| See also polluted Lea |
Essex Wharf (25/Sep/2011)
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From: Theo Thomas We have another set of water quality testing results and they are poor yet again. We get the dissolved oxygen results on the day (yesterday) with the chemical results to follow later in the week. The top line is that the Lea from south of Tottenham Lock to the Olympic site is has below the level that fish populations (and other creatures) can survive in healthy numbers. Only the species that can tolerate low levels of oxygen survive, and even then in much lower numbers. 6 mg of oxygen per litre is needed for a river to be considered healthy. As you can see from the table below it is way below that at many sites. Anything below 2 mg and no fish will live there for any reasonable period of time. Site X is just off the Lea, where the sewage outfall from Deephams enters from the Pymmes Brook (more on the Pymmes Brook in another email, we did a site visit last week and its condition is shocking).
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The Hackney Gazette ran a story about Love the Lea last week - here's the link http://www.hackneygazette.co.uk/news/pollution_levels_turning_river_lee_into_a_sewage_ditch_says_charity_1_1084563 The fear is that the Lea rarely gets above 3 mg/l meaning the river never recovers. Occasional dips a river can cope with, but this seems the opposite. The 'Love the Lea' word is getting out there. More people have heard about it, more people are signing up. I'm in the process of drawing up the next stage of the campaign that will allow us to focus on the larger scale underlying problems that need to be sorted - the Mega Pledge! Kind regards, Theo Theo Thomas. Love the Lee - Save the River! Thames21 07968012828 Email: Theo.thomas@thames21.org.uk Twitter: @theojthomas Thames21, Bow Locks, Gillender Street, Bromley-by-Bow | ||||||||||||||||||||||||||||||
| Water Quality |
Essex Wharf (25/Sep/2011) |
| Lea has 100 times as many e-coli as a Blue Flag beach! | |
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From: Theo Thomas To: theo.thomas@thames21.org.uk Sent: Monday, 3 October 2011, 14:35 Subject: Sewage bacteria results for the Lea Dear all, I've mentioned that we recorded very low oxygen levels in the Lea south of Tottenham last week. So low that fish are unable to breathe in the water and flee to areas of higher oxygen (or try to). Because fish stocks are so low already in the Lea we don't see the fish kills that we do on other rivers. The fish that do survive in the Lea are hardened to low oxygen levels. But numbers will never increase to healthy levels or beyond a few species. We can find out the dissolved oxygen levels on site. To find out how much sewage is in the water we have to take water samples to the lab at University College London where they test it for us. This takes a couple of days. They put some of the river water on a petri dish and leave it in an incubator. The bacteria react with the gel on the dish creating purple patches or colonies. These can then be counted and the amount of bacteria in the water calculated. The bacteria they are looking for are coliform or faecal bacteria. Present in the gut of all animals including human. We get UCL to do a count of all coliforms and also e-coli bateria. The more bacteria from people in the water the more chance of coming into contact with it and getting ill if you get splashed. The more bacteria the less oxygen too as they use it up as they multiply, suffocating fish. There is no limit for the amount of sewage in our rivers. But to be awarded a Blue Flag a beach is allowed no more than 100 e-coli colonies in 100ml of water. In the Lea last week at South Tottenham there were 10,000 e-coli in the 100 ml sample. As the raw sewage flows down the from Deephams Sewage Treatment works it creates dead zones, where oxygen levels plummet and life is driven out. Further down the river the pollution is joined by flows from people's homes, creating another drop in oxygen levels. I've attached the Love the Lee flyer. If you can please send it to people - we need more and more to sign up to the pledge. pledgelovethelee@thames21.org.uk We have to stop treating the rivers of East London as sewers, like something from the Middle Ages. Kind regards, Theo Theo Thomas. London Canalkeeper Love the Lee - Save the River! www.thames21.org.uk/lovethelee Thames21. The Lock Office, Gillender Street, Bromley by Bow, E3 3JY. Tel 020 7093 6385 http://www.thames21.org.uk/canalkeeper.html www.thames21.org.uk Thames21's London Canalkeeper is a member of the Waterkeeper Alliance www.waterkeeper.org | |
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From: Theo Thomas Sent: Tuesday, 27 September 2011, 17:35 Subject: Love the Lea Pollution event Dear all. The water quality testing teams were out today, taking samples from 9 sites from Tottenham Lock to Bow Locks. We test for dissolved oxygen on site, with the water samples sent to University College London for further analysis (bacteria, nitrate and phosphate). The heavy, intense rainfall yesterday coupled with the warm temperatures today have hit the river hard (as it does after every such occurrence). When the pollution gets washed into the rivers along the Lee Valley it causes bacteria to multiply - this uses up oxygen that fish need to survive. The warmer the water is the less oxygen it can hold. A healthy body of water should have more than 5 milligrammes of dissolved oxygen per litre of water. Many of the sites today had less than this meaning that fish will struggle (they rarely get above 5). The worst site had less than 3 mg of dissolved oxygen per litre, meaning it was too low for most fish to live there. Fish in these areas will either die or are more prone to diseases. Where they can they will try to swim to water with more oxygen. It's not clear whether we'll see fish dying as in many places there are very few fish (why would they choose to live there when there is so little oxygen in the water?). We'll get the rest of the results back this week, I'll let you know what they tell us. We'll soon be putting the results online so people can examine them for themselves. Kind regards, Theo Thomas Love the Lee - Save the River |
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