It was mainly fruit and vegetables in today’s shop for the lovely Mr J, although a bit less than normal as his wife is still in hospital.

My return coincided with his monthly ‘big items shop’ from Sainsbury’s so I had to help put away cartons of fruit juice and milk before I could find my way to the fridge and vegetable rack.

A few Goodgymers around the country joined the Great UK WaterBlitz

Testing the waters at Mutton Brook

Another little GoodGym citizen-science mission for Gus and me, back at Mutton Brook.

I’m really enjoying returning to the same stretch of water. There is something rather nice about sitting quietly beside the brook, fiddling around with the little test tubes and watching the colours develop — and, once you’ve done it a couple of times, the testing is actually very easy.

Today’s results were interesting. The water looked remarkably clear, but the nitrate reading appeared quite high — around the 2–5 mg/L range, possibly close to 5 — while phosphate was very low at around 0.02–0.05 mg/L.

So it’s a mixed picture. Low phosphate is encouraging, but the nitrate suggests there is still a significant nutrient input somewhere upstream. Mutton Brook starts only a few miles away in Cherry Tree Wood in East Finchley and then flows through a very urban landscape, including alongside major roads and beneath the North Circular. Urban runoff, drainage and other sources could all contribute, although one test can’t tell us exactly where the nitrate is coming from.

It also shows why these tests are worthwhile: clear-looking water isn’t necessarily clean water.

Results uploaded, another tiny piece of data added to the bigger picture — and Gus and I got a peaceful few minutes beside the brook into the bargain.

Report from Paul Browning

I did my testing on the River Quaggy in Manor Park in SE London where I have done testing several times before. Concentrations of nitrates and phosphates were both low, phosphates lower than last time I did the testing.