Bird feeding drives pollution at Tartu’s Anne Canal

Bird droppings account for most of the water contamination at Tartu’s Anne Canal, and people feeding the birds are contributing to the problem, a microbiological analysis has found, ERR reported.

Estonian and Irish researchers collected water-quality data from the canal over two years. Peeter Laas, a molecular ecology researcher at Tallinn University of Technology and the University of Tartu, said the results showed several sources of contamination, but the clearest link was between humans and ducks. Some bacteria detected can be shared by people and the birds, he said.

As part of the Linnasulps project, researchers monitored water quality in real time using an automated analyser and 12 sensors installed beside the canal. They also analysed duck and dog droppings collected from the beach, looking for traces of different species’ DNA and bacteria.

The researchers found the most contamination near the beach. Microbes were also present in the sand and sediment, where they remained at high levels, Laas said. The analysis found smaller traces of microbes associated with dogs and people.

Ducks stay at the beach over winter because people feed them regularly. Bird ecologist Marko Mägi of the University of Tartu said the problem may be caused by just a few people, but the consequences can affect many. He estimated that duck droppings could accumulate to tonnes or tens of tonnes in the canal over a winter.

Researchers suggest covering the winter swimming hole to keep ducks away and providing a place for swimmers to wash. Tartu city government plans to review the canal’s maintenance plan and put up signs warning people not to feed the birds. The canal has had problems for years.