COMPLEXATION AND PARTICLE-WATER INTERACTIONS OF NICKEL IN ESTUARIES
type: CreativeWork
description: The speciation and particle-water interactions of Ni were investigated in three estuaries with contrasting pollution levels, hydrodynamics and geochemical characteristics. Samples of water and sediments were collected seasonally from the Tamar, Tweed and Mersey Estuaries. The chemical speciation of dissolved Ni was determined by adsorptive cathodic stripping voltammetry (ACSV), and the sorptive behaviour of Ni was studied under simulated estuarine conditions using " Ni coupled to liquid scintillation counting. A relatively high particle reactivity was observed only in the Tamar Estuary, where ACSV-non labile Ni was removed in the low salinity region, followed by addition of ACSV-labile Ni in the mid-estuarine region. The largely conservative behaviour of dissolved Ni in the Tweed Estuary was attributed to the combination of rapid flushing and low suspended particles concentration. In the Mersey Estuary, dissolved Ni (and Co, Zn, Cd and Pb) often showed positive deviations from conservative behaviour, which were attributed to anthropogenic and/or geochemical inputs. The fraction of ACSV-non labile Ni behaved differently in the three estuaries, with a sharp decrease from 90 to 30% from freshwater to seawater in the Tamar, scatter between 30 and 70% in the Tweed, and relatively constant values of 50-70% in the Mersey. These differences are interpreted within the context of different hydrodynamics and geochemistry of the three estuaries. Speciation modelling showed that between 30 and 70% of dissolved Ni in the Tweed, and between 50 and 70% in the Mersey, was bound to a class of strong ligands (log K'NIL = 19.0 ± 0.4 and 18.7 ± 0.5, respectively), which were saturated by the ambient concentrations of Ni throughout the estuaries, suggesting that the ligands are highly specific towards Ni. Irradiation of riverwater samples with UV light (believed to remove dissolved organic matter) significantly enhanced Ni uptake onto estuarine suspended particulate matter, with an incre…
abstract: The speciation and particle-water interactions of Ni were investigated in three estuaries with contrasting pollution levels, hydrodynamics and geochemical characteristics. Samples of water and sediments were collected seasonally from the Tamar, Tweed and Mersey Estuaries. The chemical speciation of dissolved Ni was determined by adsorptive cathodic stripping voltammetry (ACSV), and the sorptive behaviour of Ni was studied under simulated estuarine conditions using " Ni coupled to liquid scintillation counting. A relatively high particle reactivity was observed only in the Tamar Estuary, where ACSV-non labile Ni was removed in the low salinity region, followed by addition of ACSV-labile Ni in the mid-estuarine region. The largely conservative behaviour of dissolved Ni in the Tweed Estuary was attributed to the combination of rapid flushing and low suspended particles concentration. In the Mersey Estuary, dissolved Ni (and Co, Zn, Cd and Pb) often showed positive deviations from conservative behaviour, which were attributed to anthropogenic and/or geochemical inputs. The fraction of ACSV-non labile Ni behaved differently in the three estuaries, with a sharp decrease from 90 to 30% from freshwater to seawater in the Tamar, scatter between 30 and 70% in the Tweed, and relatively constant values of 50-70% in the Mersey. These differences are interpreted within the context of different hydrodynamics and geochemistry of the three estuaries. Speciation modelling showed that between 30 and 70% of dissolved Ni in the Tweed, and between 50 and 70% in the Mersey, was bound to a class of strong ligands (log K'NIL = 19.0 ± 0.4 and 18.7 ± 0.5, respectively), which were saturated by the ambient concentrations of Ni throughout the estuaries, suggesting that the ligands are highly specific towards Ni. Irradiation of riverwater samples with UV light (believed to remove dissolved organic matter) significantly enhanced Ni uptake onto estuarine suspended particulate matter, with an incre…
author: MARTINO, MANUELA
language: eng
date published: 2000-01-01T08:00:00Z
date modified: 2026-07-24T03:49:27Z
provider: University of Plymouth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Plymouth