Degradation of a mixture of glyphosate and 2,4-D in water solution employing the UV/H2O2 process, including toxicity evaluation

MARIANI, M.L.; ROMERO, R.L.; CASSANO, A.E.; ZALAZAR, C.S.

Advanced Oxidation Processes

CRC Press/Balkema

Año: 2012;

Glyphosate (N-phosphonomethyl glycine) is one of the herbicides most widely used throughout the world due to its broad spectrum, low cost, and non-selectivity. It can be used for non-crop land as well as for a great variety of crops.Several factors have contributed to increase the agricultural use of glyphosate in the last decades: price reductions, increase in supply related to patent expiration, and mainly the implementation of genetically modified (GM) glyphosate resistants (GR) cultivars.The countries with the highest production of soybean are USA, Brazil and Argentina. According to 2010 statistics, they produce 90, 68 and 18 million tons of soybeans, respectively (FAO, FAOSTAT). GR soybean is the major crop in Argentina and its production has been accompanied by an even more important increase in the use of glyphosate. In Argentina, glyphosate use increased from 1 million to 180 million liters between 1997 and 2007 (Binimelis et al. 2009).The widespread use of this herbicide causes two important problems: water pollution, due to its high solubility, and the emergence of resisting weeds. The negative impact of glyphosate residues on the aquatic environment is a major concern due to the potential adverse effects to ecosystems and human beings. Regarding to toxicity, there is a broadening controversy, but recent studies have shown that glyphosate can affect phytoplankton and aquatic organisms. Vendrell et al. (2009) observed a growth inhibition of 10% in green algae Scenedesmus subspicatus with 1.6 mg L-1 glyphosate acid treatments. Commercial formulations are often more toxic than glyphosate alone. Tsui and Chu (2003) found a widespread commercial formulation to have seven folds higher toxicity than glyphosate alone for green algae Selenastrum capricornutum. Pérez et al. (2007) found that glyphosate can affect phytoplankton and periphyton community composition. Poletta et al. (2009) revealed adverse effects of a commercial formulation of glyphosate on Caiman latirostris DNA. A similar work by Guilherme et al. (2012) showed that commercial glyphosate can increase DNA damage in teleost fish Anguilla anguilla.