FOTO-NL Data on Long-term chemical pollution monitoring data of surface waters in the Netherlands

<p>Data on chemical pollutants in surface waters were collated from the 21 current Dutch regional Waterboards and the national Rijkswaterstaat authority, covering the whole country and the period between July 7, 1952 and August 1, 2020. Data were curated and harmonized to provide a resource, the FOTO-NL chemical pollution database, for scientific research and practical purposes in characterization, prevention and mitigation of chemical pollution of surface waters. The collated data set contains a total of 42.5 million place-time specified measured water quality parameters, representing the most dense water quality set of urope, readily available for the evaluation of the water quality policy goals of the Water Framework Directive in 2027 and beyond.&nbsp;The dataset archive contains four items:</p>
<p><strong>Input.zip</strong><br>A zip‐archive of 25 raw Excel workbooks sourced from the 21 Dutch waterboards, Rijkswaterstaat (Rhine and Meuse) and two supplementary coordinate files for Waterschap Drents Overijsselse Delta. Each workbook holds the manually curated monitoring data exactly as received.</p>
<p><strong>metadata.xlsx</strong><br>metadata.xlsx. Detailed file and column definitions, provenance notes, curation steps and contact details.</p>
<p><strong>FOTO_NL_output_clean.csv</strong><br>The fully harmonized, cleaned dataset (34.6 million records) containing only those measurements with valid CAS-numbers. In this file:</p>
<ul>
<li>Location identifiers and X and Y coordinates</li>
<li>Sampling dates</li>
<li>Parameter codes (Aquocodes) and CAS-numbers (added where missing)</li>
<li>Sample pretreatment flags (e.g. filtered vs unfiltered)</li>
<li>Measured values and original units</li>
</ul>
<p><strong>FOTO_NL_output_raw.csv</strong><br>The complete, uncurated collated dataset (42.5 million records), preserving all original measured parameters including physicochemical variables and substances without CAS-numbers original units and any unharmonized values. This file supports exploratory analyses of raw data distributions, QC assessments and reproduction of the full historical record.</p>