Water quality: information, importance, and testing
Facts about water quality
Water quality refers to the suitability of water for various uses according to its physical, chemical, biological, and organoleptic properties (relating to taste). It is especially important to understand and measure water quality as it directly affects human consumption, health, industrial and domestic use, and the natural environment.
Water quality is measured using laboratory techniques or home test kits. Laboratory tests measure several parameters and provide the most accurate results but take the longest time. Home test kits, including test strips, provide quick results but are less accurate.
Water suppliers, including municipalities and bottled water companies, often make their water quality reports publicly available on their websites. The tested water quality standards must meet standards set by local governments which are often influenced by international standards set by industry or water quality organizations such as the World Health Organization (WHO).
What is the water quality?
Water quality is “a measure of the suitability of water for a particular use based on selected physical, chemical, and biological properties,” according to the United States Geological Survey (USGS). Therefore, it is a measure of water conditions relative to human needs or purposes or even the requirements of various species of land or aquatic animals.
Three kinds of water quality parameters are measured. These include physical, chemical, and biological/microbiological factors.
- The physical measure of water quality is those determined by the senses of sight, smell, taste, and touch. These physical parameters include temperature, color, taste, odor, turbidity, and dissolved solids content.
- Chemical factors of water quality are measures of those properties that reflect the environment with which the water comes into contact. These chemical parameters can measure pH, hardness, amount of dissolved oxygen, biochemical oxygen demand (BOD), chemical oxygen demand (COD), levels of chloride, residual chlorine, sulfate, nitrogen, fluoride, iron, manganese, copper, zinc, toxic organic and inorganic substances, as well as radioactive substances.
- Biological parameters of water quality are those measurements that reflect the number of bacteria, algae, viruses, and protozoa present in the water.
Factors affecting water quality
Water quality is affected by anthropogenic activities and natural factors, such as:
- Atmospheric pollution
- Water runoff
- Erosion and sedimentation
Preliminary water quality tests
Water quality testing is done in the laboratory or at home based on local conditions and needs. Laboratory assessment of water quality relies on instrumental and chemical analysis of collected field water samples. Laboratories can measure many physical, chemical, and biological parameters of these samples and provide very accurate results. Unfortunately, laboratory testing of water quality is expensive and time-consuming.
Home water quality testing methods, such as strips, colored tablets, and digital tools, are used to quickly check for the presence of a concentration of common water contaminants. These tests can be used at home as screening tools to determine if further laboratory analysis of water quality is warranted. They are used in commercial or industrial settings as primary screening tools.
What are the water quality classes?
The categories of water quality based on its various uses are as follows:
- Water quality for human consumption
- Measurement of water quality for industrial and domestic use
- Environmental water quality
Water quality for human consumption
Water quality for human consumption covers safe drinking and cooking water that is vital to maintaining human health and forms part of public health policy. Access to high-quality water fit for human consumption, known as “drinking water,” is a basic human right and a necessity for the healthy life and development of individuals and societies. This right was enshrined in international law by United Nations Resolution No. 64/292 of July 2010.
Worldwide, not all people have access to high-quality water. According to WHO statistics, about 785 million people lack basic drinking water services and more than 2 billion people consume drinking water contaminated with feces. This is often associated with the transmission of diseases such as cholera, diarrhea, dysentery, hepatitis A, typhoid, and polio. The World Health Organization estimates that 829,000 people, including 297,000 children under the age of 5, die annually from diarrheal disease caused by the consumption of unsafe water.
Water quality for industrial and domestic use
In industrial settings, a specific type of water called “process water” is used. Process water refers to water used in industry, manufacturing processes, power generation, and similar applications. The standards for process water are aimed at preventing damage to industrial machinery and preventing contamination of industrially manufactured products.
Process water quality standards for different industries and plants vary widely. In the United States, some, but not all, treatments of water for industrial use can be found in the Water Quality Standards Committee Report, “The Green Book” (FWPCA, 1968) and Water Quality Standards 1972, “The Blue Book” (NAS/NAE, 1973). Furthermore, according to the US Environmental Protection Agency (EPA) in the absence of standards for a particular industry, which is often the case, standards established for human consumption can be substituted to protect these uses.
To highlight the complexity of the industrial use of water quality standards, the WHO international standards for water used in the pharmaceutical industry can be taken as an example. Tch
Place process water used in the pharmaceutical industry for water quality systems related to its storage, distribution, sterilization, and bio-load control, as well as monitoring, maintenance, and inspection of its distribution system.
Non-potable domestic water covers uses such as water for sanitation and hygiene which are important aspects of public health. Although one might imagine that an organization like the Environmental Protection Agency would have separate standards for non-potable household water quality, the regulations for domestic use water appear to be similar to those for drinking water.
Environmental water quality
Environmental water quality is critical to the well-being of plants and animals in oceans, rivers, lakes, swamps, and wetlands. It affects people and higher-order species that depend on these ecosystems for food and the transport of nutrients. As such, government organizations have organized different subcategories of environmental water quality.
The U.S. Environmental Protection Agency regulates environmental water quality standards to protect and breed populations of fish and shellfish, waterfowl, shorebirds, and other water-oriented wildlife. Environmental water quality standards are regulated to protect and conserve coral reefs, anchorages, groundwater, and aquifers.
Poor environmental quality associated with contamination by chemicals or microorganisms from farms, towns, and factories is an ever-growing issue. According to United Nations statistics, more than 80 percent of the world’s wastewater flows back into the environment without being treated. This degree of pollution poses risks to humans and aquatic wildlife alike.
Particularly notable examples of environmental water degradation as a result of chemical pollution occurred in Japan during the 20th century. These include the itai-itai and minamata diseases, which were the result of industrial contamination with cadmium and methylmercury of important water sources used for irrigation, drinking water, washing, and fishing by downstream people.
How important is water quality?
The importance of water quality lies in the way it ensures that end users remain healthy and function well if proper standards are maintained. End users may be people who drink healthily, industries that operate unimpeded by out-of-spec water, or natural environments that thrive due to a lack of pollution. Each user has a concentration threshold for different pollutants, beyond which poor-quality water will have adverse effects.
Effects of water quality on human health
Poor quality of drinking water, domestic use, or even recreational water due to contamination can lead to human disease. Drinking water contaminated with microbial organisms contributes significantly to the global burden of disease in the form of diarrhea, cholera, dysentery, hepatitis A, typhoid, and polio. According to the World Health Organization, cholera infects 1.4 to 4 million people and causes 21,000 to 143,000 deaths globally each year. This map from the World Health Organization shows countries where cholera was reported from 2010 to 2015.
Contamination of water sources with chemicals such as solvents, heavy metals, and pesticides poses a threat to humans.
Exposure to heavy metals such as arsenic, chromium, lead, mercury, and cadmium can increase the risk of cancers of the blood, lung, liver, urinary bladder, and kidney.
Effects of water quality on the Environment
Water pollution has negative effects on the environment and on the plants and animals that depend on it. Oil spills, radioactive leaks, garbage, chemical spills, and many other forms of pollution can kill, injure, or disrupt the biological processes of plants and animals.
One of the most important problems is eutrophication. Eutrophication occurs when the environment becomes rich in nutrients such as nitrates and phosphates.
Fertilizers from agricultural pollution are important sources of eutrophic nutrients. Excess nutrients lead to harmful algal blooms that consume massive amounts of oxygen and produce hypoxic dead zones, which are massively fish-killing. The US National Oceanic and Atmospheric Administration (NOAA) reports that up to 65 percent of estuaries and coastal waters in the United States are affected by mild to moderate degrees of eutrophication, with notable examples being the dead zones in the northern Gulf of Mexico and Laurentian. Great lakes.
Effects of water quality on Industry
Almost all industrial manufacturing processes require large amounts of water. Different industries require specific types of water in order to manufacture delicate and delicate products. For example, the manufacture of semiconductors and wafers for use in computers and medical electronics requires deionized, ultrapure water that is free of minerals, dissolved gases, and solid particles. As such, the use of potentially contaminated water containing heavy metals or other contaminants in this manufacturing process can result in imprecise and defective end products.
Similarly, according to the SUEZ Water Technologies Handbook, water used to cool processes or equipment must be free of chemical, mineral, and microbiological contaminants as elevated temperatures can affect its behavior and lead to a tendency for the system to corrode and scale. , or support microbiological growth. Similar water quality requirements can be found in pharmaceuticals, oil and gas, and other industries.
What are the factors and indicators that affect water quality?
These factors affect water:
Atmospheric pollution
mixed contamination of environmental air with gases such as carbon dioxide, sulfur dioxide, and nitrogen oxides combines with water molecules in the air to produce polluted rain, sometimes referred to as acid rain. Acid rain then pollutes the water systems.
Runoff
Surface runoff refers to the flow of excess water across the earth’s surface and into waterways. As the water flows, it can pick up agricultural and industrial pollutants like garbage, oil, chemicals, fertilizers, and other toxic substances that then pollute the water.
Erosion and sedimentation
Soil erosion increases the amount of sediment entering the water. This can contribute to deteriorating water quality because toxic chemicals or naturally occurring but unhealthy elements can stick or be absorbed into sediment particles and then transfer to bodies of water.
Water quality indicators and standards that reflect the influence of natural and artificial processes
Turbidity
Turbidity refers to the turbidity of the water and is a measure of the ability of light to pass through it. It is caused by various suspended materials in the water such as organic matter, mud, silt, and other particulate matter. High turbidity is not aesthetically pleasing and increases the cost of water treatment. The particles provide hiding places for harmful microorganisms, protect them from disinfection processes, and absorb heavy metals and other harmful chemicals.
Temperature
The temperature has indirect effects on water quality. It affects the palatability, viscosity, solubility, and smell of water. It affects disinfection and chlorination processes, biological oxygen demand (BOD), and the way heavy metals behave in water.
The color
The color reflects the concentration of vegetation and inorganic matter in the water. Although it has no direct impact on the safety of the water, it does make the water aesthetically unappealing.
Taste and smell
Taste and smell affect the aesthetic qualities of water. It is determined by the presence of natural, domestic, or agricultural foreign matter in the water.
Total Solids (TS)
There are two types of solids in water, total dissolved solids (TDS) and total suspended solids (TSS).
Solids represent the number of minerals (good or bad) and contamination present in the water. When harmful solids are present, they affect water quality by affecting turbidity, temperature, color, taste, odor, electrical conductivity, and dissolved oxygen content.
Electrical conductivity (EC)
Electrical conductivity indirectly measures the ionic concentration of water by measuring its ability to carry or conduct an electric current. Higher results mean there are more solids in the water.
pH
pH measures how acidic or basic the water is. Excessively high or low pH (<4 or >11) is harmful to using water because it alters the taste and effectiveness of the chlorine disinfection process and increases the solubility of heavy metals in the water making it more toxic.
Hardness
Hardness is a characteristic of mineral water, and it measures the concentrations of certain dissolved minerals, particularly calcium, and magnesium. Hard water can cause mineral buildup in hot water pipes and cause difficulty in producing soapy suds. Very hard water (>500 mg/l calcium carbonate) can have laxative properties.
Dissolved oxygen (DO)
Dissolved oxygen is an indirect measure of water pollution in streams, rivers, and lakes. The lower the dissolved oxygen concentration, the worse the quality. Water with very little or no oxygen tastes bad to most users.
Biochemical oxygen demand (BOD)
Biochemical oxygen demand indirectly measures the degree of microbial contamination and is mainly used as a measure of the strength of wastewater. As microorganisms metabolize organic matter for food, they consume dissolved oxygen (DO) in water. As such, BOD is an indirect indicator of organic matter in water.
Chemical oxygen demand (COD)
It measures the chemical demand for oxygen necessary for the oxidation of all water-soluble and non-soluble substances.
Toxic inorganic substances
Toxic inorganic materials measure concentrations of metallic and non-metallic compounds such as arsenic, silver, mercury, lead, cadmium, nitrates, and cyanide. Parameters of toxic inorganic substances are essential, since their presence, sometimes even in trace amounts, poses a public health risk.
Toxic organic matter
Toxic organics refer to compounds such as pesticides, insecticides, solvents, detergents, and disinfectants that reduce water quality and pose a risk to human health.
Radioactive materials
Radioactive materials decompose to emit beta, alpha, and gamma radiation, which have many harmful effects on human health. Radiation primarily affects the hematopoietic, digestive, reproductive, and nervous systems; It is highly carcinogenic. Thus, water quality standards generally monitor concentrations of alpha particles, beta particles, radium, and uranium.
Vital signs
Biological parameters of water quality analyze the presence or absence of various bacteria, algae, viruses, and protozoa.
How to test water quality
Water quality can be tested at a water quality lab or at home using ready-made test kits.
In-vitro testing requires collecting samples in sterile bottles and sending them to an accredited laboratory for analysis. General chemistry samples are kept and refrigerated before being transported. But microbiological samples must be transported to laboratories within 24 hours of sampling
Laboratory test results take days to complete but are the most accurate as well as the most expensive method of testing. The analysis is performed for hundreds of physical, chemical, biological, and radiological parameters.
Home water testing is a simpler approach to checking for concentrations of some of the most common components in a home or other small location. Home test results are fast and come in seconds or minutes. According to World Bank Water and Sanitation Specialists Jessica Ann Lawson and Pratibha Mistry, testing is done at home through the following three methods.
Test strips
These are strips of paper with squares that change color when dipped in water depending on the presence and concentration of the parameter under test. It is generally the cheapest form of test and exists for many parameters including TDS, pH, hardness, nitrates, detergent chemicals, and others. Some tapes only measure one parameter while others may have multiple measurements on a single tape. To interpret the results, the user waits a set amount of time after dipping the strip into the water, then compares the new color of the square with those on the color chart supplied with the kit.
Color disk sets
They are slightly more expensive than strips and only test one parameter at a time. A sample of water is added to a plastic container at the same time as a liquid or powdered reagent. Then insert the container into a display box with a colored disc for observation. The color dial is rotated until the color of the water sample matches the color of the dial and the concentration is read from the dial.
Digital tools
They are non-disposable, hand-held, battery-powered electronic devices. They are the most accurate and affordable home test kits. Inexpensive digital instruments can be found for $15 or less that measure pH, temperature, total dissolved solids (TDS), or electrical conductivity (EC). Portable salinity meters can cost four times as much. Colorimeters can cost several hundred to more than a thousand US dollars, but they can measure dozens of chemical and physical properties of water by measuring the wavelengths of light absorbed by the substance in the water.
