Pollution of aquatic ecosystems by pesticide contamination is a major environmental concern. Numerous authors have addressed the frequent occurrence of chronic or acute herbicide contamination of freshwater ecosystems in both agricultural and urban areas of the world (Devault et al. 2007; Gilliom 2007; Schuler and Rand 2008; Woudneh et al. 2009). The physiological characteristics of photosynthetic microorganisms make them attractive as targets for herbicides in aquatic ecosystems. Since these primary producers form the basis of trophic structure in many aquatic environments, herbicides may threaten the entire equilibrium of the ecosystems they contaminate.