As you would expect, not much secret here, we just dumped a 1 liter glass bottle with a rope attached around the neck in a few different locations of the river, and pulled it out with the rope.
And, in the name of science, we even wore gloves to not contaminate the samples!
Figure 1. Swans swimming in the river when during sample collection. Source. Swam poo bacteria?
Figure 2. Tying rope to bootle for river water sample collection. Source.
Figure 3. Dumping the bottle into the river to collect the water sample. Source.
Figure 5. Measuring the river water sample pH with a pH strip. Source. The strip is compared with the color of a mobile app that gives the pH for a given strip color.
Figure 6. Noting sample collection location on the water bottle. Source. Video 1. Dumping the bottle into the river to collect the water sample. Source. That was fun.
Ciro Santilli 
