Bioaccumulation of non-essential trace metals in tissues and organs of <i>Clarias gariepinus</i> (sharptooth catfish) from the Vaal River system – strontium, aluminium, lead and nickel

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 fish tissues. 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.

Trace element accumulation and human health risk assessment of <i>Labeo capensis</i> (Smith, 1841) from the Vaal Dam reservoir, South Africa

“…This is further evident in the BCF values determined in Table 5, as the liver, kidney and gill tissues had many BCF values greater than 1. Similar trends have been observed in previous studies conducted on fishes from the Vaal Dam reservoir, in which the gills, kidney and liver possess the highest element concentrations of the tissues studied (Retief et al, 2006;2009;Crafford and Avenant-Oldewage, 2010;2011;Gilbert and AvenantOldewage, 2014). Functioning as the primary detoxification organ, the liver performs crucial roles in blood filtration and toxicant removal (Wood, 2012).…”

Metal contamination and human health risk associated with the consumption ofLabeo rosaefrom the Olifants River system, South Africa

“…This is probably an artefact of the larger fish being captured at the impoundment with higher metal concentrations in fish muscle tissue, rather than its being biologically significant. Fish age, size, sex, life stage, fish behaviour and orientation to the sediment may play a significant role with regard to metal accumulation (Kidwell et al 1995;Crafford and Avenant-Oldewage 2010). However, the present study found no correlation between the patterns of metal concentrations in the fish muscle tissue and those of the water and sediment.…”

“…However, the present study found no correlation between the patterns of metal concentrations in the fish muscle tissue and those of the water and sediment. In addition to biological variables, physical and chemical parameters such as pH, dissolved oxygen, water hardness, salinity, alkalinity and the presence of other metals may also play a role with regard to the bioavailability of metals to fish (Palaniappan and Karthikeyan 2009;Crafford and Avenant-Oldewage 2010). It is possible that the measurement of available metals, particularly in the sediment, may not be representative of the actual bioavailability of these metals.…”

Lead in piscivorous raptors during breeding season in the Chesapeake Bay region of Maryland and Virginia, USA

“…The majority of the nestling osprey we tested in the rivers of the Coastal Plain nested on fresh water. Due to their feeding behavior and trophic position, catfish are known to accumulate lead (Crafford and Avenant-Oldewage 2010). Earlier work has shown that the lead in nestling osprey in the Chesapeake Bay region is ingested, not inhaled .…”