Glyphosate – toxic transformation in the sewage treatment plant

The weed destruction glyphosate damages many useful small creatures, which in turn represent the food of larger animals. In addition, studies show that there are already small concentrations of the interpretations of malformations in tadpoles. In humans, too, it can affect the nervous system toxic. The WHO classifies it as “probably carcinogenic”. Approved in the EU for another ten years for another ten years, the total herbicide is still one of the most frequently used sprays in the world.

So far, it has been assumed that glyphosate finds in rivers come primarily from agriculture. Recently, researchers from the University of Tübingen, led by Professor Stefan Haderlein, were able to demonstrate that there is apparently another source for this: Certain detergent additives – so -called aminopolyphosphonates – react to glyphosate. This is shown by extensive laboratory tests, the results of which in the specialist journal »Nature Communications« are printed.

Reaction with the sewage sludge

Manganese occurs almost everywhere in nature – including in the sewage sludge. Phosphonates are mainly used in liquid detergents to soften the water and stabilize bleach. Contrary to the previously used additives, they are heavily liable to surfaces. Up to 80 percent remains in the sewage sludge. “But since thousands of tons of aminopolyphosphonates are used per year, the small part, which remains in the wastewater, is sufficient to make out a significant freight,” Haderlein assures.

The scientists want to check how much glyphosate from detergents are entered in the rivers in the next step. The limit for the herbicide is 100 nanograms per liter in drinking water.

From the point of view of the interest association of the detergent industry (IKW) there is “no risk for people and the environment”. You refer to statements by the head of the chair Biotechnology of the water treatment of the Technical University in Cottbus, Marion Martienssen. A year ago, this had expressed her doubts about a chemical conversion of detergent additives to glyphosate. “If you look at the publication, we are talking about concentrations in the nanogram. These are traces. We can now prove them, but they have no relevance to the environment, ”she now says to the» ND «. Zerfalle glyphosate in sunlight and overall can be easily degradable.

Haderlein contradicts this: Rather, glyphosate is relatively stable compared to UV rays and is mainly broken down by microbes in the soil. “In the literature, the half -life of glyphosate in the soil is six days, in the AMPA mining product at 54,” reports toxicologist Peter Clausing from the Pesticide Action Network (Pan) Germany. Glyphosate is only almost completely disappeared after 19 days, aminomethylphosphonic acid (AMPA) only after half a year.

Long -lasting degradation product

The longevity of AMPA is particularly problematic: the Federal Environment Agency rates AMPA as “far toxic as glyphosate itself.” The phosphate also enriches with nutrients. That is why it has been banned in budgetary detergents since 2013.

“It is also exciting for our research result, like a group of fabric that is considered unintentional per se, can form something through natural processes that you don’t want in the water,” explains Haderlein. “Just as with the polyfluorinated compounds, the assessment has failed in advance.” The environmental mineralogy demands that chemicals to be checked much more precisely before they are approved.

If further research shows that in response to manganese, questionable amounts of glyphosate from detergent residues form, the question arises of alternatives. The predecessor substances EDTA and NTA, which are still used in the USA, were removed from the market because they mobilize heavy metals. Certainly currently only seem to be certified ecological materials with certain seals such as Ecogartie, Ecocert and NCP. “In contrast, other standards with lower environmental standards such as the EU-decolabel or the blue angel cannot ensure equally that phosphonates are excluded,” writes the Federal Association Natural Foundation Naturalware (BNN).