Animals and Money: Mussels Can Monitor Drinking Water and Potentially Save Millions of Euros

The exposure of humans and all other species to contamination by hazardous substances expands from air to land to water. Mussels quickly detect water contamination and are sensitive to small changes in water composition, including heavy metal content1,2. Water quality control is cheaper using biomonitoring than traditional laboratory analysis. These results may help water utilities decide to use a less expensive and a more environmentally friendly method of controlling water quality. 
An EU directive from 2020 orders that monitoring programmes for water intended for human consumption shall include measurements recorded by a continuous monitoring process, collection and analysis of discrete water samples4.  Clams can, therefore, be used to create a warning system for sudden contamination. The mussel valve movements can be monitored using remote sensing technologies and serve as a tool for early warning alarms for aquatic pollution5.The company PROTE (Poznań, Poland) designed the SYMBIO Biomonitoring System, which records the movement of the shells of eight bivalve Unio tumidus molluscs in a flow tank3. 
The cost for the purchase of the SYMBIO system is 40,000 Euros and maintenance costs are approximately 17 Euros net per day for a water treatment station, amounting to 6,205 Euros annually. Service and quarterly replacement of the biological material add 550 Euros net per month to 6,600 Euros net annually (numbers based on personal correspondence with company). Purchase of the system, daily maintenance and costs of service and replacement of the molluscs over a period of 10 years, amount to costs of around 168,050 Euros. 
For comparison, a one-time water quality analysis in Poland costs a few dozen to a few hundred PLN (which equals a few up to 150 Euros), and it considers only a few basic pollutants6. The price for the physico-chemical and microbiological analysis of water is about 85 Euros6,7. If the number of samples in one-time water analysis is the same as in biomonitoring, the costs of traditional analysis would have reached a level of 26.78 billion Euros over a period of 10 years. 
To establish the value of one individual mussel, all costs for the purchase, maintenance, and conservation of the SYMBIO system were deducted from the cost of a one-time water sample over a period of 10 years, meaning the benefit of SYMBIO system is 26.77 billion Euros. The system consists of eight bivalve molluscs, which are replaced every three months to assure proper sensitivity of indicator organisms3. Therefor, the benefit of 26.77 billion Euros must be divided by 8 and 40. As a result, a single mollusc can save up to 83.7 million Euros.
The SYMBIO system is unable to determine which substance caused the clam to close and trigger the alarm3. However, early recognition of possible health risks posed by contaminated water means that it can be cut off from Waterworks immediately. Traditional water testing relies on testing of samples, the results of which can be delayed up to 48h8. In this case, reaction time is more important than analyzing the contaminating agent. Sudden water contamination will be detected without delay which ensures safe and clean drinking water.

Issue 2
Klaudia Ostatek