Phytoaccumulation of Heavy Metals and Nutritional Assessments of Terrestrial Plants in Contaminated Agro-ecosystem

Abstract

The phytotoxicity of heavy metals is intense issue and heavy metals contribute significantly to driving the establishment of tolerant plant populations. The study investigated the nutritive and phytoremediation potential of some terrestrial plants, Parthenium hysterophorus, Chenopodium album and Solanum nigrum in contaminated soils of Central Punjab, Pakistan, using standard laboratory techniques including proximate analysis and spectrophotometric methods. Proximate analysis, Kjeldahl method, and wet digestion and atomic absorption spectrophotometry were used for the nutritional attributes analysis and phytoaccumulation potential for Cadmium (Cd), Lead (Pb) and Nickel (Ni) respectively of these plants. Among the studied plants, the highest crude fiber content (39.633 %) was recorded for P. hysterophorus whilst it had the lowest concentration of protein (0.075 %) and the lowest amount of carbohydrate (10.812 %), and C. album had the highest concentration of protein (5.266 %) and carbohydrate (27.39 %). Results showed that P. hysterophorus had a high potential for removal of Cadmium and Lead heavy metals at different soil metal concentrations across the sampling sites. Cadmium (Cd) and Lead (Pb) phytoremediation potential of C. album was evident. However, S. nigrum proved to be a good phytoremediator which was mainly beneficial for removing Cadmium (Cd) from the contaminated soil sites. P. hysterophorus demonstrated impressive metal accumulation, with Pb accumulating at an impressive rate of 93.6% and Ni at 43.5%. In the case of C. album, the sequence of metal accumulation followed the order of Pb > Ni > Cd. Furthermore, S. nigrum exhibited characteristics of a Cd hyperaccumulator, as evidenced by its substantial accumulation of total Cd. The concentration of Cd in the soil decreased by 29.2%, while the removal rate of Cd reached 27.9%.  Fluctuation in elemental profile of plants and composition of soil may be attributed to spatial variations or may be due to agro-climatic conditions that varies in all cities.