Phytoremediation of Heavy Metal-Contaminated Soil by Switchgrass: A Comparative Study Utilizing Different Composts and Coir Fiber on Pollution Remediation, Plant Productivity, and Nutrient Leaching

Abstract

We investigated the effects of organic amendments (thermophilic compost, vermicompost, and coconut coir) on the bioavailability of trace heavy metals of Zn, Cd, Pb, Co, and Ni from heavy metal-spiked soils under laboratory conditions. To test switchgrass (Panicum virgatum) as a potential crop for phytoremediation of heavy metal from soil, we investigated whether the addition of organic amendments promoted switchgrass growth, and consequently, uptake of metals. Compost is a valuable soil amendment that supplies nutrients for plant establishment and growth, which is beneficial for phytoremediation. However, excess application of compost can result in nutrient leaching, which has adverse effects on water quality. We tested the nutrient leaching potential of the different organic amendments to identify trade-offs between phytoremediation and water quality. Results showed that the amendments decreased the amount of bioavailable metals in the soils. Organic amendments increased soil pH, electrical conductivity (EC), and soil nutrient status. Switchgrass shoot and root biomass was significantly greater in the amended soils compared to the non-amended control. Amended treatments showed detectable levels of heavy metal uptake in switchgrass shoots, while the control treatment did not produce enough switchgrass biomass to measure uptake. Switchgrass uptake of certain heavy metals, and concentrations of some leachate nutrients significantly differed among the amended treatments. By improving soil properties and plant productivity and reducing heavy metal solubility that can otherwise hamper plant survival, organic amendments can greatly enhance phytoremediation in heavy metal-contaminated soils.

Arundo donax L. Biomass Production in a Polluted Area: Effects of Two Harvest Timings on Heavy Metals Uptake

“…The results shown in Table 2 and Figure 4, regarding the accumulation of heavy metals in the biomasses of the three different species, are in agreement with previous work reporting the bioaccumulation factor (BAF = C plant/C soil) considering only the biomass harvested of Ad [54], Pv [55] and MM [56].…”

Cadmium Hyperaccumulation and Translocation in Impatiens Glandulifera: From Foe to Friend?

“…Though many phytoaccumulator plants such as Brassica juncea or Panicum virgatum are not effective at removing Cd when soil levels are low, there are many species that show great potential to be used to bioaccumulate Cd in soils with levels as low as 0.33 mg/kg. These species include T. caerulescens, Hibiscus cannabinus, Azolla pinnata, Lemna minor, Vertiever grass, rice, maize, and sugar beet [63,64,70,72]. Indeed, even H. annus grown in control soil and not treated with Cd was found to accumulate Cd, though at a lesser extent than the Cd treatments [61].…”

Justification of the method for phytoremediation of degraded and contaminated lands by composite vermicompost briquettes

“…In the practice of phytoremediation of lands contami nated with heavy metals [17], vermicompost is used, which affects the bioavailability of elements such as Zn, Cd, Pb, Co, and Ni in soils. Vermicompost provides nutrients for the rapid growth of Panicum virgatum plants, which is useful for phytoremediation, but excessive use of compost can leach nutrients and cause water pollution.…”