Project description

Investigates where the concentrations of nitrate in the Danish drinking water is too high. The investigation was done mainly because of 2 reasons. 1) A group of Danish scientists concluded in a recent study that the risks of getting cancer was present when drinking water with nitrate levels at much lower levels (4 mg nitrate per liter water) than the current official acceptable levels (50 mg nitrate per liter water). The investigation showed that about 3.000 households with a privately-owned water well contained nitrate concentrations which was above the current acceptable levels of 50 mg nitrate per liter water. 2) The investigation was also relevant because the Danish government in the fall 2017 decided to drop the lawful requirement on collecting water samples for analysis for the described water wells – for example sampling the levels of nitrate in the water.

What makes this project innovative?

The investigation was based on scraped data from the public institution Geological Survey of Denmark who collects and stores all the samples of tested drinking water from about 40454 household owned wells. The data is only stored and presented to the Danish public when the water samples have been validated by the laboratories. By scraping the publicly available data from 40454 separate webpages with separate analysis-data for each sample the scale of the problem could be brought to light. The story was presented in collaboration with 2 Danish medias, the daily paper Information, and the niche media, which is an independent media covering the municipalities. Information published the story on the health issues on higher chances of getting cancer at much lower concentrations of nitrate in the water than the official levels is currently set to, then tapped into that story with the scraped data. The result was the publishing of the story on the front-pages of both papers. So, this was a success on collaboration and tapping into each other’s stories and resources – and in telling the public about important health issues and governmental decision-making – maybe based on lack of information which was brought to light with the presentation and analysis of this data.

What was the impact of your project? How did you measure it?

In the fall of 2017 the Danish government decided to drop the lawful requirement on collecting water samples for analysis – for example sampling the levels of nitrate in the water. For making this diction the opposition to the Danish government asked for all relevant data on where the levels of Nitrate were too high, but the Danish government did not deliver the data which our story is based on (they though supplied a report that is 13 years old from 2004), even though this data is collected and stored on an institutional level within the state - but not asked for by the government at request. Since this story was published the parliament opposition have been asking questions on why this data was not given to them before deciding to change the laws. This question is still unanswered – as well as questions on whether or not to lower the official acceptable levels of daily intake of nitrate – because of the new information on health risks (cancer).

Source and methodology

The source of the data is held within loads of html-files available to the public by the institute Geological Survey of Denmark. First html-page the public can see is a list of all 40454 active water wells registered, clicking into each of them you can see information on the specific water well. For example, the coordinates of the well and you can also see a link to all the analyzed water samples – containing information on for example nitrate, pesticides and other matters. All this information was scraped with a homemade PHP scraper. This PHP scripts contains 1113 lines of code in total with 81853 characters with spaces. The data was then stored in an MySQL-database (206093 rows of data) for further analysis. Collecting all the data, we could then see the specific water wells which had collected water samples which showed a higher concentration of nitrate than the official levels allows (50 mg of nitrate per liter water). This information was then mapped into an open source Leaflet Map, which was then presented to the readers of both Information and on paper and online. The daily paper Information brought this map on the front page as their only story.

Technologies Used

PHP for scraping and collecting the data, MySQL for storing the data, PHP for analyzing the scraping data stored in MySQL and then Leaflet for presenting the relevant data on a map – both on paper and online on web.

Project members

Story by: Jørgen Steen Nielsen at Information and Jens Holm at


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