Numerous wetlands all around the world are threatened by pollution in a variety of forms.
Pollution can be ‘point-source’, from a specific location (e.g. an outflow pipe from a factory) and can often be in the form of a major individual release or spill, or ‘diffuse’, from a wide area such as fertilisers and pesticides that are sprayed onto fields and may then accumulate in watercourses when washed off by rainfall.
Because wetlands are often found in the lower reaches of rivers or fed by numerous small streams, they are often the “receivers” of pollution from a wide area which can build up and have massive impacts. Although point-source pollution is increasingly coming under control in the UK, there are still occasions where specific pollution events can have a major impact on a wetland. In the developing world and emerging economies, where legislation is sometimes not as well developed, it is of particular concern. Diffuse pollution, particularly from agriculture, is an ongoing challenge both in the UK and overseas.
However, as well as being threatened by pollution, wetlands also have an important role to play in addressing it. Partly because they are adapted to be the receiver of materials and substances from the surrounding landscape, wetlands are extremely good at filtering and cleaning water as it passes through them. This natural function is now something that is increasingly being harnessed to deal with the pollutants that we put into the environment, through the construction of treatment wetlands.
WWT has built up a wealth of experience on the role that treatment wetlands can play in removing pollutants from water, and has installed treatment wetlands at all nine WWT centres. These treatment wetlands are managed to improve water quality, provide important habitat for wetland wildlife, and act as an educational resource to visitors to WWT centres.
Together with WWT Consulting, we have also helped to construct and manage treatment wetlands outside of our centres, including to treat landfill leachate at Shaw Hill Forest Park in Swindon and to treat waste water at Abraham Guest High School in Wigan. We are now monitoring the effectiveness of these treatment wetlands to further improve their design and management as well as inform the design of new treatment wetlands.