Selenium accumulation in submerged aquatic macrophytes Potamogeton pectinatus L. and Ruppia maritima L. from water with elevated chloride and sulfate salinity.

Submerged aquatic macrophyte species Potamogeton crispus L. (curlyleaf pondweed) and Ruppia maritima L. (widegeongrass) were examined for selenium accumulation from agricultural drainage water in the field and under laboratory conditions. High concentrations of chloride and sulfate salts were found in the drainage water of the constructed wetland at Tulare Lake Drainage District, Corcorn, California. Samples of P. crispus and R. maritima collected from the field, had similar plant-tissue Se concentrations, but the rhizomes accumulated significantly greater amounts of Se than the shoot tissues. When the plants were grown in culture solution supplemented with either chloride or sulfate salt, R. maritima was found to be more salt tolerant than P. crispus, and P. crispus accumulated more Se than R. maritima. Free seleno-amino acids were detected in the plant tissue, and organic Se was detected in the culture solution after 10 days of growth. The release of organic Se into the water by the plants may have a negative impact on the wetland environment.