3rd February 2025 Environment Monitoring Results

Here are the results for the testing safari carried out on 3rd February 2025:

1. E.coli - this month there has been a fall in the levels of E.coli pollution across most of the catchment, in large part due to lower flow after the earlier flood conditions. The change is most marked in the River Deben above Easton and in large sections of the Rivers Lark and Fynn. As usual the Anglian Water STW’s are emitting much higher levels of E.coli although at Rendlesham and Debenham, these are lower than in previous month. 

There was an E.coli spike just below Aspall which fed downstream; this has been reported to the Environment Agency Hotline for investigation.

2. Phosphate - a similar pattern of reduction can be seen in phosphate levels across most of the catchment. Phosphate as P levels were generally lower than 0.3 mg/ litre at all sampling points with the notable exceptions being at the Martlesham Creek, Rendlesham and Easton STW’s. There was also a small spike close to the Tuddenham STW on the River Fynn. These results are encouraging and show the impact of the phosphate stripping installed by Anglian Water over the past 12 months.

We are going to use these data to challenge the Environment Agency SAGIS (Source Apportionment) model which suggests that phosphate pollution results from arable/ livestock in at least equal measure to that from waste water treatment plants. Our evidence is that the arable/ livestock impact is much less than the SAGIS model predicts. 

So for example at looking Easton, SAGIS predicts that arable and livestock make up 80% of the total phosphate, with waste water at 15%  (see Deben Optimiser file). It is clear from our recent data (comparing November 2024 and February 2025 - see November map) that the STW is probably responsible for 75% plus of phosphate with livestock arable contributing to background levels only. If proven, this is good news for our river and for the farming community.

3. Nitrates - this time, I have plotted the results as a bar graph rather than as a map as you will be able to see the actual results by location on the spreadsheet. These two bar charts show that outside the Anglian Water STW’s, nitrate levels were lower this month and in many locations were within the 30 mg/ litre WFD (Water Framework Directive) guideline. There were exceptions downstream of STW’s and at Debenham / Aspall. It seems that nitrate levels in winter may well be  less of an issue in the Deben catchment than first thought by regulators and the farming community. However, local reports from tests in ditches which feed the river does still show nitrate spikes up to 200 mg/ litre in places.

4. Investigating Potential Pollution - we are always on the lookout for potential pollution and below is an example from this week’s sampling safari. This oily film was seen in a recently cleared ditch which feeds into the river; there was also evidence of a small amount of film flowing into the Deben; this was traced back to the end of the ditch.