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- 1. Metal bioaccumulation in muscle tissue of tigerfish (Hydrocynus vittatus) from the Pongolapoort Dam and Okavango River By: E. M Fisher Supervisor: Prof. V. Wepener Co-Supervisor: Dr. N Smit University of Johannesburg Zoology Department
- 4. Pongolapoort Dam University of Johannesburg Zoology Department Photos taken from DWAF(2004)
- 6. Olifants river University of Johannesburg Zoology Department http://www.dwaf.gov.za/iwqs/rhp/state_of_rivers/state_of_crocsabieolif_01/maps/olif_eco_600.jpg
- 8. Okavango River University of Johannesburg Zoology Department http://na.unep.net/AfricaAtlas/AfricaAtlas/AtlasDownload/Maps/okavango_catchments.jpg
- 18. RESULTS AND DISCUSSION Water comparison between sites 0.007 0.002 0.0001 0.003 0.002 Cu,Zn (Sawula,2004)
- 27. THANK YOU! University of Johannesburg Zoology Department
Editor's Notes
- 1. and drains an area of nearly 8000 km2 2.was built in 1972 in a gorge in the Lebombo mountains 3. and possesses a 89m high wall. 4. In 1874 this area was proclaimed the Pongola Game Reserve
- is the second largest (54 805 km2) river flowing through the Kruger National Park” 2.According to du Preez & Steyn (1992), Van Veelen (1991) said that the water entering the park is highly mineralised with no significant change in composition as it flows through the park.
- 1. and flows southeast for approximately 600km and terminates in the vast floodplane of the Okavango delta, in northwest Botswana
- 1.This study was undertaken during the “freeding frenzy” that occurs between October and December (Whitlow, 2008) 2.For the purposes of this study the data from site 5, in conjunction with the overall results from the Olifants River by du Preez & Steyn (1992) were used to compare metal concentrations between industrialized and non-industrialized areas.
- Al Acid environments solubilizes large amounts of aluminium Aluminium toxicity to fish is dependent on the aluminium species and concentration, length of exposure and previous acclimation of the fish. Aluminium related mortalities are usually associated with the production of mucus that clogs the gills, resulting in anoxia and a rapid loss of sodium due to impaired ion-exchange across the gill membrane. This is usually fatal, as it results in the dilution of the blood plasma ions, which leads to severe osmotic problems in tissues and interstitial fluids Accumulation of elevated concentrations of aluminium as a result of the consumption of fish is unlikely, since most of the aluminium in fish is deposited in the liver and gills. Target water quality guidelines pH greater than 6.5: 0.1ug/L, pH less than 6.5 0.5 ug/L As Enters aquatic systems in dissolved form through industrial discharges Metallurgical industry, glass and ceramic industry, pesticide manufacturing, and petroleum refining industries arsenic can be bio-accumulated, it needs to be monitored in the aquatic environment. arsenic interacts with many elements, among them selenium and iodine Most arsenic in water is precipitated on the surface of the body and gills of fish, and causes the production of mucous film, and death is usually attributable to suffocation. High concentrations of arsenic cause direct gill damage, which leads to anoxia and collapse of blood vessels. Some arsenical compounds are fat-soluble and therefore accumulate in fatty tissues, The TWQR for arsenic for water bodies containing fish is 0 - 0.05 mg/R. Cd The most toxic metal pollutant Cladding industry, nuclear reactors, alkaline cells and alloy industry Cadmium has low solubility under conditions of neutral or alkaline pH and is highly soluble under acidic conditions, Cadmium interacts strongly with zinc due to the chemical similarity of the two metals. In aqueous solution reduction cannot occur in water containing dissolved oxygen. Cadmium also interacts with selenium . The following factors influence the lethal concentration of cadmium. ! Temperature : cadmium toxicity is increased at high water temperatures; ! The dissolved oxygen concentration : survival decreases in water containing low dissolved oxygen concentrations; ! pH : high pH increases bioaccumulation of cadmium; ! Water hardness : a negative relationship exits between the logarithm of cadmium toxicity and the logarithm of water hardness. Increased hardness reduces bioaccumulation and toxicity of cadmium to fishes; ! Additive (synergistic) effects with other metals : additive toxicities have been found for the following combinations of metals: copper and cadmium; and cadmium and mercury ; and ! Infra-additive effects with other metals : cadmium toxicity is lowered in the presence of sublethal concentrations of zinc . There is no difference in the toxicity of cadmium in water with or without suspended solids. Cadmium may be removed from solution by adsorption. Cadmium is adsorbed on humicmaterials to a far greater extent than onto clay or silica particles Gill tissue is initially damaged by detachment of the epithelial layer with consequent hypertrophy and hyperplasia of the interlamellar epithelium. 0.15-0.4ug/L depending on water hardness Cobalt AGRICULTURE Livestock Watering Irrigation Aquaculture 0 - 1 0 - 0.05 NA mg/L Cobalt is not generally considered a plant nutrient, but appears to be essential for some plant species. Cobalt concentrations in the range of 0.1 - 5 mg/R have been found to be toxic to a variety of food crops when added to nutrient solutions. The occurrence of cobalt toxicity is rare under field conditions, presumably because it is strongly sorbed by soil. Generally cobalt does not accumulate in edible parts of plants to levels that are dangerous to consumers Elevated cobalt levels may occur in the vicinity of mines where the ores that are processed contain cobalt. Cobalt is stored in the liver, kidneys, adrenal glands and bones and is poorly retained in body tissues. Excess cobalt is rapidly excreted, primarily as urine, although cobalt is secreted in the bile and hence reabsorption is possible.
- 1. should be done on these areas to confirm results 2. for Kruger and Okavango so as to reflect the true population, and minimize error. 3. to compare the differences in the bioavailability of the metals in the different sites and to delve into the chemical interactions of these metals with other properties of the environment.