title: Sharptooth catfish shows its metal: a case study of metal contamination at two impoundments in the Olifants River, Limpopo river system, South Africa.
abstract: Clarias gariepinus is increasing in importance as a global aquaculture species with a 100 fold increase in production over the past decade but this species still remains one of the most important wild harvested freshwater food fish throughout rural Africa. However, this species has been shown to accumulate metals from contaminated inland waters. In this paper, the metal concentrations in muscle tissue of C. gariepinus from two main-stem impoundments in the Olifants River, Limpopo Basin, were measured and a desktop risk assessment based on the US-EPA methodology completed to evaluate whether long-term consumption of C. gariepinus from these impoundments may pose a health risk to rural communities. Our results show that metals are accumulating in the muscle tissue of C. gariepinus and have appeared to have increased in the last two decades. Risk assessment generated Hazard quotients (HQ) greater than 1 indicate that long term consumption of fish from these impoundments may cause adverse health impacts. We found that lead (HQ=9), antimony (HQ=14), cobalt (HQ=2) and chromium (HQ=1) at one impoundment and lead (HQ=2) at the other impoundment were above acceptable levels for weekly consumption of 150 g C. gariepinus muscle tissue.
authors.affiliation: Department of Biodiversity, University of Limpopo, P/Bag X1106, Sovenga 0727, South Africa. Electronic address: Antoinette.Jooste@ul.ac.za.
authors.forename: Antoinette
authors.initials: A
authors.lastname: Jooste
authors.affiliation: Department of Biodiversity, University of Limpopo, P/Bag X1106, Sovenga 0727, South Africa. Electronic address: sean.marr@ul.ac.za.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Marr
authors.affiliation: Department of Biodiversity, University of Limpopo, P/Bag X1106, Sovenga 0727, South Africa. Electronic address: Abe.Addo-Bediako@ul.ac.za.
authors.forename: Abraham
authors.initials: A
authors.lastname: Addo-Bediako
authors.affiliation: Department of Biodiversity, University of Limpopo, P/Bag X1106, Sovenga 0727, South Africa. Electronic address: Wilmien.Powell@ul.ac.za.
authors.forename: Wilmien J
authors.initials: WJ
authors.lastname: Luus-Powell
mesh_terms: D000818:Animals; D002397:Catfishes / Q000378:metabolism*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008670:Metals / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D018570:Risk Assessment; D045483:Rivers; D013019:South Africa; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Antimony; Clarias gariepinus; Human health risk; Lead; Metal pollution; Olifants River; Reservoir