Determination of Heavy Metals (Lead, Zinc, Nickel and Cadmium) in Medicinal Plants (Scent Leaf and Pawpaw) in Bayelsa State, Nigeria

Abstract

Aims: This study investigated the level of zinc, nickel, lead and cadmium in selected medicinal plants - Scent Leaf (Ocimum gratissimum) and Pawpaw (Carica papaya) that are traditionally used in alternative medicine in Amassoma community, Bayelsa State, Nigeria.
 Study Design: Scent leaf (Ocimum gratissimum) and Pawpaw (Carica papaya) from where these plants are grown were randomly collected for heavy metal analysis from within Amassoma community in Southern Ijaw Local Government Area of Bayelsa State, Nigeria
 Place and Duration of Study: This study was carried out in Biological Sciences, Faculty of Science, Niger Delta University, Wilberforce Island, Amassoma, Bayelsa State between March 2019 to September 2019
 Methodology: Scent leaf (Ocimum gratissimum) and Pawpaw (Carica papaya) were digested and analyzed for heavy metals using Atomic Absorption Spectrophotometer (AAS, model S471096). The method used was wet-ashing method for the analysis.
 Results: The result showed that the concentration of Lead in the pawpaw fruit with 5.99mg/kg and pawpaw seed with 3.72mg/kg, were above the WHO permissible limit. While the concentration of Cadmium in the pawpaw fruit, pawpaw leaf, pawpaw seed and scent leaf with 1.32mg/kg, 0.96mg/kg, 0.21mg/kg, and 0.59mg/kg, were all above the permissible limits. Again, Zinc in the pawpaw fruit, pawpaw leaf, pawpaw seed and scent leaf were 2.52mg/kg, 2.53mg/kg, 5.30mg/kg, and 0.79mg/kg respectively, and these are also above the permissible limit. While that of the concentration of Nickel in the pawpaw fruit, pawpaw leaf, pawpaw seed and scent leaf were observed to be within permissible limit.
 Conclusion: It is therefore recommended that caution should be taken when such plants are to be used as alternative to conventional medicine as excess of it could pose the risk of bioaccumulation and possible health effects in humans.

Absorption and Translocation Capacity of Cadmium in Papaya (Carica papaya L.) Plants With Addition of Organic Matter

“…Previous studies have observed that papaya plants have reached TF > 1 value for metals such as Cd, Pb and Zn, indicating that they have bioaccumulation capacity (Akintan et al, 2019). It has also been reported that papaya plant has been considered as an indicator of heavy metal contamination based on tree bark samples (Chukwuka & Uka, 2013), where it has been found that they can absorb elements such as Cd, Pb, Cu, Ni and Zn with the ability to translocate to aerial organs (Assayomo et al, 2021;Eludoyin & Gafar, 2020). Meng et al (2019) have reported that papaya fruit can accumulate heavy metal concentrations above the maximum permissible limits set by WHO with a potential health risk.…”