Submitted4 July 2019Accepted18 September 2019Published21 October 2019Corresponding authorTimothy Omara,prof.timo2018@gmail.comAcademic editorRachel Ann Hauser-DavisAdditional Information andDeclarations can be found onpage 22DOI10.7717/peerj.7919Copyright2019 Omara et al.Distributed underCreative Commons CC-BY 4.0OPEN ACCESSMercuric pollution of surface water,superficial sediments, Nile tilapia(Oreochromis niloticaLinnaeus 1758[Cichlidae]) and yams (Dioscorea alata)in auriferous areas of Namukombestream, Syanyonja, Busia, Uganda