Abstract
This is the first paper reporting on results obtained in a metal bioaccumulation study in the Vaal River system. It discusses concentrations of four non-essential elements (strontium, aluminium, lead and nickel) in water, sediment and various fishtissues. A second paper will report on concentration levels of the remaining five essential trace metals (chrome, copper, iron, manganese and zinc) studied. While heavy metals did accumulate in C. gariepinus tissues, no clear trends emerged with regard to differences between localities (Vaal Dam and Vaal River Barrage) or surveys. The highest non-essential element metal concentrations were generally recorded in gill (filaments and arches), followed by muscle, liver and lastly skin. This general trend appears to be in agreement with trends observed by other workers and reported in the literature. Variability in tissue metal concentrations in C. gariepinus within locality and seasons observed in this study is also reflected in results from available literature. This accentuates the importance of factors that influence the concentrations and bioavailability of trace metals.Keywords: Heavy metal pollution, bioaccumulation, Clarias gariepinus, Vaal River Barrage, Vaal Dam, strontium, aluminium, lead, nickel
Highlights
IntroductionSynopsisWith South Africa’s unallocated water supplies dwindling (Blignaut and van Heerden, 2009), pollution levels (including heavy metal pollution) will influence future water conservation and management policy-making decisions
SynopsisWith South Africa’s unallocated water supplies dwindling (Blignaut and van Heerden, 2009), pollution levels will influence future water conservation and management policy-making decisions
Heavy metals did accumulate in C. gariepinus tissues
Summary
SynopsisWith South Africa’s unallocated water supplies dwindling (Blignaut and van Heerden, 2009), pollution levels (including heavy metal pollution) will influence future water conservation and management policy-making decisions. Sorption of several metals to hydrous ferric oxide (Johnson, 1986; Hem, 1977; Swallow et al, 1980) and manganese oxide (Loganathan and Burau, 1973) has been studied Another factor affecting toxicity of metals is alkalinity (Köck et al, 1995). A large number of biological variables play a significant role with regard to metal accumulation These include interspecies variations (Giesy and Wiener, 1977; Lowe et al, 1985), orientation to the sediment and behaviour (Kligour, 1991; Kidwell et al, 1995), as well as life stages present (Mance, 1987). Effects of metal toxicity are varied, ranging from gross pathologies like scale deformation (Yoshitomi et al, 1998) and liver degeneration (Woodward et al, 1994), to the disruption of metabolic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
