title: Influence of ligands on metal speciation, transport and toxicity in a tropical river during wet (monsoon) period.
abstract: Metal speciation and transport are seldom assessed in densely populated Tropical River. An evaluation of the phase distribution for Copper (Cu), Lead (Pb) and Zinc (Zn) along with chemical speciation, variance with different water quality parameters and toxicity were conducted in the Brahmaputra River of India from upstream to downstream during wet (monsoon) periods in July 2014. Results indicated that metal free ions and carbonates were dominant in the inorganic fractions whereas metal concentrations were negligible in the anionic inorganic fractions. Due to high sediment load in the river during monsoon, metals were substantially higher in the particulate fractions than in the aqueous phase. Partition coefficient for Cu (3.1-6.1), Pb (3.4-6.5) and Zn (3.5-6.9), demonstrated strong adsorption of the metals on suspended matter. Q-mode hierarchical cluster analysis (HCA) illustrated groupings mainly governed by quality parameters rather than by the river course. R-mode results imply selectivity of the affinities of metals for different ligands. Health risk index (HRI) values were less than 1 for dissolved metal for Cu, Pb and Zn while it was greater than 1 for total metal for Pb and Cu indicating potential human health risk. The study demonstrated that binding of metals with naturally occurring dissolved organic matter or suspended particulate matter affects metal bioavailability in river during wet periods when sediment load is particularly high. A combination of empirical, computational and statistical relationships between ionic species and fractions of metals provided greater certitude in identifying the resemblance among the different locations of the river.
authors.affiliation: Department of Environmental Science, Tezpur University, Napaam, 784028, Assam, India.
authors.forename: Anindita
authors.initials: A
authors.lastname: Gogoi
authors.affiliation: Department of Civil and Environmental Engineering, University of Ruhuna, Hapugala, Galle, Sri Lanka.
authors.forename: G G
authors.initials: GG
authors.lastname: Tushara Chaminda
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, China.
authors.forename: Alicia K J
authors.initials: AKJ
authors.lastname: An
authors.affiliation: Water Science Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68583-0844, USA.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Snow
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-6105, USA.
authors.forename: Yusong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Environmental Science, Tezpur University, Napaam, 784028, Assam, India. Electronic address: manish.env@gmail.com.
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
mesh_terms: D000327:Adsorption; D000838:Anions; D016000:Cluster Analysis; D003300:Copper / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005843:Geography; D019015:Geologic Sediments; D006863:Hydrogen-Ion Concentration; D007194:India; D008024:Ligands; D019216:Metals, Heavy / Q000032:analysis*; D011336:Probability; D012306:Risk; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015032:Zinc / Q000032:analysis*
chemical_list: D000838:Anions; D008024:Ligands; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D003300:Copper; D015032:Zinc
keywords: Brahmaputra river; Cluster analyses; Health risk index; Heavy metals; India; MINTEQA2; Speciation