Trace metal cycling in the Whau Estuary, Auckland, New Zealand
Michael J. Ellwood A C , Peter Wilson B , Kay Vopel B and Malcolm Green BA Research School of Earth Sciences, Building 47, Daley Road, The Australian National University, Canberra, ACT 0200, Australia.
B National Institute of Water and Atmospheric Research, PO Box 11–115, Hamilton, New Zealand.
C Corresponding author. Email: michael.ellwood@anu.edu.au
Environmental Chemistry 5(4) 289-298 https://doi.org/10.1071/EN07077
Submitted: 22 October 2007 Accepted: 5 June 2008 Published: 19 August 2008
Environmental context. The accumulation of trace metals from urban runoff is a serious environmental concern. In the present paper we show that, in the case of the Whau Estuary, Auckland, New Zealand, there is a significant particulate Zn input, of which a significant amount of Zn is lost from the particulate phase into the dissolved phase within the water column, and via molecular diffusion across the water–sediment interface. The present study shows that changes in the chemical speciation of Zn, associated with changes in salinity, play a major role in regulating the recycling of this metal between the particulate and dissolved phases.
Abstract. Dissolved Zn, Cd, Cu, Fe, and Pb concentrations were measured along a salinity gradient in the Whau Estuary, Auckland, New Zealand. We found a mid-salinity maximum in dissolved Zn and Cd concentrations, consistent with significant loss of these metals from the particulate phase into the dissolved phase. Changes in the chemical speciation of these two metals were coupled to changes in salinity and this was the major driver for Zn and Cd loss from particulate material. Contrastingly, Cu concentrations were conservative with salinity, whereas there was significant scavenging of Fe and Pb from the dissolved phase into the particulate phase. Analysis of sediment pore-water metal concentrations indicated a peak in Zn concentration within the suboxic layer. The peak occurred at a shallower depth than those for Mn and Fe. The concentration gradient across the sediment–water interface suggests that diffusional loss of Zn from the sediment pore water into the overlying water column was occurring. Conversely, the diffusion of Cu from the water column into the sediment pore water was likely to occur because pore-water Cu concentrations were lower than the overlying water column concentrations. The results from the present study show the importance of chemical speciation and the lability of metals attached to particulate material as potentially being a critical determinant on sediment metal concentrations.
Additional keywords: contaminant fate, speciation, toxic metals, trace elements.
Acknowledgements
The New Zealand Foundation for Research, Science and Technology (C01X0307) funded the present research. We thank Bill Maher, University of Canberra, for comments on an earlier draft of the manuscript and three anonymous reviewers for their thoughtful comments.
[1]
P. G. Klinkhammer ,
M. L. Bender ,
Trace metal distribution in the Hudson River estuary.
Estuar. Coast. Shelf Sci. 1981
, 12, 629.
| Crossref | GoogleScholarGoogle Scholar |
[Verified April 2008]
[13]
D. D. Macdonald ,
R. S. Carr ,
F. D. Calder ,
E. R. Long ,
C. G. Ingersoll ,
Development and evaluation of sediment quality guidelines for Florida coastal waters.
Ecotoxicology 1996
, 5, 253.
| Crossref | GoogleScholarGoogle Scholar |
[14]
E. Long ,
D. Macdonald ,
S. Smith ,
F. Calder ,
Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments.
Environ. Manage. 1995
, 19, 81.
| Crossref | GoogleScholarGoogle Scholar |
[15]
W. W. Ahlers ,
J. P. Kim ,
K. A. Hunter ,
Dissolved trace-metals and their relationship to major elements in the Manuherikia River, a pristine sub-alpine catchment in Central Otago, New Zealand.
Aust. J. Mar. Freshwater Res. 1991
, 42, 409.
| Crossref | GoogleScholarGoogle Scholar |
[16]
L.-G. Danielsson ,
B. Magnusson ,
S. Westerlund ,
An improved metal extraction procedure for the determination of trace metals in sea water by atomic absorption spectrometry with electrothermal atomization.
Anal. Chim. Acta 1978
, 98, 47.
| Crossref | GoogleScholarGoogle Scholar |
[17]
K. W. Bruland ,
R. P. Franks ,
G. A. Knauer ,
J. H. Martin ,
Sampling and analytical methods for the determination of copper, cadmium, zinc and nickel at the nanogram per liter level in sea water.
Anal. Chim. Acta 1979
, 105, 233.
| Crossref | GoogleScholarGoogle Scholar |
[18]
H. Zhang ,
W. Davison ,
S. Miller ,
W. Tych ,
In situ high resolution measurements of fluxes of Ni, Cu, Fe, and Mn and concentrations of Zn and Cd in porewaters by DGT.
Geochim. Cosmochim. Acta 1995
, 59, 4181.
| Crossref | GoogleScholarGoogle Scholar |
[19]
W. Davison ,
H. Zhang ,
In situ speciation measurements of trace components in natural waters using thin-film gels.
Nature 1994
, 367, 546.
| Crossref | GoogleScholarGoogle Scholar |
[20]
B. L. Larner ,
A. J. Seen ,
Evaluation of paper-based diffusive gradients in thin film samplers for trace metal sampling.
Anal. Chim. Acta 2005
, 539, 349.
| Crossref | GoogleScholarGoogle Scholar |
[21]
A. M. L. Kraepiel ,
J.-F. Chiffoleau ,
J.-M. Martin ,
F. M. M. Morel ,
Geochemistry of trace metals in the Gironde estuary.
Geochim. Cosmochim. Acta 1997
, 61, 1421.
| Crossref | GoogleScholarGoogle Scholar |
[22]
E. A. Boyle ,
J. M. Edmond ,
E. R. Sholkovitz ,
Mechanism of iron removal in estuaries.
Geochim. Cosmochim. Acta 1977
, 41, 1313.
| Crossref | GoogleScholarGoogle Scholar |
[23]
H. L. Windom ,
R. G. Smith ,
M. Maeda ,
The geochemistry of lead in rivers, estuaries and the continental shelf of the south-eastern United States.
Mar. Chem. 1985
, 17, 43.
| Crossref | GoogleScholarGoogle Scholar |
[24]
E. A. Boyle ,
S. S. Huested ,
B. Grant ,
The chemical mass balance of the Amazon Plume. 2. Copper, nickel, and cadmium.
Deep-Sea Res. A 1982
, 29, 1355.
| Crossref | GoogleScholarGoogle Scholar |
[25]
A. K. Gee ,
K. W. Bruland ,
Tracing Ni, Cu, and Zn kinetics and equilibrium partitioning between dissolved and particulate phases in South San Francisco Bay, California, using stable isotopes and high-resolution inductively coupled plasma mass spectrometry.
Geochim. Cosmochim. Acta 2002
, 66, 3063.
| Crossref | GoogleScholarGoogle Scholar |
[26]
M. L. Wells ,
P. B. Kozelka ,
K. W. Bruland ,
The complexation of ‘dissolved’ Cu, Zn, Cd and Pb by soluble and colloidal organic matter in Narragansett Bay, RI.
Mar. Chem. 1998
, 62, 203.
| Crossref | GoogleScholarGoogle Scholar |
[27]
M. Willis ,
Analysis of the effects of zinc pollution on the macro-invertebrate populations of the Afon Crafnant, North Wales.
Environ. Geochem. Health 1985
, 7, 98.
| Crossref | GoogleScholarGoogle Scholar |
[28]
S. Nayar ,
B. P. L. Goh ,
L. M. Chou ,
S. Reddy ,
In situ microcosms to study the impact of heavy metals resuspended by dredging on periphyton in a tropical estuary.
Aquat. Toxicol. 2003
, 64, 293.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
[29]
A.-J. Miao ,
W.-X. Wang ,
P. Juneau ,
Comparison of Cd, Cu, and Zn toxic effects on four marine phytoplankton by pulse-amplitude-modulated fluorometry.
Environ. Toxicol. Chem. 2005
, 24, 2603.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
[30]
[31]
[32]
P. N. Froelich ,
G. P. Klinkhammer ,
M. L. Bender ,
N. A. Luedtke ,
G. R. Heath ,
D. Cullen ,
P. Dauphin ,
D. Hammond ,
B. Hartman ,
V. Maynard ,
Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic: suboxic diagenesis.
Geochim. Cosmochim. Acta 1979
, 43, 1075.
| Crossref | GoogleScholarGoogle Scholar |
[33]
H. Zhang ,
W. Davison ,
B. Knight ,
S. P. McGrath ,
In situ measurements of solution concentrations and fluxes of trace metals in soils using DGT.
Environ. Sci. Technol. 1998
, 32, 704.
| Crossref | GoogleScholarGoogle Scholar |
[34]
M. P. Harper ,
W. Davison ,
H. Zhang ,
W. Tych ,
Kinetics of metal exchange between solids and solutions in sediments and soils interpreted from DGT measured fluxes.
Geochim. Cosmochim. Acta 1998
, 62, 2757.
| Crossref | GoogleScholarGoogle Scholar |
[35]
Y.-H. Li ,
S. Gregory ,
Diffusion of ions in sea water and in deep-sea sediments.
Geochim. Cosmochim. Acta 1974
, 38, 703.
| Crossref | GoogleScholarGoogle Scholar |
