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Recent River Great Ouse nitrate levels
- Thread starter Chris Guy
- Start date
Paul Thompson
Senior Member
Hi Chris.
What are the levels supposed to be? Those Nitrate levels look sky high!
Tommo
Dan Whitelock
Senior Member
Do we know when the samples were taken? We stopped spinning on nitrogen and phosphates on the land a couple of months ago now, plus we don't apply the stuff with risk of run off because it's very expensive and also illegal.
Stephen Crowhurst
Senior Member
I’ve never heard of Earthwatch and I assume they have commissioned test kits for the project. I’m also assuming that whomever specified that kit is better qualified than I, but, that is what I would consider a low range Nitrate kit. A testing window for that parameter would typically be 0-100 rather than 0-5 and that does make me question the validity of the result. Further, with my tin foil hat on, the motivation of the distributor but il park that thought pathway.
Personally I don’t think 5ppm is high for a freshwater environment. The cut off for drinking water is 50ppm by the way. A river with no Nitrate would be a dead river or certainly a very unhealthy one. Nitrate is toxic to freshwater fish, more so than saltwater but we’d be looking at a huge increase, beyond the testable range here, for a negative impact. IIRC the danger level for fish in a marine environment is around 2000ppm. Nitrite and moreover Ammonia are the nasty ones within the nitrogen cycle. What’s more interesting is the ratio between nitrate and phosphate, which are end products, I’d expect a bigger difference like a factor of x100 n to p as opposed to a factor of 10 and the indicators that’s provides us about the biology of the system as a whole.
It’s all very interesting and good on everyone who participates in these citizen science projects.
Personally I don’t think 5ppm is high for a freshwater environment. The cut off for drinking water is 50ppm by the way. A river with no Nitrate would be a dead river or certainly a very unhealthy one. Nitrate is toxic to freshwater fish, more so than saltwater but we’d be looking at a huge increase, beyond the testable range here, for a negative impact. IIRC the danger level for fish in a marine environment is around 2000ppm. Nitrite and moreover Ammonia are the nasty ones within the nitrogen cycle. What’s more interesting is the ratio between nitrate and phosphate, which are end products, I’d expect a bigger difference like a factor of x100 n to p as opposed to a factor of 10 and the indicators that’s provides us about the biology of the system as a whole.
It’s all very interesting and good on everyone who participates in these citizen science projects.
Last edited:
Joe Winstanley
Senior Member & Supporter
I'm not sure what reading I would be taking from that Nitrate test? Somewhere just below 5?
5mg/l is reasonably high, but I would say very high for late May-early June as it's not a time of year one would expect farmland to be leaching higher rates of nitrate. That said, it has been a wet spring and there is plenty of land uncropped that has the potential to be leaching higher than expected amounts of nitrate.
It is difficult to look at one test in isolation and draw any conclusion from it. The real value in these tests is looking at the trends over the year, based on regular sampling and in particular looking at variations in results between sampling sites. It's all good citizen science and the more of this sampling undertaken the better.
5mg/l is reasonably high, but I would say very high for late May-early June as it's not a time of year one would expect farmland to be leaching higher rates of nitrate. That said, it has been a wet spring and there is plenty of land uncropped that has the potential to be leaching higher than expected amounts of nitrate.
It is difficult to look at one test in isolation and draw any conclusion from it. The real value in these tests is looking at the trends over the year, based on regular sampling and in particular looking at variations in results between sampling sites. It's all good citizen science and the more of this sampling undertaken the better.
Colin Dapp
Senior Member & Supporter
I googled it apparently the US expect a lot less nitrogen in their water compared to UK.
U.S. Environmental Protection Agency (.gov)
https://www.epa.gov › system › files › documents
What is a healthy nitrogen level in rivers?
To identify at-risk surface water bodies and protect them from eutrophication, the US EPA developed guidelines, which state that N concentrations should not exceed 0.3 mg·L−1 in streams and rivers or 0.1 mg·L−1 in lakes and reservoirs [6].25 Mar 2014
National Institutes of Health (NIH) (.gov)
https://www.ncbi.nlm.nih.gov › articles › PMC3965473
Search for: What is a healthy nitrogen level in rivers?
What are the acceptable levels of nitrate in rivers in the UK?
The UK standard is based on the World Health Organisation's guideline value for drinking water, which is also 50 mg/L. This level is intended as a safeguard against methaemoglobinaemia.
Make what you will of that
Nitrogen and Phosphorus in Streams in Agricultural Watersheds
U.S. Environmental Protection Agency (.gov)
https://www.epa.gov › system › files › documents
What is a healthy nitrogen level in rivers?
To identify at-risk surface water bodies and protect them from eutrophication, the US EPA developed guidelines, which state that N concentrations should not exceed 0.3 mg·L−1 in streams and rivers or 0.1 mg·L−1 in lakes and reservoirs [6].25 Mar 2014
Total Nitrogen Concentrations in Surface Water of Typical Agro
National Institutes of Health (NIH) (.gov)
https://www.ncbi.nlm.nih.gov › articles › PMC3965473
Search for: What is a healthy nitrogen level in rivers?
What are the acceptable levels of nitrate in rivers in the UK?
The UK standard is based on the World Health Organisation's guideline value for drinking water, which is also 50 mg/L. This level is intended as a safeguard against methaemoglobinaemia.
Make what you will of that
Angus Barnes
Senior Member & Supporter
Need to be careful that you’re comparing apples with apples when you’re looking at this. Different publications will give nitrate level as N or NO3.
To convert N to NO3 multiply by 4.43.
Agree with other comments regarding comparators. The N figure could be 5 or 10. Conceivably higher than 10 depending on the range of the kit.
I have been involved with the Angling Trust testing and agree with Joe regarding looking at trends and larger data sets.
The citizen science projects are another useful tool in gathering data to put pressure on water companies and the regulators.
There’s no denying what we all know though regarding the poor state of the vast majority of rivers we fish
To convert N to NO3 multiply by 4.43.
Agree with other comments regarding comparators. The N figure could be 5 or 10. Conceivably higher than 10 depending on the range of the kit.
I have been involved with the Angling Trust testing and agree with Joe regarding looking at trends and larger data sets.
The citizen science projects are another useful tool in gathering data to put pressure on water companies and the regulators.
There’s no denying what we all know though regarding the poor state of the vast majority of rivers we fish
Bob Edwards
Senior Member & Supporter
Just seen this ,different river, but i wonder what the levels are like downstream of it.
As the guy says its the 21st century, absolutely scandalous.
As the guy says its the 21st century, absolutely scandalous.