Re-evaluation of groundwater monitoring data for glyphosate and bentazone by taking detection limits into account

The size of glyphosate contamination in Danish groundwater without including samples with glyphosate below detection level is 10,000 to 100,000 higher than doing a parametric event-time model, where non-detect samples are left censored. The trend lines are rather similar. The broken lines are the EU drinking water directive maximum value 0.1 μg l− 1 and the dotted line the detection limit of 0.01 μg L− 1. Numbers are number of samples above detection line and total number of samples.58