ECOLOGICAL RISK ASSESSMENT OF A WETLAND EXPOSED TO BORON

A wetland located in the southeastern portion of the United States was the site of an investigation to determine the potential ecological ri sk of elevated boron concentrations to the Bora and fauna living in th e wetland. The conceptual model identified the vegetation as the prima ry receptor of concern, and thus the vegetation is the focus of this a rticle. Samples of surface water, sediments. and selected vegetation w ere collected from the study wetland and several nearby reference site s and were analyzed for boron. Concentrations of boron in all three me dia exceeded reference site concentrations. Boron concentrations were highest near the suspected source but decreased almost to reference-si te concentrations near the outer perimeter of the wetland. Some plants appeared stressed with yellowing and necrotic leaves; however, a corr elation between tissue boron concentrations and the plant's visual app earance was not apparent for all species studied. Modeling of the fate of boron indicated that the wetland has likely been at a steady state for many years and that boron concentrations were not expected to inc rease. It was concluded that no observable adverse ecological impacts to the vegetation could be attributed to boron, nor is it likely that the boron poses an unacceptable risk to the surrounding areas.