Abstract
Sediment samples from 3 dams near the gold-mining area in the Mooi River catchment, South Africa, and fish tissue from the mudfish (Labeo capensis) and largemouth bass (Micropteris salmoides) were analysed for Cu to assess environmental pollution. Copper concentrations of sediment samples in 50 mm deep profiles at Klerkskraal Dam (22.2 mg Cu·kg-1), Boskop Dam (14.1 mg Cu·kg-1) and Potchefstroom Dam (21.7 mg Cu·kg-1) and profiles 100 mm and 150 mm deep were above the risk assessment values for Cu, as implemented by the US EPA. Lowest Cu concentrations were found in gonads and blood samples in fish from both species in the 3 dams, but accumulated 3 to 5 times more, to 110.1+17.8 mg Cu·kg-1 dry mass in the liver. After 120 min Cu exposure at 20oC to 10 mg Cu·l-1 (157.3 mmol Cu·l-1) and a 96 h Cu exposure to 1 mg Cu·l-1 (15.73 mmol Cu·l-1) Cu accumulated mainly in liver tissue and gills. For the mudfish, upon exposure to 10 mg Cu·l-1 (157.3 mmol Cu·l-1), the opercular frequency increased significantly from 80 (+ 5.7) cycles·min-1 to above 100 (+ 5.8) cycles·min-1 after 90 min, but thereafter decreased to zero cycles·min-1. For largemouth bass the same increase in opercular frequency was found during 10 mg Cu·l-1 exposure, but this Cu level did not stop opercular frequency. For L. capensis the oxygen consumption rate M· O2 for the two hour exposure period at 10 mg Cu·l-1 decrease significantly from 5.17 (+ 0.32) mmol O2·l-1·kg-1· h-1 for the controls to 4.5 (+ 0.37) mmol O2.l-1·kg-1·h-1 and for experimental M. salmoides from 4.91(+ 0.45) mmol O2·l-1·kg-1·h-1 to 3.13 (+0.74) mmol O2·l-1·g-1·h-1. For the exposure period of 96 h at 1 mg Cu·l-1, M· O2 for both fish species, decreased to 2.9 (+ 0.3) mmol O2·l-1·kg-1·h-1. It is concluded that: The imported M. salmoides from the USA is biologically more tolerant to acute Cu exposure compared to the endemic mudfish, Labeo capensis For the 2 fish species Cu accumulates mainly in the liver, followed by the gills and kidney [Cu] above 20 mg Cu·kg-1 dry sediment may be released in the water column if the pH value decreases below 5 and, together with the physical disturbance of the sediment layer, acute Cu pollution will be the result Copper is about 10 times more toxic for the 2 fish species studied compared to Pb and Cd in hard water as found in previous studies.
Highlights
Effluents from eroded or disused slimes dams at the AngloGold Mine at Carletonville, previously known as the West Wits Goldfields, contain 84.97 μmol Cu·l-1 (5.4 mg·l-1 ) and 3.97 mmol Zn·l-1 (26.0 mg Zn·l-1) while the dry pelitic sediments contain 484 mg Cu·kg-1 (7616.2 μmol Cu·kg-1) and 6440 mg Zn·kg-1 (98501 μmol Zn·kg-1)
The imported M. salmoides from the USA is biologically more tolerant to acute Cu exposure compared to the endemic mudfish, Labeo capensis
This paper reports the acute effects of Cu on the M· O2 and gill frequency in hard water of an indigenous mudfish, L. capensis and the largemouth bass, Micropteris salmoides, imported from the USA
Summary
Effluents from eroded or disused slimes dams at the AngloGold Mine at Carletonville, previously known as the West Wits Goldfields, contain 84.97 μmol Cu·l-1 (5.4 mg·l-1 ) and 3.97 mmol Zn·l-1 (26.0 mg Zn·l-1) while the dry pelitic sediments contain 484 mg Cu·kg-1 (7616.2 μmol Cu·kg-1) and 6440 mg Zn·kg-1 (98501 μmol Zn·kg-1). About 139 Ml·d-1 (Winde, 2007) of underground water from these mines, mainly dolomitic in origin (Midgley et al, 1990), are pumped into the Wonderfonteinspruit, part of the upper Mooi River system. Van Aardt and Erdman (2004) found a mean value of 35 (± 7.5) mg Cu·kg-1. The [Cu] in the water of the Wonderfontein spruit is between 2 and 6 μg Cu·l-1 but in sediment from a dam located in the Wonderfonteinspruit 305 mg Cu·kg-1 was found (Coetzee et al, 2006). In Labeo capensis, a mudfish from the Mooi River Dams, Van Aardt and Erdmann (2004) found 150 (±17.8) mg Cu·kg-1 and 130 (± 23.1) mg Zn·kg-1 in dried liver. According to the South African Water Quality Guidelines (DWAF, 1996) for aquatic ecosystems the acute effect value for Cu is 12 μg Cu·l-1 in very hard water
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.