Does weeds affect ambition

Dispute over important pesticide : "No cancer risk from glyphosate"

The pesticide glyphosate has gotten into the talk. Mainly because the International Agency for Research on Cancer IARC, which reports to the World Health Organization, classified the herbicide as suspected of being carcinogenic in March. This contradicts the assessment of the Federal Institute for Risk Assessment (BfR) and other licensing authorities. How do you explain the difference?

The BfR is still of the opinion that if glyphosate is used as intended in agriculture, no carcinogenic or other health risk for humans is to be expected. Basically, the task of the IARC is rather to draw attention to substances that are less known and to point out dangers and the need for research in them. The IARC assesses dangers in general, our assessment is more comprehensive and also takes into account user exposure and residues in the environment or food. We have evaluated the IARC report in an appendix to our own assessment. Tomorrow, Tuesday (September 29), we will be in a video conference of the European Food Safety Authority EFSA together with other experts, including those from the IARC, to discuss the differences in the assessment and come to a decision.

What's next?

A reassessment of glyphosate was necessary as part of the EU testing of active substances. We were commissioned to assess the health risk. More than 1000 studies and documents were evaluated. The first draft was presented at the end of 2013, revised after a public discussion and forwarded to EFSA a year later. Another revision took place after the expert meeting at EFSA in February 2015. Then came the evaluation by the IARC in March 2015, which we now also do have still taken into account. Because of these delays, the old permit, which ran until the end of 2015, had to be extended by half a year until mid-2016. The result of the final EFSA consultation on tomorrow, Tuesday, has to be confirmed by all member states, so I assume that the EU Commission and the member states will not have a decision on the extension until March 2016.

There has been criticism that your opinion is not public. You are accused of secrecy.

The public was extensively involved in the process, as in all other deliberations on newly and reassessed pesticides. But the final scientific discussion with the experts of the member states must take place undisturbed by political influence. As soon as EFSA has taken a decision, everything will be made public. Otherwise there will be constant attempts to exert external pressure and everything will be delayed.

You said that you partly agree with the IARC's assessment.

That concerns the epidemiological studies. In other words, those studies in which the effects on farmers or agricultural workers were examined. The main finding is that there is limited evidence that glyphosate intake may be linked to non-Hodgkin's lymphoma (lymph node cancer). But we cannot rule out other influences or coincidences. Caution should therefore be exercised in interpretation. Such kind of studies cannot uncover causal relationships, but only provide clues - but we take them seriously.

Where do you disagree?

This applies to the studies on test animals that were given glyphosate. They were decisive for the cancer agency's assessment of classifying the plant protection product as likely carcinogenic. We considered eleven studies, the IARC only three. In one of the test series, kidney tumors were observed in mice. However, the tumors only appeared at extremely high doses of 4000 milligrams per kilogram of body weight after administration for two years. Even single doses from 1000 milligrams / kilogram are fatal for humans. Therefore this study is not conclusive. In a second study, hemangiosarcomas, a type of connective tissue cancer, were found in mice. But the JMPR, the pesticide expert group of the World Health Organization, did not consider this finding to be conclusive as early as 2004. There remains one study in rats that found a trend towards pancreatic cancer. However, not at high, but low dosages. There, too, we were unable to understand the IARC's assessment.

The IARC also points out that genetic changes, genotoxicity, were found in cell tests with glyphosate. They are also linked to cancer. How do you rate that?

We have evaluated many studies with the pure active ingredient in which no genotoxicity was detectable. On the basis of other working principles, the IARC has primarily evaluated studies in which pesticides containing glyphosate have also been tested. It is suspected that the co-formulants, which are used in addition to glyphosate, can trigger genetic changes. We therefore suggest that after the active substance has been approved, when each plant protection product is subsequently approved, a check is carried out to determine whether the mixtures with glyphosate could possibly cause genetic changes.

The Greens accuse the BfR of having systematically misjudged studies on glyphosate and are calling for an investigation by the federal government.

We are concerned with the scientific evaluation, I have never allowed myself to be influenced by outside pressure. I am sorry for my employees who do an excellent job. We are one of the most critical authorities in plant protection product assessment in Europe. Such allegations undermine our credibility and ultimately play into the hands of questionable industrial interests.

In late June, the Greens reported that glyphosate was found in 16 samples of breast milk. That frightened many women.

It was a shock for us too. Hundreds of mothers called and said they were going to stop breastfeeding. Glyphosate does not accumulate in the body, especially not in fatty tissue or breast milk. It is found in small, harmless traces in urine. The test used by the laboratory is not suitable for breast milk. He can easily sound the wrong alarm. We have commissioned two experienced laboratories to independently develop tests. The first results from 50 breast milk samples are now available: There is no glyphosate in it, and that is a good thing. Glyphosate has no place in breast milk.

How do you rate glyphosate compared to other pesticides?

Glyphosate is relatively less toxic to humans. When it comes to an acute, i.e. suddenly administered, dose, table salt or the pain reliever paracetamol are more dangerous. The bulk of the active ingredients in pesticides is significantly more dangerous, but the quantities used and the limit values ​​are lower. Nonetheless, the question arises whether replacing glyphosate doesn't make the problems bigger instead of smaller.

(The questions were asked by Hartmut Wewetzer.)

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