Finally, the start of some guidelines for glyphosates in South Africa…

27 January 2013

Glyphosate-based herbicides are commonly used or overused – and have been contentious in the aquatic sciences for a long time.  Their presence in surface waters has been linked to all sorts of evils, not least their being a potential source of phosphate for toxic cyanobacteria (Google this relationship if you are interested).

Way back in the 1990s, the far-sighted and outspoken University of Cape Town aquatic scientist and influential lecturer of note, Professor Bryan Davies, warned about the dangers of the ill-advised use of glyphosates.  He even went as far, back in 1999, as recommending an immediate ban of this type of herbicide.   Of course, being outspoken is a limitation as it takes someone with a spine to respond to your criticisms.  Spines are generally in short-supply and character assassination becomes the means to silence those who present a conflict to commercial interests.

I was most pleased to  read this week that

Paul Kojo Mensah, a SSAWRN student at Rhodes University in South Africa, has tackled and completed a project of great value and considerable complexity: testing the effects of herbicide use on aquatic organisms in the Eastern Cape region, and developing guidelines for herbicide use based on the responses of those organisms.

As he learned about the regional use of herbicides to control weeds and invading aquatic species, he was not surprised to find that the most widely used chemical was glyphosate, most commonly sold under the commercial name Roundup and liberally used throughout the province. He was surprised, however, to find that South Africa had no water quality guidelines for glyphosate that were based on indigenous species, unlike the United States, Australia, Canada, and the European Community – even though it has been found in high concentrations since the 1990s in the Hex River Valley, an intensive grape-farming area in the Western Cape Province.

There were reasons for urgency in creating science-based guidelines. One is that glyphosate is commonly used near and even on rivers and other waterways, draining into them when it rains. As an aquatic biologist, Paul knew that many species of aquatic animals are sensitive to chemical pollutants, and he saw the need to protect populations of economic and ecological value. Also, he learned that weed species in South Africa and elsewhere are quickly developing resistance to glyphosate, prompting some users to increase their application rates.

This work is LONG overdue – and, if Bryan (now resident in Pringle Bay) reads this, I hope he will gain some satisfaction that the warnings he sounded twenty years ago may finally be being heeded!

The wheels may turn slowly but at least they continue to turn.  However, how much unnecessary ecological damage may have been done?

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