Scientists to study storm impact on water quality
British scientists plan to monitor the effect of storms on nitrate and phosphate contamination in rivers, research they say is crucial because climate change means that the intensity and frequency of storms are likely to increase.
Results of the study by the scientists from the Universities of Southampton, Portsmouth and East Anglia and the National Oceanography Centre will be used to create a statistical model of the distribution of excess phosphates and nitrates.
The model will show how far phosphates and nitrates transfer from rivers, through estuaries and into the coastal seas and the role that storms play in the process.
The team anticipates that this will give policymakers more informed decisions on how to reduce nitrate and phosphate pollution in estuaries.
"Approximately 40% of the world's population live within 100 kilometres of the coast and estuaries making them some of the most vulnerable sites for impact from man's activities," said Dr Gary Fones, marine biogeochemist from the University of Portsmouth.
"Pollutants such as runoff from fertilised fields and discharge from sewage treatment plants are gathered by rivers from large areas of the interior and accumulate in estuaries and this is aggravated by storm activity," he added.
Acknowledging agriculture’s potential impact on water quality, the European Commission has proposed a set of measures to update its Nitrates Directive and fertilisers regulation. Its proposed reform of the Common Agricultural Policy (CAP) would give farmers cash incentives to rotate crops to reduce fertiliser use.
The Commission also wants to encourage farmers who use buffer areas that could protect streams and rivers from nitrate and chemical runoff. The proposals, if approved, would take effect in 2014. But the Commission’s ‘greening’ plan for agriculture is facing sharp criticism at a time of rising global demand for food and inevitable conflicts between conservation and production.
Farming and industry groups contend plant nutrition and protection are vital to meet the needs of rising demand, especially as the global population grows.
The British scientists will use the Hampshire Avon and Stour rivers and Christchurch Harbour in Dorset as examples. They team will spend 12 months measuring nutrient water quality and examining pollution levels when sediments in the estuary are stirred up by storms.
The team will also look at how sudden storms affect the input of nutrients and biological activity in the estuary. The research is financed by a Natural Environmental Research Council grant of more than £1 million (€ 1.26 million).
Excess concentrations of phosphate and nitrate in river water, originating from fields, crops and sewers, are some of the major pollutants affecting Britain's rivers and estuaries, researchers say. Nutrient enriched waters can cause severe problems, such as stimulating the growth of excess algae that depletes oxygen from the water.
They can also cause widespread death to fish or cause growth of poisonous algal species (red tides) that can decimate shell fisheries.
Previously, most water quality monitoring in rivers and estuaries has taken place at fixed times that are spaced too far apart to capture storms when they occur.
The project will be the first in the UK to monitor water quality in estuaries using sensors and weather prediction technology to anticipate a storm.
Rivers across Europe still suffer from contamination from industrial chemicals, metals and toxins.
Waterways in the Czech Republic, Germany and Britain are shown by the European Environment Agency to contain “excessive levels of metals, including cadmium and mercury” that threaten drinking water, while EEA studies show the Czech Republic also has among the highest levels of lead pollution.
But fertilisers and insecticides used on farms are also a major concern.
Fertilisers produce nitrate runoff, nurturing algae growth that upsets marine ecosystems. Both the Baltic and coastal France suffer from serious algae blooms blamed on nitrates.
Meanwhile, insecticides enter rivers through runoff from fields and to a lesser extent when they drift into the water during application. Contamination levels have been rising in many central and southern European countries for 20 years with the biggest growth expected in areas that now have relatively low agriculture pesticide pollution, says a study by the Helmholtz research centre in Germany.