This page shows the results of water quality monitoring that we’ve been undertaking during 2021, aiming to understand the sources of poor water quality on the River Cam around Cambridge.
Chalk streams should be crystal clear and unpolluted. The Cam should be too, but isn’t. To explore this, we’re having samples analysed for E. coli bacteria (which shows if there’s poo in the water), Phosphates and Nitrates. We’re also monitoring water clarity by taking photos.
In the map above, the latest E. coli readings are shown in 4 bands, ranging from the worst quarter of readings, which are shown with deep purple markers, to the best quarter, which are shown in yellow. Click on the marker (a star) to see the reading in units of E. coli/ 100ml of river water. The key Waste Water Treatment Works (which we suspect are the source of much of the problem) are shown by the little tap symbol
To see the results from test runs from earlier dates, click here to access the source map. You will then be able to change which layers are displayed.
You will also be able to download the full report here (when we’ve finished writing it)
The official standards for bathing water are complicated, and often based on multiple readings over a period of time. For simplicity, we’re setting an aspirational target for the Cam of no more than 100 E. coli/100ml. This is based on the EU’s guidelines for high quality bathing water that are “to be achieved where possible” and the more stringent American standards. Note that drinking water should have no ecoli at all. ie 0 ecoli/100ml, and all of our readings show more than this.
Do join us. We plan to continue our investigations, and welcome help from those with relevant expertise. We also very much welcome contributions to the costs of the lab analysis, which costs us around £1000 per set of readings.