Exposure risk and environmental impacts of glyphosate: Highlights on the toxicity of herbicide co-formulants

Abstract

Glyphosate is an extensively used herbicide globally. Its use dates back to 1970s with increasing numbers over the years. It is an effective weed killer but since it parallelly destroys non-target crops, its use during initial days was restricted. To overcome this, genetically engineered [GE] varieties of many crops entered the market. This led to a significant increase in usage of glyphosate.Over years of extensive usage, many issues related to toxicity, carcinogenicity and GE varieties cropped up. Many researchers studied the toxicological characteristics, health impacts, environmental exposures and ecological impacts of glyphosate and Glyphosate-based herbicides. Many international agencies assessed its carcinogenic potential and grouped and regrouped it based on conclusions of various studies. As an outcome of many studies, an important aspect of toxicity of adjuvants used for technical formulations of glyphosate surfaced and gave a better understanding of its overall toxicity.This review summarizes glyphosate history, global use and hazards related to glyphosate and its technical formulations. It also briefs important studies on Environmental and human health exposures and its impact. Environmental contamination due to glyphosate is studied in detail for water and soil matrices besides its presence in food commodities. Impact of glyphosate on ecosystem, human and animal health has also been detailed. Studies highlighting and inferring the carcinogenic potential of glyphosate are also summed up finally linking the use of glyphosate with the sustainable development goals [SDGs]. The overall conclusions of the review give an insight into the gaps in the current studies particularly mentioning the important role of adjuvants used in technical formulations of pesticides which may go unnoticed for risk assessment studies. Considering the extensive global usage of glyphosate, it is of utmost importance to design toxicological studies and include glyphosate and related adjuvants in the routine monitoring programs of countries. This will help understand the risks and need to restrict or ban the use of glyphosate. Some important inclusions of disclosing toxicity of active as well as other [inert] ingredients/co-formulants on labels should be a mandatory part of pesticide registration.