title: Experimental and modeling investigation of metal release from metal-spiked sediments.
abstract: In sediments that contain iron monosulfide, cadmium, nickel, lead, zinc, and silver(I) form insoluble metal sulfides that lower the metal ion activity in the sediment-pore water system, thereby reducing toxicity. However, metal sulfides are susceptible to oxidation by molecular oxygen resulting in metal solubilization. To better understand the sources and sinks of metal sulfides in sediments, iron monsulfide-rich freshwater sediments were spiked with cadmium, nickel, lead, zinc, or silver(I) and placed into cylindrical cores with an overlying layer of oxygen-saturated water. Measurements of the dissolved metal concentration in the overlying water were made as a function of time and the vertical profiles of acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM) were measured after 150 d. A one-dimensional reactive and transport model has been employed to help elucidate processes controlling the fate of metals in sediments. The model incorporates metal-sulfide formation, metal-sulfide oxidation, and metal partitioning onto sediment organic carbon and iron oxyhydroxide to simulate the vertical transport of metals throughout the sediment core.
authors.affiliation: Department of Civil and Environmental Engineering, Manhattan College, Riverdale, New York 10471, USA. richard.carbonaro@manhattan.edu
authors.forename: Richard F
authors.initials: RF
authors.lastname: Carbonaro
authors.forename: John D
authors.initials: JD
authors.lastname: Mahony
authors.forename: Alison D
authors.initials: AD
authors.lastname: Walter
authors.forename: Eve B
authors.initials: EB
authors.lastname: Halper
authors.forename: Dominic M
authors.initials: DM
authors.lastname: Di Toro
mesh_terms: D000143:Acids / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D004784:Environmental Monitoring; D005290:Ferric Compounds / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D008670:Metals / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D000143:Acids; D005290:Ferric Compounds; D008670:Metals; D009930:Organic Chemicals; D013440:Sulfides; D014874:Water Pollutants, Chemical; C021024:ferric hydroxide; D002244:Carbon