What Are the Main Indicators of Water Quality?

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main water quality indicators

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Water Quality Monitoring & Factors

Water Quality and Good Health

Water quality is crucial to biodiversity and life on our planet, so understanding the principal water indicators and their parameters is key.

Water quality is one of the most important health indicators in an ecosystem. Good quality water sustains human life, wildlife, and marine life and is a key element of maintaining biodiversity.

Water quality pollution results from many situations. The source of pollution occurs at sea due to shipping and fishing activities, sewage and wastewater discharges, agricultural and industrial practices, fuel spillages, and global warming.

Water pollution can create major issues for humans and the natural world: in terms of drinking water, our fishing and aquaculture industries, Marine Protected Areas (MPAs), wastewater treatment centers, river life, and our coastal port communities.  Monitoring water quality is therefore essential to identify potential environmental problems and to develop effective preventative strategies and their system treatment.

Water quality plays a critical role in maintaining the delicate balance of ecosystems. From freshwater streams to vast oceans, the quality of water directly impacts the health of plants, animals, and microorganisms that call these habitats home. Healthy water systems provide essential resources and habitats, contributing to the overall biodiversity of the planet.

The Key Indicators and Parameters of Water Quality

Understanding, assessing, and monitoring the main indicators of water quality and their primary parameters is vital to comply with standards. Water quality parameters include a wide range of chemical, physical and biological properties, with six principal indicators: dissolved oxygen, turbidity, pH, bioindicators, nitrate chemicals, and water temperature.  Samples of water are taken to assess and monitor water quality which provides data that gives important indicators of pollution and changes in patterns of standard behavior.  

Let us now consider the principal water quality  indicators and how they impact upon water quality.

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  1. Dissolved Oxygen (DO)

Oxygen in water is essential for humans, plants, and animals. However, if there is an abnormally high level of oxygen in the water, this can create major problems for sustaining life. That is why measuring the quantity of dissolved oxygen – the amount of oxygen available to aquatic life – is important. The quantity of dissolved oxygen is a key indicator of water quality in streams and lakes. Factors affecting levels of dissolved oxygen include sources such as a number of bacteria as well as the water temperature.

Taking fish as an example, analysis has shown all species and sizes of fish can live if the amount of dissolved oxygen in the water is in the range of 9.5 mg/L to 12 mg/L. Below that level, fewer fish survive; and if it is below 4.0 mg/L, no types of fish can do so.


  1. Turbidity and Total Suspended Solids (TSS)

Turbidity is a measure of how clean water is and its clarity.

The measurement of turbidity levels depends upon the concentration of Total Suspended Solids (TSS). TSS are particles larger than 2 microns found in water, such as gravel, sand, silt, clay, and algae. When organic matter decays – for example from animals, plants, and algae – this becomes a suspended solid. Suspended sediments can also contain high amounts of pollutants including phosphorus, pesticides, or heavy metals.  Lighter solids will settle at the bottom of a body of water; if there are a lot of solids present, the surface water becomes cloudy or less clear.

  1. Bioindicators

Bioindicators are organisms used to monitor the health of an ecosystem, for example, the quantity of microalgae present in water. They are organic and natural indicators of environmental pollution – living organisms such as plants, plankton, animals, and microbes – providing valuable information for assessing the quality of water as well as an important indicator of water pollution.

Several factors influence bioindicators in the environment, including the amount of light, water, temperature, and suspended solids in water. Changes in the composition of bioindicators, positively or negatively, are an effective way to measure the environmental impact of human activities on the health of our natural ecosystems.


  1. Nitrates

Nitrogen provides the essential nutrients for all living organisms.

However, large nitrate concentrations – often due to the flow of human and animal waste, industrial pollutants, and agricultural activity – can increase algae growth and reduce the amount of dissolved oxygen in the water, killing fish and other aquatic life. High nitrate levels are similarly harmful to humans. Monitoring the nitrate level is consequently crucial for health promotion strategies and safeguarding marine life.

Optimum nitrate levels vary according to the species. A maximum level of 2 mg NO3-N/l protects most freshwater species with a maximum level of 20 mg NO3-N/l for other animals.


  1. pH scale

pH illustrates how acidic or basic a body of water is according to a logarithmic scale, a measurement of alkalinity. The value for pH is expressed on a scale ranging from 0 to 14. Low numbers indicate the degree of acidity in the water; higher numbers how basic water is. A score of 7 is neutral.

What causes the pH level in the water to change? Factors include acid rain, automobile pollution, agricultural runoff, spills due to accidents, overflows from sewers, and other pollutants. Major changes to pH scales can have damaging impacts on water, fish, and aquatic life, so it is another key water quality indicator.


  1. Water Temperature

Water temperature is an indicator too of water quality – and various forms of aquatic organisms depend upon specific temperatures and water conditions for their optimal health.  The water temperature will also affect other parameters of water quality, such as the dissolved oxygen and vulnerability of organisms to parasites, pollution, and disease.

The time of year is another factor, with temperatures varying according to the seasons.

Monitoring the Main Parameters of Water Quality

In the past, monitoring and analyzing the main parameters of water quality depended upon manual sample data systems. These systems were slow and made it difficult to identify problems and take appropriate methods of action.

No longer… that is because Sinay now offers several digital tools, brought together in a single place, which gives you access to accurate and reliable real-time data, processed and analyzed that enables fast decision-making.

The Sinay Water Quality Module uses APIs to connect all types of sensors and transmits data at a chosen frequency, enabling the data to be easily accessible from your own dashboard – in real-time. Indeed, our systems can work with all kinds of sensors and are straightforward to use.

Furthermore, data can be collected from multiple bodies of water and brought together in a single place.  This enables you to be proactive in water pollution management by measuring the impact of environmental projects as well as monitoring compliance with international regulations.

The Water Quality module is part of the Sinay Hub, an environmental software connecting you to accurate and real-time information for all kinds of maritime sectors. We can create a bespoke dashboard to meet your exact requirements, with swift delivery and implementation.


As technology continues to evolve, the future of water quality monitoring holds promising possibilities. The integration of artificial intelligence, machine learning, and big data analytics could provide more accurate predictions of water quality trends, enabling proactive decision-making to safeguard aquatic ecosystems and human health.

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Frequently Asked Questions About: Water Quality Indicators

Water quality indicators are physical, chemical, and biological properties of water that provide information about its suitability for various uses.

The six main indicators of water quality are dissolved oxygen, turbidity, bioindicators, nitrates, pH scale, and water temperature.

The most important water quality test is bacteria. Bacteria can have very negative effects on human health and the food we eat. 

Most of Earth’s freshwater is located in glaciers and ice caps and groundwater. Only .3 percent of freshwater is found above ground.   

Water quality indicators play a critical role in water management and conservation by providing data and information that can be used to monitor and assess the health of aquatic systems, and to guide decisions about water use and protection.

Changes in water quality indicators can have significant impacts on aquatic ecosystems and human health, including declines in biodiversity, decreased water availability, and increased risks of waterborne diseases.

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