Trace element accumulation and human health risk assessment of Labeo capensis (Smith, 1841) from the Vaal Dam reservoir, South Africa

Abstract

This paper aimed to determine the trace element concentrations within water, sediment and tissues of the Orange River mudfish Labeo capensis (Smith, 1841) collected from the Vaal Dam reservoir, and to assess potential risks associated with the consumption of L. capensis muscle tissue. The study was undertaken in March 2013; 22 L. capensis were collected with the aid of gill nets. Water and sediment samples were collected on site, and additional water analysis data for the sampling period were received from Rand Water Analytical Facility in Vereeniging. Analysis of water revealed trace elements were present at trace levels. The comparison of trace element concentrations between the water, sediment and fish tissues revealed that the sediment contains the highest concentrations, followed by fish tissues and water. This trend exists as a result of the underlying geology of the Vaal Dam, the physiological and biological characteristics of L. capensis, and the physico-chemical state of the water. The risk assessment performed on the muscle tissue revealed that As and Se had total hazard quotient (THQ) values greater than one, and that the levels of As and Se were above the safety threshold values for human consumption.