Determination of Selected Metals in Pumpkin Peel Flesh and Seed Samples from three Different Areas in Ethiopia by Microwave Plasma Atomic Emission Spectrometry
No Thumbnail Available
Date
2021-07-23
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In this study the level of selected metals (Na, Mg, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd) and health risk assessment of heavy metals (Mn, Ni, Cu, Zn, Cr, Cd) in pumpkin peel, flesh and seed were determined using microwave plasma-atomic emission spectrometry. Samples were collected from three different parts of Ethiopia (Woliso, Oromiya Region; Minjar Shenkora, Amhara Region and Arbaminch, South Nations and Nationality People Region). A 0.5 g dried and powdered samples were wet acid digested (69% HNO3 and 30% H2O2) in three stages for each sample by microwave digester with optimized conditions. The calibration curves were linear with correlation coefficient (R2) value ranging from 0.996 to 0.9999 which indicates a very good linearity of curves. The calculated percentage recovery for different parts of pumpkin samples digestion method were found in the range 90-106% for peel; 92-110% for flesh and 90-108% for seed which are within the acceptable range for all metals, indicating the efficiency of the optimized procedure. The results show the mean concentration of studied metals in pumpkin peel sample from three areas were K (27806), Ca (5268), Mg (4716), Fe (157), Na (167), Mn (28.9), Zn (24.2), Cu (8.14), Ni (3.79), Cr (0.28), Cd (0.24) mg/kg. The average concentration of metals determined in pumpkin flesh were K (29531), Ca (3191), Mg (848), Fe (111), Na (63.1), Cu (15.1), Mn (9.63), Zn (10.6), Ni (2.14), Cd (0.46) and Cr (0.36) mg/kg. Pumpkin seed average metal concentration from the three sites were K (10667), Mg (4668), Ca (2919), Fe (225), Na (171), Zn (67.8), Mn (33.4), Cu (10.8), Ni (3.44), Cd (1.39) and Cr (0.69) mg/kg. The concentration levels of K, Cr, Fe, Ni, Cu and Cd obtained are higher than daily recommended values of guidelines (FAO/WHO, 2015). All calculated values of HQ from three sites were less than the permissible limit (1.0). This indicates no adverse non carcinogenic health risk due to consumption of the pumpkin from selected areas. The HI for pumpkin flesh from three areas were found to be less than unity, with HI values = 0.54, 0.42, 0.54 for Woliso, Minjar Shenkora and Arbaminch, respectively. HI values from pumpkin seed were = 0.73, 0.61 and 0.62 from Woliso, Minjar Shenkora and Arbaminch, respectively. HI values from pumpkin edible part in all selected areas are less than one and thus have no adverse health impact on consumers. This indicates ingestion of pumpkin from selected areas is safe from non-carcinogenic risk. The total cancer risk (TCR) due to the consumption of pumpkin flesh and seed through Cr and Cd from all sampling areas are between 1.1 x 10-4 to 1.8 x 10-4 which is approximately equal to the maximum
limit value of 1 x 10−4 indicating the non-risk of exposure to cancer due to the consumption of pumpkin from the selected areas. ANOVA result shows that for most of the determined metals there was a significant variation within and between sample sites which could be ascribed to different factors such as maturity of the pumpkin when collected, type of soil, the level of traditional fertilizer (dung), level of different wastes from household. The Pearson correlation coefficients of most metals from three sites have shown strong relationship. Pearson correlation coefficient between metal concentrations of pumpkin peel sample was a perfect positive relationship (+1 correlation value) between Na/Ni, Mg/Cr, Mg/Cd, Cr/Cd; a perfect negative relationship is observed between K/Fe; pumpkin flesh samples have a perfect positive relationship between K/Cu and Fe/Ni (r = +1). The perfect positive correlation is detected in between Na/Fe, Mg/Mn and a negative perfect correlation is in between Mg/Cd and Ca/Cr from the pumpkin seed samples.
Description
Keywords
Pumpkin, Metals, Health Risk, Ethiopia, Microwave Digester, Microwave Plasma-Atomic Emission Spectrometry