This stuff is not safe, but unfortunately many forestry agencies, local authorities, private-land tree-planters and bush regenerators now spray, dab, or otherwise apply glyphosate-containing substances to control weed growth prior to planting. In the U.S. in 1993, university studies declared glyphosate the third most commonly reported cause of pesticide illness among agricultural workers, and to be the most commonly reported cause of pesticide illness among landscape maintenance workers 1.
Glyphosate is the active killing ingredient in numerous proprietary pesticides, including: ROUNDUP, EAZY WEEDER, SLAM grass and weed killer, ZERO weed spray and wand, COMKILL, SQUADRON, TILLMASTER, TUMBLEWEED, etc.
Virtually all testing for long term health and environmental damage (eg: for cancer, reproductive defects, birth defects, chronic damage) has been done only on the single ingredient, glyphosate, and not on the full formulation containing solvents and surfactants 2.
Claims of biodegradability for Roundup (ie, that the herbicide breaks down when it contacts the ground) are therefore next to meaningless. Researchers have found up to 98% of the glyphosate has remained present on sprayed leaves and branches after 90 days. Likewise, if it is not able to be absorbed by a particular soil type, especially those low in organic matter, then it will remain active, often for months.
Glyphosate readily "nitrosates" to form a new compound called N-nitrosoglyphosate, which is known to cause tumours. Nitrosation occurs in the human stomach by reaction with the nitrate in normal human saliva. A forest worker spraying Roundup from a backpack, for example, could be in the high risk category for tumour growth by breathing in some of the spray drift.
Nitrosoglyphosate can apparently also form in soils under certain conditions. Research has shown that it is very persistent (ie, not biodegradable), with 7 parts per million remaining in the soil after 140 days. Admittedly, there is diverse and conflicting data put out about glyphosate. On the strength of the above, the Guide advises that you err on the side of caution.
Weed experts now say that weeds such as rye grass are becoming resistant to glyphosate-containing herbicides, which will render conventional chemical farming practices useless.
Glyphosate is illegal to spray in waterways as of June 3rd 1997. Seventy four of seventy five glyphosate-containing substances tested by the National Registration Authority for Agricultural and Veterinary Chemicals contained a surfactant toxic to frogs and other aquatic lifeforms.
The West Australian Environment Protection Agency has evidence that Roundup has killed three species of frogs 3. At first, the reaction from the National Registration Authority was dismissive, but now a snap review of the effects of Roundup in or near aquatic environments is being undertaken. It is suspected by the WA EPA that it is the surfactant in Roundup that kills the frogs.
The manufacturers, Monsanto, have not released the names of the other ingredients in Roundup and they have not been tested in the environment in conjunction with the active ingredient, glyphosphate. Monsanto has reported "severe local effects and testicular effects in rabbits", so watch out!
Roundup is only conditionally registered with the Authority, because nineteen out of twenty eight studies have still not been done. These are studies to ascertain Roundup's movement and accumulation in water, soil, air, fish, irrigated crops, aquatic systems and forests.
In the state of New York, Roundup manufacturers Monsanto are no longer allowed to label their glyphosate products "biodegradable", or "environmentally friendly" in any advertising. (Monsanto is also the manufacturer of genetically-engineered, Roundup-resistant soybeans.)
- Going Organic Magazine, Dec '95, and Pesticide Action Network North America Update Service.
Picloram (Tordon), a picolenic acid herbicide, is the type of herbicide a chemical company loves to sell and those concerned only with killing vegetation love to buy: it is persistent and can be used to kill a large variety of woody plants and annual and perennial broadleaved weeds.
A mixture of picloram and 2,4-D, known as Agent White during the Vietnam War, was sprayed by the US military on those plants that survived the initial onslaught of Agent Orange (2,4,5-T and 2,4-D). That mixture is sold in Australia as Tordon.
Picloram/Tordon can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant, where it is quite stable (ie, just sits there, waiting...).
The very characteristics of Picloram that ensure the killing of a wide variety of plants, however, are also the one ones that cause trouble in the wider environment: persistence, leaching, and broad toxicity to plants in small amounts.
Tebuthioron - Not Recommended
(to be updated)
Atrazine is the world's most widely used herbicide. It is used to control weeds in plantations, on roadsides, in parks, gardens, orchards and pastures, etc lots of places where children play. It is notorious for its tendency to contaminate groundwater, with a consequent deleterious effect on human health as documented by the World Health Organisation. Because it is a systemic poison (organochlorine), its residues penetrate the flesh of fruit and vegetables and cannot be washed off. The Australian Medical Association is opposed to Atrazine spraying.
Research 4 has indicated that atrazine is associated with prostrate, ovarian and creast cancer and also damages the endocrine system, functioning as a synthetic hormone disruptor. As a 'hormon mimic' it can block, antagonise, compete with, or mimic hormones at cellular level. This may lead to reproductive and endocrinal effects. Atrazine has also demonstrated cardiac toxicity in experimental animals. Exposure may lead to abdominal pain, impaired adrenal function, anaemia, dermatitis, diarrhoea, skin, eye and mucous membrane irritation, nausea and vomiting.
Too often, the community is not even aware of the use of this poison in public areas. It is extremely important to be vigilant when there is the prospect of such chemicals being used in the local community. With the corporatisation of forest agencies, and their hunger for short-term profits and reluctance to date to investigate environmentally-safe weed control, the 'chemical option' remains very attractive to them.
Forestry Tasmania is one such agency which has sprayed Atrazine in water catchment areas after clearfelling areas of forest or plantation. Twenty days after one such instance, Atrazine was found in the town of Derby's tap-water. Manufacturer, Ciba Geigy has tried very hard through the media to claim that Atrazine couldn't harm anyone, yet is unable to explain outbreaks of non-Hodgkins lymphoma in Italy (Europe in general has for years been getting Atrazine fog), or bowel cancer in Kansas in the U.S. (which is subjected to Atrazine rain, has 75% of its water bores contaminated with the stuff and uses identification of Atrazine residues in food imports as a trade barrier). Info from the manufacturer itself shows that metabolites of Atrazine (ie, what it breaks down into in the ecosystem), are more than twice as toxic as the original compound.
The Tasmanian foresters declared a moratorium on Atrazine (and Simazine) use until 1997, and have invested $200,000 in the investigation of alternatives to chemical use in plantations 5. Super-heated steam is one option being examined by Councils to control weeds (such as Sydney's Leichhardt Council). However, there are many more chemicals 'out there' which need to be subjected to closer community scrutiny.
1. Lismore's Big Scrub Environment Centre has published a leaflet called: Glyphosate - How Safe? Call them on [02] 6621 3123 to order a copy or enquire about their other literature. Other info, see Chemicals, Toxics Groups in the Directory.
2. See also Know Your Inerts and Toxic Chemical Combinations.
3. Frog extinctions have also been attributed to drought, acid rain, ozone depletion, salination, pesticides, predation, climate-change and viruses from ornamental fish.
4. See the book Quick Poison, Slow Poison Pesticide Risk in the Lucky Country.
5. Forestry Tasmania has published a book
on chemical-free weed control - see Chemicals,
Toxics in the Books section of the Directory.