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Side Effects of Roundup Weed Killer

Milk Weed image by Digital Photique from

Roundup has become one of the most widely used herbicides in the world. Its popularity is largely due to claims that it is safe for the environment. While it does not appear to be toxic on impact, its long-term effects are becoming better understood. Due to the large scale connection of Roundup to genetically modified crops, it will be used on an even broader scale in the future.

Roundup and Plants

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Roundup is the trade name for an herbicide containing the active ingredient glyphosate. It is applied directly to the weeds by spraying it on the plant tissue. It is mainly useful against herbaceous plants. It is a broad-spectrum, or non-selective, herbicide. This means any plant tissue it contacts will turn brown and die. In most cases it will need to be applied more than once, since it only kills what is above the ground upon first application. Because it is applied as a spray, the potential for drifting can occur. Non-target plants nearby can be killed when wind carries the herbicide. The chemical company Monsanto was the originator of this herbicide. Monsanto is developing agricultural crops such as corn and soybeans that will be immune to the herbicide. This is so Roundup can be sprayed profusely in areas near crops without harming them. Persistent spraying on this scale could completely eradicate the wild plant species in an area.

Roundup and Water

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Professor Rick Relyea conducted research on Roundup at the University of Pittsburgh in April 2005. He found a disturbing connection to Roundup and the decline of amphibians. The problem appears to be the detergents used to disperse the glyphosate. This surfactant --polyoxyethylene amine (POEA)--has a lethal effect on frogs and their tadpoles. It appears to kill certain pond insects as well. This reduces food sources for fish and other inhabitants of the pond. As a result of lower numbers of amphibians, ponds develop heavier algae bloom. Higher than normal amounts of algae reduce the oxygen level of the water. In water it takes Roundup two to 60 days to disappear. But studies found Roundup persists in pond sediment for up to 400 days. Trace amounts have also been found in surface drinking water. Although apparently harmless in small amounts, regular ingestion may prove dangerous.

Roundup and Soil

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One of the reasons Roundup appeared safe early on was its quick breakdown in the environment. Although it dissipates quickly above ground, its persistence in the soil is much longer. Tests have been done around the world on agricultural and forest sites. Documented tests in Finland and Canada reported similar findings. An average between the studies showed that Roundup persisted in soils for 250 to 350 days. The most detrimental soil findings were the negative effect it has on michorizial fungi. This fungi is found in connection with the roots of most plants. The plant and fungi have a symbiotic relationship. The fungi feeds off of the plant sugars, and in turn the fungi supplies the plant with nutrients and water. Earthworms found in soils laced with Roundup appeared to be softer and slower acting. Earthworms are important to soils since they help to break down chemicals, and loosen the soil particles.

Roundup and Mammals

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It is true that Roundup is less toxic to humans and other mammals than some previous herbicides. But this does not mean it is entirely safe. Naturally there are poisonings, even deaths, reported from ingesting the herbicide. The main problems that occur from applying the herbicide are skin-related irritations such as dermatitis and eczema. As with any substance there are allergic reactions in some individuals. The most disturbing findings were reported by scientists at the University of Caen in France in December 2008. The article stated that in low doses, a component of Roundup (POEA) can kill human embryonic cells. It was proven in lab tests. They also found that farm women regularly exposed to the compound were shown to have high rates of premature births and miscarriages. They found the same result with mice. Forest mammals are indirectly affected by the herbicide, due to the decline in frogs and other food sources.

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