How do we make our water even cleaner?

Since the 1980s, the quality of the water has improved in leaps and bounds. As a result, otters can once again be seen swimming in the Nieuwkoopse Plassen lakes and salmon in the Rhine.

But this is not enough.

The concentrations of nutrients such as nitrate and phosphate and pesticides in the surface water remain a problem (Water advisory committee, ‘advies waterkwaliteit 2016 (Dutch)’; EU Environmental Implementation Review 2017). This has consequences for the ecological and chemical quality of the water and its usability as drinking water.

Runoff

The nutrients end up in the surface water as a result of runoff and leaching. Once fertiliser has been applied, some of this is washed with the rain over and through the soil into the ditches and groundwater. ‘Much has been improved, but valuable fertilisers continue to leach into the ground and surface water,’ explains Ivo Demmers. Demmers is the programme manager for Sustainable water management at Wageningen Environmental Research (previously Alterra). ‘While nature and biodiversity are hard-hit by this contamination, it also affects fishers and holiday-makers that use the water. They are often affected by poisonous algae and aquatic plants that are thriving because of the excess of nutrients in the water while drinking water companies also have to make a greater effort to bring the water to the quality level of drinking water.’

It will require extra measures to reach the targets set by the European Water Framework Directive (WFD) while the Sustainable Development Goals calls for the improvement of water quality by limiting contamination and by protecting and restoring aquatic-based ecosystems. Thus, there is every reason to put in extra effort.

Much has been improved, but valuable fertilisers continue to leach into the ground and surface water

Contextualisation

Scientists from Wageningen University and Research are researching how to clean up the surface water in the Netherlands in a variety of ways. According to Peter Schipper, water quality project manager at Wageningen Environmental Research, in order to sustainably improve the water quality, you have to start at the beginning and view the problem in its specific context ‘After all, what doesn't enter the water, doesn't have to be taken out.’ The processing of fertilisers can play an important role in this, in addition to more knowledge about the interplay between plants, soil and hydrology.

Medicine and plant protection agents

Wageningen University and Research is also working on several fronts simultaneously when it comes to medicines and plant protection agents. Research is being done about the effects of traces of medicines and pesticides on water quality. Medicine traces are especially difficult to measure, but they already cause effects in low concentrations in the water and the bottoms of ditches.

The effects of pesticides on plants and animals vary between the different types. ‘We use the knowledge resulting from this research to make the application of pesticides more efficient and safer for the environment,’ explains Demmers.

Impetus

Wageningen University and Research, together with farmers, the business community, provinces, water boards and drinking water companies, has taken the initiative to jointly stimulate knowledge about water quality in the next few years. ‘Through this we work towards improving the water quality, for a healthy, safe living environment and sustainable food production,’ states Schipper.

About Ivo Demmers

Ivo Demmers is programme manager for Sustainable water management at Wageningen Environmental Research. He has been working on water management, water quality and spatial development in the Netherlands and elsewhere in different positions at companies and semi-public organisations.