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Assessing toxic elemental concentrations in marine fish Trachurus capensis (Cape Horse Mackerel) and implications for public health

100%

Debipersadh S. , Selvarajan R. , Sibanda T. , Naidoo R.

Polish Journal of Environmental Studies

2018

tom 27

nr 3

While fish is considered a healthy component of the human diet, consumption of fish with high levels of trace metals in their flesh constitutes a public health risk as trace metals have been proven to be toxic. We investigated the concentrations of toxic elements in seawater and also in different body parts of the fish Trachurus capensis caught near Durban, South Africa, using inductively coupled plasma-atomic emission spectrometry (ICP-AES). The highest metal concentration in fish body parts was observed for Pb, followed by Zn. Significantly higher levels of Mn were observed in fish gills as compared to the tissue (muscle) and fish frame. With respect to bioaccumulation, significantly higher Pb levels were observed in fish tissues compared to As, Cr, and Mn. In the frame, significantly higher Pb levels were observed compared to all other metals except Ba. There were no significant differences in the concentrations of different metals in fish gills. Overall, the toxic metal concentrations in the muscle of cape horse mackerel were below levels of concern for human consumption as defined by the FAO and WHO.

Investigations of operation problems at a 200 MWe PF boiler

88%

Peta S. , Toit C. d. , Naidoo R. , Schmitz W. , Jestin L.

Chemical and Process Engineering

2015

tom Vol. 36, nr 3

305--320

To minimize oxides of nitrogen (NOx) emission, maximize boiler combustion efficiency, achieve safe and reliable burner combustion, it is crucial to master global boiler and at-the-burner control of fuel and air flows. Non-uniform pulverized fuel (PF) and air flows to burners reduce flame stability and pose risk to boiler safety by risk of reverse flue gas and fuel flow into burners. This paper presents integrated techniques implemented at pilot ESKOM power plants for the determination of global boiler air/flue gas distribution, wind-box air distribution and measures for making uniform the flow being delivered to burners within a wind-box system. This is achieved by Process Flow Modelling, at-the-burner static pressure measurements and CFD characterization. Global boiler mass and energy balances combined with validated site measurements are used in an integrated approach to calculate the total (stoichiometric + excess) air mass flow rate required to burn the coal quality being fired, determine the actual quantity of air that flows through the burners and the furnace ingress air. CFD analysis and use of at-the-burner static, total pressure and temperature measurements are utilized in a 2-pronged approach to determine root-causes for burner fires and to evaluate secondary air distribution between burners.