Project description

At least 113 out of Denmark’s approx. 2,500 large waterworks delivering water to at least 10 households each have filled the taps of consumers with water with quantities exceeding the limit values of the pesticide Desphenyl-Chloridazon. In addition, the pesticide is also found in quantities below the limit of 214 waterworks. This shows a survey made by The pesticide was forbidden in the 90’ies and then forgotten. The state did since not require the Danish water wells to do analysis on whether or not this pesticide was found and in what quantities. But in the summer of 2017 the pesticide was found in alarming quantities in a municipality in Denmark and new regulation was quickly agreed by the MEP’s to test and analyze the get a grip of the extend. The whole investigation, research, analysis and presentation, is done by one journalist, Jens Holm. The whole editorial at consists of an editor, 2 journalists and a journalist intern.

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 2,500 large water works – each suppling water to 10 households or more. 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 thousands of separate webpages with separate analysis-data for each sample the scale of the problem could be brought to light. Scraping and analyzing this data enabled to map exactly where (GPS coordinates) and to which extent the acceptable levels of pesticide was exceeded.

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

"It looks like a disaster for the water supply, there is no doubt. This is a huge problem to an extent that we have not experienced since the most widely problematic pesticide, BAM. And this might be a bigger problem than BAM, said a biologist at the Danish Water and Wastewater Association (Danva) at the release of the article. Since then it’s been found that the pesticide is the worst in the history of pesticides finding its way to the Danish groundwater in levels exceeding the acceptable limits.

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 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 pesticides, nitrate 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 (1053953 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 Desphenyl-chloridazon than the official levels allows. This information was then mapped into an open source Leaflet Map for the readers.

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.


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