Meta-Analysis of the Copper, Zinc, and Cadmium Absorption Capacities of Aquatic Plants in Heavy Metal-Polluted Water

Abstract

The use of aquatic plants for phytoremediation is an important method for restoring polluted ecosystems. We sought to analyze the capacity of different aquatic plant species to absorb heavy metals and to summarize available relevant scientific data on this topic. We present a meta-analysis of Cu, Zn, and Cd absorption capacities of aquatic plants to provide a scientific basis for the selection of aquatic plants suitable for remediation of heavy-metal pollution. Plants from the Gramineae, Pontederiaceae, Ceratophyllaceae, Typhaceae and Haloragaceae showed relatively strong abilities to absorb these metals. The ability of a particular plant species to absorb a given metal was strongly correlated with its ability to absorb the other metals. However, the absorption abilities varied with the plant organ, with the following trend: roots > stems > leaves. The pH of the water and the life habits of aquatic plants (submerged and emerged) also affect the plant’s ability to absorb elements. Acidic water aids the uptake of heavy metals by plants. The correlation observed between element concentrations in plants with different aquatic life habits suggested that the enrichment mechanism is related to the surface area of the plant exposed to water. We argue that this meta-analysis would aid the selection of aquatic plants suitable for heavy-metal absorption from polluted waters.

Plant traits related to the heavy metal removal capacities of wetland plants

“…The correlations between the uptakes of the various metals were mostly strong, indicating that plants that successfully removed one studied metal likely also removed the others (Table 4), corroborating Li et al (2015), who found correlations of r ¼ 0.74-0.90 between the uptakes of Cd, Cu, and Zn in a large range of species. In fact, the correlations between the uptakes of different metals in our study were often stronger than the correlations between metal uptake and the other measured traits, indicating that there are traits not included in this study that could further explain the variation between species.…”

“…Plants with large fibrous root systems removed markedly more metals than did plants with coarser roots (Table 2). Larger root systems have greater surface areas, which absorb and adsorb more metals (Li et al 2015); this is especially important for Pb, which readily binds to organic matter such as roots (Ignatius et al 2014). The lack of restricting tissue, such as exodermis, in young fine roots enables high absorption to the apoplast.…”

“…In treatments based on free-floating plants, the removal efficacy for heavy metals depends on the plant's growth rate, heavy metal tolerance, and adaptability to various conditions (Rezania et al 2016). In wetlands and rivers, the root biomass of aquatic plants is an essential trait, and plant species accumulating one metal are likely to accumulate other present metals as well (Li et al 2015). In biofilters, where polluted water is filtered through vegetated coarse soil material, only weak correlations between heavy metal removal and plant traits were found because the heavy metals were mainly bound to the filter material (Read et al 2009).…”

Effects and Mechanisms of Microbial Remediation of Heavy Metals in Soil: A Critical Review

“…Soil heavy metal pollution mainly refers to the deposition of heavy metals, such as mercury, cadmium, lead, chromium, and other bio-toxic significant heavy elements in the soil [1], resulting in concentrations that exceed background values. Metals are not biodegradable, and through biological amplification, their concentrations can be increased thousands of times, with significant effects on human health [2]. In recent years, discharges of large volumes of heavy metals from industrial activity and mining, with final deposition in the soil, have led to increases in soil heavy metal concentrations.…”

Activity of Antioxidant System and Growth Intensity in Common Carp After Feeding Diet With Different Contents of Copper and Zinc

“…За двох гранично допустимих концентрацій у комбікормі Мідь нагромаджується у всіх тканинах організму коропів однаково, а Цинк -більшою мірою у зябрах і печінці, ніж у скелетних м'язах. За Ключевые слова: ФЕРМЕНТЫ, ПРОДУКТЫ ПЕРЕКИСНОГО ОКИСЛЕНИЯ ЛИПИДОВ, МЕДЬ, ЦИНК, ЖАБРЫ, ПЕЧЕНЬ, СКЕЛЕТНЫЕ МЫШЦЫ, КАРПЫ As a result of industrial and agricultural production, fishponds can accumulate increased concentrations of heavy metals [1,2], those, depending on their properties, valence and content, can affect metabolic processes in the freshwater fishes [3][4][5], mainly as a constituents of numerous enzymes [6]. For instance, Zinc is a part of the antioxidant enzyme superoxide dismutase; also, it regulates the activity of Δ 3 -, Δ 4 -, Δ 5 -and Δ 6 -desaturases [6][7][8].…”