Related Research Articles
β-Galactosidase is a glycoside hydrolase enzyme that catalyzes hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides.
Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often supplied through taps, in which case it is also called tap water.
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed. The most common standards used to monitor and assess water quality convey the health of ecosystems, safety of human contact, extent of water pollution and condition of drinking water. Water quality has a significant impact on water supply and often determines supply options.
Water pollution is the contamination of water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources. These are sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. Water pollution may affect either surface water or groundwater. This form of pollution can lead to many problems. One is the degradation of aquatic ecosystems. Another is spreading water-borne diseases when people use polluted water for drinking or irrigation. Water pollution also reduces the ecosystem services such as drinking water provided by the water resource.
Bacteriological water analysis is a method of analysing water to estimate the numbers of bacteria present and, if needed, to find out what sort of bacteria they are. It represents one aspect of water quality. It is a microbiological analytical procedure which uses samples of water and from these samples determines the concentration of bacteria. It is then possible to draw inferences about the suitability of the water for use from these concentrations. This process is used, for example, to routinely confirm that water is safe for human consumption or that bathing and recreational waters are safe to use.
The Walkerton E. coli outbreak was the result of a contamination of the drinking water supply of Walkerton, Ontario, Canada, with E. coli and Campylobacter jejuni bacteria. The water supply was contaminated as a result of improper water treatment following heavy rainfall in late April and early May 2000, that had drawn bacteria from the manure of nearby cattle used to fertilize crops into the shallow aquifer of a nearby well. The first reported case was on May 17. The contamination caused gastroenteritis and sickened more than 2,000 people and resulted in seven deaths, and left others with chronic illnesses.
Coliform bacteria are defined as either motile or non-motile Gram-negative non-spore forming bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35–37 °C. They can be aerobes or facultative aerobes, and are a commonly used indicator of low sanitary quality of foods, milk, and water. Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system. While coliform bacteria are not normally the cause of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume. Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites. Every drinking water source must be tested for the presence of these total coliform bacteria.
The coliform index is a rating of the purity of water based on a count of fecal bacteria. It is one of many tests done to assure sufficient water quality. Coliform bacteria are microorganisms that primarily originate in the intestines of warm-blooded animals. By testing for coliforms, especially the well known Escherichia coli, which is a thermotolerant coliform, one can determine if the water has possibly been exposed to fecal contamination; that is, whether it has come in contact with human or animal feces. It is important to know this because many disease-causing organisms are transferred from human and animal feces to water, from where they can be ingested by people and infect them. Water that has been contaminated by feces usually contains pathogenic bacteria, which can cause disease. Some types of coliforms cause disease, but the coliform index is primarily used to judge if other types of pathogenic bacteria are likely to be present in the water.
Wilderness-acquired diarrhea is a variety of traveler's diarrhea in which backpackers and other outdoor enthusiasts are affected. Potential sources are contaminated food or water, or "hand-to-mouth", directly from another person who is infected. Cases generally resolve spontaneously, with or without treatment, and the cause is typically unknown. The National Outdoor Leadership School has recorded about one incident per 5,000 person-field days by following strict protocols on hygiene and water treatment. More limited, separate studies have presented highly varied estimated rates of affliction that range from 3 percent to 74 percent of wilderness visitors. One survey found that long-distance Appalachian Trail hikers reported diarrhea as their most common illness. Based on reviews of epidemiologic data and literature, some researchers believe that the risks have been over-stated and are poorly understood by the public.
Simmons' citrate agar is used for differentiating gram-negative bacteria on the basis of citrate utilization, especially for distinguishing Gammaproteobacteria of the family Enterobacteriaceae or even between species of the same genus. For example, Salmonella enteritidis would yield a positive (blue) result on Simmons’ agar and thus be distinguished from other Salmonella species like Salmonella typhi, Salmonella pullorum, and Salmonella gallinarum, which would yield a negative (green) result.
Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water. They are not dangerous to human health but are used to indicate the presence of a health risk.
Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.
Indicator organisms are used as a proxy to monitor conditions in a particular environment, ecosystem, area, habitat, or consumer product. Certain bacteria, fungi and helminth eggs are being used for various purposes.
The IMViC tests are a group of individual tests used in microbiology lab testing to identify an organism in the coliform group. A coliform is a gram negative, aerobic, or facultative anaerobic rod, which produces gas from lactose within 48 hours. The presence of some coliforms indicate fecal contamination.
Sewage is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residences and from commercial, institutional and public facilities that exist in the locality. Sub-types of sewage are greywater and blackwater. Sewage also contains soaps and detergents. Food waste may be present from dishwashing, and food quantities may be increased where garbage disposal units are used. In regions where toilet paper is used rather than bidets, that paper is also added to the sewage. Sewage contains macro-pollutants and micro-pollutants, and may also incorporate some municipal solid waste and pollutants from industrial wastewater.
Freshwater environmental quality parameters are those chemical, physical and biological parameters that can be used to characterise a freshwater body. Because almost all water bodies are dynamic in their composition, the relevant quality parameters are typically expressed as a range of expected concentrations.
The Portland Water Bureau is the municipal water department for the city of Portland in the U.S. state of Oregon. The bureau manages a water supply that comes mainly from the Bull Run River in the foothills of the Cascade Range east of the city and secondarily from the Columbia South Shore Well Field near the Columbia River. As of 2023, Mingus Mapps was the city commissioner in charge of the bureau, and the chief administrator is Michael Stuhr. Budgeted departmental revenues for fiscal year 2015–16 included about $157 million for charges for services.
Escherichia coli is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infections in humans. Unlike normal flora E. coli, the pathogenic varieties produce toxins and other virulence factors that enable them to reside in parts of the body normally not inhabited by E. coli, and to damage host cells. These pathogenic traits are encoded by virulence genes carried only by the pathogens.
The SOS chromotest is a biological assay to assess the genotoxic potential of chemical compounds. The test is a colorimetric assay which measures the expression of genes induced by genotoxic agents in Escherichia coli, by means of a fusion with the structural gene for β-galactosidase. The test is performed over a few hours in columns of a 96-well microplate with increasing concentrations of test samples. This test was developed as a practical complement or alternative to the traditional Ames test assay for genotoxicity, which involves growing bacteria on agar plates and comparing natural mutation rates to mutation rates of bacteria exposed to potentially mutagenic compounds or samples. The SOS chromotest is comparable in accuracy and sensitivity to established methods such as the Ames test and is a useful tool to screen genotoxic compounds, which could prove carcinogenic in humans, in order to single out chemicals for further in-depth analysis.
Paper-based biosensors are a subset of paper-based microfluidics used to detect the presence of pathogens in water. Paper-based detection devices have been touted for their low cost, portability and ease of use. Its portability in particular makes it a good candidate for point-of-care testing. However, there are also limitations to these assays, and scientists are continually working to improve accuracy, sensitivity, and ability to test for multiple contaminants at the same time.
References
- 1 2 3 4 Doyle, M. P., and M. C. Erickson. 2006. "Closing the door on the fecal coliform assay." Microbe 1:162–163. ISSN 1558-7460.
- ↑ Water Quality Monitoring – A Practical Guide to the Design and Implementation of Freshwater Quality Studies and Monitoring Programmes Edited by Jamie Bartram and Richard Ballance Published on behalf of United Nations Environment Programme and the World Health Organization. 1996 UNEP/WHO ISBN 0 419 22320 7 (Hbk) 0 419 21730 4 (Pbk)
- ↑ Fresno County Department of Public Health. Fresno, CA (2009)."E. coli or Fecal Coliform Bacteria Contamination in Your Water Supply." Archived 2011-07-18 at the Wayback Machine Notice distributed to private well owners.
- ↑ U.S. Environmental Protection Agency (EPA). Washington, DC (2008). "Analytical Methods Approved for Drinking Water Compliance Monitoring under the Total Coliform Rule." June 2008.
- ↑ Hinks, Jamie; et al. (2016). "Naphthoquinone glycosides for bioelectroanalytical enumeration of the faecal indicator Escherichia coli". Microbial Biotechnology. 9 (6): 746–757. doi: 10.1111/1751-7915.12373 . PMC 5072191 . PMID 27364994.
- ↑ EPA (1989-06-29). "Drinking Water; National Primary Drinking Water Regulations; Total Coliforms (Including Fecal Coliforms and E. Coli)." Final rule. Federal Register,54 FR 27544
- ↑ EPA (2013-02-13). "National Primary Drinking Water Regulations: Revisions to the Total Coliform Rule." 78 FR 10269
- ↑ EPA (2014-02-26). "National Primary Drinking Water Regulations: Minor Corrections to the Revisions to the Total Coliform Rule." 79 FR 10665