Water polluted with glyphosate formulations: effectiveness of a decontamination process using Chlorella vulgaris growing as bioindicator

Toxicity response of Chlorella microalgae to glyphosate herbicide exposure based on biomass, pigment contents and photosynthetic efficiency

“…Previous reports have demonstrated that at low glyphosate concentrations, cell growth of C. vulgaris increased within 24-48 hr, which is similar to our results that the cell growth of Chlorella species can recover after 24 hr. This is attributed to the phosphorus content in glyphosate, which is essential to microalgae growth (20). Several other studies also suggested that Chlorella species, including C. pyrenoidosa, C. saccharophila, C. sorokiniana and C. vulgaris are sensitive to glyphosate depending on its concentration and exposure time, which are critical parameters to determine the damage to the balance of the aquatic environment (31,37,42,48,58).…”

“…The Chlorella genus pertains to a small globular single-celled green algae belonging to the Chlorophyta division, is found in many aquatic systems, and is a representative of microalga in aquatic systems (12). The Chlorella species has attracted much interest for its importance in several applications, including agrochemical treatments (13,14), animal feed (15-17, biofuels (18,19), biological indicator (20,21), food supplement (22)(23)(24)(25) and wastewater treatment (26)(27)(28). As previously mentioned, this species, including C. kessleri (29), C. Protothecoides (30), C. pyrenoidosa (31), C. sorokiniana (30) and C. vulgaris (20) has also been considered a potential bio-indicator of the ecosystem, such as for chemical contamination in aquatic environments.…”

“…Specifically, glyphosate interferes with 5-enol-pyruvyl-shikimate-3-phosphate synthase (EPSPS), which block enzymes and prevents the production of aromatic amino acids, including phenylalanine, tyrosine and tryptophan in plants and microorganisms, through the shikimate pathway (32)(33)(34). Previous studies have been demonstrated that toxicity differences to glyphosate exposure in Chlorella microalgae, including C. kessleri (35,36), C. pyrenoidosa (37)(38)(39)(40)(41), C. saccharophila (42), C. sorokiniana (43) and C. vulgaris (20,42,(44)(45)(46)(47)(48)(49). While the toxicity of Chlorella microalgae can be evaluated based on their ubiquity and short life cycle (50), there are no reports on the half-maximal inhibition in response to glyphosate exposure at 24 hr acute toxicity.…”

Removal of dissolved glyphosate from waters by adsorption under the influence of metals

“…Studies concerning glyphosate removal revealed that existing conventional processes in the traditional waste water treatment plant such as flocculation, coagulation and sedimentation are not entirely efficient because of the small size of the organic pollutant and low concentration levels in source water [27]. Studies has been conducted on the biodegradation of glyphosate [28], using algae [29,30] and microorganisms [31]. On the other hand, a variety of developed technologies such as advance oxidation processes [32], coagulation [33,34], membrane technology [35], and adsorption [36] have been demonstrated more effective for the abatement of glyphosate from the aqueous phase.…”

“…Adsorption has significant advantages over other methods because it is simple, environment friendly, and cost effective. Activated carbon [29], biochar [30], hydro char [31], carbon nanotubes [37], and hierarchically structured carbon [38] are some carbonbased materials extensively studied for their adsorption efficiency. However, different surface characteristics of adsorbent play a significant role in the adsorption process.…”