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Accuracy: The closeness of an indication or reading of a measurement device to the actual value of the quantity being measured.

Acid: A substance that has a pH of less than 7 at 25 °C.

Ex: Lemon juice, Battery acid

Activated charcoal: This is the most commonly used adsorption medium, produced by heating carbonaceous substances or cellulose bases in the absence of air. It has a very porous structure and is commonly used to remove organic matter and dissolved gases from water.

Alkaline: The condition of water or an aqueous solution that contains a sufficient amount of alkali substance to raise the pH above seven.

Ex: Sea water, Milk of magnesia

Analog: A parameter which varies in a continuous, rather than incremental manner.

Area: The amount of surface space an object covers. Area is usually measured in square units e.g. square centimeters (𝑐𝑚2 ), square meters (𝑚2 ) etc.

Aquaculture: The is the culture of aquatic plants and animals under controlled or semi-controlled conditions with varying degrees of intervention in their life cycles, from predation control to feeding and substrate management.


Bacteria: Prokaryotic unicellular round, spiral, or rod-shaped single-celled microorganisms that live in soil, water, organic matter, or the bodies of plants and animals (singular bacterium).

Base: A substance that has a pH of more than 7 at 25 °C.

Ex: Baking Soda, Ammonia

Bicarbonate: Natural inorganic compounds that contain twice as many carbonate compounds as a carbonate.

Boiling Point: The temperature at which a substance in the liquid phase transforms to the gaseous phase; commonly refers to the boiling point of water which is 100°C (212°F) at sea level.

Brightness: Brightness is the relative lightness or darkness of a particular color, from black (no brightness) to white (full brightness).


Calibrate: To determine the indication or output of a device with respect to a standard.

Capacity: The maximum amount of space an object/container can hold. Capacity is measured in standard weight measurement units such as liters(L), grams (g), kilograms(kg), pounds(lbs) etc.

Ex: The maximum capacity of the test tube is 15ml.

Carbonates: the collective term for the natural inorganic chemical compounds related to carbon dioxide that exist in natural waterways.

Ex: Li2CO3, Na2CO3, K2CO3 etc.

CFU: Colony Forming Units. A CFU is defined as a single, viable propagule that produces a single colony (a population of the cells visible to the naked eye) on an appropriate semisolid growth medium. Concentrations of water quality indicator organisms such as fecal coliform bacteria are measured in CFU/100 ml.

Chlorination: The process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid.

Circumference: The distance all the way around a circle. Circumference can be measured using the formula 2𝜋r.

Colorimetry: A scientific technique that is used to determine the concentration of colored compounds in solutions by the application of the Beer–Lambert law, which states that the concentration of a solute is proportional to the absorbance.

Correlation: The measure of the strength of a linear relationship between two quantitative variables (e.g., height, weight) This is when one variable changes the other also changes.

Ex: If the amount of the NaCl in water increases, then the conductivity of the water also increases. There is a direct correlation between the amount of NaCl being added and the conductivity of the water.

Cuvette: It is fundamentally a test tube designed for use with optical analysis with devices such as spectrophotometers, fluorometers etc.

Cuvettes are generally square or rectangular in their cross section in order to avoid refraction. Depending on what part of the spectrum is under consideration, they may be made of quartz or optical glass although plastic cuvettes do exist for less demanding measurements.


Dissolved oxygen (in water) : The level of free oxygen that is dissolved in a given water source or sample. Levels that are too high or too low can harm aquatic life and affect water quality. DO is measured using a dissolved oxygen meter, and is measured in percentage (%).


Electrical conductivity : The capacity of water to conduct electrical current. It is directly proportional to the concentration of salts dissolved in the water. Conductivity is measured with a probe and a meter. Voltage is applied between two electrodes in a probe immersed in the sample water. The drop in voltage caused by the resistance of the water is used to calculate the conductivity per centimeter. Electrical conductivity is measured in μS/cm.


Fluorosis: A health condition that causes the appearance of faint white lines or streaks on the teeth. Ingestion of excess fluoride, most commonly in drinking-water, can cause fluorosis which affects the teeth and bones. Moderate amounts lead to dental effects, but long-term ingestion of large amounts can lead to potentially severe skeletal problems.

Freshwater/Fresh water: Any naturally occurring water except seawater and brackish water. Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. Though the term specifically excludes seawater and brackish water, it does include mineral-rich waters such as springs. Fresh water may include water in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers, streams, and even underground water.


Groundwater: The water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells.


Hardness: A water quality indication of the concentration of alkaline salts in water, mainly calcium and magnesium.

Ex: If the water you use is "hard" then more soap, detergent or shampoo is necessary to raise a lather.

Heuristic: In the context of computer science or mathematical reasoning, a heuristic is a problem-solving method that uses shortcuts to produce good-enough solutions in the shortest time possible. Heuristic methods usually trade off accuracy, precision, optimality, or completeness for speed

The objective of a heuristic is to produce a solution to a given problem in a reasonable time frame that is good enough for solving the problem at hand. The solution produced by the heuristic may not be the best of all possible solutions to the given problem, it may even simply approximate the exact solution. But it is still valuable because finding it does not require an extremely long time.

Hue: A hue refers to the dominant colour — or pure spectrum colours — in a colour family, one without black or white pigment. Primary and Secondary colors (Yellow, Orange, Red, Violet, Blue, and Green) are considered hues and tertiary colors (mixed colors where neither color is dominant) would also be considered hues.


International System of Units: The International System of Units, also commonly known as the SI system or the modern metric system is an internationally used system of measurement. It is the only system of measurement with an official status in nearly every country in the world.

The International System of Units (SI) bases all types of physical measurements on seven base units

Length: Meter (m)

Mass: Kilogram (kg)

Time: Second (s)

Electric current: Ampere (A)

Temperature: Kelvin (K)

Amount of a Substance: Mole (mol)

Luminous Intensity: candela (cd)

Industrial water use: Water used for industrial purposes in such industries as steel, chemical, paper, and petroleum refining. Water for industrial uses comes mainly from self-supplied sources, such as local wells or withdrawal points in a river, but some water comes from public-supplied sources, such as the city water department.




Luminous intensity: Also known as 'Luminance', it is the quantity of visible light that is emitted in unit time per unit solid angle. The unit for the quantity of light intensity is called the ‘lumen’.


Maximum contaminant level (MCL): The designation given by the U.S. Environmental Protection Agency (EPA) to water-quality standards promulgated under the Safe Drinking Water Act. The MCL is the greatest amount of a contaminant that can be present in drinking water without causing a risk to human health.

Measurement: A collection of quantitative or numerical data that describes the property of an object or an event. Measurements are made by comparing a quantity or a quality with its standard unit.

Milligrams per liter (mg/l): A unit of the concentration of a constituent in water or wastewater. It represents 0.001 gram of a constituent in 1 liter of water. It is approximately equal to one part per million (PPM).

Municipal water system: A water system that has at least five service connections or which regularly serves 25 individuals for 60 days; also called a public water system.


Nephelometric Turbidity Unit (NTU): The unit of measure for the turbidity of water. Essentially, a measure of the cloudiness of water as measured by a nephelometer. Turbidity is based on the amount of light that is reflected off particles in the water.


Organic matter: Plant and animal residues, or substances made by living organisms. All are based upon carbon compounds.


Parts per billion: The number of "parts" by weight of a substance per billion parts of water. Used to measure extremely small concentrations.

Parts per million: The number of "parts" by weight of a substance per million parts of water. This unit is commonly used to represent pollutant concentrations.

pH: A measure of the relative acidity or alkalinity of water. Water with a pH of 7 is neutral; lower pH levels indicate increasing acidity, while pH levels higher than 7 indicate increasingly basic (alkaline) solutions.

Pipette: A small apparatus which typically consists of a narrow tube into which fluid is

drawn by suction through a squeezable bulb. It is used to measure or move small amounts of liquids.

Potable water: Potable water is defined as water that is suitable for human consumption (i.e., water that can be used for drinking or cooking). The term implies that the water is drinkable, safe, free of unpleasant odors, tastes and colors, and is within reasonable limits of temperature. 'Safe water' refers to water that contains no toxins, carcinogens, pathogenic microorganisms, and does not pose a threat to human health.

Precision: The precision of a device refers to the closeness of two or more values that have been read by a device to each other.

Ex: If a 1.00 kg block of iron is weighed three times on two different weighing scales, and scale A reads the weight as exactly 1.00 kg every time while scale B reads it as 1.00kg, 1.02kg, 1.05kg each time, scale A is said to be more precise.



Raw water: Water straight from it’s natural source, that has not been processed through a treatment plant.

Residual chlorine: The available chlorine which remains in a water source or sample after the required amount has been consumed by micro organisms or chemical reactions.

Repeatability: The closeness of independent test results, obtained in the same conditions, i.e., with the same method, on the same test material, in the same laboratory, by the same operator, and using the same equipment within short intervals of time.


Salinity: The amount of a salt dissolved in a given amount of water. It is usually measured in parts per million(ppm).

Saline water: Water that contains significant amounts of dissolved salts.

Parameters for saline water are

Fresh water - Less than 1,000 parts per million (ppm)

Slightly saline water - From 1,000 ppm to 3,000 ppm

Moderately saline water - From 3,000 ppm to 10,000 ppm

Highly saline water - From 10,000 ppm to 35,000 ppm

Saturation (chemistry): The degree or extent to which something is dissolved or absorbed compared with the maximum possible, usually expressed as a percentage.

Saturation (color): The intensity of a hue from gray tone (no saturation) to pure, vivid color (high saturation).

Sensitivity: The minimum change in input to which a device can respond.

Shade: Shade is a mixture of pure colors to which only black is added in varying quantities to form different shades of the particular color(s). It contains no white or gray. A shade is a darker form of the color, but the hue remains the same.

Specific conductance: A measure of the ability of water to conduct an electrical current as measured using a 1-cm cell and expressed in units of electrical conductance, i.e., Siemens per centimeter ( S/m) at 25 degrees Celsius. Specific conductance can be used for approximating the total dissolved solids content of water by testing its capacity to carry an electrical current. In water quality, specific conductance is used in groundwater monitoring as an indication of the presence of ions of chemical substances that may have been released by a leaking landfill or other waste storage or disposal facility.

Spectrophotometer: A device used to measure the intensity of light in a part of the spectrum, as transmitted or emitted by particular substances.


Temperature Coefficient: The change in a parameter produced by a change in temperature. It is normally expressed in %/°C or ppm/°C. There are two types of temperature coefficients-

-Positive temperature coefficient ( there there is an increase in temperature coefficient)

-Negative temperature coefficient (where there is a decrease in temperature coefficient).

Thermal conductivity: The ability of a substance to transfer heat by conduction. It is denoted by the symbol 'k'.

Ex: A metal spoon heating up when placed in a vessel of hot liquid.

Tint: A tint refers to any hue or mixture of pure colors to which white is added varying quantities to produce different tints of the particular color(s).

Ex: Pastel colors.

Tone: Tone is a hue or mixture of pure colors to which only pure gray (equal amounts of black and white) is added in varying amounts to produce different tones of the particular color(s).

Total Dissolved Solids (TDS): A quantitative measure of the inorganic salts and small amounts of organic matter present in solution in water. The principal constituents are usually calcium, magnesium, sodium, and potassium cations and carbonate, hydrogen carbonate, chloride, sulfate, and nitrate anions. the residual minerals dissolved in water that remain after evaporation of a solution. TDS is usually expressed in milligrams per liter (mg/l) or in parts per million (ppm).

Turbidity: The cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. Turbidity in water is caused by suspended and colloidal matter such as clay, silt, organic and inorganic matter, and microscopic organisms. Water high in turbidity appears murky and contains sediments in suspension. Turbid water may be the result of soil erosion, urban runoff, algal blooms, and bottom sediment disturbances which can be caused by boat traffic and abundant bottom feeders. Turbid water may also result in higher concentrations of contaminants and pathogens that bond to the particles in the water.




Wastewater: Any water that has been contaminated by human use. Wastewater is ‘used’ water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff or storm water, and any sewer inflow or sewer infiltration. The characteristics of wastewater vary depending on the source.

Types of wastewater include: domestic wastewater from households, municipal wastewater from communities (also called sewage) and industrial wastewater.

Water Quality: A term used to describe the chemical, physical, and biologic characteristics of water with respect to its suitability for a particular use. Some of these characteristics include salinity, turbidity, alkalinity, hardness, acidity etc.

Well water: Ground water that is untreated and obtained through a well. Well drillers drill down to an aquifer, which is an underground layer of permeable rock containing water. Then, a pump or pulley system is installed to carry the water up from the underground water source to the consumer.




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What is iron? Iron is one of the most abundant elements by mass on the earth, it is a metal found naturally throughout the earth soil and deeper making up 32.1% of the earth’s mass. It occurs naturall