EnviSci A - Water Quality Parameters (Physical, Chemical, Biological)

Physical Parameters

These parameters include temperature, turbidity, and color/odor

Chemical Parameters

These parameters include solids content (total solids, TSS, TDS), pH level, alkalinity, dissolved oxygen, oxygen demand (COD, BOD), nutrients, and heavy metals.

Biological Parametes

These parameters include micro-organisms (bacteria, protozoa, algae, fungi, viruses) and coliform (total and fecal coliform)

Temperature

An increase in this parameter causes more damage than a decrease

5°C

Even a change of ____ in temperature can significantly alter the balance and health of an aquatic environment

Turbidity

This parameter is a measure of the light-transmitting properties of water

Clarity

It is another name for the Turbidity parameter

1 mg/L of silica (in suspension)

This is equivalent to one Turbidity Unit (TU)

NTU (Nephelometric Turbidity Unit)

Another unit for Turbidity other than TU

Nephelometer

This instrument for Turbidity measures the amount of scattered light electronically

Limnology

This is the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater

Secchi Disks

In limnology, this is a weighted circular plate, 8 inches in diameter with opposing black and white quarters painted on the surface, used to determine the clarity or transparency of the water

Less than 5 NTU

A drinking water’s turbidity should be _____

Algae, zooplankton, water color, and silt

These are factors that reduce the clarity of the water

More than 5 NTU

The turbidity of the water becomes noticeable in this range

As high as 25 TU

The turbidity of a relatively clear lake would be _____

More than 100 NTU

In muddy water, the turbidity of the water is ______

PCU (Platinum-Cobalt Units)

This is a metric where the higher the measure, the more dirty and dark the color of the water is

Solids Content

This parameter refers to the presence of matter in water or wastewater

Total Solids (TS)

This is composed of floating matter, settleable matter, colloidal matter and dissolved matter in both water and wastewater. After evaporation, this is the material that remains as residue

103°C

For total solids, the matter remains as residue upon evaporation at _____

Total Suspended Solids (TSS)

This is the amount of matter suspended in the water. This is determined by taking a measured quantity of water and filtering it through a pre-weighed glass microfiber filter. After drying, this is the material remaining on the remaining on the filter

Total Dissolved Solids (TDS)

This is the amount of matter dissolved in water. This includes dissolved salts such as calcium and magnesium chloride and sulfate as well as the dissolved organic matter present in the water. This is the residue if water sample is passed through a glass fiber filter to remove the suspended solids and then evaporated the filtrate in an evaporating dish

TDS = TS - TSS

This is a formula that can be used to obtain the TDS, as well as the TS and TSS through manipulation

pH

This is hydrogen-ion concentration in water, which tells the acidity or basicity of the water.

Acidity

It is a measure where the pH scale is less than 7. It indicates a high concentration of hydrogen ions in a medium

Basicity

It is a measure where the pH scale is more than 7. It indicates a high concentration of hydroxide ions in a medium

6.5 - 7.2 pH

In the pH scale, water is typically around this range

> 9.5 pH or < 4.0 pH

Most bacteria cannot tolerate pH levels

6.5 - 7.5 pH

The optimum pH for bacterial growth lies around what range

Alkalinity

This is the capacity of water to neutralize acids and is due to the presence of hydroxides, carbonates, and bicarbonates of calcium, magnesium, sodium, potassium

Buffering Capacity

This is a term used to refer the ability to resist changes in the pH in natural waters

Dissolved Oxygen (DO)

This is the amount of molecular oxygen dissolved in water. This is also the amount of oxygen available to living aquatic organisms, so there is usually competition among aquatic organisms for the availability of this.

Wet Chemistry

A way to measure dissolved oxygen using chemicals

Dissolved Oxygen meter

A way to measure dissolved oxygen using a special portable meter. This can be used in surface water and groundwater monitoring and testing by qualified field technicians

1 mg / L

1 parts per million (ppm) is equivalent to what

8-9 ppm of DO

For aquatic life, the quality of water is “Good” if the dissolved oxygen content is around _____ at 20°C

6.7-8 ppm of DO

For aquatic life, the quality of water is “Slightly polluted” if the dissolved oxygen content is around _____ at 20°C

4.5-6.7 ppm of DO

For aquatic life, the quality of water is “Moderately polluted” if the dissolved oxygen content is around _____ at 20°C

< 4.5 ppm of DO

For aquatic life, the quality of water is “Heavily polluted” if the dissolved oxygen content is around _____ at 20°C

< 4 ppm of DO

For aquatic life, the quality of water is “Gravely polluted” if the dissolved oxygen content is around _____ at 20°C

Biochemical oxidation

These are reactions that involve the conversion of organic material using oxygen and nutrients into carbon dioxide, water and new cells

Organic material + O2 + nutrients ---> CO2 + H2O+ new cells + nutrients + energy

This is the equation of the biochemical oxidation reaction

Oxygen Demand

This is a term for the amount of oxygen required to oxidize a waste, and an an indirect measure of the amount of organic (or carbon-containing) impurities in wastewater

Biochemical oxygen demand (BOD)

It is the amount of oxygen required to oxidize any organic matter present in the water biochemically, and an indirect measure of the amount of organic pollution in streams or lakes

Standard Conditions for BOD measurement

• 20°C, in the dark
• an excess of nutrients for the microorganisms
• an incubation period of 5 days

Chemical oxygen demand (COD)

This is the equivalent amount of oxygen required to oxidize any organic matter in a wastewater sample by means of a strong chemical oxidizing agent

organic matter (CaHbOc ) + Cr2O7^-2 + H^+ —(heat and catalyst)—-> Cr^+3 + CO2 + H2O

This is the equation of the chemical oxidation reaction

Nutrients

An excess of these can lead to algal growth particularly in lakes. However, they are important because they are required for growth of the microorganisms used in wastewater treatment processes, and because oxidation of reduced nitrogen forms can consume considerable amounts of oxygen

Eutrophication

Is a process that occurs when a body of water becomes enriched with nutrients, leading to the excessive growth of aquatic plants and algae

Aerobic

A term used to describe conditions that can occur due to the presence of oxygen

Anaerobic

A term used to describe conditions that can occur even in the absence of oxygen

Anthropogenic

A term which means “man-made”. In context, this refers to eutrophication caused by human activity

Nitrogen

Can come in different forms, such as organic, ammonia, nitrite, nitrate, and molecular

Organic nitrogen

They come as amines in organic compounds like amino acids and proteins, which are converted to ammonia during the oxidation of organic compounds

Ammonia nitrogen in aqueous solution

This is commonly measured for domestic wastewater and appear as degradation products of proteins and urea

NH3 + H2O ←→ NH4^+ + OH^–

This is the ammonia nitrogen in aqueous solution reaction

> 7 pH

Ammonia predominates when the pH level is

< 7 pH

Ammonium ion predominates when the pH level is

NH3 + 3/2 O2 ---> H^+ + NO2^- +H2O
NO2^- + ½ O2 ---> NO3^-

The nitrification reaction

Nitrite

These are relatively unstable and is easily oxidized to nitrate form. This is important in wastewater or water-pollution studies because of its extreme toxicity to most fish

Nitrate

This encourages the production of bacteria and algae in water and commonly measured in drinking water and occasionally in wastewater. It is the most highly oxidized form of nitrogen found in waste waters and its presence can indicate the degree of stabilization of the wastewater.

Denitrification

It is the anoxic conversion of nitrate to nitrogen gas

Anoxic

A term used to describe the absence of oxygen. It refers to the state of an environment rather than a condition or a process.

NO3^- + organics ----> N2 (g) + CO2 + H2O

The denitrification reaction

Phosphorus

It is an essential nutrient that contributes to algal growth and eutrophication of lakes. It can enter water from sewage or from agricultural run-off like manure

Total phosphates

A unit for quantifying phosphorus in water labs

Heavy metals

These are trace quantities of materials such as nickel, manganese, lead, chromium , cadmium, zinc, copper, iron and mercury. Some of these are required for growth of microorganisms.

Atomic absorption spectroscopy

It is an instrumental method of analysis for heavy metals

Micro-organisms

These are microscopic, single-celled organisms that may or may not be disease-causing. These include bacteria, protozoa, algae, fungi, and viruses

Water Borne Diseases/Pathogens

These are harmful microorganisms that can contaminate water and lead to illnesses, like protozoa, bacteria, and viruses.

Protozoa

These are single-celled eukaryotic micro-organisms. Examples of these and the disease they cause are:

• Entamoeba histolytica - amoebic dysentery

• Giardia lamblia - intestinal disease

• Cryptosporidium - intestinal disease

Bacteria

These are single-celled prokaryotic micro-organisms. Examples of these and the disease they cause are:

• Vibrio cholera - cholera

• Yersinia enterocolitica - gastroenteritis

• Escherichia coli - gastroenteritis

• Shigella sp.- gastroenteritis

• Listeria monocytogenes - flu-like symptoms

• Salmonella sp. - gastroenteritis, typhoid

• Campylobacter jejuni - gastroenteritis (animal sources)

Viruses

These are submicroscopic infectious agents. Examples of these and the disease they cause are:

• Polio Virus - paralytic poliomyelitis

• Rotaviruses - gastroenteritis

• Norwalk Viruses - gastroenteritis

• Hepatitis Type A and E - liver inflammation

Difficulties With Routine Testing Of Pathogens in Water

• present in low numbers

• limited survival time

• numerous pathogens to analyze

• time and cost prohibitive

Requirements of Indicator Organisms

• present when pathogens present in water

• absent in uncontaminated water

• present in higher numbers than pathogens in contaminated water

• better survival in water than pathogens

• easy to analyze

Coliform Bacteria

These are bacteria in the family Enterobacteriaceae and are indicators of fecal contamination. They are present in the intestinal tract of numerous organisms.

Total Coliform Bacteria

This refers to all coliform bacteria, including both fecal and non-fecal, used to assess water quality. Sources of these include fecal material, soil, water and grain, and some capable of reproduction in the environment.

Fecal Coliform Bacteria

This is a subset of coliform bacteria that originate specifically from fecal material, indicating potential contamination. Its source is from fecal material and a primary example is Escherichia coli

Escherichia coli

This is a type of fecal coliform bacteria typically found in the intestines of warm-blooded organisms like humans. Its presence in water indicates fecal contamination

Membrane Filter Method

A method in detecting and quantifying coliform bacteria by passing the water through a filter which traps bacteria in the membrane using endo agar.

Multiple Tube Fermentation Method

A method in quantifying coliform bacteria by using multiple tubes of broth with different dilutions of the sample and observing gas production

(number of colonies/mL of sample) * 100

This is the formula to calculate coliform concentrations (per 100 mL)