Processing of Particulate Organic Carbon Associated with Secondary-Treated Pulp and Paper Mill Effluent in Intertidal Sediments: A 13C Pulse-chase Experiment

• Published in: Environmental science & technology Vol. 47; no. 23; pp. 13258 - 13265
• Main Authors: Oakes, Joanne M, Ross, Donald J, Eyre, Bradley D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 2013
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied sciences; Biological and medical sciences; Brackish water ecosystems; Carbon Dioxide - analysis; Carbon Isotopes - administration & dosage; Carbon Isotopes - analysis; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; External geophysics; Fundamental and applied biological sciences. Psychology; Geologic Sediments - analysis; Industrial wastewaters; Models, Chemical; Physical and chemical properties of sea water; Physics of the oceans; Phytoplankton - metabolism; Pollution; Pollution, environment geology; Sewage; Synecology; Tasmania; Waste Disposal, Fluid - methods; Waste Disposal, Fluid - standards; Wastewaters; Water Pollutants, Chemical - analysis; Water treatment and pollution; Australia; Tasmania; Oceania; Brackish water environment; Isotope labelling; Carbon Isotopes; Estuaries; Particulate carbon; Sediments; Coastal zone; Paper industry; Mud flats; Dissolved organic carbon; Intertidal zone; Industrial waste water; Environment impact; Stable isotopes; Waste water discharge; Dissolved inorganic carbon; Carbon 13
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es402814u

To determine the benthic transformation pathways and fate of carbon associated with secondary-treated pulp and paper mill (PPM) effluent, 13C-labeled activated sludge biomass (ASB) and phytoplankton (PHY) were added, separately, to estuarine intertidal sediments. Over 28 days, 13C was traced into sediment organic carbon, fauna, seagrass, bacteria, and microphytobenthos and into fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) from inundated sediments, and carbon dioxide (CO2(g)) from exposed sediments. There was greater removal of PHY carbon from sediments (∼85% over 28 days) compared to ASB (∼75%). Although there was similar 13C loss from PHY and ASB plots via DIC (58% and 56%, respectively) and CO2(g) fluxes (<1%), DOC fluxes were more important for PHY (41%) than ASB (12%). Faster downward transport and loss suggest that fauna prefer PHY, due to its lability and/or toxins associated with ASB; this may account for different carbon pathways. Secondary-treated PPM effluent has lower oxygen demand than primary-treated effluent, but ASB accumulation may contribute to sediment anoxia, and respiration of ASB and PHY-derived DOC may make the water column more heterotrophic. This highlights the need to optimize secondary-treatment processes to control the quality and quantity of organic carbon associated with PPM effluent.