Water quality
Water quality refers to the
Impacts on public health
Over time, there has been increasing recognition of the importance of drinking water quality and its impact on public health. This has led to increasing protection and management of water quality.[4]
The understanding of the links between water quality and health continues to grow and highlight new potential health crises: from the chronic impacts of
Categories
The parameters for water quality are determined by the intended use. Work in the area of water quality tends to be focused on water that is
Human consumption
Contaminants that may be in untreated water include
The United States Environmental Protection Agency[6] (EPA) limits the amounts of certain contaminants in tap water provided by US public water systems. The Safe Drinking Water Act authorizes EPA to issue two types of standards:
- primary standards regulate substances that potentially affect human health;[7][8]
- secondary standards prescribe aesthetic qualities, those that affect taste, odor, or appearance.[9]
The U.S. Food and Drug Administration (FDA) regulations establish limits for contaminants in bottled water. [10] Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of these contaminants does not necessarily indicate that the water poses a health risk.
In urbanized areas around the world, water purification technology is used in municipal water systems to remove contaminants from the source water (surface water or groundwater) before it is distributed to homes, businesses, schools and other recipients. Water drawn directly from a stream, lake, or aquifer and that has no treatment will be of uncertain quality in terms of potability.[3]
The burden of polluted drinking water disproportionally effects under-represented and vulnerable populations.[11] Communities that lack these clean drinking-water services are at risk of contracting water-borne and pollution-related illnesses like Cholera, diarrhea, dysentery, hepatitis A, typhoid, and polio.[12] These communities are often in low-income areas, where human wastewater is discharged into a nearby drainage channel or surface water drain without sufficient treatment, or is used in agricultural irrigation.
Industrial and domestic use
Environmental water quality
Environmental water quality, also called ambient water quality, relates to water bodies such as lakes, rivers, and oceans.[16] Water quality standards for surface waters vary significantly due to different environmental conditions, ecosystems, and intended human uses. Toxic substances and high populations of certain microorganisms can present a health hazard[17] for non-drinking purposes such as irrigation, swimming, fishing, rafting, boating, and industrial uses. These conditions may also affect wildlife, which use the water for drinking or as a habitat. According to the EPA, water quality laws generally specify protection of fisheries and recreational use and require, as a minimum, retention of current quality standards.[18] In some locations, desired water quality conditions include high dissolved oxygen concentrations, low chlorophyll-a concentrations, and high water clarity.[19]
There is some desire among the public to return water bodies to pristine, or pre-industrial conditions.
Sampling and measurement
Sample collection
The complexity of water quality as a subject is reflected in the many types of measurements of water quality indicators. Some measurements of water quality are most accurately made on-site, because water exists in
depth.Sampling of water for physical or chemical testing can be done by several methods, depending on the accuracy needed and the characteristics of the contaminant. Sampling methods include for example simple random sampling, stratified sampling, systematic and grid sampling, adaptive cluster sampling, grab samples, semi-continuous monitoring and continuous, passive sampling, remote surveillance, remote sensing, and biomonitoring. The use of passive samplers greatly reduces the cost and the need of infrastructure on the sampling location.
Many contamination events are sharply restricted in time, most commonly in association with rain events. For this reason "grab" samples are often inadequate for fully quantifying contaminant levels.[21] Scientists gathering this type of data often employ auto-sampler devices that pump increments of water at either time or discharge intervals.
More complex measurements are often made in a laboratory requiring a water sample to be collected, preserved, transported, and analyzed at another location.
Issues
The process of water sampling introduces two significant problems:
- The first problem is the extent to which the sample may be representative of the water source of interest. Water sources vary with time and with location. The measurement of interest may vary seasonally or from day to night or in response to some activity of man or natural populations of aquatic maxima and minima require individual measurements over a range of times, locations or events. The sample collection procedure must assure correct weighting of individual sampling times and locations where averaging is appropriate.[23]: 39–40 Where critical maximum or minimum values exist, statistical methods must be applied to observed variation to determine an adequate number of samples to assess the probability of exceeding those critical values.[24]
- The second problem occurs as the sample is removed from the water source and begins to establish chemical equilibrium with its new surroundings – the sample container. Sample containers must be made of materials with minimal reactivity with substances to be measured; pre-cleaning of sample containers is important. The water sample may dissolve part of the sample container and any residue on that container, and chemicals dissolved in the water sample may sorb onto the sample container and remain there when the water is poured out for analysis.[23]: 4 Similar physical and chemical interactions may take place with any pumps, piping, or intermediate devices used to transfer the water sample into the sample container. Water collected from depths below the surface will normally be held at the reduced pressure of the atmosphere; so gas dissolved in the water will collect at the top of the container. Atmospheric gas above the water may also dissolve into the water sample. Other chemical reaction equilibria may change if the water sample changes temperature. Finely divided solid particles formerly suspended by water turbulence may settle to the bottom of the sample container, or a solid phase may form from biological growth or chemical precipitation. Microorganisms within the water sample may biochemically alter concentrations of oxygen, carbon dioxide, and organic compounds. Changing carbon dioxide concentrations may alter pH and change solubility of chemicals of interest. These problems are of special concern during measurement of chemicals assumed to be significant at very low concentrations.[22]
Sample preservation may partially resolve the second problem. A common procedure is keeping samples cold to slow the
Testing in response to natural disasters and other emergencies
After events such as earthquakes and tsunamis, there is an immediate response by the aid agencies as relief operations get underway to try and restore basic infrastructure and provide the basic fundamental items that are necessary for survival and subsequent recovery.[26] The threat of disease increases hugely due to the large numbers of people living close together, often in squalid conditions, and without proper sanitation.[27]
After a natural disaster, as far as water quality testing is concerned, there are widespread views on the best course of action to take and a variety of methods can be employed. The key basic water quality parameters that need to be addressed in an emergency are bacteriological indicators of fecal contamination, free chlorine residual, pH, turbidity and possibly conductivity/total dissolved solids. There are many decontamination methods.[28][29]
After major natural disasters, a considerable length of time might pass before water quality returns to pre-disaster levels. For example, following the
Chemical analysis
The simplest methods of
Making these complex measurements can be expensive. Because direct measurements of water quality can be expensive, ongoing monitoring programs are typically conducted and results released by government agencies. However, there are local volunteer programs and resources available for some general assessment.[33] Tools available to the general public include on-site test kits, commonly used for home fish tanks, and biological assessment procedures.
Biosensors
Biosensors have the potential for "high sensitivity, selectivity, reliability, simplicity, low-cost and real-time response".[34] For instance, bionanotechnologists reported the development of ROSALIND 2.0, that can detect levels of diverse water pollutants.[35][36]
Real-time monitoring
Although water quality is usually sampled and analyzed at laboratories, since the late 20th century there has been increasing public interest in the quality of drinking water provided by municipal systems. Many water utilities have developed systems to collect real-time data about source water quality. In the early 21st century, a variety of sensors and remote monitoring systems have been deployed for measuring water pH, turbidity, dissolved oxygen and other parameters.[37] Some remote sensing systems have also been developed for monitoring ambient water quality in riverine, estuarine and coastal water bodies.[38][39]
The following is a list of indicators often measured by situational category:
- Alkalinity
- Color of water
- pH
- Taste and odor (geosmin, 2-Methylisoborneol (MIB), etc.)
- Dissolved metals and salts (sodium, chloride, potassium, calcium, manganese, magnesium)
- Microorganisms such as Giardia lamblia; see Bacteriological water analysis
- Dissolved metals and metalloids (lead, mercury, arsenic, etc.)
- Dissolved organics: colored dissolved organic matter (CDOM), dissolved organic carbon (DOC)
- Radon
- Heavy metals
- Pharmaceuticals
- Hormone analogs
Environmental indicators
Physical indicators
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Chemical indicators
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Biological indicators
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Individuals interested in monitoring water quality who cannot afford or manage lab scale analysis can also use biological indicators to get a general reading of water quality. One example is the IOWATER volunteer water monitoring program of Iowa, which includes an EPT indicator key.[42]
Bivalve molluscs are largely used as
The Southern African Scoring System (SASS) method is a biological water quality monitoring system based on the presence of benthic macroinvertebrates (EPT). The SASS
Climate change impacts
Weather and its related shocks can affect water quality in several ways. These depend on the local climate and context.[45] Shocks that are linked to weather include water shortages, heavy rain and temperature extremes. They can damage water infrastructure through erosion under heavy rainfall and floods, cause loss of water sources in droughts, and make water quality deteriorate.[45]
Climate change can reduce lower water quality in several ways:[46]: 582
- Heavy rainfall can rapidly reduce the water quality in rivers and shallow groundwater. It can affect water quality in reservoirs even if these effects can be slow.[47] Heavy rainfall also impacts groundwater in deeper, unfractured aquifers. But these impacts are less pronounced. Rainfall can increase fecal contamination of water sources.[45]
- Floods after heavy rainfalls can mix floodwater with wastewater. Also pollutants can reach water bodies by increased surface runoff.
- Groundwater quality may deteriorate due to droughts. The pollution in rivers that feed groundwater becomes less diluted. As groundwater levels drop, rivers may lose direct contact with groundwater.[48]
- In coastal regions, more saltwater may mix into freshwater aquifers due to sea level rise and more intense storms.[49]: 16 [50] This process is called saltwater intrusion.
- Warmer water in lakes, oceans, reservoirs and rivers can cause more eutrophication. This results in more frequent harmful algal blooms.[46]: 140 Higher temperatures cause problems for water bodies and aquatic ecosystems because warmer water contains less oxygen.[51]
- Permafrost thawing leads to an increased flux of contaminants.[52]
- Increased meltwater from glaciers may release contaminants.[53] As glaciers shrink or disappear, the positive effect of seasonal meltwater on downstream water quality through dilution is disappearing.[54]
Standards and reports
In the setting of standards, agencies make political and technical/scientific decisions based on how the water will be used.
Another general perception of water quality is that of a simple property that tells whether water is
International
- The World Health Organization (WHO) published updated guidelines for drinking-water quality (GDWQ) in 2017.[3]
- The International Organization for Standardization (ISO) published [when?] regulation of water quality in the section of ICS 13.060,[57] ranging from water sampling, drinking water, industrial class water, sewage, and examination of water for chemical, physical or biological properties. ICS 91.140.60 covers the standards of water supply systems.[58]
National specifications for ambient water and drinking water
European Union
The water policy of the
- Directive on Urban Waste Water Treatment (91/271/EEC) of 21 May 1991 concerning discharges of municipal and some industrial wastewaters;
- The Drinking Water Directive (98/83/EC) of 3 November 1998 concerning potable water quality;
- Water Framework Directive (2000/60/EC) of 23 October 2000 concerning water resources management.
India
- Indian Council of Medical Research (ICMR) Standards for Drinking Water.
South Africa
Water quality guidelines for South Africa are grouped according to potential user types (e.g. domestic, industrial) in the 1996 Water Quality Guidelines.[59] Drinking water quality is subject to the South African National Standard (SANS) 241 Drinking Water Specification.[60]
United Kingdom
In England and Wales acceptable levels for drinking water supply are listed in the "Water Supply (Water Quality) Regulations 2000."[61]
United States
In the United States,
Drinking water standards, which are applicable to public water systems, are issued by EPA under the Safe Drinking Water Act.[8]
See also
- Aquatic toxicology
- Permanganate index
- Stiff diagram, a graphical representation of chemical analyses
- Water clarity
- Water quality modelling
- Water testing
- Water treatment
References
- ^ Cordy, Gail E. (March 2001). "A Primer on Water Quality". Reston, VA: U.S. Geological Survey (USGS). FS-027-01.
- .
- ^ ISBN 9789241549950.
- ^ PMID 36196073. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
- ^ "Other Uses and Types of Water". Atlanta, GA: US Centers for Disease Control and Prevention (CDC). 10 August 2021.
- ^ "What is water quality? Eight key characteristics". Water Rangers. Retrieved 10 November 2022.
- ^ U.S. Environmental Protection Agency (EPA), Washington, D.C. "National Primary Drinking Water Regulations." Code of Federal Regulations, 40 CFR 141.
- ^ a b "Drinking Water Regulations". Drinking Water Requirements for States and Public Water Systems. EPA. 20 September 2022.
- ^ "Secondary Drinking Water Standards: Guidance for Nuisance Chemicals". EPA. 17 February 2022.
- ^ "FDA Regulates the Safety of Bottled Water Beverages Including Flavored Water and Nutrient-Added Water Beverages". Food Facts for Consumers. Silver Spring, MD: U.S. Food and Drug Administration. 22 September 2018.
- ISBN 978-3-319-71388-5.
- ^ "Drinking-water". WHO. 21 March 2022. Fact sheet.
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- ^ WHO (2004). "Consensus of the Meeting: Nutrient minerals in drinking-water and the potential health consequences of long-term consumption of demineralized and remineralized and altered mineral content drinking-waters." Rolling Revision of the WHO Guidelines for Drinking-Water Quality (draft). From 11–13 November 2003 meeting in Rome, Italy at the WHO European Centre for Environment and Health.
- ^ "Supplemental Module: Human Health Ambient Water Quality Criteria". EPA. 28 June 2022.
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Plastic is the most common type of marine debris found in oceans, and it is the most widespread problem affecting the marine environment. It also threatens ocean health, food safety and quality, human health, and coastal tourism, and it contributes to climate change
- ^ Water Quality Standards Handbook Chapter 3: Water Quality Criteria (PDF). EPA. 2017. EPA 823-B-17-001.
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- ^ "Watershed Restoration Program". Washington, DC: US Forest Service. Retrieved 5 October 2022.
- ^ "Sampling - KFUPM School , nature is us - Forums - Tunza Eco Generation". tunza.eco-generation.org. Archived from the original on 7 March 2023. Retrieved 19 September 2021.
- ^ a b
Goldman, Charles R.; Horne, Alexander J. (1983). "6. Chemicals and Growth Factors". Limnology. McGraw-Hill. ISBN 0-07-023651-8.
- ^ ISBN 0-87553-078-8
- ^ "Chapter 8. Data Analysis". Handbook for Monitoring Industrial Wastewater (Report). EPA. August 1973. EPA 625/6-73/002.
- ^ "Definitions of Quality-Assurance Data". Denver, CO: USGS, Quality Systems Branch. 28 August 2009. Archived from the original on 7 March 2023. Retrieved 5 October 2022.
- ^ Natural Disasters and Severe Weather (13 August 2014). "Tsunamis: Water Quality". CDC.
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- ^ Method 1680: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation using Lauryl Tryptose Broth (LTB) and EC Medium (Report). EPA. April 2010. EPA 821-R-10-003.
- ^ WHO (2011). "WHO technical notes for emergencies." Archived 12 February 2016 at the Wayback Machine Water Engineering Development Centre, Loughborough University, Leicestershire, UK.
- ^ State of California Environmental Protection Agency Representative Sampling of Ground Water for Hazardous Substances (1994) pp. 23–24
- ^ An example of a local government-sponsored volunteer monitoring program: "Monitoring Our Waters". Watershed Restoration. Rockville, MD: Montgomery County Department of Environmental Protection. Retrieved 11 November 2018..
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- ^ "DNA computer could tell you if your drinking water is contaminated". New Scientist. Retrieved 16 March 2022.
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- ^ Distribution System Water Quality Monitoring: Sensor Technology Evaluation Methodology and Results (Report). EPA. October 2009. EPA 600/R-09/076.
- ^ "Water Quality Monitoring". Lyndhurst, New Jersey: Meadowlands Environmental Research Institute. 6 August 2018.
- ^ "Eyes on the Bay". Annapolis, MD: Maryland Department of Natural Resources. Chesapeake Bay. Retrieved 5 December 2018.
- ^ "Whole Effluent Toxicity Methods". Clean Water Act Analytical Methods. EPA. 1 August 2020.
- ^ Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms (Report). EPA. October 2002. EPA-821-R-02-012.
- ^ IOWATER (Iowa Department of Natural Resources). Iowa City, IA (2005). "Benthic Macroinvertebrate Key."
- ^ "Center for Coastal Monitoring and Assessment: Mussel Watch Contaminant Monitoring". Ccma.nos.noaa.gov. 14 January 2014. Archived from the original on 7 September 2015. Retrieved 4 September 2015.
- ^ Dickens CWS and Graham PM. 2002. The Southern Africa Scoring System (SASS) version 5 rapid bioassessment for rivers "African Journal of Aquatic Science", 27:1–10.
- ^ PMID 34826465.
- ^ a b Caretta, M.A., A. Mukherji, M. Arfanuzzaman, R.A. Betts, A. Gelfan, Y. Hirabayashi, T.K. Lissner, J. Liu, E. Lopez Gunn, R. Morgan, S. Mwanga, and S. Supratid, 2022: Chapter 4: Water. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 551–712, doi:10.1017/9781009325844.006.
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- ISBN 978-92-808-6038-2, United Nations University
- doi:10.1088/1748-9326/aaba52. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
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- ^ "What Are Water Quality Standards?". Standards for Water Body Health. EPA. 14 April 2022.
- ^ Daniels, Mike; Scott, Thad; Haggard, Brian; Sharpley, Andrew; Daniel, Tommy (2009). "What is Water Quality?" (PDF). University of Arkansas Division of Agriculture. Archived from the original (PDF) on 1 December 2020. Retrieved 2 December 2020.
- ^ International Organization for Standardization (ISO). "13.060: Water quality". Geneva. Retrieved 4 July 2011.
- ^ ISO. "91.140.60: Water supply systems". Retrieved 4 July 2011.
- ^ Republic of South Africa, Department of Water Affairs, Pretoria (1996). "Water quality guidelines for South Africa: First Edition 1996."
- ^ Hodgson K, Manus L. A drinking water quality framework for South Africa. Water SA. 2006;32(5):673–678 [1].
- ^ National Archives, London, UK. "The Water Supply (Water Quality) Regulations 2000." 2000 No. 3184. 2000-12-08.
- ^ U.S. Clean Water Act, Section 303, 33 U.S.C. § 1313.
- ^ U.S. Clean Water Act, Section 303(d), 33 U.S.C. § 1313; Section 305(b), 33 U.S.C. § 1315(b).
- ^ "Overview of Listing Impaired Waters under CWA Section 303(d)". Impaired Waters and TMDLs. EPA. 31 August 2022.
- ^ "National Water Quality Inventory Report to Congress". Water Data and Tools. EPA. 7 December 2021.
- ^ More information about water quality in the United States is available on EPA's "How's My Waterway" website.
External links
- Global Freshwater Quality Database (GEMStat) – United Nations environment program
- Water policy in the European Union
- U.S. Centers for Disease Control and Prevention (CDC) – Drinking water quality and testing (United States)
- U.S. Environmental Protection Agency – Water Data and Tools of the USEPA
- U.S. Geological Survey – National Water Quality Assessment Program of the USGS
Archived 24 March 2018 at the Wayback Machine – Professional association