## 4 Discussion
procera_, which was similar to that reported by [PERSON] and [PERSON] [49] and [PERSON] and [PERSON] [87] on _Plantago major_ L. [PERSON] et al. [88] showed that BAF >1 could suggest plant capacities for metal accumulation. BAF > 1 was recorded in _C. procera_ plant tissues (Table 4). Similarly, [PERSON] et al. [31] observed accumulation ratios under natural conditions and showed that _C. procera_ has a robust phytoextraction potential. Pb and Cd accumulation in leaves was greater than in roots in the _C. procera_ plant samples, suggesting that metals were more heavily allocated to leaves. [PERSON] [89] reported that _C. procera_ is one of the most useful bioindicators for monitoring pollution levels in Mn, Cr, and Zn polluted areas. The BAF in roadside areas was higher than 1 in root than the whole plant indicating that metal is retained in roots compared to aerial parts. Significant anthropogenic activities were present in the roadside sample, which may have contributed to the high metal content around the soil and plants. Simultaneously, the opposite is true for residential and control areas, which may be the cause of low metal concentrations, which would allow plant growth and favour metal transfer to aerial portions, thus increasing the transfer factor. The BAF was >1 at roadside areas, which indicates that _C. procera_ can absorb and accumulate these metals [74]. Among the studied areas (road, urban, and rural), the Cu content range of BAF (BAF > 1) was significantly higher at roadside areas, which show the phytotoxicityof this metal. It was expected that this metal has a high concentration in soil because Cu is essential for plant growth [56; 90]. BAF of Pb was less than one in roots, which suggested that Pb's bioavailability is <1, and the plant can only absorb but not accumulate it. Pb concentration shows a significant accumulation of BAF between the root and the whole plant. The BAF for Cd in the studied areas was found to be less than 1.0 (Table 4), which suggests that _C. procera_ can absorb and accumulate Cd but less efficiently than Pb, Zn, and Cu. The results reveal that the roots of plants tend to accumulate more Cd than the stems and leaves as was reported by [91]. [PERSON] and [PERSON] [87] found that roadside plants had significant bioaccumulation of Cd. Cd uptake may have been linked to organic matter [43; 92] and soil pH [87]. The TF is important in relocating metal in living tissues, from root to stem, stem to leaf, and from leaf to flower of a plant body. TFs for roadside and residential areas show a similar pattern at all the studied sites. The TF was <1 from root to stem and >1 from stem to leaf [90]. The results indicate that these metals are transferred marginally to the stem from the root zones but easily mobilize to the leaf if available in the stem [93]. The Pb TF from root to stem and leaf was >1 at roadside areas. The translocation factor in most of the sites was >1, indicating the plant's ability to efficiently transport metal in the upper parts of the plant. The Zn TF order is the root to stem \(\geq\) stem to leaf > leaf to flower. Zn translocation decreases in floral parts so that floral parts may receive a lower quantity of Zn than Pb and Cu and more Cd. The highest Cu translocation was from root to stem, followed by the stem to leaves, and less translocation from leaf to flowers. Cd was less mobile compared to Pb, Zn, and Cu. Cd translocation was found to be higher from leaves to flowers. Only plant species with a BAF and TF value of more than one have the potential to be employed for metal phytoextraction, according to [PERSON] et al. [23]. Many studies in Pakistan, e.g., [47] and abroad, e.g., [9; 29; 48], have shown similar patterns of HMs content in soils and _C. procera_ plant parts. Compared to these reports, minor changes in mean concentrations were found due to traffic intensity, industry type, urbanization level, and residential sewage.