Impact of North Mara gold mine on the element contents in fish from the river Mara, Tanzania Najat K. Mohamed 1 • A. V. R. Ntarisa 1 • I. N. Makundi 1 • J. Kucˇera 2 Received: 15 September 2015 Ó Akade´miai Kiado´, Budapest, Hungary 2016 Abstract The aim of the study was to determine element concentrations in lungfish and catfish from the river Mara with INAA and EDXF to assess the health impact of the North Mara gold mine (NMGM) in Tanzania. Twenty samples of each species were collected from two sites downstream and upstream along the river Mara in the vicinity of NMGM. The sampling sites were 70 km apart. Significantly higher concentrations (p B 0.05) of Cr, Ni, Cu, and Se in one of the species taken downstream than in those taken upstream might indicate contamination of the river Mara caused by the mining activities. Keywords Gold mining  Contamination  Lungfish  Catfish  INAA  EDXRF Introduction Tanzania introduced large-scale mining in 1998, which has been growing very rapidly after the economy reforms of the 1990s. There are three gold fields in Tanzania, the most prominent being the Lake Victoria Gold Field (LVGF) that spreads between Tabora, Shinyanga, Simiyu, Geita, Mwanza, Kagera and Mara regions. This gold field produces about 90 % of all gold that is mined in Tanzania. The NMGM, located near the river Mara, is a part of LVGF [1, 2]. The NMGM is located in Tarime District in the north- western part of Tanzania. This mine has three open pits, two of them located along the river Tighite that is the biggest tributary of the river Mara in the Tarime district. In 2009 a spill from a tailing dam and leachate was observed around NMGM. A small-scale study, performed after the event, detected high levels of several metals in this river above the permissible levels set by the World Health Organization (WHO). Since the river Tighite is a tributary of the river Mara, the metal levels were assumed to be high in this river as well. The river Mara is home to several species of fish, of which catfish (Clarias mossambicus) and lungfish (Protopterus aethiopicus) are the ones most con- sumed by the inhabitants. Several studies conducted in different places in the world have also shown that metal contamination in fish is associ- ated with mining activities [3, 4]. The fish in these studies were likewise collected from waters in the neighbourhood of metal mines. Hence, there is a compelling reason to measure metal concentrations in fish taken from the river Mara in the proximity of the biggest gold mine in Tanzania. Fish from the river Mara are consumed by approximately 300,000 people living near the river. If contaminated by extraneous and/or toxic metals, the fish will pose a health hazard to a large population. This study aims at determining metal concentrations in two most commonly eaten fish species (catfish and lungfish) from the river Mara near NMGM. Experimental Sampling and sample preparation NMGM, operated by the African Barrick Gold Company is located in the North Western part of Tanzania in the & J. Kucˇera kucera@ujf.cas.cz 1 University of Dar es Salaam, P.O. Box 35091, Dar es Salaam, Tanzania 2 Nuclear Physics Institute CAS, 250 68 Husinec-R ˇ ezˇ 130, Czech Republic 123 J Radioanal Nucl Chem DOI 10.1007/s10967-016-4756-y