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Water Quality Monitoring

Smart watches and a whole range of mobile apps have become increasingly popular in recent years, offering us an intuitive and unobtrusive means to track and measure body metrics and workouts, such as the number of calories burnt or total steps walked in a day. Using these fitness trackers allows people to set goals and follow their progress over the hours, days and months. But whilst it is important that people look after their bodies, we all need to look at the bigger picture, the one concerning the health of the very planet that we live on.

It is therefore a very good thing that is now just as easy to monitor changes in the environment as it is measure the changes in our own body temperature. No we can track fluctuations in things as varied as fish populations, the rate of glacial melting and the quality of water in our rivers, streams and lakes.

Water quality monitoring is a crucial aspect of our being able to determine whether or not progress is being made in clearing and cleaning our waterways. Only by monitoring water quality can we gain insight into the composition and health of our waterways, both at the present moment and over days, months and years.

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Why Monitor Water Quality?

The importance of monitoring fluctuations in water quality should not be underestimated. Put simply, the continued existence of our species, our health and our livelihoods depend on a steady and reliable supply of clean water. Monitoring of drinking water is legally mandatory in many jurisdictions, including the EU and the US, with authorities setting standards for monitoring procedures and safe levels of contaminants, chemicals and micro-organisms.

Wastewater Monitoring Standards

Regulations also cover the monitoring of discharge released into our waterways. As such, wastewater monitoring is vital to any programme aimed at managing and reducing the amount of water-borne pollution. Primary sources of wastewater include run-off from urban roads, farms, factories and sewage treatment plants.

Monitoring of both waterways and wastewater discharge provides valuable data for scientists, legislators and businesses, confirming whether or not pollution management schemes are working and forming a basis on which new programmes can be devised.

Water Quality Monitoring Case Study: Phosphorus

Indicators of wastewater quality include quantities of fecal coliform bacteria and levels of dissolved oxygen, nitrate and phosphorus, among other factors. Excessively high levels of phosphorus are a particular concern, as the chemical has many sources and can be difficult to resolve. Monitoring the degree of phosphorus pollution in a given waterway informs us not only about that single point in the flow but also what might be going on upstream of that point.

Phosphorus run-off comes overwhelmingly from land use, from farm field erosion to poorly managed building sites. Monitoring for phosphorus run-off is based around two main concepts: concentration and load. Concentration is straightforward, measuring the mass of phosphorus in a given volume of water.

Load is calculated by multiplying the concentration by the flow of water over a set period of time. For example, two samples could be taken at the same point in a stream, one after a storm and one in the height of summer. The storm sample will be larger, say twice the size of the summer sample, due to the larger flow. The concentration of phosphorus in both samples could be equal, but the load in the storm sample will be double that of the summer sample.

Using these two indicators together, we can calculate the quantity of phosphorus moving downstream at any given point in time and space. Long-term monitoring of phosphorus load and concentration is vital to understanding how shifts in land management, use and precipitation affect water quality.