Metals evaluation in coastal wetlands receiving treated wastewater

摘要

Purpose - The purpose of this paper is to describe the investigation of distribution of metals in water and sediment samples of Poydras-Verret wetland, an area that has received approximately 40 years input of secondarily treated municipal effluent. Design/methodology/approach - Water and sediment samples were analyzed for metals for a period of 18 months. These metals were also monitored for the secondarily treated effluent, and at a reference/control wetland that does not receive wastewater. Analysis of variance (ANOVA) and Student Newman-Keuls post-hoc ANOVA analysis were conducted to evaluate the pattern of metal distribution within the Poygras-Verret wetland and compare results to the reference wetland. Heavy metal criteria established by United States Environmental Protection Agency (USEPA) and State of Louisiana were also used to assess the potential chronic and acute health impacts of heavy metals in the Poydras-Verret wetland. Findings - Concentrations of metals of the Poydras-Verret wetland water are not different from those found in the reference wetland water, suggesting no observed accumulation of these metals within the receiving wetland water. All metals are below the acute criteria. Originality/value - Historical data regarding metal accumulation in wetlands in the published literature is limited. This paper provides supporting evidence that using wetlands to assimilate wastewater could be a long-term, practical solution with the side benefits including wetland restorations and protection from wave erosion and storm surge.