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Even highly hazardous pesticides pose no risk if used while wearing adequate protective clothing .
Let us review a pyrethroid . Deltamethrin is a yellow band product meaning it is harmful . I fact , this hazard classification is debatable as the toxicity ranges from LD50 87 mg / kg to over 5,000 mg / kg . The wide range is due to the different types of carrier used ( such as corn oil , water , etc .) and variations in experimental conditions . When taken as an agricultural remedy in a formulation it is benign in terms of human toxicity . The hazard classification for people is therefore low and the risk for people who prepare spray mixtures and apply it is negligible . However , when applied close to water bodies , deltamethrin poses a very high risk to fish and amphibians . It also extremely toxic to invertebrates . Deltamethrin is therefore a low hazard , very low risk for people but extremely high risk product for fish , frogs and insects .
Lastly one has to consider the current debate around glyphosate . It was branded by the International Agency for Research on Cancer ( IARC ) as a Class 2A carcinogen or cancer causing substance based on a review of studies with mice . Only one out of five studies showed that glyphosate increased the incidence in mice that were predisposed to cancer development . In none of the other studies with mice did glyphosate produce any adverse effects . Take note that the dosages that these laboratory animals were exposed to were ridiculously high and that it is practically impossible to achieve such levels of exposure in field conditions . Technically , the IARC erroneously “ awarded ” glyphosate “ cancer causing ” status . Glyphosate is technically non-toxic to mammals , birds , insects and it has a very low toxicity to most fish species . When applied as a herbicide it poses a risk to green plants but very little risk to woody parts with mature bark . Glyphosate is , despite the erroneous classification by the IARC of very low hazard and risk to animal life but is of high risk to most actively growing plants like non-GMO crops that do not have the glyphosate tolerant gene .
It is important for farmers to start paying attention to risks and hazards . Focusing only on the latter may skew the perception while ignoring the former may result in an undue impact on specific biota . Farmers need to engage specialists who understand the science of toxicology to be more precise in their farming . This will result in more precise pesticide use , more economical application of pesticides and fewer impacts on human health and the environment .
Dr Gerhard H Verdoorn , CropLife South Africa , nesher @ tiscali . co . za 082-446-8946