Physicochemical and biological properties of aqueous herbicide compositions based on N-(phosphonomethyl)glycine and succinic acid in a range of low concentrations

Self-organization, physicochemical properties (specific electrical conductivity, surface tension), UV absorption, and fluorescence of aqueous herbicide compositions based on N-(phosphonomethyl)glycine and plant growth regulator succinic acid (SA) were studied in a range of herbicide concentrations of 1·10−19−1·10−1 g L−1 at the constant concentrations of SA 1·10−3 g L−1 (series 1) and 1·10−13 g L−1 (series 2). Such compositions are used in agriculture for decreasing toxic effects on cultural plants and environment. A comparison of the nonmonotonic concentration dependences of the size and ξ-potential of the disperse phase, properties, and bioeffects of systems 1 and 2 revealed significant distinctions in these compositions in the ability of self-organization and surfactant properties, which can cause, as a whole, their substantial difference in the degree of harmful influence on aquatic life and higher plants. The influence of the compositions of series 1 is accompanied by a decrease in the harmful effect on the chosen biological test objects compared to the herbicide, and that of series 2 results in an almost complete elimination of the harmful effect against multicellular organisms (cladocerans and wheat roots) and an insignificant effect on unicellular aquatic life (infusoria and algae). The influence of the compositions of series 2 on aquatic life is related to the formation of a negatively charged disperse phase accompanied by an increase in the fluorescence intensity in a range of 300–360 nm (λexc = 225 nm).