News & Events

Newsletter

May 2005

Contaminant Candidate List 2


The USEPA’s Contaminant Candidate List (CCL) contains contaminants prioritized for sampling, research, and rulemaking consideration. Finalized earlier this year, the second CCL contains 51 contaminants that were previously included on the first CCL (of 1998) but for which regulatory determinations were not made.


Preliminary regulatory determinations on the CCL2 are anticipated in the summer of 2005, with final decisions expected in August of 2006. In addition, the USEPA has set some goals for itself when creating future CCLs:


  • Evaluate a wider range of information;
  • Screen contaminants more systematically; and
  • Develop a more comprehensive CCL by expanding the number of contaminants being reviewed for inclusion on the next CCL.


A few of the microbial and chemical contaminants on the second Contaminant Candidate List are summarized below. For more information, including a complete list of the 9 microbial contaminants and 42 chemical contaminants on the CCL2, visit the USEPA CCL website.

Adenoviruses
The family Adenoviridae is classified into the two genera Mastadenovirus (mammal hosts) and Aviadenovirus (avian hosts). Adenoviruses are widespread in nature, infecting birds, mammals and amphibians. To date, 51 antigenic types of human adenoviruses (HAds) have been described.


HAds have been shown to occur in substantial numbers in raw water sources and treated drinking-water supplies. In view of their prevalence as an enteric pathogen and detection in water, contaminated drinking-water represents a likely but unconfirmed source of HAd infections.


Excerpts from:

Aeromonas hydrophila
Aeromonas hydrophila are Gram-negative, non-spore-forming, rod-shaped, facultative anaerobic bacilli belonging to the family Aeromonadaceae. Aeromonas spp. can cause infections in humans, including septicaemia, particularly in immunocompromised patients, wound infections and respiratory tract infections. There have been some claims that Aeromonas spp. can cause gastrointestinal illness, but epidemiological evidence is not consistent.


Aeromonas spp. are generally readily found in most fresh waters, and they have been detected in many treated drinking-water supplies, mainly as a result of growth in distribution systems. The factors that affect the occurrence of Aeromonas spp. in water distribution systems are not fully understood, but organic content, temperature, the residence time of water in the distribution network and the presence of residual chlorine have been shown to influence population sizes.


Excerpts from:

Caliciviruses
The family Caliciviridae consists of four genera of single-stranded RNA viruses with a non-enveloped capsid (diameter 35–40 nm), which generally displays a typical surface morphology resembling cup-like structures. Human caliciviruses (HuCVs) include the genera Norovirus (Norwalk-like viruses) and Sapovirus (Sapporo-like viruses).


HuCVs are a major cause of acute viral gastroenteritis in all age groups. Drinking-water and a wide variety of foods contaminated with human faeces have been confirmed as major sources of exposure. Numerous outbreaks have been associated with contaminated drinking-water, ice, water on cruise ships and recreational waters.


Excerpts from:

Helicobacter pylori
Helicobacter pylori, originally classified as Campylobacter pylori, is a Gram-negative, microaerophilic, spiral-shaped, motile bacterium. There are at least 14 species of Helicobacter, but only H. pylori has been identified as a human pathogen.


Humans appear to be the primary host of H. pylori. Consumption of contaminated drinking-water has been suggested as a potential source of infection, but further investigation is required to establish any link with waterborne transmission.


Excerpts from:

Microsporidia
The term "microsporidia" is a non-taxonomic designation commonly used to describe a group of obligate intracellular protozoa belonging to the phylum Microspora. More than 100 microsporidial genera and almost 1000 species have been identified.


Microsporidia are emerging human pathogens identified predominantly in persons with AIDS, but their ability to cause disease in immunologically normal hosts has been recognized. Little is known about transmission of microsporidia. Waterborne transmission has been reported, and infection arising from contaminated drinking-water is plausible but unconfirmed.


Excerpts from:

Mycobacterium avium intracellulare (MAC)
Non-tuberculous or "atypical" species of Mycobacterium are natural inhabitants of a variety of water environments. These aerobic, rod-shaped and acid-fast bacteria grow slowly in suitable water environments and on culture media. The term M. avium complex (MAC) has been used to describe a group of pathogenic species including M. avium and M. intracellulare. However, other atypical mycobacteria are also pathogenic.


Detections of atypical mycobacteria in drinking-water and the identified routes of transmission suggest that drinking-water supplies are a plausible source of infection. There are limited data on the effectiveness of control measures that could be applied to reduce the potential risk from these organisms.


Excerpts from:

1,1,2,2-Tetrachloroethane
In the past 1,1,2,2-tetrachloroethane was used in large amounts to produce other chemicals and as an industrial solvent. Its production has decreased significantly in the United States. Other chemicals are now available to replace this solvent, and large-scale commercial production has stopped.


Most 1,1,2,2-tetrachloroethane released into the environment eventually moves into the air or ground water. Although individuals may be exposed to 1,1,2,2-tetrachloroethane from contaminated drinking water, this rarely happens, at least in larger community drinking water systems. In a few instances, 1,1,2,2-tetrachloroethane has been found in private well water that may have been used for drinking.


Excerpts from:

1,1-Dichloroethane
1,1-Dichloroethane is used as a chemical intermediate and solvent. 1,1-Dichloroethane has been found in drinking water in the United States at levels that range from trace amounts to 4.8 parts per billion (ppb). 1,1-Dichloroethane has not been detected in any surface water samples from rivers, lakes, or ponds. Because of the widespread use and disposal of this chemical, its occurrence in groundwater may increase.


Excerpts from:

1,2-Diphenylhydrazine
1,2-Diphenylhydrazine is a white solid that dissolves only slightly in water and does not change into a gas unless it is heated to very high temperatures. Once in water or exposed to air it is changed into other chemicals within minutes, including the toxic chemicals azobenzene and benzidine.


Excerpts from:

1,3-Dichloropropene
1,3-Dichloropropene is a soil fumigant, the commercial product being a mixture of cis and trans isomers. It is used to control a wide variety of soil pests, particularly nematodes in sandy soils. Notwithstanding its high vapor pressure, it is soluble in water at the gram per liter level and can be considered a potential water contaminant.


In high crop-producing states like California where it has been used often, very little 1,3-dichloropropene has actually been found in groundwater. However it may be a problem at hazardous waste sites. In addition, small amounts of 1,3-dichloropropene can form in drinking water when chlorine is added to the water supply.


Excerpts from:

Aluminum
Aluminum is the most abundant metallic element and constitutes about 8% of the Earth’s crust. Aluminum salts are widely used in water treatment as coagulants to reduce organic matter, color, turbidity and microorganism levels. Such use may lead to increased concentrations of aluminum in finished water.


The concentration of aluminum in natural waters is generally below 0.1 parts per million (ppm) unless the water is very acidic. People generally consume very little aluminum from drinking water – even when drinking water is treated with aluminum salts, aluminum levels generally do not exceed 0.1 ppm.


Excerpts from:

Boron
Boron compounds are used in the manufacture of glass, soaps and detergents and as flame retardants. The general population obtains the greatest amount of boron through food intake, as it is naturally found in many edible plants. Boron is found naturally in groundwater, but its presence in surface water is frequently a consequence of the discharge of treated sewage effluent, in which it arises from use in some detergents, to surface waters.


Excerpts from:

Diazinon
Diazinon is the common name of an organophosphorus insecticide used to control pest insects. Diazinon may enter the environment during the manufacturing process, but most environmental contamination comes from agricultural and household application of the chemical to control insects.


In the environment, diazinon is rapidly broken down into a variety of other chemicals, but can move through the soil and contaminate ground water. Diazinon has been found in surface and ground water samples collected at many locations, however only a few of these samples contained high levels of diazinon contamination.


Excerpts from:

Metolachlor
Metolachlor is a selective pre-emergence herbicide used on a number of crops. It can be lost from the soil through biodegradation, photodegradation and volatilization. It is fairly mobile and under certain conditions can contaminate groundwater, but it is mostly found in surface water. Little is known regarding the relative distribution of metolachlor in drinking water and food.


Excerpts from:

Molinate
Molinate is a herbicide used to control broad-leaved and grassy weeds in rice. The available data suggest that groundwater pollution by molinate is restricted to some rice-growing regions. Data on the occurrence of molinate in the environment are limited. Molinate is of low persistence in water and soil, with a half-life of about 5 days.


Excerpts from:


We are making our newsletters available by email. The WaterTrax Newsletter contains information on water and wastewater quality and regulatory issues, client stories, and WaterTrax service features. Please click the "signup for our Newsletter" button above and fill out the form.  You will then be sent an email with a confirmation link, please click the link to be added to our email list and to receive our quarterly newsletter.


Free Web Seminar

Attend this seminar to discover an easier way to manage your water or wastewater data efficiently.

Request for Information

Sign up for our newsletter, request someone to contact you to discuss how WaterTrax can help you with your data management, or set up a personal, detailed demonstration of the WaterTrax service.

Client Sign In