Glyphosate - A non-toxic pesticide?
Katedry Biofizyki Skazeń Srodowiska Uniwersytetu Łódzkiego. Medycyna pracy
(Impact Factor: 0.4).
Glyphosate is currently the most commonly applied herbicide and its use is still growing. Nowadays, over 50 commercial preparations containing this compound are used, and these formulations are much more toxic than their active compound, glyphosate, owing to the presence of many surfactants and carrier compounds. Toxicological investigations provide evidence that glyphosate is an extremely "safe" herbicide for animals. This is why its use in agriculture is universal. In June 1991, the Environmental Protection Agency (EPA) categorized this compound into class E (according to EPA there are five categories of carcinogenicity), which means that it is probably not carcinogenic to humans. Unfortunately, the study carried out by Swedish oncologists in 2001 showed that glyphosate may induce cancer of the lymphatic system. The results of the Swedish study have changed our opinion about "safety" of this herbicide. Investigations concerning both its accumulation and toxic effect in animals and plants are now under way in many laboratories.
Available from: Zafar Mahmood
- "The potential activity of glyphosate is through competitive inhibition of the enolpyruvyl-shikimate-phosphate synthase, an enzyme essential to the synthesis of aromatic amino acids in plants . Toxicological profile of glyphosate, showed that it is a comparatively safe herbicide for animals . Glyphosate alone or with its formulation products, such as, surfactants and permeabilizing agents is usually considered to be harmless under both normal usage and chronic exposure . "
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ABSTRACT: Glyphosate is a widely used broad spectrum herbicide, reported to induce various toxic effects in non-target species, but its carcinogenic potential is still unknown. Here we showed the carcinogenic effects of glyphosate using 2-stage mouse skin carcinogenesis model and proteomic analysis. Carcinogenicity study revealed that glyphosate has tumor promoting activity. Proteomic analysis using 2-dimensional gel electrophoresis and mass spectrometry showed that 22 spots were differentially expressed (>2 fold) on glyphosate, 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) application over untreated control. Among them, 9 proteins (translation elongation factor eEF-1 alpha chain, carbonic anhydrase III, annexin II, calcyclin, fab fragment anti-VEGF antibody, peroxiredoxin-2, superoxide dismutase [Cu-Zn], stefin A3, and calgranulin-B) were common and showed similar expression pattern in glyphosate and TPA-treated mouse skin. These proteins are known to be involved in several key processes like apoptosis and growth-inhibition, anti-oxidant responses, etc. The up-regulation of calcyclin, calgranulin-B and down-regulation of superoxide dismutase [Cu-Zn] was further confirmed by immunoblotting, indicating that these proteins can be good candidate biomarkers for skin carcinogenesis induced by glyphosate. Altogether, these results suggested that glyphosate has tumor promoting potential in skin carcinogenesis and its mechanism seems to be similar to TPA.
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ABSTRACT: A hundred and sixty female white mice, each weighing 35–40 g, were used in this study. The animals were assigned into eight groups as one control group and 7 experimental groups. Groups 2, 3 and 4 were administered N-acetylcysteine (NAC), proanthocyanidin and vitamin E alone, at doses of 100 mg/kg/body weight/day by intra-peritoneal, oral route and, intramuscular, respectively. Group 5 was administered a single dose of cyfluthrin (100 mg g/kg/body weight ∼1/3LD50) by oral, whereas Groups 6, 7 and 8 were given cyfluthrin+NAC, cyfluthrin+proanthocyanidin and cyfluthrin+vitamin E, at the same dose, respectively. The administration of the drugs was initiated following the administration of cyfluthrin, and continued until the end of the seventh day of the study. Blood samples were collected from each group, 24 h, and 3, 7 and 9 days after the administration of cyfluthrin for the assessment of blood malondialdehyde (MDA) levels and superoxide dismutase (SOD) and catalase (CAT) activities. According to the data obtained, compared to the control group, increase in the plasma MDA level of the group administered cyfluthrin alone, and decrease in erythrocyte SOD activities in some periods and CAT activities in all periods were determined. On the other hand, especially, MDA levels and CAT activities were observed to move closer to values of the control group, in the groups that were administered NAC, proanthocyanidin and vitamin E in addition to cyfluthrin. In other words, in most periods, decrease in plasma MDA levels, and increase in erythrocyte CAT and SOD activities were observed in comparison to the group administered cyfluthrin alone. Statistical analyses demonstrated significant differences to exist between the groups on the third, seventh and ninth days with respect to plasma MDA levels, and the third and ninth days with respect to erythrocyte SOD and CAT activities (P < 0.05). However no significant difference was demonstrated in any of the periods in the groups that were administered NAC, proanthocyanidin and vitamin E alone in comparison to the control group (P > 0.05). In view of the parameters examined, animals were concluded to be affected by cyfluthrin and the administration of the three compounds at the indicated doses and for the indicated periods were considered to alleviate the adverse effects of cyfluthrin partly throughout the study period.
Available from: Marcus J Collier
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ABSTRACT: With the introduction of genetically modified (GM) crops there has been increasing concern on their potential impact, particularly their possible ecological impact. This report follows from earlier research that examined this issue in detail and investigates the potential biodiversity impact of two GM crops that are most likely to suit Irish agronomic conditions. These are glyphosate or glufosinate herbicide tolerant (HT) maize and oilseed rape. The research reported here is an extensive analysis of the scientific literature on the subject and was carried out between August 2009 and July 2010. There are several key conclusions from this analysis.
There are many ‘wild’ species related to oilseed rape in Ireland, none of whom are native and many of whom are highly unlikely to survive when crossed with the current oilseed rape crop plant (Brassica napus). The only exception is wild turnip (Brassica rapa), which is an earlier oilseed crop now no longer farmed but anecdotally present in marginal habitats. Worldwide, there have been ongoing and intensive surveys of the potential for GMHT B. napus to transfer herbicide tolerance to B. rapa. While it has been shown that this may occur, the resulting offspring may not survive without being ‘selected’ – that is being sprayed with the herbicide for which they have a tolerance. In Ireland, marginal habitats are not routinely sprayed. There is no likelihood of maize impacting on wild relatives as none exist in Ireland.
In real-world conditions, there are some scenarios where accidental spraying may occur and where management arrangements may give rise to an opportunity for a GMHT plant to prevail in the landscape. This was examined and presented in a series of five hypothetical scenarios. It is shown that there are no creditable scenarios where a GMHT crop can persist or prevail over time any more than a non-GM crop. Furthermore, it is also shown that it is in the management of the GM or non-GM crop that the potential for biodiversity impact is at its greatest.
Glyphosate and glufosinate toxicity was examined in detail and it is shown that these two compounds have significantly less toxicity that other compounds currently used. There are systemic and do not persist in the soil. Their impact on water biodiversity is low. Using a recently-developed index of biodiversity impact (CINMa), the two GMHT crops were subjected of a rigorous analysis of their potential for impact. It is shown that in the management of GMHT maize there is the potential for benefiting landscape biodiversity by lowering toxic materials and management frequency. The same may be said for oilseed rape management, but there is some likelihood for transfer of genetic material to a wild relative. The potential impact of this is low and there is a net beneficial impact as with maize.
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