The NERC-funded study, led by the University of Bristol's Department of Civil Engineering, has looked at nitrate transport from agricultural land to water in the Thames basin. The team used a simple model to estimate the amount of nitrate able to leach from soils to the groundwater based on land use practices along with an algorithm that determined the route nitrate would take to reach surface or groundwater from agricultural areas.
The Thames River catchment provides a good study example because the water quality in the river, which supplies drinking water to millions of people, has been monitored for the past 140 years, and the region has undergone significant agricultural development over the past century.
The study found that nitrate concentrations in the Thames rose significantly during and after World War II to about double their previous level, then increased again in the early 1970s. Nitrite concentrations have remained at that high level even though nitrate from inputs from agriculture declined from the late 1970s to early 2000s.
The researchers observed it takes some time for nitrate to reach the river, and their analysis suggests that the jump in nitrate concentrations from 1968 to 1972 is due to the delayed groundwater response to ploughing of permanent grasslands during World War II.
Dr Nicholas Howden, Senior Lecturer in Water in the Department of Civil Engineering, who led the research, said: "Balancing the needs for agriculture and clean groundwater for drinking requires understanding factors such as the routes by which nitrate enters the water supply and how long it takes to get there.
"Our results suggest it could take several decades for any reduction in nitrate concentrations of river water and groundwater, following significant change in land management practices."
Co-author of the research paper, Dr Fred Worrall in the Department of Earth Sciences at Durham University, added: "The 60s and 70s saw a gradual intensification of food crop production and consequent nitrate release from the land. If your input is dispersed, your output is dispersed; if your input is sharp, your output is sharp. The aquifer is just transporting it; it's not processing it. The nitrate comes through as a pulse."
Co-author, Professor Tim Burt in the Department of Geography at Durham University, said: "You can work out the budget, and there is a phenomenal amount of nitrogen accumulating somewhere in the Thames basin. We don't know where and we don't know in what form, but it represents a potential legacy for a long time. The effects of land-use changes can take decades to filter through the river basin and this has major implications for policies to manage rivers."
The researchers found that any solution to the nitrate issue will require a long-term vision for water-quality remediation. In terms of sustainable groundwater, there seem to be no ''quick fixes'' and if groundwater nitrate concentrations continue to rise in the UK the worst may be yet to come.
The study could help water and land management planners identify practices that best preserve both agricultural production and water quality.
Paper: Nitrate pollution in intensively farmed regions: What are the prospects for sustaining high-quality groundwater?, Nicholas J K Howden, Tim P Burt, Fred Worrall, Simon Mathias, and Mick J Whelan, Water Resources Research, Vol 47, 12 November, 2011
Joanne Fryer | EurekAlert!
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy