Nitrogen pollution of water systems poses a significant problem in Western Europe. Despite widespread implementation of monitoring networks and action plans in EU Member States, recent statistics show that nitrogen levels in water vary greatly and continue to rise in many areas. Intensely farmed regions are more susceptible to nitrogen pollution as the fertilisers used in agriculture are a major source of nitrates.
In 1991, the Nitrates Directive was imposed with the aim of reducing concentrations of nitrogen in water systems. The later European Water Framework Directive (WFD)1, imposed in 2000, introduced new targets for maintaining water quality at levels close to those which would be seen under natural conditions, without human impacts. Innovative measures are needed to achieve these goals.
One country that has seen dramatic improvements in water quality in recent years is Denmark. A new study highlights the success of seven national action plans in reducing nitrogen concentrations in Danish waters. Between 1989 and 2004, nitrogen concentrations in streams dropped by around a third, as did nitrogen levels leached from agricultural land. The researchers say this has been achieved during a period of intense agricultural activity and growth. They claim therefore, that it is possible for Denmark and other nations with strong farming industries to reach the targets set by the WFD without negatives impacts on agriculture.
The seven policy measures introduced in Denmark focus on controlling the amount of manure and fertiliser used in agriculture, as well as on establishing wetlands, which play an important role in nitrogen cycling and removing harmful nitrates from the environment. All measures were developed following discussions with researchers and farmer groups, in line with WFD requirements for public consultation. Future policy changes will be implemented with the aim of integrating measures designed to reduce nitrogen pollution with other aspects of water and land management.
A key finding of the study, say the researchers, is that there may be a long lag between implementation of a new policy and decreases in nitrogen levels. They concede that original targets for halving nitrogen levels in water within five years were unrealistic. Policy makers are often keen to see fast results, but it inevitably takes time for farmers to adopt new farming methods and for reductions in nitrogen levels used in agriculture to transfer to water systems.