What are the main indicators of water quality?

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

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

Water pollution results from many situations. Pollution occurs at sea due to shipping and fishing activities, from sewerage 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 the water we drink, for our fishing and aquaculture industries, for Marine Protected Areas (MPAs), wastewater treatment centers, in our rivers and our coastal port communities.  Monitoring water quality is therefore essential to identify potential environmental problems and to develop effective preventative strategies and their treatment.

The key indicators and parameters of water quality

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

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

  1. Dissolved oxygen (DO)

Oxygen is essential for both 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 the number of bacteria as well as the water temperature.

Taking fish as an example, 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 depends upon the concentration of Total Suspended Solids (TSS). TSS are particles larger than 2 microns found in the 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 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 water becomes cloudy or less clear.


  1. Bioindicators

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

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


  1. Nitrates

Nitrogen provides the essential nutrients for all living organisms.

However, large concentrations of nitrates – often due to 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 levels of nitrates are similarly harmful to humans. Monitoring the level of nitrates 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 it 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 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 data systems. These systems were slow and made it difficult to identify problems and take appropriate action.

No longer… that is because Sinay now offer 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 locations 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.

Want to start your real-time monitoring project?

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