Water testing and its components
Basically, water testing has 7 main components of testing: dissolved oxygen or in short DO, temperature, pH level, nutrients level, toxic level, turbidity, bacteria level and these can be with the aid of visual surveys and biological sampling. We can use several instruments like secchi disks, probes, gauges, temperature strips, testing liquids to help make accurate findings.
Temperature
Significance - important as it is responsible for the oxygen levels in water bodies and the microorganisms and plant growth.
Instruments - This can be calculated simply with a thermometer. A healthy water temperature would depend on the climatic conditions, place and organisms living there. For Singapore, around 29°C would be an acceptable temperature.
pH level
Definition - measurement of the hydrogen levels in waters. In other words, the acidic or alkali levels of water, with 7 being neutral.
Acceptable range - The acceptable range would be 6.5 to 8.5 pH. Where the range escalates from 0 as acidic to 14 alkali.
Instruments - We can use a probe to do this and find the pH level on a data logger. However, similar to temperature based on the type of water, the acceptable pH level can differ from the standard range.
Nutrients level
Significance - essential for aquatic animals and plants to grow. However too much of it can be detrimental to the aquatic organisms as well. Mainly nitrogen and phosphorus are measured.
Acceptable ranges - for phosphorus would be 3-50ppm and for nitrogen: 2mg/litres to 6mg/litres.
Instruments - We can use nutrient analysers and smell tests to determine nutrients levels.
Turbidity
Definition - the clarity of the water and the amount of particulates is important as it determines how polluted the water and the pollution can negatively affect both aquatic organisms and the consumers of the water.
How it is measured - This would require Secchi disk or turbidity meters to measure the clarity of the water and the acceptable range of contaminants size for water bodies would be from 0.04mm to 1.00mm.
Bacteria Level
Significance - Bacteria mainly fecal coliforms affect how potable the water is for both the aquatic animals breathing through gills and human consumers as they are normally harmless, but carry viruses and pathogens which can be harmful to the intestines of animals.
Instruments - Normally, scientists look for creatures sensitive to bacteria. If they are present, than the bacterial level are low. Such animals include the Riffle Bug.
Dissolved oxygen
Significance - necessary as aquatic animals depend on this heavily for survival.
Appropriate range - This is most optimaly found in abundance as oxygen is the most fundamental necessity for living things especially for the aquatic animals.
Instruments - We can use thermometers to find the temperature of the water as dissolved oxygen depend on temperature majorly.
Other factors - which can affect this is the speed of the flowing water an also the abundance of algae and water plants which also links to water transparency which can be measured with a Secchi disk. We can also use a dissolved oxygen meter attached to a data logger.
Toxic Level
Definition - Toxic level refers to the abundance of harmful toxic substances and particles in water.
Instruments - According to our research, we found that actually, scientist use biological samples and determine the water safety based on the existence of such organisms like Brine shrimps and rainbow trouts.
Types of toxic - Such types of substances are fluoride, arsenic and even chlorine which in the case of consuming it, will deteroirate one's health.
Signifcance - These substances are of concern as the toxic levels can actually affect the health of both the organsims consuming and living in the water bodies.
For More Info : http://water.epa.gov/learn/resources/measure.cfm
