Green waste compost as an amendment during induced phytoextraction of mercury-contaminated soil

Abstract

Phytoextraction of mercury-contaminated soils is a new strategy that consists of using the higher plants to make the soil contaminant nontoxic. The main problem that occurs during the process is the low solubility and bioavailability of mercury in soil. Therefore, some soil amendments can be used to increase the efficiency of the Hg phytoextraction process. The aim of the investigation was to use the commercial compost from municipal green wastes to increase the efficiency of phytoextraction of mercury-contaminated soil by Lepidium sativum L. plants and determine the leaching of Hg after compost amendment. The result of the study showed that Hg can be accumulated by L. sativum L. The application of compost increased both the accumulation by whole plant and translocation of Hg to shoots. Compost did not affect the plant biomass and its biometric parameters. Application of compost to the soil decreased the leaching of mercury in both acidic and neutral solutions regardless of growing medium composition and time of analysis. Due to Hg accumulation and translocation as well as its potential leaching in acidic and neutral solution, compost can be recommended as a soil amendment during the phytoextraction of mercurycontaminated soil.

The influence of compost and nitrilotriacetic acid on mercury phytoextraction by Lepidium sativum L.

“…The comparison analysis of results obtained for blank and control treatments pointed that combined use of compost + NTA increased L. sativum L. growth. The earlier study demonstrated that compost can stimulate the plant growth due to increasing macro‐ and micro‐elements input to the soil . However, the use of NTA as a growing medium component did not show toxicity symptoms, which is in agreement with results obtained by Quartacci et al The moderate concentration of NTA was not phytotoxic to Brassica juncea L. while its higher concentrations reduced dry weight of plant shoots .…”

“…Lepidium sativum L. is a fast growing plant that is characterized by low nutrition requirements. The plant showed its potential in Cd, arsenic (As) and Hg accumulation . The previous study of Smolinska 27 demonstrated that this plant species is able to translocate Hg to its aerial tissues.…”

“…The characteristics of the soil and compost from green wastes are presented in Table . The methods of physico‐chemical soil and green waste compost parameters determination were described in detail by Smolinska …”

Photosynthetic pigments and peroxidase activity of Lepidium sativum L. during assisted Hg phytoextraction

“…The results of Smolinska (2015) showed that application of compost to the polluted soil may lead to formation of organic matter complexes with Hg, which in turn lead to decreasing Hg toxicity. On the other hand, CA enhanced other heavy metal accumulation (like Cd) because of its chelating ability (Ehsan et al 2014).…”

In situ remediation technologies for mercury-contaminated soil

“…Similarly, applying ammonium thiosulfate increased Hg accumulation in the shoot tissues of B. juncea from <1 to >40 mg kg −1 at a site containing Hg at 2.82 mg kg −1 of soil. Smolinska (2014) recently investigated the enhanced phytoextraction of mercury-contaminated soil by Lepidium sativum L. using green waste compost as an amendment. The green compost was composed of leaves, grasses, branches, and other green wastes and, therefore, had high content of organic matters.…”