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Dutch lakes more polluted in the past than today

For the first time in history, Utrecht University biologists have been able to show how the ecological conditions in small lakes in the Netherlands have changed over hundreds of years. Contrary to expectations, some lakes were found to have been much more polluted in the past than they are today. The researchers’ findings were recently published in the Journal of Paleolimnology and Hydrobiologia.


Farmland and waste water
One of the lakes studied by Professor Andy Lotter and his colleagues was De Waay lake, near Culemborg. They discovered that 500 years ago, when this lake first existed, the water was heavily polluted by manure from the surrounding farmland and waste water from Culemborg. The water quality in De Waay was highest in the 19th century, when drainage improved. According to Andy Lotter, ‘Man has been affecting water quality in the Netherlands for such a long time that there are virtually no natural lakes that have never been affected by human activity. This makes it more difficult to set standards for the natural water quality of water in a particular lake.’


E.P. Kirilova, H. Cremer, O. Heiri, A.F. Lotter. Eutrophication of moderately deep Dutch lakes during the past century - flaws in the expectations of water management? (2010) Hydrobiologia, 637, 157–171.
E.P.Kirilova, M. van Hardenbroek, O. Heiri, H. Cremer, A.F. Lotter. 500 years of trophic-state history of a hypertrophic Dutch dike-breach lake (2009) Journal of Paleolimnology, DOI: 10.1007/s10933-009-9371-2.

More information (in Dutch).