Metal accummulation in Labeo umbratus (Smith, 1841) collected from the Vaal Dam and human health risks

Author(s)

Beric Gilbert , Ebrahim Hussain , Franz Jirsa, Annemarie Avenant-Oldewage

Abstract

The Vaal Dam is one of the largest dams in

South Africa, located between the Gauteng Province and Orange Free state, and supplies

water to approximately 11.6 million people. Recreational and small scale

subsistence fishing activities have been noted for the dam along with

consumption of fish by local people. Labeo umbratus (moggel) was collected from

the Vaal Dam and muscle, liver, kidney, gill and spinal cord samples were

obtained post mortem and frozen. Defrosted samples were weighed, dried and

digested for analysis of 19 trace elements by Inductively Coupled Plasma – Mass

Spectrometer (ICP-MS). Metals in the muscle tissue were lower compared to other

organs analysed. The levels of As, Co, Cr, Cu, Fe, Se, Sr and Zn in muscle

tissue were above guidelines recommended by the USEPA, with Zn being highest at

31.5 mg/kg (dw). Calculated target hazard quotients indicated that there is a

risk of exposure to As (1.46) for humans consuming L. umbratus muscle tissue,

whereas, no risk was found for the other elements analysed. The total health

hazard index (HI) for moggle, however, did indicate that there is an overall

health risk to humans consuming muscle tissue from this fish species. It has

consistently been shown that trace elements in the water of the Vaal Dam are

below guidelines set out in government legislation for aquatic ecosystems and

aquaculture conditions. However, studies detailing the accumulation of metals

by fish inhabiting the dam have indicated that elements in muscle tissue are

above food safety guidelines set out by the USEPA. Comparison of the HI between

benthic and pelagic fish species from the dam indicates greater health risks

are associated with the consumption of the former group of fish.

Organisation(s)

Department of Inorganic Chemistry

External organisation(s)

University of Johannesburg (UJ)

Publication date

01-2016

Austrian Fields of Science 2012

104023 Environmental chemistry, 106027 Ecotoxicology, 303023 Parasitology

Sustainable Development Goals

SDG 3 - Good Health and Well-being

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