Biogenic calcium improved Cd2+ and Pb2+ immobilization in soil using the ureolytic bacteria Bacillus pasteurii

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Bioremediation based on microbial-induced carbonate precipitation (MICP) was conducted in cadmium and lead contaminated soil to investigate the effects of MICP on Cd and Pb in soil. In this study, soil indigenous nitrogen was shown to induce MICP to stabilize heavy metals without inputting exogenous urea. The results showed that applying Bacillus pasteurii coupled with CaCl2 reduced Cd and Pb bioavailability, which could be clarified through the proportion of exchangeable Cd and Pb in soil decreasing by 23.65 % and 12.76 %, respectively. Moreover, B. pasteurii was combined separately with hydroxyapatite (HAP), eggshells (ES), and oyster shells (OS) to investigate their effects on soil heavy metals' chemical fractions, toxicity characteristic leaching procedure (TCLP)-extractable Cd and Pb as well as enzymatic activity. Results showed that applying B. pasteurii in soil significantly decreased the heavy metals in the exchangeable fraction and increased them in the carbonate phase fraction. When B. pasteurii was combined with ES and OS, the content of carbonate-bound Cd increased by 114.72 % and 118.81 %, respectively, significantly higher than when B. pasteurii was combined with HAP, wherein the fraction of carbonate-bound Cd increased by 86 %. The combination of B. pasteurii and biogenic calcium effectively reduced the leached contents of Cd and Pb in soil, and the TCLP-extractable Cd and Pb fractions decreased by 43.88 % and 30.66 %, respectively, in the BP + ES group and by 52.60 % and 41.77 %, respectively, in the BP + OS group. This proved that MICP reduced heavy metal bioavailability in the soil. Meanwhile, applying B. pasteurii and calcium materials significantly increased the soil urease enzyme activity. The microstructure and chemical composition of the soil samples were studied, and the results from scanning electron microscope, Fourier transform infra-red spectroscopy, and X-ray diffraction demonstrated the MICP process and identified the formation of CaCO3, Ca0.67Cd0.33CO3, and PbCO3 in heavy metal-contaminated soil.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:921

Enthalten in:

The Science of the total environment - 921(2024) vom: 15. März, Seite 171060

Sprache:

Englisch

Beteiligte Personen:

Zhang, Li [VerfasserIn]
Wang, Wenjun [VerfasserIn]
Yue, Caili [VerfasserIn]
Si, Youbin [VerfasserIn]

Links:

Volltext

Themen:

00BH33GNGH
2P299V784P
Bacillus pasteurii
Biogenic calcium
Biomineralization
Cadmium
Calcium
Calcium Carbonate
Carbonates
H0G9379FGK
Heavy metals
Journal Article
Lead
Metals, Heavy
SY7Q814VUP
Soil
Soil Pollutants

Anmerkungen:

Date Completed 11.03.2024

Date Revised 11.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.scitotenv.2024.171060

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM368680754