Comparative Study of Nutrient Values and Heavy Metals Content of Corchorus olitorius Collected from Farm Land (Post Service) and Dumpsite (Oko Fili) In Lagos, Nigeria.

Abstract

Africa is blessed with great diversity of plant resources that play major role in the continent's food, socio-economic and cultural development. These traditional leafy vegetables help to improve the nutritional status of populations and generate significant income in both rural and urban areas.Hence, this study investigated the nutrient contents and level of heavy metals in Corchorus olitorius collected from dumpsite (Oko fili in Alimosho Local Government Area) and farmland (Post Service in Ojo Local Government Area) using a standard procedure and t-test analysis. The results showed the presence of amino acids(aspartic acid, glutamic acid, serine, glycine, histidine, Arginine, threonine, alanine, proline, tyrosine, valine, methionine, cysteine, iso-leucine, leucine, phenylalanine and lysine) in C. olitorius from both sites, however no significant (p>0.05) difference exists between the mean of all the amino acids taken from both sites. Values of metals recorded in dumpsites were higher than that from farmland. However, only calcium (Ca), iron(Fe), potassium(K), magnesium(Mg), sodium(Na), phosphorus(P), and zinc (Zn) had higher significant differences in values for both the soil and C. olitorius. The respective values of these metals (mg/100g) in C. olitorius at dumpsite and farmland are: Ca (985.3±310.8, 633.8±190.1), Fe (141.4±18.314, 5.415±0.742), K (112.200±51.477, 32.200±13.717), Mg (308.050±121.552, 107.050±3.889), Na(37.995±16.497, 25.015±5.550), P(305.635±257.860, 137.500±39.739) and Zn(18.235±13.103, 4.380±1.810). Potassium/sodium ratio (K/Na) for C. olitorius at both sites is comparable to recommended value of 1.00. In conclusion, all the values of metals (except Na in soil and K in plant) are within WHO/FAO maximum recommended limits. Therefore, C. olitorius examined in this study is safe for consumption while the metals in both farmland and dumpsite are considered to be less   concentrated.