to reduce the potential for viral, bacterial and fungal disease epidemics. Irrigation water is treated with chlorine to control plant pathogens such as Phytophthora cinnamomi and P. capsisci in addition to preventing bacterial slime and biofilm accumulation.

Reducing foodborne illness

As the Food Processing Center’s examination of the use of chlorine-based disinfectants in food processing suggests, processing facilities recognize the importance of proper sanitization of equipment and even foodstuffs in order to ensure the safety of the food supply. The industry’s multibarrier approach to protection, including the use of disinfectants such as chlorine-based products, significantly reduces incidents of foodborne illness.

The report may be ordered from the University of Nebraska by contacting Dan Moser at dmoser3@unl.edu or 103 Agriculture Communications Building, Lincoln, NE 68583-0918.

To find out more about the Food Processing Center at the University of Nebraska, visit their website at http://www.foodsci.unl.edu/fpc/index.htm

For a description of the USDA’s food safety programs, go to http://www.reeusda.gov/1700/programs/fsafety.htm

Chloramines Seen as an Attractive Option for Meeting Disinfection Byproduct Requirements
By Gerald F. Connell

In recent years, cities such as Maui and Santa Barbara have started using chloramines as a component of their drinking water disinfection process. Last November, Washington, DC and Arlington, Virginia also made the switch, citing improvements to taste and a desire to decrease disinfection byproduct levels. The completed Stage 1 and pending Stage 2 Disinfectants and Disinfection Byproducts Rules (DBPR) issued by the Environmental Protection Agency (EPA) are likely to spark an increase in the number of communities utilizing chloramines.

The Stage 1 rule is currently being implemented; the Stage 2 rule was issued in December 2000 as an agreement in principle. They seek to improve microbial protection while enacting more stringent rules reducing the level of allowed disinfection byproducts (DBPs).

Stage 2 Microbial/Disinfection Byproducts Rule

The agreement calls for a two-phase approach to control disinfection byproduct peaks in distribution systems. During phase one, the maximum contaminant levels (the maximum permissible level of a contaminant in water which is delivered to any user of a public water system) for total trihalomethanes and five haloacetic acids will be 0.080 and 0.060 mg/L respectively (based on individual utilities system-wide running annual averages). Additionally, standards for locational running annual averages (annual averages at each sampling site) of 0.120 and 0.100 mg/L will be introduced.

During phase 2, the maximum levels for the more stringent locational running annual averages will be reduced to 0.080 mg/L for trihalomethanes and 0.060 mg/L for the five haloacetic acids and the compliance locations will be changed to those identified under an intensive DBP monitoring and characterization program.

Benefits of chloramines

Chloramines are an attractive disinfectant choice in this new regulatory environment because they stop the formation of trihalomethanes that occurs if free chlorine remains in the distribution system. According to the US Environmental Protection Agency (EPA), utilities using chloramines can minimize DBP levels by maintaining an optimal three to five ratio of chlorine to ammonia in the water.

Chloramines have additional benefits that have been known for more than 80 years. Recognizing that chloramines are less likely to react with organic compounds in water distribution systems and therefore produce water with improved taste and odor, the City of Denver began using chloramines in 1917. Because it was inexpensive and easy to make, chloramination was used regularly during the 1930s and 1940s until a shortage of ammonia during World War II decreased its use.

According to the American Water Works Association, chloramines are the second most popular water disinfectant with nearly 30 percent of large- and medium-sized water agencies in the US using them in 1998. In addition to reduced DBP levels and taste and odor benefits, chloramines also provide strong protection against bacterial regrowth because it offers a stable and long-lasting residual. Chloramine residual is very effective at penetrating and controlling biofilms, thereby reducing coliform concentrations and biofilm-induced corrosion.

Secondary disinfectant

Even with these benefits, chloramines are rarely used as a primary disinfectant because they are relatively ineffective at inactivating certain viruses. Instead, they are often employed as a secondary disinfectant in combination with a primary chlorine treatment.

This combination is effective because chlorine disinfection occurs in two distinct phases. During the initial phase in the treatment plant, organic compounds cause the rapid disappearance of free available chlorine; however, when ammonia is present (in the form of chloramines), the water is still actively disinfected even though the amount of free chlorine in the water has been reduced. During the second phase, inorganic chloramines provide additional disinfection for added protection in the distribution system.

Impacts on dialysis patients and pet fish

Utilities considering a change to chloramines should be prepared to address the important effects of such a transition. Chloramines are toxic to pet fish, reptiles and amphibians, and must therefore be removed from water these pets inhabit. Chloramines do not dissipate rapidly in water and must be removed by biological filters, natural zeolites and pH control methods to reduce the toxic effects of ammonia to these animals.

Water treated with chloramines must be specially filtered for use in kidney dialysis machines because it comes in contact with a patient’s blood across a permeable membrane as part of the dialysis process. In such cases, chloramines can be removed by adding ascorbic acid or using granular activated carbon treatment. Hospitals are well-prepared to implement such simple precautions when properly notified of future changes.

Excess nitrates

Utilities should also be prepared to monitor and control nitrate levels in water associated with chloramine imbalances. According to the EPA, if ammonia is in excess of the required chlorine, it can promote the growth of bacteria, which in turn converts excess ammonia to nitrates. If this persists, the total chlorine residual will be reduced to very low or zero levels, leading to potential increases in HPC bacteria and coliforms. Excessive levels of nitrate in drinking water can cause serious illness.

Nitrification can be controlled by monitoring strategic locations throughout the distribution system for monochloramine residuals. The problem can then be neutralized by decreasing the detention time, temperature, or excess ammonia concentration; or by increasing the pH or the chlorine-to-ammonia ratio.

Implementing the changeover

With many utilities considering a changeover to chloramines, Janice M. Skadsen of the American Water Works Association and the Ann Arbor Water Utilities Department reminds agencies that project planning and preparation are essential to ensuring an efficient changeover, maintaining a dependable and safe system and preserving public confidence in the water purveyor.

The EPA recommends that the following areas should be considered in preparation for a changeover: raw water composition and suitability to chloramination, a comprehensive monitoring program, employee training, potential environmental impacts and public notification and education. Providing local residents, businesses and health care providers with comprehensive information about changeover impacts is extremely important, particularly for those with special concerns such as fish owners and kidney dialysis patients.

Gerald F. Connell has been involved in the study and application of drinking water and wastewater treatment technologies for more than 30 years. He is the author of “The Chlorination/Chloramination Handbook,” published by the American Water Works Association in 1996.

For more information on chloramines, visit the EPA’s website or the AWWA site.

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