Seasonal influence on the efficacy of aquatic macrophytes as potential phytoremediation agents in urban wetlands.

Globally, metal contamination raises serious concerns within aquatic ecosystems. In aquatic systems, metal contamination can be removed by phytoremediation. This study assessed the ability of four macrophyte species (i.e. Phragmites australis, Typha capensis, Cyperus papyrus, and Cyperus dives) for phytoremediation of metals from five different wetlands across three seasons (i.e. cool-dry, hot-wet, hot-dry). In addition, this study used the bioconcentration factor (BCF) and translocation factor (TF) to determine the accumulation and translocation of metals within macrophyte species. The study indicated that different macrophytes accumulated different metals within the roots and leaves of all species during the cool-dry followed by hot-dry and hot-wet seasons. The study further indicated high BCF and TF of > 1 in all macrophytes during the cool-dry and hot-dry seasons. Phragmites australis had low accumulation of metals amongst the species studied. The TF was generally > 1, indicating efficient movement of most metals from roots to leaves, particularly during the hot-dry and cool-dry seasons. Cyperus dives and T. capensis exhibited potential as phytoremediation candidates. Aquatic macrophytes in urban wetlands accumulated and translocated metals, indicating their phytoremediation potential. However, elevated concentrations in these macrophytes can pose both ecological and health risks, as they can enter food-chain and can interfere and disrupt key physiological processes like photosynthesis, respiration, and nutrient uptake in these macrophytes. Therefore, regular monitoring of aquatic macrophytes with phytoremediation potential is recommended to enhance wetland health and pollution reduction.