Uptake and phytotoxicity of soil-sorbed atrazine for the submerged aquatic plant,Potamogeton perfoliatus L.

Abstract

The photosynthetic inhibitory effect of atrazine-sorbed soil placed on the leaf surfaces ofPotamogeton perfoliatus was investigated under laboratory conditions. Leaves simultaneously exposed to atrazine both in solution and sorbed to soil exhibited a similar uptake of atrazine and associated photosynthetic reduction as did leaves exposed to the same concentration of atrazine in solution only. A small quantity of atrazine (0.19 μ/gdw leaf) was found in leaves treated with atrazine-sorbed soil at 120 μ/kg whereas a significantly larger amount (3.57 μg/gdw leaf) was present in leaves treated with dissolved atrazine at a concentration of 100 μg/L. It is concluded that atrazine sorbed to soil on leaf surfaces is less available for uptake by aquatic plants than atrazine in solution. Of greater physiological concern is the physical presence of the soil on the leaves and the resultant reduction of light.