The occurence and level of mercury and cadmium in fish (monk, hake and kingklip)

Abstract

Abstract by author:

Lenntech (1998) available at http://www. lenntech. com/heavv-metals. htm defines heavy metals as any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations. Mercury is the heavy metals that occur throughout the environment found in various forms. In water, mercury accumulates in fish. Fish is the main source of dietary mercury in our body and almost all of it is in the toxic form methyl mercury. Cadmium refers to heavy metals that accumulate in the environment and it has 48 atomic weight. A large number of potential harmful metals and elements are known pollutants but so far only mercury has been implicated in disease occurring in humans caused by the consumption of fish. The research is carried out in order to test my level of understanding in the quality control of fish, especially the limit of human consumption. A statistical test is required to determine that the level of cadmium and mercury are equal or not. The probability of significant level is chosen at 0. 05. The calculated t- value will be compared with the tabulated values at t0. 05 and n-1 degrees of freedom. The data was collected at the beginning of this year from SABS during field attachment. According to them the data was collected from the specimens of three different kinds of fish (hake, kingklip and monk). Dithozine method has been used in determining the levels of mercury in fish (2ug/l). Cadmium ion reacts with dithizone to form a pink/red colour that can be extracted with chloroform and the Detection limits is 0. 5ug/g Cd in a 15 ml final volume with a 15 cm light path. It was concluded that at the probability level of 0. 05 and degree of freedom 9-1 there is a differences in the mean of the two heavy metals