Biosorption of Mercury by Selected Plants – a Preliminary Study

Abstract

Traditionally, mercury (Hg) is considered among the most toxic elements with several major health issues and serious environmental challenges. With the frequent release of Hg from artisanal and small-scale gold mining (ASGM) operations, aquatic plants or staple crops in environments polluted with mercury may accumulate significant amounts of mercury. Thus, result in mercury entering the food supply chain posing health challenges to humans. In order to ascertain the bio-sorption characteristics of some staple crops for mercury; beans, millet, corn and groundnut were tested. The plants were contacted with 10 mg/L and 50 mg/L solution of mercury concentration for 7 days followed by subsequent metal analysis of residual solution. The results delineate that, metal uptake ranges of 4.6-9.3 mg/l, 3.2-9.6 mg/l, 4.7-9.3 mg/l and 3.0-7.7 mg/l for beans, corn, groundnut and millet respectively for the 10 ppm Hg solution. In addition, 16.2-42.0 mg/l, 18.2-35.7 mg/l, 17.6-34.2 mg/l and 26.0-30.2 mg/l are the Hg metal uptake ranges for the 50 ppm concentration. This shows that the plants have the capacity to uptake mercury metal to certain degree. This also confirms that beans, corn, millet, and groundnut are potential bio-accumulators of mercury in mercury contaminated sites. Notably, the findings from this study affirm the hypothesis that in situations where the mercury is bioavailable, some food items harvested in such polluted areas may eventually enter the food chain.