The contest was to see how much of the weed killer could be detected in their urine. Around 140 parliamentarians submitted urine samples that will be analyzed over the coming week. The anonymous results will show how much of the substance the European political representatives have in their bodies.

The stunt, led by parliamentarians from the Green party, was meant to put pressure on their peers ahead of a controversial vote on a resolution calling for the European Union to pull authorization for the substance when its 15-year review comes up in June. The parliamentarians say recent studies linking the weed killer to cancer mean a reauthorization is too risky.

"We want to politicise the whole debate on glyphosate," says Bart Staes, a Green representative from Belgium. "Ordinary citizens do have glyphosate in their bodies, in their urine - as politicians, we want to show the general public that we dare to do these tests."

But denying reauthorization could have huge economic impacts on farmers. Glyphosate is the most commonly applied herbicide in the world, famously used in products such as Roundup by Monsanto, and others by Syngenta and Dow. European representatives from the right side of the aisle needed more convincing.

Pee pressure

The power of the pee stunt may have persuaded them. Earlier in the week, Manfred Weber, leader of the center-right EPP group in the European Parliament, urged caution.

"We want to discuss this, because there are differing opinions from experts as to carcinogenicity of glyphosate," he told journalists. "It's a major topic for agriculture."

In the end, the center-right representatives agreed to a resolution calling for any reauthorization to be limited to seven years instead of the usual 15, with new limits attached to its use.

Governments split

The parliament vote is only a non-binding resolution. The decision on whether and how to reauthorize must be taken by a committee of national government representatives from the 28 EU countries.

And those countries are split. France and Italy want to halt authorization. The United Kingdom wants a full reauthorization. Germany is undecided - but leaked memos indicate the government is leaning toward reauthorization.

Another recent publicity stunt over glyphosate involved an analysis of residues in German beer.

If no majority opinion can be reached, a decision will have to be taken by the European Commission, the EU's executive branch, before the current authorization runs out on June15.

The parliamentarians are turning their pee-pressure onto other EU institutions. This week, they sent a letter to European Commission President Jean-Claude Juncker asking him to submit a urine sample to test for glyphosate.

During a group meeting in Strasbourg, they cornered EU Health Commissioner, Vytenis Andriukaitis, presenting him with vials and asking him to provide a sample. He politely declined.

Unsettled science

The plant protection industry says that lawmakers are getting carried away with these theatrics, and that there is not yet any credible reason to be changing the way glyphosate is authorised in the EU.

Thoralf Kuechler, a engagement lead for Monsanto in Berlin, says the same conditions apply as 15 years ago.

"The science is evolving - and that's why there is a reassessment in the regulatory process in the US and other countries after a certain amount of time," Keuchler told DW.

The differing views relate also to different methods of analysis. In 2015, scientists at the World Health Organisation (WHO) caused a ripple when it found that the substance is "probably carcinogenic [cancer-causing] to humans."

This appeared to contradict an updated assessment from last November by the European Food Safety Authority (ESFA), the EU regulator, which found it "unlikely" to pose a health risk.

But Kuechler says the WHO uses an entirely different type of assessment that regulators, analyzing general hazards and not the actual risks of how the substance is used in practice.

Green representatives say the original EFSA finding was based on unpublished reports by industry-funded groups. They want the regulator to undertake a new, more transparent assessment before the product is reauthorized.

They say the EU should follow the "precautionary principle" when making this decision, which says risks should avoided by not taking them.

"We think it is senseless to reauthorize glyphosate for another 15 years, that's what the debate in the parliament is about," says Staes. "We want to help those 11 member states who are rather reluctant for reauthorizing."