Four generations to snail Armageddon

June 2015

Photo Creative Commons

A recent publication has just blown yet another hole in the 'Roundup is safe for animals' myth.

In Egypt, the equivalent product to Roundup is 'Herfosate'. Herfosate is made up of 48% glyphosate herbicide and 52% 'inert' ingredients needed to allow the glyphosate to penetrate plant cells. 

Such glyphosate-based herbicides are widely used to control weeds in fields of GM glyphosate-resistant crops as well as for pre-planting field-clearance, pre-harvest dry-down, waterway clearance, and weed-control in urban public areas and private gardens. A proportion of the spray ends up in surrounding areas, in the soil and in drainage water.

The assumption that a chemical which targets a plant-specific biochemical pathway can't harm animals has diverted attention away from environmental issue but gradually the science is being done.

Snails are a useful 'bioindicator' because their health reflects the quality of the ecosystem. Due to their body structure, their habitat, and how they move and feed, snails are very intimately exposed to the water and to the plants in their environment.

An Egyptian team of scientists has investigated the effects of Herfosate on a common freshwater snail. The snails were exposed to the herbicide at a border-line toxic level (those found to kill one quarter of them within 24 hours).

After a 2-week exposure, the tissues of the surviving snails were analysed, revealing clear toxic responses which the animals weren't able to neutralise. These included toxic stress-markers, high energy demand, protein degradation, liver damage and cell death. A significant reduction in DNA and in RNA (the molecules generated by DNA in the process of making proteins) was noted.

The Egyptian team also investigated the possibility of cumulative DNA damage due to Herfosate. Snails were bred for four generations during which time each generation was treated with the herbicide for a fortnight. Analysis of their DNA at the end of the fortnight revealed small changes in the DNA profiles of the first three generations. However, the fourth generation showed marked structural damage in all of the four sections of DNA analysed. 

The authors remarked on a visible loss of some 45% of DNA fragments which may have been due to actual gene loss or due to epigenetic (gene-associated) changes known to interfere with the analytical technique. Either way, significant changes in gene functions are indicated.

OUR COMMENT

Snails aren't humans, but we're both animals and have a great deal of cell structure and function in common. The possible implications of this experiment to the health of our environment and of our great grand-children shouldn't be ignored.


SOURCE:
Fayez A. Bakry, et al., 2015, Glyphosate herbicide induces genotoxic effect and physiological disturbances in Bulinus truncatus snails, Pesticide Biochemistry and Physiology, online January 2015