Metals and metalloid in gold mine pit lakes and fish intake risk assessment, Burkina Faso.

Abstract

This study aimed to determine the levels of metals and metalloid (arsenic) in pit lakes from a gold mining site and in their fishes and assess their potential health effect on the local human population, in order to evaluate whether pit lakes can be safely used for aquaculture. Water quality data were collected from two pit lakes, namely West Pit 1 (WP1) and West Pit 2 (WP2), and the Nakambé River (NR) in Burkina Faso. Fish consumption rates in different villages were assessed through a survey. Commonly available fish were sampled from the pit lakes and the NR. Fish from the pit lakes contained higher amounts of metals and metalloid than fish from the river (WP1 ~ WP2 < NR). Of the four species of fish considered, Oreochromis niloticus and Hydrocynus forskahlii had the highest metals and metalloid content and Bagrus bajad and Clarias anguillaris had the lowest. The results indicated that the consumption of the whole fish results in higher metals and metalloid intake than consumption of the fleshy part only. Due to the low fish intake of 5.34 ± 2.60g/day/adult deduced from the nutritional survey, exposure to metals and metalloid was below referential doses. The highest arsenic intake comes from eating entire O. niloticus (0.058mg/day/adult) from WP1. Eating O. niloticus and C. anguillaris exposes people to an arsenic intake of 0.01mg/day/adult. The arsenic contents of H. forskahlii and B. bajad were below the method detection limit.