Effect of mercury-contaminated soil from an abandoned open pit mine in Puerto Princesa City, Palawan, the Philippines on the growth and survival of Raphanus sativus L.

Abstract

The increasing heavy metal pollution in the world calls for the introduction of different methods of alleviating its effects. Phytoextraction, which harnesses the ability of plants to tolerate the effects of heavy metal contaminants, has shown promise in removing pollutants from the environment. This study reports that the presence of mercury in the soil has no significant effect on the seed germination of radish (Raphanus sativus L.). The shoot length and root dry weight of radish in the treatment group even showed a significant increase while there was no significant change in the root length. Root: shoot ratio also showed the skewed resource allocation of radish development towards the shoot. The results could be attributed to the abundance of other nutrients in the contaminated soil, the limited translocation of mercury from roots to shoots, and/or the possible mechanisms used by radish for heavy metal tolerance. The results provide further evidence of the potential of radish in the phytoextraction of mercury with its ability to tolerate the negative effects of the heavy metal. Further research that addresses the limitations of the study is needed such as analysis of nutrient concentration in the soil samples, increasing the duration of the experiment, and varying the concentration of the heavy metal.