title: Sediment baseline study of levels and sources of polycyclic aromatic hydrocarbons and heavy metals in Lake Nicaragua.
abstract: Selected metals and polycyclic aromatic hydrocarbons (PAHs) were analyzed in sediment samples from 24 sites in Lake Nicaragua sampled May 2010 to provide a baseline of pollution levels. Cu exceeded the Consensus-Based Sediment Quality Guideline (CBSQG) Threshold Effect Concentrations (TECs) at 21 sites while Ni exceeded the value at one site. Comparison of the sampling sites showed that the south-eastern shore and a central part of the lake contained the highest levels of As, Cd, Cr, and Ni, while the western part of the lake contained the highest levels of Cu, Pb, and Zn. Analysis of PAH levels showed that the CBSQG TECs were exceeded by naphthalene at five sites. The sum concentrations of the 16 US EPA priority PAHs (∑PAH16) ranged from 0.01 mg kg(-1) dw to 0.64 mg kg(-1) dw. The highest ∑PAH16 concentration was found upstream in River Mayales and the PAH composition revealed a heavy PAH fraction (e.g., creosote). The main sources of PAHs in Lake Nicaragua were determined as of diffuse petrogenic and pyrogenic origin as well as diagenetic produced perylene. The relative importance of these PAH sources was determined by interpretation of loading and score plots from a principal component analysis. This study concluded that areas of Lake Nicaragua represent an important pollution baseline for future studies in this lake and other tropical lakes.
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. Electronic address: scheibye@plen.ku.dk.
authors.forename: Katrine
authors.initials: K
authors.lastname: Scheibye
authors.forename: Johan
authors.initials: J
authors.lastname: Weisser
authors.forename: Ole K
authors.initials: OK
authors.lastname: Borggaard
authors.forename: Martin M
authors.initials: MM
authors.lastname: Larsen
authors.forename: Peter E
authors.initials: PE
authors.lastname: Holm
authors.forename: Katherine
authors.initials: K
authors.lastname: Vammen
authors.forename: Jan H
authors.initials: JH
authors.lastname: Christensen
mesh_terms: D003625:Data Collection; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis* / Q000592:standards; D009527:Nicaragua; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000592:standards; D014481:United States; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000592:standards
chemical_list: D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Contaminants; Lake Nicaragua; Principal component analysis; Sediment; Source identification