Fate and transport simulations for inorganic pollutants in selected South African
water systems
*Magu, M. M.; Govender, P. P. & Ngila, J. C.
Applied chemistry Department, Faculty of Science, University of Johannesburg
P. O. Box 17011 Doornfontein 2028
*Corresponding author contacts:
magujnr@gmail.com
Abstract
Water is of great necessity to life and is required by both living things. Drinkable water is not sufficient and
the little available is polluted from various sources [1]. Inorganic pollutants such as metals pose great
danger to aquatic organisms as well as animals including human beings [2]. When these pollutants are
present in the water, they may cause cancer, disrupt endocrine systems, still births, among other effects
which are detrimental to life [3].
This study focuses on determination and speciation of some specific metals present in surface and treated
water systems in South Africa. The samples were collected from various surface water and treated
wastewater systems within Kwazulu Natal and Gauteng Provinces in South Africa respectively. Water
samples were analysed for physicochemical parameters and later prepared in order to pre-concentrate [4,
5] the metal content before analysis was carried out [4, 6]. Metals were analyzed using Inductively Coupled
Plasma optical emission spectroscopy (ICP-OES) as well as Inductively Coupled Plasma coupled with
Mass Spectrometer (MS) [7, 8].
Three metals, Mercury, (Hg), Lead (Pb) & Zinc (Zn) [9-13], were selected for fate and simulation study.
Geochemist’s workbench reactive transport models [14] were used to generate contour maps and
‘chromatograms’ from year one all the way to after 50 years. Adsorption [15] and other self-cleansing
mechanisms were thought to be contributing factors during transport and final fate of these contaminants.
One and dimension models were used and simulation results interpreted [3, 16, 17]. Advection transport
speciation was also done with PHREEQC software.[3, 18]
Presence of these metals may have originated from various anthropogenic activities surrounding the water
systems in agrochemicals, detergents, soaps, disinfectants, bleaching solutions among other household
chemicals [9, 19-21].
References
1.
Magu, M.M., P.P. Govender, and J.C. Ngila, Geochemical modelling and speciation
studies of metal pollutants present in selected water systems in South Africa. Physics and
Chemistry of the Earth, Parts A/B/C.
2.
Liu, E.F. and J. Shen, A comparative study of metal pollution and potential eco-risk in the
sediment of Chaohu Lake (China) based on total concentration and chemical speciation.
Environmental Science and Pollution Research, 2014. 21(12): p. 7285-7295.
3.
Caruso, B.S., et al., Metals fate and transport modelling in streams and watersheds: state
of the science and USEPA workshop review. Hydrological Processes, 2008. 22(19): p.
4011-4021.
4.
Oreste, E.Q., et al., Sample preparation methods for determination of Cd, Pb and Sn in
meat samples by GFAAS: use of acid digestion associated with a cold finger apparatus
versus solubilization methods. Analytical Methods, 2013. 5(6): p. 1590-1595.
5.
Anzano, J.M. and M. Ruiz-Gil, Comparison of microwave acid digestion with the wet
digestion and ashing methods for the determination of Fe, Mn, and Zn in food samples by
flame AAS. Atomic Spectroscopy, 2005. 26(1): p. 28-33.
6.
Ghanthimathi, S., et al., Comparison of Microwave Assisted Acid Digestion Methods for
ICP-MS Determination of Total Arsenic in Fish Tissue. Sains Malaysiana, 2012. 41(12):
p. 1557-1564.
7.
Begum, Z., et al., Determination of trace and rare earth elements in marine sediment
reference materials by ICP-MS: Comparison of open and closed acid digestion methods.
Atomic Spectroscopy, 2007. 28(2): p. 41-50.
8.
Ferrarello, C.N., M.R.F. de la Campa, and A. Sanz-Medel, Multielement trace-element
speciation in metal- biomolecules by chromatography coupled with ICP-MS. Analytical
and Bioanalytical Chemistry, 2002. 373(6): p. 412-421.
9.
Michel, K., M. Roose, and B. Ludwig, Comparison of different approaches for modelling
heavy metal transport in acidic soils. Geoderma, 2007. 140(1–2): p. 207-214.
10.
Pan, L., et al., A regional analysis of the fate and transport of mercury in East Asia and an
assessment of major uncertainties. Atmospheric Environment, 2008. 42(6): p. 1144-1159.
11.
Roberts, P.V., Identifying Process Mechanisms Governing Contaminant Transport - Is the
Model the Message. Ground Water, 1987. 25(5): p. 612-612.
12.
Ryaboshapko, A., et al., Comparison of mercury chemistry models. Atmospheric
Environment, 2002. 36(24): p. 3881-3898.
13.
Traina, S.J. and V. Laperche, Contaminant bioavailability in soils, sediments, and aquatic
environments. Proceedings of the National Academy of Sciences of the United States of
America, 1999. 96(7): p. 3365-3371.
14.
Bethke, C., Modelling transport in reacting geochemical systems. Comptes Rendus De L
Academie Des Sciences Serie Ii Fascicule a-Sciences De La Terre Et Des Planetes, 1997.
324(7): p. 513-528.
15.
Brusseau, M.L., Factors Influencing the Transport and Fate of Contaminants in the
Subsurface. Journal of Hazardous Materials, 1992. 32(2-3): p. 137-143.
16.
Huang, S.L., Equations and their physical interpretation in numerical modeling of heavy
metals in fluvial rivers. Science China-Technological Sciences, 2010. 53(2): p. 548-557.
17.
Caruso, B.S., Modeling metals transport and sediment/water interactions in a mining
impacted mountain stream. Journal of the American Water Resources Association, 2004.
40(6): p. 1603-1615.
18.
Kirk Nordstrom, D., Trace metal speciation in natural waters: Computational vs.
analytical. Water, Air, and Soil Pollution, 1996. 90(1-2): p. 257-267.
19.
Lee, S.-G., et al., Fate and transport of zinc in a sand tank model: monitoring of 2-D plume
using TDR method. Environmental Earth Sciences, 2014. 72(1): p. 1-9.
20.
Pintilie, S., et al., Modelling and simulation of heavy metals transport in water and
sediments. Environmental Engineering and Management Journal, 2007. 6(2): p. 153-161.
21.
Rueda, F.J., S.G. Schladow, and J.F. Clark, Mechanisms of Contaminant Transport in a
Multi- Basin Lake. Ecological Applications, 2008. 18(8): p. A72-A88.