The Loskop Dam in South Africa is the most contaminated waterbody in the Olifants River which is a transboundary river that flows into Mozambique. The present study measured selected metal concentrations in the muscle of Labeo rosae and Oreochromis mossambicus from Loskop Dam, and assessed the human health risks associated with consumption of these fish species. Trace metals were below detection level in the surface water whereas bottom sediment exhibited relatively higher concentrations. A significant seasonal variations (p < 0.05) as well as inter-species difference (p < 0.05) of metal concentrations were observed in the fish muscle. Selenium concentration showed to have increase over the recent few years. Concentrations exceeding permissible level for human consumption was recorded for As, Se and Sb in both species. Other metals which THQ > 1 was Cr for L. rosae and Co for O. mossambicus. The current study shows that there could be some serious health and environmental implications for rural communities making use of Loskop Dam fish as food source. These findings add to knowledge in Africa, particularly South Africa, where other fish species have been identified as being potentially dangerous for human consumption in terms of Se, Sb, As, Co and Cr levels.

The Onderstepoort Journal of Veterinary Research (OJVR), is the official publication of the Onderstepoort Veterinary Institute. It publishes scientific papers reporting original research on diseases and disease vectors of livestock and wildlife with a focus on Africa, but with results of more than local interest.

The Olifants River, a tributary of the Limpopo River system, is one of the most polluted rivers in South Africa. In May 2011 the concentrations of metals in fish muscle tissue from two impoundments...

Urban rivers are regarded as unnatural because they drain catchments characterized by impervious surfaces. The present study explored macroinvertebrate communities in relation to water and habitat quality along the longitudinal gradient of an urban Palmiet River in Durban, South Africa. Sampling was conducted across six sites along the river. The water quality has shown a significant variation (ANOVA, p < 0.05) across six sites. Good-quality water was observed at Site 6, whereas Site 5 exhibiting hypertrophic condition. Sites 4 to 1 were all eutrophic; however, nutrient levels showed to decrease from Site 4 down to Site 2 and increased again at Site 1. A similar trend was observed for habitat quality, with Site 6 showing excellent and Site 5 exhibited poor habitat. Coinciding with water and habitat quality, macroinvertebrate diversity and abundance showed significant differences across six sites. Sensitive palaemonids, notonemourids, and amphipods were only observed in the headwaters and have contributed over 50% of the variation in abundance between Site 6 and other sites. The non-metric multidimensional scaling (NMDS) plot has also shown clear discrimination (MANOVA, p < 0.001) for the Average Score Per Taxon (ASPT) across the six sites. Macroinvertebrate communities have shown a clear association between water and habitat quality. These findings affirm the ecological importance of urban rivers as they provide refuge to aquatic biodiversity, with anthropogenic litter providing additional habitats for other taxa. Despite the current conditions supporting biodiversity and the functioning of the river, it is unclear if the system could endure further disturbance.

One of the largest river systems in South Africa, the Olifants River, has experienced significant changes in water quality due to anthropogenic activities. Since 2005, there have been various “outbreaks” of the inflammatory disease pansteatitis in several vertebrate species. Large-scale pansteatitis-related mortality events have decimated the crocodile population at Lake Loskop and decreased the population at Kruger National Park. Most pansteatitis-related diagnoses within the region are conducted post-mortem by either gross pathology or histology. The application of a non-lethal approach to assess the prevalence and pervasiveness of pansteatitis in the Olifants River region would be of great importance for the development of a management plan for this disease. In this study, several plasma-based biomarkers accurately classified pansteatitis in Mozambique tilapia (Oreochromis mossambicus) collected from Lake Loskop using a commercially available benchtop blood chemistry analyzer combined with data interpretation via artificial neural network analysis. According to the model, four blood chemistry parameters (calcium, sodium, total protein and albumin), in combination with total length, diagnose pansteatitis to a predictive accuracy of 92 percent. In addition, several morphometric traits (total length, age, weight) were also associated with pansteatitis. On-going research will focus on further evaluating the use of blood chemistry to classify pansteatitis across different species, trophic levels, and within different sites along the Olifants River.