The polluted Bosphorus, Istanbul
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Cleaning up the Bosphorus
22nd October, 2012
The Bosphorus - which divides Istanbul into the European and Asian side - is one of the most active and most polluted sea-straits in the world. Resident Alina Lehtinen discovers it's not the garbage but sewerage that is the key pollutant in the city's ailing waterways.
The city's waste water treatment systems are not sustainable
Istanbul, a massive city of around 15 million people, is surrounded by water. Massive population growth - together with rapid industrialism - has put increasing pressure on the Bosphorus, with the city's leaders warning that the current water treatment facilities are not sufficient enough for the future.
In the last 70 years the population of Istanbul has grown 15-fold and this rapid urban development has come at a price: the Bosphorus, which has been used as a garbage dumb for centuries, is now so badly polluted that floating rubbish is a common sight alongside many of Istanbul’s waterfront neighbourhoods.
“The sea takes almost all the garbage. The population is too big and getting bigger all the time, " warns Tanla Silay, Communications Coordinator of Turkish Marine Environment Protection Association (TURMEPA).
TURMEPA- founded in 1994 -is one of the first environmental organisations in Turkey focusing on the waterways. One of its first projects was to cleanup the Bosphorus and this year around 70 kilos of garbage was removed from the river, the majority - 80% - was plastic.
The main problem, however, is not the rubbish thrown in the Bosphorus, but the sewage water pumped into it, according to Silay. “80% of the water doesn’t get properly treated. The municipality is not making enough efforts with water treatment plants, because it’s costly,” she adds.
Dr. Gurdal Kanat of Yildiz Technical University in Istanbul, who specialises in environmental issues and who, together with Dr Hurrem Bayhan, published a report last year on the water quality of Istanbul’s Prices Islands, agrees with Silay that the current water treatment system in Istanbul is not going to meet the future need. He says “At the moment they only do pre-treatment of the waste water by the Bosphorus. The water doesn’t get biologically treated which is what is needed."
The reasons this does not happen are, of course all down to cost. According to Kanat, the municipality hired a research company from Denmark to help find a cheaper way to treat the sewage water. “The company reported that you can use the strong currents in the Bosphorus [for the time being] to have cheaper treatment,” Kanat said. “For the near future it is enough, but the nitrogen and phosphorus levels will go up and eventually they will need more proper water treatment facilities,” he added.
The depth of the water in the Bosphorus varies from 36 to 124 meters. The strait is 30 km long and has a maximum width of 3,700 meters. There has already been a rise in the nitrogen and phosphorus levels leading to eutrophication - a common water pollution problem. It causes an increase of phytoplankton - as well as depletion of oxygen - which can then adversely impact certain fish and sea animal species.
At the moment, Istanbul discharges the wastewater with a method called deep-sea discharge. "The water in the Bosporus flows in three levels," explains Dr Hurrem Bayhan, of Yildiz Technical University. “First level is the water that comes from the Black Sea, the second level is the water from the Sea of Marmara that goes upstream to the Black Sea and the third level is the deep sea discharge that comes from the water treatment facilities."
The main governmental departments charged with cleaning up the seawater in Istanbul are Istanbul Water and Sewerage Administration (ISKI) and Istanbul Metropolitan Municipality Marine Services Directorate (ISTAC).
ISTAC was founded in 1994. However, the company didn’t send a single cleaning ship to clean up the Bosphorus until 2004 claiming that prior to that time, Turkish legislation prevented any clean up operation.
According to Dr Bayhan, ISKI monitors the water in Istanbul monthly. “They start in the Black Sea and go all the way to the Sea of Marmara to check the nitrogen and phosphorus levels,” he said.
The monitoring confirms that one of the most polluted areas is the Golden Horn - an inlet of the Bosphorus that suffers high levels of pollution because it has very few currents. So the municipality now plans transport 260,00 cubic meters of clean water daily to the Golden Horn through a 14-kilometer tunnel - a proposal that was tested for the first time earlier this year.
“They will pump clean water from the Istinye district of the Bosphorus, to Kagathane riverthat flows to the Golden Horn,” Kanat explained, adding that one key reason the municipality wants cleaner waters around the Golden Hornis to attract more international corporates to invest there.
Every year TURMEPA collects 18 thousand tons of wastewater and a thousand ton of solid waste from the boats in Turkey. Already in the last 50 years the biodiversity in these waters has dropped dramatically with more than 120 different fish species having disappeared in the last half century.
As well as the financial obstacles, one of the problems dealing with environmental issues are people’s attitudes. “There is a dilemma between industrialism and environmentalism,” Kanat said. “People want better houses and cars.”
Aslin Karanfil, Project Coordinator of TURMEPA agrees: “If you ask a Turk if he is environmentally conscious he would say yes but you will probably find the truth is very different.”
Alina Lehtinen is a freelance journalist based in Istanbul. Follow her @AlinaLehtinen
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