Aqua Vantage - EPA

Toxins In Your Water

2006-01-22T21:30:00.000-07:00

This is a warning you are used to hearing when you travel abroad, but now it's hitting home.

According to the Washington, D.C. based Environmental Working Group (EWG), manufacturers dumped more than one billion pounds of toxic chemicals into rivers, lakes and other bodies of water between 1990 and 1994. EWG also estimates that manufacturers contributed about 450 million additional pounds via sewage.

In the 1940's, a billion pounds of synthetic chemicals were produced each year. By the 1980's, production was up to 500 billion pounds, and 1000 new chemicals are introduced each year. Yet the Federal Safe Drinking Water Act only addresses 100 contaminants.

Pesticides are another problem. Two billion pounds of pesticides are used every year. That's eight pounds for every American. These pesticides enter water systems via disposal sites, animal waste, runoff, sewage, etc. After reviewing published (but not publicized) State data and conducting its own tests, EWG found that a single glass of Midwestern tap water has three or more pesticides in it.

The following excerpt from Tap Water Blues, produced by the EWG and Physicians for Social Responsibility, states: "Every spring, farmers across the Corn Belt apply 150 million pounds of five herbicides--atrazine, cyanazine, simazine, alacholor and metolachlor to their corn and soybean fields. Every spring, rains wash a substantial portion of those chemicals into the drinking water of 11.7 million people in the Midwest and Louisiana. According to this article, none of these herbicides are removed by the conventional city municipalities drinking water treatment technologies that are used by more than 90% of all water utilities in the United States."

As recently as July 1999, a USA Today article outlined a wide-ranging government report which concludes that much of the nation's ground water and many of its streams are contaminated with pesticides and unhealthy levels of fertilizer chemicals. Many of the streams that are most heavily polluted with insecticides were in metropolitan areas such as those of Dallas-Fort Worth, Denver, Indianapolis, Las Vegas, Nev., Portland, Ore., Tallahassee, Fla., and Washington. However, to researchers' surprise, some of the worst contamination by insecticides was in urban streams.

Though banned in 1972, DDT turned up in stream sediment and fish in both urban and rural areas across the US. So did similar insecticides that were banned years ago. Most of the test sites had more than one contaminant. No one knows how combinations of contaminants, at low levels, affect human health or wildlife.

Clean air, contaminated water.

The additive, MTBE, is used in "reformulated" gasoline required by the Environmental Protection Agency in all or parts of 17 states. That accounts for about a third of the gasoline sold in the country. This additive allows gasoline to burn cleaner, but with terrible consequences.

Federal research shows that MTBE causes tumors in rats and may do the same in humans. A University of California study showed that the additive has affected at least 10,000 groundwater sites throughout the state. These discoveries are causing a national furor since MTBE travels farther and faster in groundwater and doesn't breakdown naturally.

Who is protecting our children?

EWG tests show that atrazine contaminates the tap water of almost 10 million people in 800 cities and towns in the Midwest. In many places, children receive their lifetime dose of this carcinogen in their first 4 months. Atrazine levels in water are highest in spring and summer, when farmers are spraying their fields, and kids get hot and drink a lot of water.

European countries do a much better job of protecting their children from atrazine. It's banned in many countries, including Germany, Italy and Sweden. In Switzerland where Novartis, the manufacturer of atrazine, is based, the drinking water standard for the substance is 30 times stricter than in the U.S.

Debugging the clean water myth

In this country, cities purify drinking water by using sedimentation, filtration, ion exchange and disinfection. Disinfection uses ozonation, and, particularly, chlorination to kill disease-causing microbes. Chlorine, once the salvation of the twentieth century, controls cholera, typhoid fever and other water-borne diseases. Now, scientists know it combines easily with other chemicals and naturally occurring organic materials to create organochlorines--potentially carcinogenic substances. Over 96% of agricultural chemicals contain chlorine.

Incidents in the United States -such as the outbreak of the microorganism cryptosporidium in Milwaukee's water supply in 1993 that killed more than one hundred people and sickened over 400,000, and lead and pesticide contamination-while not affecting most, threaten the tap water of millions Americans.

Beware. Bottled water may not be your answer.

Bottled water is regulated, but not stringently. It's only requirement is that it is as safe as tap water. It may be nothing more than filtered tap water from some municipality. Point of use, multi-stage filtration is best. If the water is to be stored for any length of time, glass containers should be used whenever possible.

You aren't even safe in the shower!

As hot water steams, chemicals evaporate and are inhaled.

The amount of chlorine absorbed by your body in a 10-minute shower equals about two gallons of tap water consumption. Taking showers is a health risk, according to research presented in a meeting of the American Chemical Society. Showers-and to a lesser extent baths-lead to a greater exposure to toxic chemicals contained in water supplies than does drinking water. The chemicals evaporate out of the water and are inhaled. They can also spread through the house

USEPA characterizes many unregulated DBPs

2006-01-22T21:10:00.000-07:00

Source: http://www.awwa.org/Communications/news/index.cfm?ArticleID=287

03/05/2004

USEPA researchers have quantified the occurrence of more than 200 previously unidentified disinfection by-products (DBPs) for the first time and determined that disinfectants other than chlorine can produce comparable levels of DBPs that may pose health risks, according to a new report from the agency’s Ecosystems Research Division.

Using gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), and gas chromatography/infrared spectroscopy (GC/IR) techniques to identify unknown DBPs, USEPA conducted a nationwide DBP occurrence study of more than 50 unregulated DBPs determined to be of health concern from among some 500 DBPs that have been reported in scientific literature.

The agency team sampled drinking water across the United States from a dozen utilities in six regions using water from different sources and quality, including sources with elevated levels of bromide, and disinfecting with chlorine and alternatives such as ozone, chlorine dioxide and chloramines.

While noting that most of the analysis involved “unconventional” techniques and “a great deal of scientific interpretation,” the researchers quantified the occurrence of more than 200 unregulated DBPs, partly to help prioritize them for health effects testing.
They also discovered that while alternative disinfectants lowered the levels of regulated trihalomethanes and haloacetic acids compared to chlorine, such disinfectants formed many of the high priority DBPs higher levels.

“For example, the highest levels of iodinated DBPs were found in chloraminated drinking water, the highest levels of trihalonitromethanes were found in pre-ozonated drinking water, MX and brominated MX analogs (BMXs) were highest at a plant using chlorine dioxide (followed by chlorine-chloramines), and dihaloaldehydes were highest at a plant using chloramines and ozone,” they report.

Follow-up work, they noted, will include obtaining occurrence data on the iodinated DBPs in chloraminated waters, where levels are expected to be highest, and applying a toxicity-based approach (using mammalian cell and medaka fish assays) to ensure identification of “toxicologically important” DBPs.

A study expected to begin this year will strive to identify target DBPs in concentrated drinking water samples through testing in a battery of in vivo and in vitro toxicity assays, with an emphasis on newer reproductive and developmental health effects.

The work will also try to determine how toxicologically significant bromonitromethane DBPs, which are more genotoxic and cytotoxic to mammalian cells than most of the currently regulated DBPs, are formed.

Byproduct of water-disinfection process found to be highly toxic

2006-01-22T20:50:00.000-07:00

Source: http://www.news.uiuc.edu/news/04/0914water.html

A recently discovered disinfection byproduct (DBP) found in U.S. drinking water treated with chloramines is the most toxic ever found, says a scientist at the University of Illinois at Urbana-Champaign who tested samples on mammalian cells.

The discovery raises health-related questions regarding an Environmental Protection Agency plan to encourage all U.S. water-treatment facilities to adopt chlorine alternatives, said Michael J. Plewa [PLEV-uh], a genetic toxicologist in the department of crop sciences.

“This research says that when you go to alternatives, you may be opening a Pandora’s box of new DBPs, and these unregulated DBPs may be much more toxic, by orders of magnitude, than the regulated ones we are trying to avoid.”

Plewa and colleagues, three of them with the EPA, report on the structure and toxicity of five iodoacids found in chloramines-treated water in Corpus Christi, Texas, in this month’s issue of the journal Environmental Science & Technology. The findings, which appeared online in advance, already have prompted a call from the National Rural Water Association for a delay of EPA’s Stage 2 rule aimed at reducing the amount of previously identified toxic DBPs occurring in chlorine-treated water.

“The iodoacids may be the most toxic family of DBPs to date,” Plewa said in an interview. One of the five detailed in the study, iodoacetic acid, is the most toxic and DNA-damaging to mammalian cells in tests of known DBPs, he said.

“These iodoacetic acids raise new levels of concerns,” he said. “Not only do they represent a potential danger because of all the water consumed on a daily basis, water is recycled back into the environment. What are the consequences? The goal of Stage 2 is to reduce DBPs, particularly the ones that fall under EPA regulations, and especially the ones that have been structurally identified and found to be toxic.”

The use of chloramines, a combination of chlorine and ammonia, is one of three alternatives to chlorine disinfectant, which has been used for more than 100 years. Other alternatives are chlorine-dioxide and ozone. All treatments react to compounds present in a drinking water source, resulting in a variety of chemical disinfectant byproducts.

Some 600 DBPs have been identified since 1974, Plewa said. Scientists believe they’ve identified maybe 50 percent of all DBPs that occur in chlorine-treated water, but only 17 percent of those occurring in chloramines-treated water, 28 percent in water treated with chlorine-dioxide, and just 8 percent in ozone-treated water. Of the structurally identified DBPs, he said, the quantitative toxicity is known for maybe 30 percent.

Some DBPs in chlorine-treated water have been found to raise the risks of various cancers, as well as birth and developmental defects.
Corpus Christi’s water supply has high levels of bromide and iodide because of the chemical makeup of the ancient seabed under the water source. Local water sources lead to different DBPs. Whether the types of iodoacids found in Corpus Christi’s treated water might be simply a reflection of local conditions, and thus a rare occurrence, is not known.

The DBPs in Corpus Christi’s water were found as part of an EPA national occurrence survey of selected public water-treatment plants done in 2002. The survey reported on the presence of 50 high-priority DBPs based on their carcinogenic potential. The report, published in April, also identified 28 new DBPs.

Because so many new DBPs are being found in drinking water, Plewa said, two basic questions should be asked: How many are out there? And how many new ones will be formed as chlorine treatments are replaced with alternative methods?

Co-authors with Plewa on the EPA-funded study were Elizabeth D. Wagner, a scientist in the department of crop sciences at Illinois; Susan D. Richardson and Alfred D. Thruston Jr. of the EPA’s National Exposure Research Laboratory; Yin-Tak Woo of the EPA’s Risk Assessment Division, Office of Pollution Prevention and Toxics; and A. Bruce McKague of the CanSyn Chemical Corp. of Toronto.

Data Sought for 26 Drinking Water Contaminants

2006-01-22T20:31:00.000-07:00

Source: http://yosemite.epa.gov

Release Date: 08/12/2005

Twenty-six unregulated contaminants will be monitored by many U.S. drinking water suppliers under a new rule proposed by the Environmental Protection Agency. This second cycle of the Unregulated Contaminant Monitoring Rule (UCMR 2) also proposes the use of nine analytical methods to detect the contaminants

The data collected will help EPA determine whether to regulate the contaminants, their occurrence in drinking water, the potential population exposed to each, and the levels of exposure.

(Washington, D.C.-August 12, 2005) Twenty-six unregulated contaminants will be monitored by many U.S. drinking water suppliers under a new rule proposed by the Environmental Protection Agency. This second cycle of the Unregulated Contaminant Monitoring Rule (UCMR 2) also proposes the use of nine analytical methods to detect the contaminants.

The data collected will help EPA determine whether to regulate the contaminants, their occurrence in drinking water, the potential population exposed to each, and the levels of exposure.

The rule encompasses some contaminants that are not regulated under existing law. EPA currently has regulations for more than 90 contaminants. The Safe Drinking Water Act requires EPA to identify up to 30 contaminants for monitoring every five years. The first cycle, UCMR 1, published in 1999, covered 25 chemicals and one microorganism.

The contaminants are divided into two lists: assessment monitoring and screening surveys. EPA has information from some public water systems on 11 contaminants chosen for assessment monitoring but lacks a national estimate of how widely they occur. EPA needs to collect more data on the 15 selected for screening surveys because analytical methods have been only recently developed.

All public water systems serving more than 10,000 people and a sample of 800 systems serving 10,000 people or fewer will monitor those contaminants on the assessment list for 12 months during July 2007 through June 2010. Additionally, 322 systems serving more than 100,000 people and 800 serving 100,000 or fewer will conduct the screening surveys during a 12-month period from July 2007 through June 2009.

The substances were chosen through a process that included a review of:

•An existing list of "reserved" contaminants for which no analytical methods were yet available.

•EPA's Contaminant Candidate List, which contains priority contaminants that are researched to make decisions about whether regulations are needed. The contaminants on the list are known or anticipated to occur in public water systems. However, they are currently unregulated by existing national drinking water regulations.

•Additional contaminants of concern based on current research of occurrence and various health-risk factors.

Costs for the five-year UCMR 2 will total approximately $42.1 million. EPA will conduct and pay for the monitoring for those water systems serving 10,000 people or fewer at a cost of $8.05 million.

The Safe Drinking Water Act (SDWA)

2006-01-22T20:17:00.000-07:00

Proposed Rule

Source: http://www.epa.gov/safewater/ucmr/ucmr2/factsheet.html

Unregulated Contaminant Monitoring Regulation (UCMR 2) monitoring is proposed to occur during 2007-2010 and includes 26 unregulated contaminants and nine associated analytical methods to be used in this monitoring cycle. The UCMR program was developed in coordination with the Contaminant Candidate List (CCL). The CCL is a list of contaminants that are not regulated by national primary drinking water regulation, are known or anticipated to occur at public water systems, and may warrant regulation under the Safe Drinking Water Act. The data collected through the UCMR program is being stored in the National Contaminant Occurrence Database (NCOD) to support analysis and review of contaminant occurrence, to guide the CCL selection process, and to support the Administrator's determination of whether to regulate a contaminant in the interest of protecting public health.

Background

The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to establish criteria for a program to monitor unregulated contaminants and to identify no more than 30 contaminants to be monitored every five years. EPA identified and published unregulated contaminants for the previous UCMR cycle (i.e., UCMR 1), and a revised approach for monitoring, in the Federal Register dated September 17, 1999. UCMR 1 established a tiered monitoring approach, and required all large public water systems (PWSs) and a representative sample of small PWSs (serving 10,000 or fewer people) to monitor for unregulated contaminants from 2001-2005. (The original unregulated contaminant monitoring program (1988-1997) utilized State primacy and required PWSs serving greater than 500 people to monitor.)

About this regulation

EPA is proposing to require monitoring of 26 chemicals using nine different analytical methods (see table below). EPA is proposing to require all public water systems (PWSs) serving more than 10,000 people, and a representative sample of 800 PWSs serving 10,000 or fewer people, to conduct Assessment Monitoring (List 1) for 11 chemicals during a 12-month period between July 2007 - June 2010. As under UCMR 1, EPA would continue to conduct and pay for the monitoring required for those selected PWSs serving 10,000 or fewer people. All very large PWSs serving more than 100,000 people, 320 large representative PWSs serving 10,001 to 100,000 people, and 480 small representative PWSs serving 10,000 or fewer people will be required to conduct the Screening Survey (List 2) for 15 contaminants, which will primarily be measured with analytical method technologies that are more specialized and not in common use. The Screening Survey will be conducted during a 12-month period between July 2007 - June 2009.

Central Calif. Water District Ordered to Remove Chemical From Drinking Water

2006-01-22T19:54:00.000-07:00

Source: http://www.waterchat.com/News/Environment/05/Q4/env_051222-01.htm

San Francisco, CA – The U.S. Environmental Protection Agency has ordered the Groveland Community Services District in Tuolomne County, Calif. to reduce levels of disinfection byproducts from the drinking water it provides to customers.
In this case, the byproduct chemicals are detectable in very trace amounts. The EPA does not suggest that customers need alternative or bottled water.

“Chemical byproducts in treated drinking water need to be monitored, reported and reduced to meet the federal health standard,” said Marvin Young of the EPA’s Drinking Water Office in the Pacific Southwest region. “In this case, the district notified the public and has begun changing their operations to prevent the byproduct from forming.”

The byproduct chemicals detected in the district’s water system are total trihalomethanes and haloacetic acids, which after many years of consumption may cause some people to experience liver, kidney or central nervous system problems and may increase the risk of cancer.

While the system exceeds the standard, no effects on human health are anticipated from this short-term exposure.

Although detected in trace amounts over the federal drinking water standard, the district is required to notify the public when detection goes above health-based standards. The drinking water standard for total trihalomethanes is 80 parts-per-billion; the Groveland system had a range from 126 to 142 ppb. The drinking water standard for haloacetic acids is 60 ppb; the Groveland system had a range from 75 to 110 ppb.

The district was required to monitor its water system for these chemicals on a quarterly basis beginning January 2004. The district violated the standard from Jan. 1, 2004 to Sept. 30, 2005, and the violations are expected to continue until new treatment processes are built.

The order requires the district to submit a compliance plan – including a treatment construction schedule – within 21 days of receiving the order and to reduce disinfection byproducts to below federal standards no later than Sept. 30, 2008.

The EPA has worked closely with the California Department of Health Services which administers most of the Safe Drinking Water program in the state. However, the state has not yet obtained primary enforcement responsibility for the new byproduct regulations.

The EPA approved new disinfection byproduct regulations in December 1998 to protect public health from potentially harmful byproduct chemicals formed when chlorine reacts with natural organic compounds during the treatment process.

The Disinfection and Disinfection Byproduct rule began regulating surface water systems serving ten thousand or more customers in January 2002. Phased implementation of smaller surface systems as well as groundwater systems began in 2004.

This is the third action taken by the EPA against a small water system in California under the agency’s disinfection byproduct regulation. The Groveland Community Services District serves as many as 9,000 customers in Groveland, Big Oak Flat and Pine Mountain Lake.

EPA Announces New Rules that Will Further Improve and Protect Drinking Water

2006-01-22T19:43:00.000-07:00

Source: http://www.waterchat.com/News/Environment/05/Q4/env_051215-03.htm

Thursday December 15, 2005

-- EPA finalized two related drinking water protection rules today -- one that reduces the risk of disease-causing microorganisms from entering water supplies and the other that requires water systems to limit the amount of potentially harmful "disinfection byproducts" (DBPs) that end up in our drinking water.

Signed as EPA enters the 31st anniversary year for the Safe Drinking Water Act, the rules were proposed in August 2003, and were developed from consensus recommendations from a federal advisory committee comprised of state and local governments, tribes, environmental, public health and water industry groups.

"Clean drinking water is a key ingredient to keeping people healthy and our economy strong," said EPA Administrator Stephen L. Johnson. "Over the past seven years EPA has worked collaboratively with stakeholders to develop regulations that will provide a balance between the need to disinfect drinking water and protect citizens from potentially harmful contaminants."

The rules are important public health measures that will decrease the incidence of gastrointestinal illnesses caused by microbial contaminants and reduce potential cancer risks associated with disinfectant byproducts in drinking water. Finalizing the two rules represents the last phase of a congressionally required rulemaking strategy under the 1996 Amendments to the Safe Drinking Water Act.

Long Term 2 Enhanced Surface Water Treatment Rule (LT2)

The "Long Term 2 Enhanced Surface Water Treatment Rule" (LT2), increases monitoring and treatment requirements for water systems that are prone to outbreaks of Cryptosporidium, a waterborne pathogen. Consuming water with Cryptosporidium causes gastrointestinal illness which can be severe in people with weakened immune systems, such as infants or the elderly and could be fatal in people with severely compromised immune systems, such as cancer and AIDS patients. LT2 will improve public health by reducing illness due to Cryptosporidium and other harmful microorganisms in drinking water.

The rule requires that public water systems that are supplied by surface water sources monitor for Cryptosporidium. Those water systems that measure higher levels of Cryptosporidium or do not filter their water must provide additional protection by using options from a "microbial toolbox" of treatment and management processes, such as ultraviolet disinfection, and watershed control programs.

The rule also addresses risks of contamination in systems that store treated drinking water in open reservoirs, where water quality can be compromised by exposure to outdoor elements. The rule requires open reservoirs to either be covered or receive added treatment.

Stage 2 Disinfection Byproducts Rule (Stage 2 DBP)

The "Stage 2 Disinfection Byproducts Rule" (Stage 2 DBP), was developed to balance the benefits and risks posed by drinking water disinfection While disinfection is commonly known as one of the major public health advances of the 20th century, it also creates harmful byproducts that are formed when disinfectants, such as chlorine, combine with naturally occurring materials in water.

The final rule targets water systems that have the greatest risk of high DBPs by using more stringent methods for determining compliance. Under the rule, water systems are required to find monitoring sites where higher levels of DBPs are likely to occur and use these new locations for compliance monitoring. If DBPs are found to exceed drinking water standards at any of these new monitoring locations, water systems must begin to take corrective action.

USEPA Reports Scale and Film in Pipes Can Leach High Levels of Contaminants

2006-01-22T19:25:00.000-07:00

U.S.Environmental Protection Agency (EPA) personnel reported disturbing drinking water distribution system revelations at the Inorganic Contaminants Workshop sponsored by the American Water Works Association on Feb. 1—3. Agency field engineers have been discovering that "regulated inorganic and radiological contaminants present in source water above detectable [analytical detection levels] but less than the safety standard, can accumulate in distribution systems to a significant number of times above their respective standard and that this is a largely unknown, unexplored and universal phenomena."

In other words, though the water leaving a municipal treatment plant complies with all EPA criteria, events occurring in the water distribution system after water leaves the plant can lead to significant spikes in contaminant levels.

Case histories were reported in which scales and biofilm that sheared off or otherwise leached from pipe walls have caused drinking water levels exceeding tens and thousands of milligrams per liter for iron and copper and exceeding hundreds of micrograms per liter as well for arsenic, lead, zinc, and manganese–well above levels considered safe for consumption.

This same phenomenon occurs with radium and causes two distinct problems.

1. Radium in pipe deposits far exceeds the Safe Drinking Water Act MCL of 5 picoCuries per liter.

2. Radium decays to radioactive radon, which is released into the flowing water supply.

One EPA researcher reported that scales in household plumbing could literally cause the home’s water pipe system to exceed the federal government’s toxicity characterization leaching procedure (TCLP) limits–making those deposits, by definition, a "hazardous waste"!

Another meeting report noted a related adverse reaction in household plumbing that is actually being created by the increasing use of chloramination for public water system disinfection. Chlorine typically dissipates from chloramines as water resides in home water pipes. This auto-decomposition creates ammonia, which can then change to nitrites. This "nitrification" lowers water pH in low alkalinity waters–which can lead to iron and copper corrosion in home plumbing.

WQA Technical Director Joseph F. Harrison, P.E., CWS-VI says, "Water Quality Association supports the need for further research into the public health significance of these discoveries. We also urge new research into all possible remedies, such as more effective central treatment and control schemes and the feasibility of using of point-of-use and point-of-entry (POU/POE) water treatment approaches inside the home to provide safeguard barriers for consumers’ public health protection."

Source: WQA February 16, 2004

Drinking water treated with chloramines found to contain highly toxic chemicals, says EPA

2006-01-22T19:20:00.000-07:00

Original source: http://www.newstarget.com/002902.html

INTRODUCTION

Summary:

• Genetic toxicologist Michael Plewa and Elizabeth Wagner, principal research specialist, both in the department of crop scieces, collaborated with three EPA researchers on research into a disinfection byproduct found in drinking water treated with chloramines.

• The discovery raises health-related questions regarding an Environmental Protection Agency plan to encourage all U.S. water-treatment facilities to adopt chlorine alternatives, said Michael J. Plewa [PLEV-uh], a genetic toxicologist in the department of crop sciences.

• "This research says that when you go to alternatives, you may be opening a Pandora's box of new DBPs, and these unregulated DBPs may be much more toxic, by orders of magnitude, than the regulated ones we are trying to avoid."

• Plewa and colleagues, three of them with the EPA, report on the structure and toxicity of five iodoacids found in chloramines-treated water in Corpus Christi, Texas, in this month's issue of the journal Environmental Science & Technology.

• "Not only do they represent a potential danger because of all the water consumed on a daily basis, water is recycled back into the environment.

• The use of chloramines, a combination of chlorine and ammonia, is one of three alternatives to chlorine disinfectant, which has been used for more than 100 years.

• Scientists believe they've identified maybe 50 percent of all DBPs that occur in chlorine-treated water, but only 17 percent of those occurring in chloramines-treated water, 28 percent in water treated with chlorine-dioxide, and just 8 percent in ozone-treated water.

• The DBPs in Corpus Christi's water were found as part of an EPA national occurrence survey of selected public water-treatment plants done in 2002.

The Occurrence of Disinfection By-Products (DBPs) of Health Concern in Drinking Water

2006-01-22T18:45:00.000-07:00

Results of a Nationwide DBP Occurrence Study

EPA/600/R-02/068 September 2002
Source:
http://www.epa.gov/athens/publications/EPA_600_R02_068.pdf

INTRODUCTION

More than 500 disinfection by-products (DBPs) have been reported in the literature for the major disinfectants currently used (chlorine, ozone, chlorine dioxide, chloramines), as well as their combinations (Richardson, 1998). Of these reported DBPs, only a small percentage have been quantified in drinking waters. Thus, there is significant uncertainty over the identity and levels of DBPs that people are actually exposed to in their drinking water. Moreover, only a limited number of DBPs have been studied for adverse health effects. To determine whether the other DBPs pose an adverse health risk, more comprehensive quantitative occurrence and toxicity data are needed. To address this issue, scientists at the U.S. Environmental Protection Agency’s (USEPA’s) National Exposure Research Laboratory (NERL) initiated a proposal for a Nationwide DBP Occurrence Study.

Due to the large number of DBPs identified in drinking waters in the United States and other countries, it is not feasible to quantify all of them, so a way of prioritizing them was needed. Prior to this occurrence study, a multidisciplinary group of experts from the USEPA Office of Water and the USEPA Office of Prevention, Pesticides, and Toxic Substances had initiated a prioritization effort for the >500 DBPs reported in the literature according to their predicted adverse health effects (Woo et al., 2002). An in-depth, mechanism-based, structural activity relationship (SAR) analysis, supplemented by an extensive literature search for genotoxicity and other data, was used to rank the carcinogenic potential of these DBPs. Approximately 50 DBPs that received the highest ranking for potential toxicity, and that were not already included in the USEPA’s Information Collection Rule (ICR), were selected for this occurrence study. Those ~50 DBPs are denoted ‘high priority’ DBPs in this report.

The ‘high priority’ DBPs include brominated, chlorinated, and iodinated species of halomethanes, brominated and chlorinated forms of haloacetonitriles, haloketones, haloacids, and halonitromethanes, as well as analogues of MX [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone] (Table 1). Chemical Abstract Services (CAS) numbers are provided in Table 1 when they were available. Previously, MX had been determined to be the most mutagenic (to Salmonella bacteria) DBP ever identified in drinking water, accounting for as much as 20-50% of the total mutagenic activity measured in chlorinated drinking water samples (Kronberg and Vartiainen, 1988; Backlund et al., 1988; Meier et al., 1987). MX has also been shown to be carcinogenic in laboratory animals (Komulainen et al., 1997). Yet, very little drinking water occurrence data has been obtained for MX, so its potential hazard to humans has not been determined. There have also been recent reports of brominated DBP forms of MX (BMXs) (Suzuki and Nakanishi, 1995). These brominated DBP species are of concern because brominated species of DBPs have been shown to be significantly more carcinogenic than their chlorinated analogues. Brominated nitromethanes have also been recently shown to be extremely cytotoxic and genotoxic in mammalian cells (Plewa et al., 2002; Kargalioglu et al., in press). Specifically, they have been shown to be at least an order of magnitude more genotoxic to mammalian cells than MX and have genotoxicities greater than all of the regulated DBPs, except for monobromoacetic acid. It is interesting that dibromonitromethane and 11 bromonitromethane received the highest priority ranking of all DBPs in the SAR toxicity analysis effort.

It should be noted that Table 1 lists the identity of more than 50 high priority target species. During method development, additional species in the same analyte group were included for some of the drinking water plant surveys.

Because most of the high priority DBPs were from chlorine or chloramine disinfection, a few additional ozone and chlorine dioxide DBPs that were not ranked as a high priority were also included for completeness (i.e., to provide more information on those alternative disinfectants). In addition, methyl tert-butyl ether (MtBE) and methyl bromide, which are volatile organic compounds (VOCs) but not DBPs, were included in the list of target analytes because they are important source water pollutants, and their measurement would provide valuable occurrence information. Regulated and some ICR DBPs were also included in this study for comparison purposes (Table 2). In addition, routine water quality measurements, such as total organic carbon (TOC), total organic halide (TOX), assimilable organic carbon (AOC), and bromide were determined.

What is in Our Drinking Water?

2006-01-19T19:13:00.000-07:00

What is in Our Drinking Water?

Identification of New Chemical Disinfection By-products (DBPs)

What is a DBP? A drinking water disinfection by-product (DBP) is formed when the chemical used for disinfecting the drinking water reacts with natural organic matter and/or bromide/iodide in the source water. Popular disinfectants include chlorine, ozone, chlorine dioxide, and chloramine. Source waters include rivers, lakes, streams, groundwater, and sometimes seawater. We have only known about DBPs since 1974, when chloroform was identified by Rook as a DBP resulting from the chlorination of tap water. Since then, hundreds of DBPs have been identified in drinking water.

So what? Millions of people in the U.S. are exposed to these drinking water DBPs every day. While it is vitally important to disinfect drinking water, as thousands of people died from waterborne illnesses before we started disinfection practices in the early 1900s, it is also important to minimize the chemical DBPs formed. Several DBPs have been linked to cancer in laboratory animals, and as a result, the U.S. EPA has some of these DBPs regulated. However, there are many more DBPs that have still not been identified and tested for toxicity or cancer effects. Currently, we have only identified <50% of the total organic halide (TOX) that is measured in chlorinated drinking water. There is much less known about DBPs from the newer alternative disinfectants, such as ozone, chlorine dioxide, and chloramine, which are gaining in popularity in the U.S. Are these alternative disinfectants safer than chlorine? What kinds of by-products are formed? And, what about the unidentified chlorine DBPs that people are exposed to through their drinking water--both from drinking and showering/bathing? The objective of our research is to find out what these DBPs are--to thoroughly characterize the chemicals formed in drinking water treatment--and to ultimately minimize any harmful ones that are formed.

Our research approach

• Gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), and gas chromatography/infrared spectroscopy (GC/IR) techniques are used to identify the unknown by-products

• NIST and Wiley mass spectral databases are used first to identify any DBPs that happen to be present in these databases

• Because many DBPs are not in these databases, most of our work involves unconventional MS and IR techniques, as well as a great deal of scientific interpretation of the spectra

• High resolution MS provides empirical formula information for the unknown chemical (e.g., how many carbons, hydrogens, oxygens, nitrogens, etc. are in the chemical’s structure)

• Chemical ionization MS provides molecular weight information when this is not provided in conventional electron ionization mass spectra

• IR spectroscopy provides functional group information (e.g., whether the oxygens are due to a carboxylic acid group, a ketone, an alcohol, or an aldehyde)

• LC/MS is used to identify compounds that cannot be extracted from water (the highly polar, hydrophilic ones). This is a major missing gap in our knowledge about DBPs--so far, most DBPs identified have been those that are easily extracted from water

• Novel derivatization techniques are also applied to aid in the identification of highly polar DBPs

• Formation and fate & transport studies are conducted to better understand how certain priority DBPs are formed and transformed in treatment and distribution systems

• Once DBPs are identified, ones that are predicted to have adverse health effects are studied in order to determine how they are formed (so that the treatment can be modified to ultimately minimize their presence in drinking water)

Currently

We recently completed a major nationwide DBP occurrence study EPA/600/R-02/068, where we sampled drinking water across the U.S. (disinfected with the different disinfectants and with different water quality, including elevated levels of bromide in the source water). A group of >50 DBPs that resulted from a prioritization of >500 DBPs in the literature for predicted adverse health effects was quantified in these drinking waters. Fate and transport studies were also conducted in the drinking water distribution systems to determine whether these DBPs changed in concentration or were transformed in the distribution systems. In addition to obtaining important quantitative information on these new DBPs (to help in prioritizing health effects testing), important new discoveries were made regarding the use of alternative disinfectants. While the use of alternative disinfectants lowered the levels of the four regulated trihalomethanes and five haloacetic acids (as compared to chlorine), many of the other prioritized DBPs were formed at higher levels with these alternative disinfectants. For example, the highest levels of iodinated DBPs were found in chloraminated drinking water, the highest levels of trihalonitromethanes were found in pre-ozonated drinking water, and dihaloaldehydes were highest at a plant using chloramines and ozone.

Our new work includes obtaining quantitative occurrence information on the iodo-acids that were identified for the first time in the Nationwide DBP Occurrence Study. Chloraminated waters (where levels are expected to be highest) are targeted for this work. In addition, a toxicity-based identification approach (using mammalian cell and medaka fish assays) will be used to ensure toxicologically important DBPs are not being missed. The full study of the Four Lab Study is also expected to begin in 2005 (where drinking water is treated and concentrated, comprehensive DBP identifications are carried out, and drinking water concentrates are tested in a battery of in vivo and in vitro toxicity assays, with an emphasis on newer reproductive and developmental health effects). This Four Lab Study involves the collaboration of EPA's national laboratories and centers (NHEERL, NERL, NRMRL, and NCEA). Finally, work continues in determining how the toxicologically significant bromonitromethane DBPs are formed. These bromonitromethanes are more genotoxic and cytotoxic to mammalian cells than most of the DBPs currently regulated and are also currently the focus of in vivo testing at NHEERL (RTP, NC) and at the National Toxicology Program (NTP, NIEHS).

Recent results

• A recent Nationwide DBP Occurrence Study has provided important new quantitative information on unregulated DBPs that have the potential to cause adverse health effects based on a structure-activity analysis (Woo et al., 2002); several of these DBPs have concentrations similar to some that are already regulated

• The use of alternative disinfectants can produce higher levels of these DBPs, as compared to chlorine

• A recent study reveals that iodoacetic acid (one of five new iodo-acids recently identified in chloraminated drinking water) is a potent cytotoxin and genotoxin in mammalian cells (Plewa et al., 2004a) (work is in progress on the toxicity of other iodo-acids)

• The presence of natural bromide in the source water results in a tremendous shift from chlorine-containing DBPs to bromine-containing DBPs when chlorine or chloramine is used as a disinfectant (even in combination with ozone)

• New analytical methods have been developed (and are continuing to be developed) for the analysis of highly polar DBPs

• Collaborations have been forged with health effects researchers to study selected DBPs for potential adverse health effects

Upcoming event

There will be a new Gordon Research Conference on drinking water DBPs on August 13-18, 2006, at Mount Holyoke College in South Hadley, Massachusetts. Title of meeting: Drinking Water Disinfection By-products: Integrating Occurrence and Formation, Exposure, Toxicity, and Epidemiology. Updates on this meeting can be found at www.grc.org/programs/2006/drinking.htm. Contact Susan Richardson for more information (richardson.susan@epa.gov).

Source http://www.epa.gov/athens/research/process/drinkingwater.html